Upload
samruddha-thakur
View
70
Download
7
Embed Size (px)
DESCRIPTION
Microstrip Patch Antenna Design using ADS
Citation preview
IEEE 2007 International Symposium on Microwave, Antenna, Propagation, and EMC Technologies For Wireless Communications
Design of Broad-Band Circularly Polarized Microstrip PatchAntenna Array
Dong TaoSatellite Application System Department,China Academy of Space Technology,Beijing 100086,China
Email:[email protected]
Abstract: A Broadband circularly polarized microstripantenna array is presented in this paper. This array
has 8X8 elements and a parallel feed networks. The
whole size of this X band array is 190mm X 190mm X
0. 787mm. The measurement of the bandwidth of this array
is 7. 32%(VSWR<2), the gain is about 24dB and the axial
ratio is less than 3dB in the operating band. This
single layer microstrip antenna array is promising in
application because of its compact size and excellent
characteristics.
Index Terms: microstrip array, circularly polarized,broad-band, single layer
characteristics is realized by the truncated corner of the
square patch method. The gain of the element is about7dBi and the axial ratio is ldB.
1 Introduction
Microstrip patch antenna array is widely used in
radar, communication and other electronic systemsbecause of its compact size, low cost, easymanufacture and excellent characteristics. In this paper,a single layer circularly polarized microstrip patchantenna array is proposed. This array has compact sizeand excellent characteristics, such as broadband, highgain and good circularly polarized axial ratio.
2 Design and Simulation
2.1 circularly polarized patch element designThe circularly polarized microstrip patch element
is optimized by Ansoft Designer. The optimizationgoals are resonant frequency, gain and axial. Theelement planar EM model is shown in Fig.l.Thesubstrate is RT/duriod 5880 (sr = 2.2,tan 8 = 0.0009)with a thickness of 0.787mm. The circularly polarized
1-4244-1044-4/07/S25.00 ©2007 IEEE.
Fig.l microstrip pach element2.2 parallel feed networks design
This antenna array was formed by 2 X 2 elements,the layout of 2 X 2 feed networks is also optimized byAnsoft Designer. The optimization goals are resonant
frequency, transmission and reflection coefficients. Thesimulation circuit model is shown in Fig.2, and the
planar EM model is shown in Fig.3.
£^Av>
Fig.2 layout of 2 X 2 feed networks(circuit model)
636-
IEEE 2007 International Symposium on Microwave, Antenna, Propagation, and EMC Technologies For Wireless Communications
-160 -120 -80 -40 0 40
angle(DEG)
Fig.3 layout of 2 X 2 feed networks(planar EM model)2.3 whole size patch array simulation
The whole size 8X8 elements array is shown Fig.4,which is simulated by Ansoft HFSS. It can be seen
that the array is parallel fed, each element has equalamplitude and phase excitation. The spacing between
two elements is 0.7 A0 in two dimensions. The whole
size of this X band array is 190mm X 190mm X0.787mm.The radiation pattern of simulation in the
principal plane is shown in Fig.5.
Fig.4 simulation model
Fig.5 radiation pattern(simulation)
3 Measurement and Results
A prototype of the antenna is shown in Fig. 6. TheVSWR is measurement by using Agilent 8757D scalarnetwork analyzer. The measurement results andsimulation results(by Ansoft Designer and HFSS) are
compared in Fig. 7. We can see that they are good in
agreement. The bandwidth(VSWR<2)of the antenna
array is 7.32%(8.56GHz~9.21GHz) .The radiation
pattern, gain and axial of this single layer antenna
array are measured in the anechoic chamber. Circular
polarization gain and axial ratio are measured by usinga spinning horn and a gain comparison method. Theradiation pattern in the central frequency is presentedin Fig. 8. It can be seen that the gain is about 24.5dBiand the SLL is about -12dB.
Fig.6(a) Prototype ofproposed antenna(top)
¦637-
IEEE 2007 International Symposium on Microwave, Antenna, Propagation, and EMC Technologies For Wireless Communications
Fig.6(a) Prototype of proposed antenna(bottom)
5.5-
5.0-
4.5
4.0-
3.5
3.0
2.5
2.0
1.5-
1.0-
-HFSS_simDesigner_sim
-test
8.9 9.0 9.1 9.2 9.3 9.4
frequency(GHz)
Fig.7 measurement ofVSWR
v -10J
120 160 200 240
angle(DEG)
Fig.8 radiation pattern(measurement)
4 ConclusionsThis paper presents a high-performance single
layer 8X8 elements circularly polarized microstrippatch array antenna. The measurement of thebandwidth of this array is 7.32%(VSWR<2),the gain isabout 24dB and the axial ratio is less than 3dB in the
operating band.References
[l]Kwok L. Chung,'A circularly polarized stacked
electromagnetically coupled patch antenna," IEEE
Trans.Antennas Propaga.,Vol.52(5),ppl365-1370, 2004.
[2]Hao Wang,'A compact single layer monopulse microstripantenna array," IEEE Trans.Antennas
Propaga.,Vol.54(2),pp503-509,2006[3]S.Holzworth, "planar antenna design at 60 GHz for high date
rate point-to-point connections," Antennas and PropagationSociety International Symposium, IEEE , 2005
[4] M. L. Oberhart, Y. T. Lo, and R. Q. H. Lee, "New simplefeed network of an array module of four microstrip elements,"Electron. Lett., vol. 23,no. 9, pp. 436-437, 1987.
638-