A 24-29.5 GHz Voltage-Combined Doherty Power Amplifier Based on Compact Low-Loss Combiner

• Published in: IEEE transactions on circuits and systems. II, Express briefs Express briefs, 2021-07, Vol.68 (7), p.2342-2346
• Main Authors: Wang, Dehan, Chen, Wenhua, Chen, Xiaofan, Liu, Xin, Ghannouchi, Fadhel M., Feng, Zhenghe
• Format: Article
• Language: English
• Subjects: Bandwidth; Bandwidths; Capacitors; Circuits; compact low-loss combiner; design procedure; Doherty power amplifiers (DPAs); Electric potential; Impedance; Inductance; Microprocessors; Millimeter waves; mm-wave; Optimized production technology; Power amplifiers; Power generation; SiGe; Voltage
• ISSN: 1549-7747; 1558-3791
• DOI: 10.1109/TCSII.2021.3053309

In this brief, a 24-29.5 GHz millimeter-wave (mm-wave) voltage-combined Doherty power amplifier (DPA) based on compact low-loss combiner is proposed for the fifth-generation (5G) applications. By maximizing the use of parasitic parameters in the circuit, a compact low-loss combiner is proposed to achieve the required impedance transformation with only one additional series capacitor. A detailed design procedure is also introduced in the brief. Based on the proposed combiner, a fully integrated Doherty PA is implemented in 0.13- {\mu }\text{m} SiGe BiCMOS process with a core area of only 0.29 mm 2 . The DPA achieves a 27% −3-dB small-signal gain fractional bandwidth and a 15.9 dB small signal gain at the center frequency of 27 GHz. The −1-dB Psat bandwidth covers 24-29.5 GHz (20% fractional bandwidth), and the maximum output power is 20.8 dBm ± 0.4 dB. From 24 to 29.5 GHz, the designed DPA provides 23.2% to 28.4% power-added efficiency (PAE) at saturated output power, and 18.3% to 21.9% PAE at 6 dB of output power back-off (OPBO).