research article a wideband end-fire conformal vivaldi...

Research ArticleA Wideband End-Fire Conformal Vivaldi Antenna ArrayMounted on a Dielectric Cone

Zengrui Li1 Xiaole Kang1 Jianxun Su1 Qingxin Guo1

Yaoqing (Lamar) Yang2 and Junhong Wang3

1School of Information Engineering Communication University of China Beijing 100024 China2Department of Electrical and Computer Engineering University of Nebraska-Lincoln Omaha NE 68182 USA3Institute of Lightwave Technology Beijing Jiaotong University Beijing 100044 China

Correspondence should be addressed to Xiaole Kang darever1988126com

Received 28 March 2016 Revised 1 June 2016 Accepted 12 June 2016

Academic Editor Yu Jian Cheng

Copyright copy 2016 Zengrui Li et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

The characteristics of a novel antipodal Vivaldi antenna array mounted on a dielectric cone are presented By employing antipodalVivaldi antenna element the antenna array shows ultrawide bandwidth and end-fire radiation characteristics Our simulations showthat the cone curvature has an obvious influence on the performance of the conformal antenna in terms of both the bandwidthand the radiation patterns The thickness and permittivity of the dielectric cone have an effect on the bandwidth of the conformalantenna Measurement results of both single antenna and conformal antenna array show a good agreement with the simulatedresults The measured conformal antenna can achieve a minus10 dB |119878

11| with bandwidth of 22ndash12GHz and demonstrate a typical end-

fire radiation beam These findings provide useful guidelines and insights for the design of wideband end-fire antennas mountedon a dielectric cone

1 Introduction

Wideband antennas are required for many electromagneticapplications such as radio astronomy and UWB technologyThe Vivaldi antenna which was firstly created by Gibson in1979 [1] has beenwidely used due to its simple structure lightweight wideband high efficiency and high gains In [2] aVivaldi antenna with a parasitic meandered shaped elementand a PIN diode for DVB-T and UWB applications has beenpresented The PIN diode is used to switch the lower fre-quency band in addition to the high frequency band Corru-gation edges structure was reported in [3] which was used toreduce the width of the antenna without degrading the radia-tion patterns A miniaturized antipodal Vivaldi antenna withtapered slot edge (TSE)was proposed in [4] Compared to theregular slot edge (RSE) the TSE is able to take full use of thepatch area for its coordinated shapewith the antenna slot pro-file A printed Vivaldi antenna with two pairs of eye-shapedslots was presented in [5] By using the eye-shaped slots theside lobe levels of the radiation pattern can be reduced In

this paper a circular-shape-load antipodal Vivaldi antenna[6] with a metal director is used to study the conformalcharacteristics due to its small size broad bandwidth highgain and stable radiation pattern

It is well known that the conformal antennas are mainlyused in aviation radars andmilitary systems For these appli-cations conformal antennas need to cover a wide bandwidthand have end-fire radiation beam A variety of conformalantennas have been investigated during the past two decadesincluding monopole antennas [7 8] slot antennas [9 10]microstrip antenna arrays [11ndash13] log-periodic antennas[14] balanced antipodal Vivaldi antenna [15] and substrateintegrated waveguide (SIW) antennas [16 17] However mostof these antennas are mounted on metallic surfaces and havebroadside radiation beam A few of studies about end-fireconformal antennas can be found in literatures [14ndash16]

The contributions of our work are as follows(1) The impacts of cone curvature cone thickness and

cone permittivity on the conformal antennarsquos band-width radiation performance are comprehensively

Hindawi Publishing CorporationInternational Journal of Antennas and PropagationVolume 2016 Article ID 9812642 11 pageshttpdxdoiorg10115520169812642

2 International Journal of Antennas and Propagation

W

We

Wd

B

Ld

Inner edge

(x2 y2)

(x4 y4)

(x1 y1) (x3 y3)

D

L

Outer edgeParallel stripline A C

Transition

m

d

x

y

Wf

Hd

Figure 1 Configuration of the plane antenna element

investigated The antipodal Vivaldi antenna can beeasily mounted on a dielectric cone The curvatureof cone has an influence on bandwidth and radiationpatterns of conformal antenna The thickness anddielectric constant of cone mainly affect the band-width of the conformal antenna

(2) Measurement results with a prototype of the proposedconformal antenna array with four antenna elementsare presented and compared with the simulatedresults

2 Antenna Element

In this section a plane antipodal Vivaldi antenna is proposedand studied as shown in Figure 1 This antenna is printed onTeflon-F4B substrate with a dielectric constant of 35 and losstangent of 0003 The thickness of the substrate is 05mm

In this design of an antipodal Vivaldi antenna two armsmetalized on either side of the substrate are flared in theopposite direction to form a tapered slotThe antennamainlyconsists of four partsThe first section is a quarter of ellipticaltaper whose minor axis is 2d to achieve transition frommicrostrip line to parallel stripline The second part is theparallel stripline which is a balanced structure providingwideband transitions The third part is a diamond-shapedmetal director which is designed to improve the gain in theupper bandwidth The comparison of the simulated gainsbetween the antennawith a diamond-shaped director and theone without a diamond-shaped director is plotted in Figure 2The result shows that the gain of the antenna with a directoris definitely improved in high frequency band The last partis the radiation patch which includes two exponential curvesand a half of elliptical curve The inner edge of the taperedradiation flares satisfies the following exponential curves

