In this paper, a design method for an over octave hybrid continuous mode power amplifier (PA) based on modified real frequency technique (MRFT) is proposed. The extended continuous class-F/F-1 modes greatly expand the design space, which provides the possibility of over octave design, the optimal impedances at internal current-generator (I-Gen) plane and package plane are investigated. Then a novel broadband matching network based on MRFT is presented for impedance match. To verify the proposed methodology, an over octave PA with radial stub is fabricated and measured. The PA achieves a bandwidth of 133% from 0.8GHz to 4GHz, over this frequency range, the drain efficiency is 58.3-68.7% and large-signal gain is greater than 9.6dB.

This letter presents a dual-band load-modulated sequential amplifier (LMSA). The proposed amplifier changed the attenuator terminated at the isolation port of the four-port combiner of the traditional sequential power amplifier (SPA) architecture into a reactance modulation network (RMN) for load modulation. The impedance can be maintained pure resistance by designing RMN, thus realizing high efficiency and a good portion of the output power in the multiple bands. Compared to the dual-band Doherty power amplifier with a complex dual-band load modulation network (LMN), the proposed LMSA has advantages as maintaining high output power back-off (OBO) efficiency, wide bandwidth and simple construction. A 10-watt dual-band LMSA is simulated and measured in 1.7-1.9GHz and 2.4-2.6GHz with saturated efficiencies 61.2-69.9% and 54.4-70.8%, respectively. The corresponding 9dB OBO efficiency is 46.5-57.1% and 46.4-54.4%, respectively.

Analog beamforming with broadband large-scale antenna arrays in millimeter wave (mmWave) multiple input multiple output (MIMO) systems faces the beam squint problem. In this paper, we first investigate the sensitivity of analog beamforming to subarray spatial separations in wideband mmWave systems using hybrid arrays, and propose optimized subarray separations. We then design improved analog beamforming after phase compensation based on Zadoff-Chu (ZC) sequence to flatten the frequency response of radio frequency (RF) equivalent channel. Considering a single-carrier frequency-domain equalization (SC-FDE) scheme at the receiver, we derive low-complexity linear zero-forcing (ZF) and minimum mean squared error (MMSE) equalizers in terms of output signal-to-noise ratio (SNR) after equalization. Simulation results show that the improved analog beamforming can effectively remove frequency-selective deep fading caused by beam squint, and achieve better bit-error-rate performance compared with the conventional analog beamforming.

This letter proposes a power amplifier (PA) with compact matching network. This structure is a parallel dual radial microstrip line in the output matching network branch. The input impedance expression based on the structure is deduced through theoretical analysis, and the load impedance that satisfies the class EFJ PA is obtained through the impedance expression. Compared with the traditional design method, this design method is simple and novel, and the structure is more compact. In order to further improve efficiency and expand bandwidth, the input matching network adopts a stepped impedance matching method. In order to verify the correctness of the design, a broadband high-efficiency PA was designed using GaN HEMT CGH40010F. The test results show that the drain efficiency is 61%-71% in the frequency band 1.4-3.8GHz, the saturated output power is 40.3-41.8dBm, and the size is 53×47mm2.

This paper proposes a methodology for designing broadband class B/J power amplifier based on a mirrored lowpass filter matching structure. According to this filter theory, the impedance of this design method is mainly related to the cutoff frequency. Series inductors and shunt capacitors filter out high frequencies. The change of input impedance with frequency is small in the passband. Which can suppress higher harmonics and expand bandwidth. In order to confirm the validity of the design method, a broadband high-efficiency power amplifier in the 1.3 - 3.9GHz band is designed and fabricated. Measurement results show that the output power is greater than 40.5dBm, drain efficiency is 61.2% - 70.8% and the gain is greater than 10dB.