A K-Band Reconfigurable GaN Power Amplifier Using Switch-Loaded Coupled Line

This letter presents a K-band power amplifier (PA) monolithic microwave integrated circuit (MMIC) with frequency reconfigurable operation in a 0.15-<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text {m}$</tex-math> </inline-formula> GaN-on-SiC process. The proposed reconfigurable PA (RPA) is composed of a broadband output power stage and a driver stage with a reconfigurable interstage matching network (ISMN). Frequency reconfiguration is achieved by combining and embedding a switch-loaded coupled line (SLCL) and a switch-loaded transmission line (SLTL) inductor within the ISMN. The operating frequency band of the proposed RPA can be changed using the switch device in ISMN. Measurements results indicate that the proposed RPA features a maximum power-added efficiency (PAE) of 26.5% and an output power of over 30 dBm at a lower frequency band (19.5–21.5 GHz). When configured at a higher frequency operating mode, the RPA achieves a maximum PAE of 21% and an output power over 30dBm at 23.5–25.5 GHz. The modulation tests are performed using a 100-MHz 64-QAM modulated signal with 6.09-dB peak-to-average power ratio (PAPR). The proposed RPA achieves better than −27.5-dBc adjacent channel leakage ratio (ACLR) at 19.5GHz and −29 dBc at 24.5 GHz without digital predistortion (DPD), respectively.