Abstract: An active microwave antenna device includes a two-port micropatch antenna which receives signals having a first circular polarization and transmits signals of opposite circular polarization. The device includes an integrated active circuit for amplifying and, optionally, filtering the signal. An array of such devices can be formed on a single substrate, each device being an independent active antenna, thus eliminating the need for RF or IF feed networks between the devices. Such arrays are believed to be particularly suitable for spatial power combining, rapid beam scanning, microwave imaging, frequency-polarization selective processes, and other related applications. The arrays may be either reflective or transmissive.