Tuning Space Mapping Based Design of High-Performance Doherty Power Amplifier MMIC

In this paper, a fast optimization method for millimeter-wave Doherty power amplifier (DPA) monolithic microwave integrated circuit (MMIC) is proposed based on the tuning space mapping (TSM). To validate the proposed approach, a Ka-band DPA MMIC is implemented with a highly compact die size of 2.0 × 1.0 mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>, The optimized circuit obtains a 27-28.4 GHz bandwidth. Within the operating band, the DPA exhibits a saturation output power of 31–32 dBm, a saturated PAE of 40%~43%, and a PAE at 6-dB output power back-off (OBO) of 30%,….,32% according to simulation results. It is demonstrated that this method can reduce the number of necessary electromagnetic (EM) simulations from 203 to 10, resulting in over 20 times design speed acceleration.