This brief presents a dual power mode (DPM) Q/V-band SiGe HBT cascode power amplifier (PA) for emerging very low-earth-orbit (VLEO) satellite communication (SATCOM). A novel reconfigurable four-way Wilkinson power combiner balun (WPCB) is proposed, where built-in a collector-to-base (CB) junction of upper HBTs in a SiGe HBT cascode is reconfigured to either reverse- or forward-biased to support high power (HP) or low power (LP) modes of the PA, respectively. This DPM scheme neither requires any lossy series switch at the PA output nor dual power supplies, which improves PA efficiency at power back off (PBO) and reduces system complexity. The DPM PA prototype is fabricated in 0.13 μm SiGe HBT BiCMOS. For HP/LP modes, the PA attains measured peak output power (POUT) and peak power added efficiency (PAE) 23.3/18.7 dBm and 30.4/25.8% at 45.0 GHz, respectively, demonstrating its DPM capability. For HP/LP modes at 45 GHz, it delivers linear POUT (PAVG) of 17.0/11.8 dBm with average PAE (PAEAVG) of 17.7/13.0% at 250MHz symbol rate DVB-S2X 64 ASPK modulation signal.
Manuscript received September 17, 2024; revised November 1, 2024; and accepted November 25, 2024; This work was supported in part by Institute for Information & communications Technology Planning & Evaluation (IITP) grant funded by the Korea Government (MSIP) (No. 2018-0-00190, Development of Core Technology for Satellite Payload) and in part by the New Faculty Research Fund of Ajou University.(Correspondingauthor:InchanJu) Inchan Ju is with the Department of Electrical and Computer Engineering, Ajou University Suwon 16499, South Korea (iju@ajou.ac.kr) Insu Han, Hanjung Lee, and Inchan Ju are with the Department of Intelligence SemiconductorEngineering, Ajou University Suwon 16499,SouthKorea(e-mail: ishan98@ajou.ac.kr; zach98@ajou.ac.kr;) Seong-Mo Moon is with Satellite Payload Research Section, Electronics and Telecommunications Research Institute, Daejeon 34129, South Korea (e-mail: smmoon@etri.re.kr) Color versions of one or more of the figures in this article are available online at http://ieeexplore.ieee.org. Digital Object Identifier xx.xxxx/TCAS-II.2024.xxxxxxxx Fig. 1. Adjusting antenna array aperture (left) and PA output power control (right) for the adaptive mode of operation in Q/V-band VLEO SATCOM.ACKNOWLEDGMENT The authors Thank GlobalFoundries SiGe team for chip fabrication. They appreciate Mii laboratory for equipment use. This work was supported by the Korea Basic Science Institute (National research Facilities and Equipment Center) grant funded by the Korea government (MSIT)(RS-2024-00399663).
