An $X$ -Band Pulsed Load Modulation Transmitter With Multilevel Envelope Delta–Sigma Modulations
The design and measured performance of X-band power amplifier MMICs that utilize 0.15μm GaN on SiC process technology are presented. Under continuous wave operating conditions these single and 2-stage MMICs demonstrate peak power added efficiencies (PAE) from 45% to 69%, output powers from 2.5-13 W, and up to 20 dB of large signal gain. Designed for drain modulated applications, the power amplifiers maintain good performance at reduced drain bias voltage. The output power of the two stage MMIC can be varied from 2 W to 13 W when the drain bias is varied between 7.5 V and 20 V while maintaining a PAE above 54%.