119909 = 119888

1119890

120572119910+ 119888

2 (1)

2 3 4 5 6 7 8 9 10 112

3

4

5

6

7

8

9

10

11

Antenna without director Antenna with director

Frequency (GHz)

Gai

n (d

Bi)

Figure 2 Simulated gains of plane antipodal Vivaldi antenna withand without a director

Table 1 Optimized parameters of the antipodal Vivaldi antenna

Parameters 119871 119882 119882119890119898 119889 119882

119891119871

119889119882

119889119867

119889

Valuesmm 116 124 64 222 304 11 15 10 1104

where 1198881and 1198882are determined by the opening rate 120572 and two

points 1199011(119909

1 119910

1) and 119901

2(119909

2 119910

2)

119888

1=

119909

2minus 119909

1

119890

1205721199102minus 119890

1205721199101

119888

2=

119910

1119890

1205721199102minus 119910

2119890

1205721199101

119890

1205721199102minus 119890

1205721199101

(2)

And the outer edge of the tapered radiation flares alsosatisfies (1) while 119888

1and 1198882are determined by the opening

rate 120573 and two points 1199013(119909

3 119910

3) and 119901

4(119909

4 119910

4)

To cover the desired bandwidth (2GHzndash12GHz) theantipodal Vivaldi antenna was simulated and optimized withthe assistance of ANSYSHigh Frequency Structure Simulator(HFSS) Version 14 After optimization on the proposedantenna it is fabricated with the parameters indicated inTable 1 Some of the parameters are specified as follows 120572 =00785 and 120573 = 03

The prototype of the antipodal Vivaldi antenna is shownin Figure 3 It wasmeasured by anAgilent E5071CVectorNet-work Analyzer in an anechoic chamber in CommunicationUniversity of China

Figure 4 shows the comparisons of |11987811| between the

simulated andmeasured results of the plane antipodal Vivaldiantenna It is found that the measured results show areasonable agreement with the simulation results over thefrequency band (|119878

11| le minus10 dB) between 236GHz and

12GHzThe small deviation of the two results may be causedby the imperfection of hand-soldering of the SMA connector

The far field radiation patterns in the 119864-plane (119909119900119910 plane)and 119867-plane (119910119900119911 plane) at different frequencies were mea-sured and shown in Figure 5 The measured copolarization

International Journal of Antennas and Propagation 3

Front view Back view

Figure 3 Prototype of the proposed antenna

2 4 6 8 10 12minus50

minus40

minus30

minus20

minus10

0

Frequency (GHz)SimulatedMeasured

|S11| (

dB)

Figure 4 Measured and simulated |11987811| of the plane antipodal

Vivaldi antenna

radiation patterns and the simulated results show a goodagreement in both planes However the measured cross-polarization radiation patterns are larger than the simulatedresults It may be caused by the deviation of the relativeposition between test antenna and reference antenna Theproposed antenna has good unidirectional radiation patternsand the main lobes are fixed in the end-fire direction (119910-axisdirection) within the effective bandwidth

The measured front-to-back ratios of the antipodalVivaldi antenna are listed in Table 2 According to Table 2 thefront-to-back ratios of the antenna achieve more than 12 dBexcept for a few of frequency points which confirmed theend-fire characteristic of the antenna Within the operatingfrequency band the simulated and measured gain of theantenna in end-fire direction vary between 25 dBi and98 dBi as shown in Figure 6

Since the linear phase response of the antenna in the timedomain is one of themost important parameters in widebandsystems the group delay of two antipodal Vivaldi antennaswith a distance of 30 cm has also been measured Figure 7shows the variation of the group delay less than 5 ns withinthe desired frequency bands which indicates that the phase ofthe antenna shifts little within the operating frequency band

Table 2 Measured front-to-back ratio of the proposed antenna

Frequency (GHz) 2 4 6 8119864-plane (dB) 6 12 13 13119867-plane (dB) 12 13 16 15

Table 3 Simulated half power beam-width of the antipodal Vivaldiantenna mounted on different cones

Frequency (GHz) 2 3 4 5 6 7 8 9 10 11119864-plane (deg) 62 56 48 40 40 54 50 50 50 40119867-plane (deg) 116 106 76 60 56 50 54 58 56 56

Thus the proposed antenna achieves a desirable time domaincharacteristic

3 Conformal Antenna Performances

31 Effects of Cone Curvature The proposed antipodalVivaldi antenna is mounted on a dielectric cone to investi-gate the conformal antenna characteristics The antenna ison dielectric cones with different curvatures as shown inFigure 8The outer diameters of the three conesrsquo top and bot-tom surfaces are 300360mm 190210mm and 130150mmrespectivelyThe height thickness and dielectric constant are350mm 05mm and 21 for all three cones

