An MMIC linearized amplifier using active feedback

Abstract

A single 2.4-mm*2.4-mm MMIC (monolithic microwave integrated circuit) chip that includes an L-band tuned MESFET main amplifier and a nonlinear feedback path to improve its carrier-to-intermodulation margin (C/I) is discussed. The circuit uses the concept of amplifier intermodulation distortion (IMD) cancellation, in which a small-area MESFET-based linearizer is directly applied to the terminals of the main active device. The linearizer provides a 15-dB improvement of C/I, over a relative bandwidth of more than 12%.<>