effect of flare angle on directional pattern of pyramidal...

19 Dr. E.Kusuma Kumari, K.srikavya, Gopinadh Gowd, Mounik

International Journal of Engineering Technology Science and Research

IJETS R

www.ijetsr.com

ISSN 2394 – 3386

Volume 2 Issue 7

July 2015

Effect of Flare Angle on Directional Pattern of Pyramidal

Horn Antenna

Dr. E.Kusuma Kumari1, K.srikavya

2, Gopinadh Gowd

3, Mounik

4

1. Assoc.Professor, Dept. Of ECE, Sri Vasavi Engineering College 2,3,4 Final B.Tech ECE students, Sri Vasavi Engineering College, Tadepalligudem.

ABSTRACT: This paper discusses the Effect of Flare angle on the Directional pattern of Pyramidal horn antenna with high gain,

light weight, linearly polarized, suppressed side lobes for UWB applications. The procedure is straightforward, and

determines the physical dimensions of pyramidal horn for different Flare angles that determine the performance of the

antenna. The performance of the proposed antennas are compared in terms of VSWR, Return losses, Gain, Directivity

and Radiation pattern of the antenna. The proposed antennas are simulated with commercially available packages such

as Ansoft HFSS. The antenna gives decent gain of about 20 dB over operating range of 8 -12 GHz .

Keywords: UWB, HFSS, flare angle, horn antenna

I. INTRODUCTION Horn antennas have been widely used for space applications from the very beginning due to their capability of being best operation from Megahertz to Gigahertz to Terra hertz range. Advantages of horn antenna over other types of antennas are: (a) High data rate systems needs to be operated at a higher frequency range in order to achieve higher bandwidth. This can be easily achieved using a horn antenna (b) Complexity involve in the design of horn antenna is less as compared to phased array antennas & corrugated cousins [3]. (c) Feeding a horn antenna is less complex as compared to other antennas which require complex feeding techniques (d) If horn antenna is properly designed & optimized than side lobes can be suppressed to very low levels. (e) Power handling capability of horn antenna is superior to other antennas as it is waveguide fed antenna, especially in the use of TWTs used in satellites, radars and many other applications making it an ideal choice for space applications. Horns have conventionally been used in terrestrial microwave communications. They can also be found on many Line-Of-Site (LOS) microwave relay towers . Horn Antennas are used in remote sensing satellites, communication satellites, geographic information & weather satellite. Various space programs in which horn antennas are used by NASA, ESA.

II DESCRIPTION OF PYRAMIDAL HORN

ANTENNA Antennas are one of the most important parts of a communication chain. In Modern times need for wideband applications has increased. The Horn Antenna is widely used in the EMC measurement, radar and communication system. If flaring is done only in one direction, then sectorial horn is produced. Flaring in the direction of Electric vector and magnetic vector , the sectorial E-plane horn and sectorial H-plane horn are obtained respectively. If flaring is done along both the walls of the rectangular Wave guide, then Pyramidal horn is obtained. Pyramidal Horn is the best horn as it has equal radiation patterns in both E-plane and H-plane along with its high gain and directivity. So, the need to develop a Wideband horn antenna for communication and calibration purposes[6]. With the development of measurement, communication system, radar techniques and electromagnetic, the horn antenna has been widely used which made it one of the most practical antennas. this horn antenna can effectively extend the working bandwidth of the antenna and improve the impedance matching between waveguide and free space. III. ANTENNA DESIGN

The horn is nothing more than a hollow pipe of different cross sections, which has been tapered (flared) to a larger opening. The type, direction,



IJETS R

www.ijetsr.com

ISSN 2394 – 3386

Volume 2 Issue 7

July 2015

and amount of taper (flare) can have a profound effect on the overall performance of the element as a radiator. The design was performed to accomplish better performance characteristics. The selected frequency range is 8-12 GHz i.e X band The Antennas were designed using advance EM simulation software HFSS uses Finite Element Method as analysis & solution to Electromagnetic problems. Ansoft HFSS with waveguide dimensions of a =22.86 mm and b=10.16 mm, waveguide length of L=30 mm, at feeding stage and wall thickness t=1mm. Different Horn rectangular apertures and flare lengths are calculated for different Flare angles as follows. and is shown in fig. 1. The “air-box” and the “ground plane” have been set as an ideal propagation space and a perfect electric conductor, respectively.

