A novel polarization-agile amplifier-type active microstrip array is proposed

in which the polarization agility and amplification of signal for the whole microstrip antenna array can be realized by electrically controlling one active circuit only.Using corner-fed square patch element

a new 16 element dual-polarized array with high isolation and low cross-polarization is designed.Its co-and cross-polarization radiation patterns are analyzed.The design method of active circuit is introduced

in which by changing the gate voltage of FET of a phase shifter

0°or 90°phase shift between dual ports is electrically controlled

resulting in the agility from the linear to circular polarization.The LNA enhances the active gain by 12-14dB

and improves the VSWR bandwidth and the isolation of the antenna as well.The experimental comparisons between passive dual-polarized arrays and active arrays are presented to verify the theory.