Design of an S/X dual-band dual-polarised microstrip antenna array for SAR applications

A novel design of dual-band dual-polarised microstrip antenna arrays for synthetic aperture radar applications with a frequency ratio of about 1:3 is presented. Stacked microstrip dipoles and square patches are used as the radiating elements at S- and X-bands, respectively. The microstrip dipoles are proximately coupled and the square patches are probe-fed. Experimental data show good agreement between simulated and measured results. The measured impedance bandwidth (VSWR≤2) the prototype array reaches 8.9% and 17% for S- and X-bands, respectively, and the measured isolation between polarisations for both bands are better than −20 dB. The measured crosspolarisation level is ≤−26 dB for the S-band and ≤−31 dB for the X-band. The work verifies the practicability of the dual-band dual-polarised microstrip antenna array design, using the combination of microstrip dipoles and patches, and good bandwidth and isolation performance of the prototype array has been achieved.