A Design of 6-18 GHz Power Amplifier for Efficiency Enhancement at Saturation

The design and performance of a 6–18 GHz power amplifier (PA) using active load modulation is presented. Owing to the imperfection of the matching networks, multi-octave PAs usually have disappointing efficiency performance. Hence, this paper introduces a control signal via the balanced PA structure to modulate the apparent load impedance of the main PA actively. The load modulated balanced amplifier (LMBA) is fabricated and measured, the experimental results under continuous wave demonstrate a peak output power of 41.1dBm to 43.3dBm, with the power added efficiency (PAE) of 21.8%-42.7% over the band of 6–18 GHz. Moreover, the PAE is over 40% from 10.5 GHz to 12 GHz in the X band.