Figure 9 shows the simulated voltage standing wave ratio(VSWR) of the conformal antenna with different curvaturesIt can be observed that with the increasing of cone curvaturethe VSWR deteriorates especially in the low and middlefrequency bands The simulated radiation patterns of theconformal antenna with different cones curvatures at 2GHz4GHz 6GHz and 8GHz are plotted in Figure 10 It is shownthat the variation of cone curvature has little effects on thecopolarization radiation patterns of the conformal antennaSince the antenna is bent on the cone there exists an extraelectric current component in minus119885 direction Therefore thecross-polarization of the conformal antenna becomes largerwith the increasing of cone curvature Besides to illustratethe impacts of cone curvature on radiation pattern betweenplanar Vivaldi antenna and curved surface antenna whichis bent on a cone with the diameters of 190210mm thesimulated radiation pattern at 4GHz is given in Figure 11It is observed that the cross-polarization of the conformalantenna is larger than the planar antenna The simulated halfpower beam-width of the conformal antenna is less than 116degrees as shown in Table 3

32 Effects of Cone Thickness In this subsection the antipo-dal Vivaldi antenna is mounted on cones with different thick-ness (5mm 7mm and 10mm) so as to examine the effectof the cone thickness on the characteristics of the conformalantenna The outer diameters of the conesrsquo top and bottomsurfaces are 190 and 210mm respectively The height anddielectric constant of cones are 350mm and 21 respectively


0

30

6090

120

150

180

210

240270

300

330

minus40minus30minus20minus10

0

minus50minus40minus30minus20minus10

0

E-plane_8GHz

0

30

6090

120

150

180

210

240270

300

330


0


0

H-plane_8GHz

0

30

6090

120

150

180

210

240270

300

330


0


0

E-plane_6GHz

0

30

6090

120

150

180

210

240270

300

330


0


0

H-plane_6GHz

0

30

6090

120

150

180

210

240270

300

330


0


0

E-plane_4GHz

0

30

6090

120

150

180

210

240270

300

330


0


0

H-plane_4GHz

0

30

6090

120

150

180

210

240270

300

330


0


0

E-plane_2GHz

0

30

6090

120

150

180

210

240270

300

330


0


0

H-plane_2GHz

Figure 5 Measured and simulated radiation patterns of the antipodal Vivaldi antenna -998771- measured copolarization mdash measured cross-polarization -- simulated copolarization and -I- simulated cross-polarization

Figure 12 presents the simulated VSWR of conformalantenna with different cone thickness It is found that as thethickness increases the VSWR becomes larger in the lowerfrequency band The VSWR varies between 1 and 3 in thewhole operating band Figure 13 shows the radiation patternswith different cone thickness at 7GHz The gain variationwith different cone thicknesses for the conformal antennais demonstrated in Figure 14 It turned out that with theincreasing cone thickness the gain has obvious decreases in

the middle frequency band due to the enlargement of thecross-polarization

33 Effects of Cone Dielectric Constants We studied theperformance of the antenna mounted on cones with differentdielectric constants of 21 27 and 44 respectively The outerdiameters of the conesrsquo top and bottom surfaces are 190 and210mm The height and thickness of cones are 350mm and5mm


2 3 4 5 6 7 8 9 10 110123456789

1011

Measured gainSimulated gain

Frequency (GHz)

Gai

n (d

Bi)

Figure 6 Measured and simulated gain of the plane antipodal Vivaldi antenna

2 3 4 5 6 7 8 9 10

minus4

minus3

minus2

minus1

0

1

2

3

4

Frequency (GHz)

Gro

up d

elay

(ns)

Figure 7 Measured group delay of the proposed antenna

Conformalantenna

Dielectriccone

300360mm 190210mm 130150mm

Figure 8 Configuration of the proposed antennamounted on coneswith different curvatures

Figure 15 shows that the cone dielectric constant hasan effect on VSWR of conformal antenna It is found thatwith the increasing of the dielectric constant the VSWRdeteriorates at the low frequency band Radiation patternswith different cone dielectric constants at 8GHz are shownin Figure 16 It is shown that the cross-polarization become

2 3 4 5 6 7 8 9 10 111

2

3

4

Frequency (GHz)

VSW

R

300mm 360mm190mm 210mm

130mm 150mm

Figure 9 Simulated VSWR of conformal antenna with differentcone curvatures

larger with the increased dielectric constant Figure 17 illus-trates the gain variation of the conformal antenna withdifferent dielectric constantsWith respect to the enlargementof cross-polarization the gain decreases dramatically in highfrequency bandwidth

4 Experimental Results

A prototype of conformal antenna array is built by mountingfour proposed antennas on the surface of a polypropylenecone with a dielectric constant of 23 as shown in Figure 18The height thickness and top and bottom surfacesrsquo outerdiameter of the cone are 274mm 3mm and 188204mmrespectively The prototype was measured by an AgilentE5071C Vector Network Analyzer in an anechoic chamber inCUC


0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

E-plane_2GHz H-plane_2GHz




Figure 10 Simulated radiation patterns of conformal antenna with different cone curvatures -◼- copolarization (300360mm) (the blackdash lines) cross-polarization (300360mm) -998771- copolarization (190210mm) (the red dash lines) cross-polarization (190210mm) -e-copolarization (130150mm) and mdash cross-polarization (130150mm)

Themeasured and simulated |11987811| of the proposed antipo-

dal Vivaldi antenna are shown in Figure 19 Good impedancematching with the 50Ω coaxial line is achieved whichsatisfies the required operating frequency band from 22GHzto 12GHz

