The authors present a quasioptical power combining transmission amplif
ier for increasing the power level available from solid-state circuits
. Receiving and transmitting arrays of patch antennas, input/output is
olation, MESFETs, bias and matching circuitry are contained on a singl
e substrate, making monolithic millimetre-wave integration possible. T
he flexibility of selecting input polarisation with respect to the out
put while maintaining amplifier stability is demonstrated. A 24-MESFET
patch antenna amplifier array is presented.