Multi-Band Dual-Polarized Shared-Aperture Microstrip Array Antenna

Due to the increasing requirements of multi-band dual-polarization operation andcompact structure for future space/air-borne synthetic aperture radar (SAR) systems,the multi-band dual-polarization (MBDP) shared-aperture array antennas for SARapplication are studied, and several novel designs are proposed in the dissertation.The main subjects are listed below:1) For the S/X dual-band dual-polarized (DBDP) shared aperture array, a newdesign with the frequency ratio of about3.5:1is proposed and its experimentalverification is completed. Similar VSWR≤1.5bandwidths of10%are measuredin both X and S bands. The factors affecting element isolation in the arrayconfiguration are studied, and isolation improvement methods are discussed andvalidated.2) For the L/S/X tri-band dual-polarized (TBDP) shared aperture array, a newdesign of combining two L/S, L/X DBDP sub-arrays and an L banddual-polarized (DP) sub-array into TBDP aperture is proposed in the dissertation,with most part of design and experimental work finished. Measured VSWR≤2bandwidths of13.4%,14.8%and16.8%are achieved in L, S and X band,respectively, with in-band array isolation better than37dB in all bands.According to the published papers, the antenna is likely to be the first TBDPshared-aperture microstrip antenna array.3) The L/C overlapped structure and L/C single-layer perforated structure unit cells,are designed, fabricated and validated, which is a preliminary study of “single-layer perforated”-type L/C-DBDP full array. The merits and downsides of eachstructure are discussed and concluded by theoretical analysis and experimentalcomparison.