Figure 20 shows the measured and simulated radiationpatterns of the conformal antenna in both 119864-plane (119909119900119910plane) and 119867-plane (119910119900119911 plane) at 2GHz 4GHz 6GHz8GHz and 10GHz It is found that the conformal antenna

has end-fire radiation beams in both planes Figure 21 showsthe comparisons of the simulated and measured gain ofthe conformal antipodal Vivaldi antenna The measuredradiation patterns and gain both show good agreements withthe simulated results The isolation between the adjacentports of the conformal antenna is also investigated It can beobserved in Figure 22 that the measured result is less thanminus25 dB in the operating frequency bands which is good forthe port isolation of the conformal antenna


0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0


Figure 11 Simulated radiation patterns of plane antenna and conformal antenna -◼- copolarization (plane) --- cross-polarization (plane)-998771- copolarization (conformal) and mdash cross-polarization (conformal)

2 3 4 5 6 7 8 9 10 11Frequency (GHz)

1

2

3

4

VSW

R

5mm7mm

10mm

Figure 12 Simulated VSWR of conformal antenna with different cone thickness

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0


Figure 13 Simulated radiation patterns of conformal antenna with different cone thickness -◼- copolarization (5mm) (the black dash lines)cross-polarization (5mm) -998771- copolarization (7mm) (the red dash lines) cross-polarization (7mm) -e- copolarization (10mm) and mdashcross-polarization (10mm)

5 Conclusion

This paper presented a novel wideband end-fire conformalantenna array mounted on a dielectric cone The effects ofthe cone curvature thickness and dielectric constant onthe performance of the conformal antenna are thoroughlyinvestigated and some inspiring results for end-fire conformalantenna design have been obtained Measured and simulatedresults of the prototype show the conformal antenna has wide

frequency bands end-fire radiation patterns and wide halfpower beam-width The proposed antenna array has a greatpotential to be used in conformal systems such as missilesradars and aircrafts

Competing Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper


0

2

4

6

8

10

Gai

n (d

Bi)

2 3 4 5 6 7 8 9 10 11Frequency (GHz)

5mm7mm

10mm

Figure 14 Simulated gain of conformal antenna with different cone thickness

1

2

3

4

VSW

R

2 3 4 5 6 7 8 9 10 11Frequency (GHz)

21

27

44

Figure 15 Simulated VSWR of conformal antenna with different dielectric constants

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0


Figure 16 Simulated radiation patterns of conformal antenna with different dielectric constants -◼- copolarization (21) (the black dashlines) cross-polarization (21) -998771- copolarization (27) (the red dash lines) cross-polarization (27) -e- copolarization (44) and mdash cross-polarization (44)


0

2

4

6

8

10

Gai

n (d

Bi)

2 3 4 5 6 7 8 9 10 11Frequency (GHz)

21

27

44

Figure 17 Simulated gain of conformal antenna with different dielectric constants

Figure 18 Prototype of four antipodal Vivaldi antennas mounted on a dielectric cone

2 3 4 5 6 7 8 9 10 11 12minus50

minus40

minus30

minus20

minus10

0

SimulatedMeasured

Frequency (GHz)

|S11| (

dB)

Figure 19 Measured and simulated |11987811| of the conformal antenna


minus30minus20minus10

0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330






Figure 20 Measured and simulated radiation patterns of conformal antenna -I- simulated copolarization (the blue dash lines) simulatedcross-polarization -998771- measured copolarization and (the red dash lines) measured cross-polarization


2 3 4 5 6 7 8 9 10 110123456789

1011

Frequency (GHz)

Gai

n (d

Bi)

SimulatedMeasured

Figure 21 Measured and simulated gain of the conformal antenna

2 3 4 5 6 7 8 9 10 11 12minus55

minus50

minus45

minus40

minus35

minus30

minus25

minus20

Frequency (GHz)

|S21| (

dB)

Figure 22 Measured isolation of the conformal antenna

Acknowledgments

This work was supported in part by theMajor Program of theNational Natural Science Foundation of China (NSFC) underGrant no 61331002 in part by Excellent Innovation Teamof CUC under Grant no yxtd201303 and in part by CUCscientific research project under Grant no 3132016XNG1604

References

[1] P J Gibson ldquoThe Vivaldi aerialrdquo in Proceedings of the 9thEuropean Microwave Conference pp 101ndash105 Brighton UKSeptember 1979

[2] D M Elsheakh and E A Abdallah ldquoUltrawideband Vivaldiantenna for DVB-T WLAN and WiMAX applicationsrdquo Inter-national Journal of Antennas and Propagation vol 2014 ArticleID 761634 7 pages 2014

[3] P Fei Y-C Jiao W Hu and F-S Zhang ldquoA miniaturizedantipodal vivaldi antenna with improved radiation character-isticsrdquo IEEE Antennas and Wireless Propagation Letters vol 10pp 127ndash130 2011

[4] C Deng and Y-J Xie ldquoDesign of resistive loading Vivaldiantennardquo IEEE Antennas and Wireless Propagation Letters vol8 pp 240ndash243 2009

[5] K Ma Z Q Zhao J NWu M S Ellis and Z P Nie ldquoA printedvivaldi antenna with improved radiation patterns by using twopairs of eye-shaped slots for UWB applicationsrdquo Progress inElectromagnetics Research vol 148 pp 63ndash71 2014

[6] J Bai S Y Shi and DW Prather ldquoModified compact antipodalvivaldi antenna for 4ndash50GHzUWB applicationrdquo IEEE Transac-tions on Antennas and Propagation vol 59 no 4 pp 1051ndash10572011

