An efficient technique to realize low‐profile dual‐band multi‐polarized shared‐aperture slot antenna array

Abstract

An efficient technique to realize dual-band multi-polarized shared-aperture slot antenna array is proposed in this paper, featuring in all-metal, low-profile, light-weight and high radiation efficiency. The cavity-backed longitudinal slots are used at L-band for vertical polarization, while horizontal and vertical polarizations are both achieved at C-band, by utilizing interleaved ridged waveguides with two different kinds of slots. A coaxial-feed end-grounded metallic bridge is developed to excite the L-band cavity-backed slots, so the volume and weight of the L-band cavity can be obviously reduced. To further make the whole antenna structure compact and tight, the reduced L-band cavity is embedded into the serration, surrounding by two adjacent C-band ridged waveguides for vertical polarization and one for horizontal polarization. An array prototype, which consists of two L-band single-polarized antennas and four pairs of C-band dual-polarized antennas, is fabricated and measured. Experimental results are well consistent with the simulated ones, showing a satisfying impedance bandwidth of 12% in L-band and 5.5% in C-band, and besides high radiation efficiency above 85% for both bands. The all-metallic structure of this proposed array provides the thermal and mechanical advantages for space-borne synthetic aperture radar (SAR) application.