Dual Band Dual Linear Polarized Equal Cross Track Beam Microstrip Antenna for Airborne SAR

Abstract

This paper presents the design of common aperture dual band dual linearly polarized microstrip array antenna, working at L and S-band for airborne synthetic aperture radar (SAR). The antenna has been designed to offer equal beamwidth across the track of aircraft at both bands. The probe fed square annular patch antenna at L-band and electromagnetically coupled stacked patch antenna at S-band have been selected as array elements and distributed in 2 × 6 and 2 × 12 arrays on the same aperture, respectively. The aperture size is 0.35 × 1.2 m. The antenna has been developed and characterized in the compact antenna test field. The achieved 1:2 VSWR bandwidth is 200 MHz at L-band and 400 MHz at S-band. The measured peak gain is 16.3dBi at 1.25 GHz and 19.0dBi at 3.2 GHz. The developed antenna has also resulted in greater than 30dB port-to-port isolation and cross-polarization at both frequencies.