[7] H-Y Liang H-C Yang and J Zhang ldquoA cylindrical conformaldirectional monopole antenna for borehole radar applicationrdquoIEEE Antennas and Wireless Propagation Letters vol 11 pp1525ndash1528 2012

[8] Z-Q Liu Y-S Zhang Z P Qian Z P Han and W M NildquoA novel broad beamwidth conformal antenna on unmannedaerial vehiclerdquo IEEE Antennas andWireless Propagation Lettersvol 11 pp 196ndash199 2012

[9] S Nikolaou G E Ponchak J Papapolymerou and MM Tentzeris ldquoConformal double exponentially tapered slotantenna (DETSA) on LCP for UWB applicationsrdquo IEEE Trans-actions on Antennas and Propagation vol 54 no 6 pp 1663ndash1669 2006

[10] G E Ponchak J L Jordan and C T Chevalier ldquoCharacteristicsof Double Exponentially Tapered Slot Antenna (DETSA) con-formed in the longitudinal direction around a cylinderrdquo IEEEAntennas and Wireless Propagation Letters vol 6 pp 60ndash632007

[11] B D Braaten S Roy S Nariyal et al ldquoA self-adapting flexible(SELFLEX) antenna array for changing conformal surfaceapplicationsrdquo IEEE Transactions on Antennas and Propagationvol 61 no 2 pp 655ndash665 2013

[12] K Wincza S Gruszczynski and K Sachse ldquoConformal four-beam antenna arrays with reduced sidelobesrdquo Electronics Let-ters vol 44 no 3 pp 174ndash175 2008

[13] P Knott T Bertuch H Wilden O Peters A R Brenner andI Walterscheid ldquoSAR Experiments using a conformal antennaarray radar demonstratorrdquo International Journal of Antennasand Propagation vol 2012 Article ID 142542 7 pages 2012

[14] X Gao Z Shen and C Z Hua ldquoConformal VHF log-periodic balloon antennardquo IEEE Transactions on Antennas andPropagation vol 63 no 6 pp 2756ndash2761 2015

[15] P Wang G J Wen H B Zhang and Y H Sun ldquoA widebandconformal end-fire antenna array mounted on a large conduct-ing cylinderrdquo IEEE Transactions on Antennas and Propagationvol 61 no 9 pp 4857ndash4861 2013

[16] Y Zhao Z X Shen andWWu ldquoConformal SIWH-plane hornantenna on a conducting cylinderrdquo IEEE Antennas andWirelessPropagation Letters vol 14 pp 1271ndash1274 2015

[17] Y J Cheng H Xu D Ma J Wu L Wang and Y FanldquoMillimeter-wave shaped-beam substrate integrated conformalarray antennardquo IEEE Transactions on Antennas and Propaga-tion vol 61 no 9 pp 4558ndash4566 2013

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Chemical EngineeringInternational Journal of Antennas and

Propagation




Navigation and Observation



DistributedSensor Networks



W

We

Wd

B

Ld

Inner edge

(x2 y2)

(x4 y4)

(x1 y1) (x3 y3)

D

L

Outer edgeParallel stripline A C

Transition

m

d

x

y

Wf

Hd

Figure 1 Configuration of the plane antenna element

investigated The antipodal Vivaldi antenna can beeasily mounted on a dielectric cone The curvatureof cone has an influence on bandwidth and radiationpatterns of conformal antenna The thickness anddielectric constant of cone mainly affect the band-width of the conformal antenna

(2) Measurement results with a prototype of the proposedconformal antenna array with four antenna elementsare presented and compared with the simulatedresults

2 Antenna Element

In this section a plane antipodal Vivaldi antenna is proposedand studied as shown in Figure 1 This antenna is printed onTeflon-F4B substrate with a dielectric constant of 35 and losstangent of 0003 The thickness of the substrate is 05mm

In this design of an antipodal Vivaldi antenna two armsmetalized on either side of the substrate are flared in theopposite direction to form a tapered slotThe antennamainlyconsists of four partsThe first section is a quarter of ellipticaltaper whose minor axis is 2d to achieve transition frommicrostrip line to parallel stripline The second part is theparallel stripline which is a balanced structure providingwideband transitions The third part is a diamond-shapedmetal director which is designed to improve the gain in theupper bandwidth The comparison of the simulated gainsbetween the antennawith a diamond-shaped director and theone without a diamond-shaped director is plotted in Figure 2The result shows that the gain of the antenna with a directoris definitely improved in high frequency band The last partis the radiation patch which includes two exponential curvesand a half of elliptical curve The inner edge of the taperedradiation flares satisfies the following exponential curves

119909 = 119888

1119890

120572119910+ 119888

2 (1)

2 3 4 5 6 7 8 9 10 112

3

4

5

6

7

8

9

10

11

Antenna without director Antenna with director

Frequency (GHz)

Gai

n (d

Bi)

Figure 2 Simulated gains of plane antipodal Vivaldi antenna withand without a director

Table 1 Optimized parameters of the antipodal Vivaldi antenna

Parameters 119871 119882 119882119890119898 119889 119882

119891119871

119889119882

119889119867

119889

Valuesmm 116 124 64 222 304 11 15 10 1104

where 1198881and 1198882are determined by the opening rate 120572 and two

points 1199011(119909

1 119910

1) and 119901

2(119909

2 119910

2)

