Cao Meng-Yi(曹梦逸) a) , Lu Yang(卢 阳) a) , Wei Jia-Xing(魏家行) b) , Chen Yong-He(陈永和) a) , Li Wei-Jun(李卫军) b) , Zheng Jia-Xin(郑佳欣) a) , Ma Xiao-Hua(马晓华) a)b) † , and Hao Yue(郝 跃) a) a) Key Laboratory for Wide Band-

A high-efficiency C-band internally matched power amplifier, developed with 12 mm AlGaN/GaN high-electron mobility transistors is described. The second-harmonic frequency (2f 0) tuning network is applied to confine the impedance at 2f 0 in safe efficiency regions. The packaged power amplifier achieves 71% power-added efficiency (PAE) and 102 W output power, associated with 17 dB power gain. The PAE is believed to be the highest of the C-band GaN power amplifiers reported to date. power of more than 92 W. At 4 GHz, a PAE of 71% is achieved with an output power of 102 W. To the best of our knowledge, this is the state-of-the-art performance ever reported for a C-band internally matched 12 mm GaN HEMTs power amplifier.

The appearance of third-generation semiconductors represented by gallium nitride (GaN) material greatly improves the output power of a power amplifier (PA), but the efficiency of the PA needs to be further improved. The Class-F PA reduces the overlap of drain voltage and current by tuning harmonic impedance so that high efficiency is achieved. This paper begins with the principle of class-F PA, regards the third harmonic voltage as an independent variable, analyzes the influence of the third harmonic on fundamental, and points out how drain efficiency and output power vary with the third harmonic voltage with an I–V knee effect. Finally, the best third harmonic impedance is found mathematically. We compare our results with the Loadpull technique in advanced design system environment and conclude that an optimized third harmonic impedance is open in an ideal case, while it is not at an open point with the I–V knee effect, and the drain efficiency with optimized third harmonic impedance is 4% higher than that with the third harmonic open.

A new reflection-type wideband 360° monolithic-microwave integrated-circuit (MMIC) analog phase shifter at the Ka-band is proposed. The phase shifter is designed based on the principle of vector synthesis. Three Lange couplers are employed in the phase shifter, which is fabricated by the standard 0.25-μm GaAs process. We use four 4 × 40 μm GaAs HEMTs as the reflection loads. A microstrip line in parallel with the device is used as an inductance to counteract the parasitic capacitance of the device so that the reflection load performs like a pure resistance and the insertion loss can be decreased. In this phase shifter, a folded Lange coupler is utilized to reduce the size of the chip. The size of the proposed MMIC phase shifter is only 2.0 × 1.2 mm2. The measurement results show that the insertion loss is 5.0 ± 0.8 dB and a 360° continuously tunable range across 27–32 GHz is obtained with miniscule DC power consumption.