Fig1: Pyramidal Horn Antenna

Design of Horn Antenna 1 For ƟE = 18

o and ƟH = 18

o and at 10 Ghz Centre

frequency, where ƟE and ƟH ƟE = 56λc ƟH = 67λc and A B Flared Length = B

2/(2 λc)

From the above the Horn Antenna aperture dimensions can be calculated as A = 111.6mm, B = 93.3mm and Flared Length(FL)= 145mm The geometrical 3D view of designed Pyramidal Horn Antenna for ƟE = 18

o and ƟH = 18

o in HFSS

is shown below in fig.2

The simulated Results for the above horn antenna like S- Parameter, VSWR, Gain, Directivity are shown below.

8.00 8.50 9.00 9.50 10.00 10.50 11.00 11.50 12.00Freq [GHz]

-50.00

-45.00

-40.00

-35.00

-30.00

-25.00

-20.00

dB

(S(W

ave

Po

rt1

,Wa

ve

Po

rt1

))

Ansoft Corporation HFSSDesign1XY Plot 5

Curve Info

dB(S(WavePort1,WavePort1))

Setup1 : Sw eep1

Fig : S-Parameter (Return losses) Vs Frequency in

GHz

-200.00 -150.00 -100.00 -50.00 0.00 50.00 100.00 150.00 200.00Theta [deg]

-50.00

-40.00

-30.00

-20.00

-10.00

0.00

10.00

20.00

30.00

dB

(Ga

inT

ota

l)


Curve Info

dB(GainTotal)

Setup1 : LastAdaptive

Freq='12GHz' Phi='0deg'

dB(GainTotal)



Fig: Directivity Plot

-40.00

-20.00

0.00

20.00

90

60

30

0

-30

-60

-90

-120

-150

-180

150

120

Ansoft Corporation HFSSDesign1Radiation Pattern 2

Curve Info

dB(GainTotal)



dB(GainTotal)



dB(GainTotal)



dB(GainTotal)



dB(GainTotal)



dB(GainTotal)


Fig: 3D Polar plot of Radiation pattern

8.00 8.50 9.00 9.50 10.00 10.50 11.00 11.50 12.00Freq [GHz]

1.00

1.02

1.04

1.06

1.08

1.10

1.12

1.14

ab

s(V

SW

R(W

ave

Po

rt1

))


m1

Curve Info

abs(VSWR(WavePort1))

Setup1 : Sw eep1

Name X Y

m1 12.0000 1.1347

Fig: VSWR Plot



IJETS R

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ISSN 2394 – 3386

Volume 2 Issue 7

July 2015


o and ƟH = 20


frequency From the above the Horn Antenna aperture dimensions can be calculated as A= 100.5 mm, B=84 mm and Flared Length(FL)= 117.6 mm The geometrical 3D view of designed Pyramidal Horn Antenna for ƟE = 20

o and ƟH = 20

o in HFSS

is shown below.

Fig: Pyramidal Horn antenna For ƟE = 20

o and ƟH

= 20o

The simulated Results for the above horn antenna like S- Parameter, VSWR, Gain, Directivity are obtained as follows.

8.00 8.50 9.00 9.50 10.00 10.50 11.00 11.50 12.00Freq [GHz]

-27.00

-26.00

-25.00

-24.00

-23.00

-22.00

-21.00

-20.00

dB

(S(W

ave

Po

rt1

,Wa

ve

Po

rt1

))


m1

Curve Info


Setup1 : Sw eep1

Name X Y

m1 12.0000 -26.3813

Fig : S-Parameter (Return losses) Vs Frequency in

GHz

8.00 8.50 9.00 9.50 10.00 10.50 11.00 11.50 12.00Freq [GHz]

1.10

1.12

1.14

1.16

1.18

1.20

1.22

ab

s(V

SW

R(W

ave

Po

rt1

))


Curve Info


Setup1 : Sw eep1

Fig: VSWR Plot

-34.00

-18.00

-2.00

14.00

90

60

30

0

-30

-60

-90

-120

-150

-180

150

120


m1

Curve Info

dB(GainTotal)



dB(GainTotal)



Name Theta Ang Mag

m1 0.0000 0.0000 20.1578

Fig: 2 Dimensional Radiation Pattern

Directivity:

-200.00 -150.00 -100.00 -50.00 0.00 50.00 100.00 150.00 200.00Theta [deg]

-50.00

-40.00

-30.00

-20.00

-10.00

0.00

10.00

20.00

30.00

dB

(Ga

inT

ota

l)


m1

Curve Info

dB(GainTotal)



dB(GainTotal)



Name X Y

m1 0.0000 20.1578

Fig: Directivity Plot

3-D Polar plot


o and ƟH = 30


frequency From the above the Horn Antenna aperture dimensions can be calculated as A= 67 mm, B=56 mm and Flared Length(FL)= 52.26 mm The geometrical 3D view of designed Pyramidal Horn Antenna for ƟE = 30

o and ƟH = 30

o in HFSS

is shown below.