119888

1=

119909

2minus 119909

1

119890

1205721199102minus 119890

1205721199101

119888

2=

119910

1119890

1205721199102minus 119910

2119890

1205721199101

119890

1205721199102minus 119890

1205721199101

(2)

And the outer edge of the tapered radiation flares alsosatisfies (1) while 119888

1and 1198882are determined by the opening

rate 120573 and two points 1199013(119909

3 119910

3) and 119901

4(119909

4 119910

4)

To cover the desired bandwidth (2GHzndash12GHz) theantipodal Vivaldi antenna was simulated and optimized withthe assistance of ANSYSHigh Frequency Structure Simulator(HFSS) Version 14 After optimization on the proposedantenna it is fabricated with the parameters indicated inTable 1 Some of the parameters are specified as follows 120572 =00785 and 120573 = 03

The prototype of the antipodal Vivaldi antenna is shownin Figure 3 It wasmeasured by anAgilent E5071CVectorNet-work Analyzer in an anechoic chamber in CommunicationUniversity of China

Figure 4 shows the comparisons of |11987811| between the

simulated andmeasured results of the plane antipodal Vivaldiantenna It is found that the measured results show areasonable agreement with the simulation results over thefrequency band (|119878

11| le minus10 dB) between 236GHz and

12GHzThe small deviation of the two results may be causedby the imperfection of hand-soldering of the SMA connector

The far field radiation patterns in the 119864-plane (119909119900119910 plane)and 119867-plane (119910119900119911 plane) at different frequencies were mea-sured and shown in Figure 5 The measured copolarization




2 4 6 8 10 12minus50

minus40

minus30

minus20

minus10

0


|S11| (

dB)


Vivaldi antenna














0

30

6090

120

150

180

210

240270

300

330


0


0

E-plane_8GHz

0

30

6090

120

150

180

210

240270

300

330


0


0

H-plane_8GHz

0

30

6090

120

150

180

210

240270

300

330


0


0

E-plane_6GHz

0

30

6090

120

150

180

210

240270

300

330


0


0

H-plane_6GHz

0

30

6090

120

150

180

210

240270

300

330


0


0

E-plane_4GHz

0

30

6090

120

150

180

210

240270

300

330


0


0

H-plane_4GHz

0

30

6090

120

150

180

210

240270

300

330


0


0

E-plane_2GHz

0

30

6090

120

150

180

210

240270

300

330


0


0

H-plane_2GHz






2 3 4 5 6 7 8 9 10 110123456789

1011


Frequency (GHz)

Gai

n (d

Bi)


2 3 4 5 6 7 8 9 10

minus4

minus3

minus2

minus1

0

1

2

3

4

Frequency (GHz)

Gro

up d

elay

(ns)


Conformalantenna

Dielectriccone

300360mm 190210mm 130150mm



2 3 4 5 6 7 8 9 10 111

2

3

4

Frequency (GHz)

VSW

R

300mm 360mm190mm 210mm

130mm 150mm






0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0











0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0



2 3 4 5 6 7 8 9 10 11Frequency (GHz)

1

2

3

4

VSW

R

5mm7mm

10mm


0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0



5 Conclusion



Competing Interests



0

2

4

6

8

10

Gai

n (d

Bi)

2 3 4 5 6 7 8 9 10 11Frequency (GHz)

5mm7mm

10mm


1

2

3

4

VSW

R

2 3 4 5 6 7 8 9 10 11Frequency (GHz)

21

27

44


0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0




0

2

4

6

8

10

Gai

n (d

Bi)

2 3 4 5 6 7 8 9 10 11Frequency (GHz)

21

27

44



2 3 4 5 6 7 8 9 10 11 12minus50

minus40

minus30

minus20

minus10

0

SimulatedMeasured

Frequency (GHz)

|S11| (

dB)




0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330








2 3 4 5 6 7 8 9 10 110123456789

1011

Frequency (GHz)

Gai

n (d

Bi)

SimulatedMeasured


2 3 4 5 6 7 8 9 10 11 12minus55

minus50

minus45

minus40

minus35

minus30

minus25

minus20

Frequency (GHz)

|S21| (

dB)


Acknowledgments


References




















RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation












2 4 6 8 10 12minus50

minus40

minus30

minus20

minus10

0


|S11| (

dB)


Vivaldi antenna














0

30

6090

120

150

180

210

240270

300

330


0


0

E-plane_8GHz

0

30

6090

120

150

180

210

240270

300

330


0


0

H-plane_8GHz

0

30

6090

120

150

180

210

240270

300

330


0


0

E-plane_6GHz

0

30

6090

120

150

180

210

240270

300

330


0


0

H-plane_6GHz

0

30

6090

120

150

180

210

240270

300

330


0


0

E-plane_4GHz

0

30

6090

120

150

180

210

240270

300

330


0


0

H-plane_4GHz

0

30

6090

120

150

180

210

240270

300

330


0


0

E-plane_2GHz

0

30

6090

120

150

180

210

240270

300

330


0


0

H-plane_2GHz






2 3 4 5 6 7 8 9 10 110123456789

1011


Frequency (GHz)

Gai

n (d

Bi)


2 3 4 5 6 7 8 9 10

minus4

minus3

minus2

minus1

0

1

2

3

4

Frequency (GHz)

