Millimeter-wave Microstrip Antenna

The major research of this paper is about microstrip patch antenna at the frequency of 24GHz, including single patch antennas and patch arrays .Single antennas consist of centre side-fed, offset side-fed and inset-fed patches, while patch arrays consist of series-fed linear arrays, uniform and Taylor distributed parallel-fed linear arrays. Firstly, the paper presents the fundamental principle of microstrip patch antenna, focusing on the principle and design method of the three arrays mentioned above. Secondly, analysis and optimization of the antennas have been done utilizing EM software. Finally, measurement of realized antenna has been carried out.Measured results show that single antennas have good reflection characteristics, resonating at 24GHz hereabout and the bandwidth (S11<-10dB) between 2.1% and 3.6%. The measured single antenna patterns are quite different from simulated ones, which may be caused by improper measurement. The gain of the single antennas are between 4.4dBi and 7.1dBi. Compared with single antennas, patch arrays have much better measured results. The basic characteristics of center side-fed linear array and inset-fed four-patch arrays are as follows, respectively: bandwidth (S11<-10dB) 4.17% and 2%, gain 11.2dBi and 11dBi, sidelobe suppression 12.6dBi and 11.1dBi, cross polarization suppression 22.3dB and 24.4dB. While uniform distributed four-patch parallel-fed array realizes 4.17% of bandwidth (S11<-10dB), 9.5dBi of gain, 14dB of sidelobe suppression. A Taylor distributed eight-patch parallel-fed array, whose bandwidth (S11<-10dB) is 6.1%, gain 11.7dBi, cross polarization suppression 20.2dB, realizes theoretic 20dB sidelobe suppression. The E-plane and H-plane half power beamwidths of all linear arrays are 15 ~25°and 65 ~75°, respectively. The arrays have achieved expected goals and fit for vehicle anti-collision radar.