A Broadband Reconfigurable Load Modulated Balanced Amplifier (LMBA)

Abstract

The Load Modulated Balanced Amplifier (LMBA) uses a control signal (CSP), injected to the normally terminated port at the output coupler of a balanced amplifier (BA), to modulate the BA transistor's impedance. The hybrid circuit demonstrator described here uses metal-backed multilayer organic substrate and GaN discrete devices. Maximum output power levels above 39.5 dBm are achieved at around P3dB. DE above 60% is seen between 4.5 and 7.5 GHz for power back-off to 7 dB with a fixed CSP of 1 W, and the bias between 18 to 28 V.