IJETS R

www.ijetsr.com

ISSN 2394 – 3386

Volume 2 Issue 7

July 2015

Fig: Pyramidal Horn antenna For ƟE = 30o and ƟH

= 30o

The simulated Results for the above horn antenna as follows.

8.00 8.50 9.00 9.50 10.00 10.50 11.00 11.50 12.00Freq [GHz]

-27.00

-26.00

-25.00

-24.00

-23.00

-22.00

-21.00

-20.00

-19.00

dB

(S(W

ave

Po

rt1

,Wa

ve

Po

rt1

))

Ansoft Corporation 30-30XY Plot 1

m1

Curve Info


Setup1 : Sw eep1

Name X Y

m1 12.0000 -26.4496

Fig : S-Parameter (Return losses) Vs Frequency in GHz

2-Dimensional Radiation Pattern Plot

-28.00

-16.00

-4.00

8.00

90

60

30

0

-30

-60

-90

-120

-150

-180

150

120

Ansoft Corporation 30-30Radiation Pattern 1

m1m2

Curve Info

dB(GainTotal)



dB(GainTotal)



Name Theta Ang Mag

m1 0.0000 0.0000 17.2909

m2 -5.0000 -5.0000 16.7186

Directivity:

-200.00 -150.00 -100.00 -50.00 0.00 50.00 100.00 150.00 200.00Theta [deg]

-40.00

-30.00

-20.00

-10.00

0.00

10.00

20.00

dB

(Dir

To

tal)

Ansoft Corporation 30-30XY Plot 4

Curve Info

dB(DirTotal)



dB(DirTotal)



VSWR Plot:

8.00 8.50 9.00 9.50 10.00 10.50 11.00 11.50 12.00Freq [GHz]

1.08

1.10

1.12

1.14

1.16

1.18

1.20

1.22

1.24

1.26

ab

s(V

SW

R(W

ave

Po

rt1

))Ansoft Corporation 30-30XY Plot 2

Curve Info


Setup1 : Sw eep1


o and ƟH = 35


frequency From the above the Horn Antenna aperture dimensions can be calculated as A= 57.42mm, B=48 mm and Flared Length(FL)= 38.4 mm The geometrical 3D view of designed Pyramidal Horn Antenna for ƟE = 35

o and ƟH = 35

o in HFSS

is shown below.



IJETS R

www.ijetsr.com

ISSN 2394 – 3386

Volume 2 Issue 7

July 2015

The simulated Results for the above horn antenna like S- Parameter, VSWR, Gain, Directivity are obtained as follows

VSWR Plot

8.00 8.50 9.00 9.50 10.00 10.50 11.00 11.50 12.00Freq [GHz]

1.14

1.16

1.18

1.20

1.22

1.24

1.26

1.28

1.30

ab

s(V

SW

R(W

ave

Po

rt1

))


m1

Curve Info


Setup1 : Sw eep1

Name X Y

m1 12.0000 1.1451

Directivity Plot:

-200.00 -150.00 -100.00 -50.00 0.00 50.00 100.00 150.00 200.00Theta [deg]

-40.00

-30.00

-20.00

-10.00

0.00

10.00

20.00

dB

(Dir

To

tal)


Curve Info

dB(DirTotal)



dB(DirTotal)



2- Dimensional Radiation pattern:

-28.00

-16.00

-4.00

8.00

90

60

30

0

-30

-60

-90

-120

-150

-180

150

120


Curve Info

dB(GainTotal)



dB(GainTotal)



S-Parameter or Return losses Plot:

8.00 8.50 9.00 9.50 10.00 10.50 11.00 11.50 12.00Freq [GHz]

-24.00

-23.00

-22.00

-21.00

-20.00

-19.00

-18.00

-17.00

dB

(S(W

ave

Po

rt1

,Wa

ve

Po

rt1

))


m1

Curve Info


Setup1 : Sw eep1

Name X Y

m1 12.0000 -23.3951

IV COMPARISION OF SIMULATED RESULTS AND DISCUSSION:

S.No Parameter For ƟE = 18

o

and ƟH = 18o

For ƟE = 20o

and ƟH = 20o

For ƟE =

30o and ƟH

= 30o

For ƟE = 35o

and ƟH =

35o

1 S-parameter/

Return Losses -24 dB -26. 87 dB -26. 44 dB -23. 4 dB

2 VSWR 1.14 abs 1. 09 abs 1.10 abs 1.14 abs

3 Gain 19. 5 dB 20. 5 dB 17. 2647 dB 16.19 dB

4 Directivity 19. 5 dB 20. 5 dB 17. 26 dB 16.19 dB



IJETS R

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ISSN 2394 – 3386

Volume 2 Issue 7

July 2015

The simulated Results like S-parameter, VSWR, Gain and Directivity are obtained for various Pyramidal horn antennas which are designed at different flared angles. From the above results it is observed that for low Flared angles, the antenna gives poor performance due to less negative S-parameter and high VSWR. At improved Flared angles i.e for ƟE = 20

o and ƟH = 20

o the antenna

gives most beautiful performance like highest negative S-parameter, Lowest VSWR(closer to 1), and highest Gain and Directivity. For further improved Flared angles i.e ƟE = 30

o and ƟH = 30

o

and ƟE = 35o and ƟH = 35

o again the pyramidal

horn antenna gives some what poor performance in all parameters. If the flare angle is very large, the wave front on the mouth of the horn will be curved rather than plane. This will result in non uniform phase distribution over the aperture resulting increased beam width and decreased directivity and vice versa occurs if the flare angle is very small as the small angle results in small aperture area for a specified length. The Directivity is proportional to the aperture size for a given aperture distribution results poor directivity. Thus there is optimum aperture for certain Flare angle should be selected

V CONCLUSION This pyramidal horn antenna can be used in space applications. All the parameters of antenna have been carefully optimized to achieve superior performance with in the limited constraints. The antenna’s gain is 20 dB, with return loss of – 26.87 dB, side lobe level of -23 dB. These measurement results confirmed the results of the simulations and satisfied the design requirements. Desired results are achieved and the simulated structures are suitable for our applications. Structures are yet to be fabricated and measurement results will be presented accordingly. Efforts are going on to further improve bandwidth so as to accumulate even wider frequency range especially K Band and lower bands (L and S)..

REFERENCES [1] Yeongming Hwang, “Satellite Antennas”.

[2] Brian Kidney,”Horn antennas”Engineering, 98 16 –

Antennas 2001 .

[3] Kirpal singh,Ajay Siwach,Loveline Kaur

“Advancement in designingwide band Horn

Antenna”,IJETT,2013.

[4] Ramesh Chandra gupta,Shasank saxena ,Milind

B.Maharajan,Rajeevjyoti,”Design of Dual-Band

Multimode Profiled Smooth-Walled HornAntennas

for Satellite Communication “ IEEE Antennas and

wirelesspropagation letters,vol9,2010

[5] Lei Yang, Weihua Tan, Zhongxiang Shen, and Wen

Wu “Wide-Band Wide-Coverage Linear Array of

Four emi- CircularSector Horns” IEEE t ransactions

on antennas and propagation, vol. 60, no.8, August

2012

[6] Constantine. A. Balanis, "Antenna Theory Analysis

& Design", John Wiley, & Sons INC, Third Edition.

[7] Thomas A Milligan, "Modem Antenna Design",

John Wiley & Sons INC, Second Edit ion.

[8] HFSS Help/ Instruction Manual

[9] Antenna and Wave Propagation by K.D.Prasad

BIOGRAPHY

Author 1:

Dr.E.Kusuma Kumari obtained AMIE degree in ECE from Institution of Engineers, Calcutta in 2000. She received her M. Tech degree from JNTU Kakinada in 2005. She did Ph.D on Patch Antennas. Currently she is working as an Assoc.Professor , Dept. of ECE in Sri Vasavi Engineering College. Her areas of Interest are Antenna Design, RADAR Engineering and Microwave Remote Sensing.

Author 2 : Miss. R. Pavani obtained B.Tech in 2013, present she is pursuing M.Tech in the Department of ECE in Sri Vasavi Engineering College .

effect of flare angle on directional pattern of pyramidal...

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