| Artificial magnetic conductor(AMC)structure is a perodic structure with special electromagnetic properties,with which in phase reflection of plane wave in specific frequency band can be realized.Due to these unique properties,AMC has already been widely studied for the applications of electromagnetic radiating and scattering.With the rapid development of wireless communication technology,multifuction and high-performance antennas are increasingly needed in microwave and millmeter wave region.Meanwhile,antenna is the crucial component of radar and communication system,how to reduce the radar cross section(RCS)of itself effectively has become the key issue in modern war.Therefore,this article is mainly focusing on improving the performance of antennas and reducing the RCS of target by AMC structures.The contents can be summarized as:Two kinds of artificial ground planes,including a square patch of AMC and a polarization rotation AMC(PRAMC)structure are studied for their applications in microstrip antennas.By replacing the metal ground with PRAMC ground,a wideband and high gain circular polarization microstrip antenna is designed.Combining the square AMC ground with linear polarization microstrip antenna and circular polarization microstrip antenna respectively,four types of high-performance antennas are proposed.The impedance bandwidth,3 d B axial ratio bandwidth and gain of those antennas have been improved.A novel AMC unit with broadband in-phase reflection bandwidth is proposed.By arranging the broadband AMC and square ring AMC around the microstrip antenna and waveguide slot antenna in a chessboard configuration,two kinds of low RCS antenna are proposed.Then,both a simultaneous improvement of radiating and scattering performance for the two antennas can be obtained.In order to validate the design,the low-RCS microstrip antenna is fabricatied,and great agreements are obtained between the measurments and the simulations.Applications of mixed AMC structure for low-RCS metasurface are studied.According to the concept of phase compensation,four different AMC units,arranging in a windmill configuration,are proposed to realize the ultra-wideband monostic RCS reduction.Combining metasurface with the concept of digital coding,a presudo-random surface with the property of ultra-wideband RCS reduction under both monastic and biastic status is designed,with which backscattering waves can be redirected into multiple directions. |
