8/2/2019 Planar L-strip Fed Broadband Micro Strip Antenna

1/3

P FED BROADBANDIP ANTENNA, Sreedevi K. Menon, B. Lethakumary , Binu Paul,

, and P . Mohananrtment of Electronicsin University of Science and Techn ologyin 682 022, India

broadband rectangular tnicrostrip antenna utilizing

dy shows a 2:1 VSWR bandwidth of a 10% and excell entalmost as

NOLO GY LET TERS / Vol. 34, No. 2, July 20 2002 115

8/2/2019 Planar L-strip Fed Broadband Micro Strip Antenna

2/3

Grand planeSubume ISubwwe 2

Mkrowlpp.lthfeed Iine

Figure 1 Geom etry of the proposed planar L-strip fed antenna

antenna is suitable for broadband 2002 Wiley Periodicals, Inc. Microwave Opt

online in Wiley Inter-

: microstrip antenna; bandwidth enhancement ; L-strip feed;gnetic coupling

its planar and compact nature,systems.

is a major drawback of theseBandwidth enhancement is of great concern among

been suggested in the literature [ 1,2]idth enhancement. The L-shaped probe has been applied

antenna designs [3] for improv-

in Figure I.

Feed segment length(S3Figure 3 Variation of percent bandwidth with feed segmdifferent substrates (e,, = 4.28 , h, = 1.6 mm ). Dot-dash h2 = 1.1 mm; solid line-e,, = 4 . 28. h, = 1.6 min ; dot10.2, h2=0.6min

3. EXPERIMENTAL RESULTSA rectangular patch antenna with L = 40 mm and Wfabricated on a substrate with ere = 4.28, h2 = 1parameters of the L-strip feed are optimized to obtpercentage bandwidth. The variation of the return losantenna with the optimum feed parameters S, = 8 mmand S, 25 min is shown in Figure 2. The antenna 3.03-3.38-GHz band giving a 2:1 VSWR bandwiwith a center frequency of 3.3 GHz. The experiment i

E-plan. Foot..,,.

.4 . r .1ea

t.)

N-pMn. PettM

.10

(b )

8/2/2019 Planar L-strip Fed Broadband Micro Strip Antenna

3/3

antennas resonating at the same frequency, fabricated on differsubstrates. Variation in the percentage bandwidth with feed sment length (S,) is shown in Figure 3.

Radiation patterns of the antenna at the operating band edand midband frequencies for the above feed parameters are shoin Figure 4. The HPBW of the antenna in the E and H planes92 and 66, respectively, at the resonant frequency. The cpolarization of the antenna is better than -30 dB.

4. CONCLUSIONSA microstrip antenna with an electromagnetically coupled L-sfeed giving large bandwidth is presented. The remarkable featof the proposed antenna is its compact structure to achievehanced bandwidth, The feeding technique is very simple compato the other methods.REFERENCES1. A. Shackelford, K.F. Lee, D. Chatterjee, Y.X. Guo. K.M. Luk, an

Chair, Small-size wide-bandwidth microstrip patch antennas, IAP-S International Sym posium, Boston , MA, Vol. 1, pp. 86-89, 2

2. M. Clent and L. Shafai , Wideband single layer microstrip antennarray applications. Electron Lett 35 (1999), 1292-1293.

3. C.L. Mak, K.M. Luk, K.F. Lee, and Y.L. Chow, Experimental studa microstrip patch antenna with an L-shaped probe, IEEE Trans tennas Propagat AP -48 (2000), 777-782.

2002 W iley Periodicals, Inc.