Gro

up d

elay

(ns)


Conformalantenna

Dielectriccone

300360mm 190210mm 130150mm



2 3 4 5 6 7 8 9 10 111

2

3

4

Frequency (GHz)

VSW

R

300mm 360mm190mm 210mm

130mm 150mm






0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0











0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0



2 3 4 5 6 7 8 9 10 11Frequency (GHz)

1

2

3

4

VSW

R

5mm7mm

10mm


0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0



5 Conclusion



Competing Interests



0

2

4

6

8

10

Gai

n (d

Bi)

2 3 4 5 6 7 8 9 10 11Frequency (GHz)

5mm7mm

10mm


1

2

3

4

VSW

R

2 3 4 5 6 7 8 9 10 11Frequency (GHz)

21

27

44


0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0




0

2

4

6

8

10

Gai

n (d

Bi)

2 3 4 5 6 7 8 9 10 11Frequency (GHz)

21

27

44



2 3 4 5 6 7 8 9 10 11 12minus50

minus40

minus30

minus20

minus10

0

SimulatedMeasured

Frequency (GHz)

|S11| (

dB)




0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330








2 3 4 5 6 7 8 9 10 110123456789

1011

Frequency (GHz)

Gai

n (d

Bi)

SimulatedMeasured


2 3 4 5 6 7 8 9 10 11 12minus55

minus50

minus45

minus40

minus35

minus30

minus25

minus20

Frequency (GHz)

|S21| (

dB)


Acknowledgments


References




















RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










0

30

6090

120

150

180

210

240270

300

330


0


0

E-plane_8GHz

0

30

6090

120

150

180

210

240270

300

330


0


0

H-plane_8GHz

0

30

6090

120

150

180

210

240270

300

330


0


0

E-plane_6GHz

0

30

6090

120

150

180

210

240270

300

330


0


0

H-plane_6GHz

0

30

6090

120

150

180

210

240270

300

330


0


0

E-plane_4GHz

0

30

6090

120

150

180

210

240270

300

330


0


0

H-plane_4GHz

0

30

6090

120

150

180

210

240270

300

330


0


0

E-plane_2GHz

0

30

6090

120

150

180

210

240270

300

330


0


0

H-plane_2GHz






2 3 4 5 6 7 8 9 10 110123456789

1011


Frequency (GHz)

Gai

n (d

Bi)


2 3 4 5 6 7 8 9 10

minus4

minus3

minus2

minus1

0

1

2

3

4

Frequency (GHz)

Gro

up d

elay

(ns)


Conformalantenna

Dielectriccone

300360mm 190210mm 130150mm



2 3 4 5 6 7 8 9 10 111

2

3

4

Frequency (GHz)

VSW

R

300mm 360mm190mm 210mm

130mm 150mm






0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0











0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0



2 3 4 5 6 7 8 9 10 11Frequency (GHz)

1

2

3

4

VSW

R

5mm7mm

10mm


0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0



5 Conclusion



Competing Interests



0

2

4

6

8

10

Gai

n (d

Bi)

2 3 4 5 6 7 8 9 10 11Frequency (GHz)

5mm7mm

10mm


1

2

3

4

VSW

R

2 3 4 5 6 7 8 9 10 11Frequency (GHz)

21

27

44


0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0




0

2

4

6

8

10

Gai

n (d

Bi)

2 3 4 5 6 7 8 9 10 11Frequency (GHz)

21

27

44



2 3 4 5 6 7 8 9 10 11 12minus50

minus40

minus30

minus20

minus10

0

SimulatedMeasured

Frequency (GHz)

|S11| (

dB)




0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330








2 3 4 5 6 7 8 9 10 110123456789

1011

Frequency (GHz)

Gai

n (d

Bi)

SimulatedMeasured


2 3 4 5 6 7 8 9 10 11 12minus55

minus50

minus45

minus40

minus35

minus30

minus25

minus20

Frequency (GHz)

|S21| (

dB)


Acknowledgments


References




















RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










2 3 4 5 6 7 8 9 10 110123456789

1011


Frequency (GHz)

Gai

n (d

Bi)


2 3 4 5 6 7 8 9 10

minus4

minus3

minus2

minus1

0

1

2

3

4

Frequency (GHz)

Gro

up d

elay

(ns)


Conformalantenna

Dielectriccone

300360mm 190210mm 130150mm



2 3 4 5 6 7 8 9 10 111

2

3

4

Frequency (GHz)

VSW

R

300mm 360mm190mm 210mm

130mm 150mm






0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0











0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0



2 3 4 5 6 7 8 9 10 11Frequency (GHz)

1

2

3

4

VSW

R

5mm7mm

10mm


0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0



5 Conclusion



Competing Interests



0

2

4

6

8

10

Gai

n (d

Bi)

2 3 4 5 6 7 8 9 10 11Frequency (GHz)

5mm7mm

10mm


1

2

3

4

VSW

R

2 3 4 5 6 7 8 9 10 11Frequency (GHz)

21

27

44


0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0




0

2

4

6

8

10

Gai

n (d

Bi)

2 3 4 5 6 7 8 9 10 11Frequency (GHz)

21

27

44



2 3 4 5 6 7 8 9 10 11 12minus50

minus40

minus30

minus20

minus10

0

SimulatedMeasured

Frequency (GHz)

|S11| (

dB)




