A Modular Dual-Polarized Antenna Array with Four Interleaved 4×4 Arrays for Synthetic Aperture Radar (SAR) Applications

A modular, dual-polarized array with four interleaved 4 x 4 arrays is presented for application in L-band synthetic aperture radar (SAR). One array is for transmit and one array is for receive in horizontal polarization and the other two arrays are for transmit and receive in vertical polarization. The design enables direct connection to transmit and receive circuitry without the need for circulators or switches. Each antenna element has a dedicated channel, which is particularly advantageous for beamforming scenarios. The antenna elements, realized as printed dipoles on a substrate mounted on a ground plane, use a printed balun to enable broadband, balanced excitation. The array is simulated and measured for two cases: with all receive modules terminated with a 50 Ωload and all receive modules left open-circuited. The realized gain exceeds 19 dBi in the open-circuit case for both polarizations. When the receive modules are terminated with the load, the gain is reduced to 16 dBi. The reduction is attributed to coupling between the closely spaced transmit and receive modules.