0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330








2 3 4 5 6 7 8 9 10 110123456789

1011

Frequency (GHz)

Gai

n (d

Bi)

SimulatedMeasured


2 3 4 5 6 7 8 9 10 11 12minus55

minus50

minus45

minus40

minus35

minus30

minus25

minus20

Frequency (GHz)

|S21| (

dB)


Acknowledgments


References




















RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0











0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0



2 3 4 5 6 7 8 9 10 11Frequency (GHz)

1

2

3

4

VSW

R

5mm7mm

10mm


0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0



5 Conclusion



Competing Interests



0

2

4

6

8

10

Gai

n (d

Bi)

2 3 4 5 6 7 8 9 10 11Frequency (GHz)

5mm7mm

10mm


1

2

3

4

VSW

R

2 3 4 5 6 7 8 9 10 11Frequency (GHz)

21

27

44


0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0




0

2

4

6

8

10

Gai

n (d

Bi)

2 3 4 5 6 7 8 9 10 11Frequency (GHz)

21

27

44



2 3 4 5 6 7 8 9 10 11 12minus50

minus40

minus30

minus20

minus10

0

SimulatedMeasured

Frequency (GHz)

|S11| (

dB)




0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330








2 3 4 5 6 7 8 9 10 110123456789

1011

Frequency (GHz)

Gai

n (d

Bi)

SimulatedMeasured


2 3 4 5 6 7 8 9 10 11 12minus55

minus50

minus45

minus40

minus35

minus30

minus25

minus20

Frequency (GHz)

|S21| (

dB)


Acknowledgments


References




















RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0



2 3 4 5 6 7 8 9 10 11Frequency (GHz)

1

2

3

4

VSW

R

5mm7mm

10mm


0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0



5 Conclusion



Competing Interests



0

2

4

6

8

10

Gai

n (d

Bi)

2 3 4 5 6 7 8 9 10 11Frequency (GHz)

5mm7mm

10mm


1

2

3

4

VSW

R

2 3 4 5 6 7 8 9 10 11Frequency (GHz)

21

27

44


0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0




0

2

4

6

8

10

Gai

n (d

Bi)

2 3 4 5 6 7 8 9 10 11Frequency (GHz)

21

27

44



2 3 4 5 6 7 8 9 10 11 12minus50

minus40

minus30

minus20

minus10

0

SimulatedMeasured

Frequency (GHz)

|S11| (

dB)




0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330








2 3 4 5 6 7 8 9 10 110123456789

1011

Frequency (GHz)

Gai

n (d

Bi)

SimulatedMeasured


2 3 4 5 6 7 8 9 10 11 12minus55

minus50

minus45

minus40

minus35

minus30

minus25

minus20

Frequency (GHz)

|S21| (

dB)


Acknowledgments


References




















RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










0

2

4

6

8

10

Gai

n (d

Bi)

2 3 4 5 6 7 8 9 10 11Frequency (GHz)

5mm7mm

10mm


1

2

3

4

VSW

R

2 3 4 5 6 7 8 9 10 11Frequency (GHz)

21

27

44


0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0




0

2

4

6

8

10

Gai

n (d

Bi)

2 3 4 5 6 7 8 9 10 11Frequency (GHz)

21

27

44



2 3 4 5 6 7 8 9 10 11 12minus50

minus40

minus30

minus20

minus10

0

SimulatedMeasured

Frequency (GHz)

|S11| (

dB)




0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330








2 3 4 5 6 7 8 9 10 110123456789

1011

Frequency (GHz)

Gai

n (d

Bi)

SimulatedMeasured


2 3 4 5 6 7 8 9 10 11 12minus55

minus50

minus45

minus40

minus35

minus30

minus25

minus20

Frequency (GHz)

|S21| (

dB)


Acknowledgments


References




















RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










0

2

4

6

8

10

Gai

n (d

Bi)

2 3 4 5 6 7 8 9 10 11Frequency (GHz)

21

27

44



2 3 4 5 6 7 8 9 10 11 12minus50

minus40

minus30

minus20

minus10

0

SimulatedMeasured

Frequency (GHz)

|S11| (

dB)




0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330








2 3 4 5 6 7 8 9 10 110123456789

1011

Frequency (GHz)

Gai

n (d

Bi)

SimulatedMeasured


2 3 4 5 6 7 8 9 10 11 12minus55

minus50

minus45

minus40

minus35

minus30

minus25

minus20

Frequency (GHz)

|S21| (

dB)


Acknowledgments


References




















RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation











0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330


0


0

0

30

6090

120

150

180

210

240270

300

330








2 3 4 5 6 7 8 9 10 110123456789

1011

Frequency (GHz)

Gai

n (d

Bi)

SimulatedMeasured


2 3 4 5 6 7 8 9 10 11 12minus55

minus50

minus45

minus40

minus35

minus30

minus25

minus20

Frequency (GHz)

|S21| (

dB)


Acknowledgments


References




















RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










2 3 4 5 6 7 8 9 10 110123456789

1011

Frequency (GHz)

Gai

n (d

Bi)

SimulatedMeasured


2 3 4 5 6 7 8 9 10 11 12minus55

minus50

minus45

minus40

minus35

minus30

minus25

minus20

Frequency (GHz)

|S21| (

dB)


Acknowledgments


References




















RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation











RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation









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