Correction to “5.8 GHz 4-Channel Beamforming Tx IC for Microwave Power Transfer”

In the above article [1], the received power in dc referred from the reference [2], which is the reference [35] in the original article [1], was incorrectly introduced. It was written as 0.2 W (dc) in the introduction of [1], but the correct received power in the specified condition is 2 W (dc)

5.8 GHz 4-Channel Beamforming Tx IC for Microwave Power Transfer

The microwave power transfer (MPT) system requires a massive Tx array for building a focused radio wave to efficiently transfer power to the Rx. Beamforming IC is one of the core elements for the massive Tx array. This paper presents a 5.8 GHz 4-channel beamforming Tx IC based on a CMOS process. The beamforming Tx IC includes a resistive 4-way power splitter, 5-bit differential phase shifters, drive amplifiers, and power amplifiers. Each channel is designed to transmit a power of no less than 100 mW. To verify the Tx IC, a 16-channel beamforming Tx module based on 16 patch antennas and four 4-channel Tx ICs was designed. The module also includes a PLL, a frequency doubler, and a 4-way Wilkinson power divider. MPT experiments to verify the beamforming IC and module were carried out using the implemented 16-channel Tx module at 5.8 GHz. Received power levels of 13 dBm and 2.1 dBm were achieved at distances of 0.4 and 1.4 m, respectively. The results are almost similar to the values acquired from the calculation using the Friis equation

Broadband Virtual-Stub Doherty Power Amplifier Using Asymmetric Structure

The load networks of advanced Doherty power amplifiers (DPAs) have traditionally been designed according to the ABCD parameters. In this paper, design conditions as an impedance transformation condition and an effective electrical length were used to design the output matching networks (OMNs) for the carrier and peaking amplifiers of the virtual-stub DPAs (VS-DPAs). An optimization method for the effective electrical length was proposed that was specifically constructed for the load impedances of the carrier amplifier at the low power level to have broadband characteristics through the load-pull simulation. Using the optimized design conditions for broadband design, compact OMNs for the carrier and peaking amplifiers were designed using quasi-lumped components. Moreover, an asymmetric structure with an increased power capacity of the peaking amplifier for the VS-DPA was proposed to compensate for a relatively low peak fundamental current of the peaking amplifier due to its deep class-C operation as well as the extended output back-off (OBO) range of the VS-DPA. To verify the proposed load network, a broadband asymmetric VS-DPA for the 3.3 - 4.2 GHz band was designed and implemented using GaN HEMTs with power capacities of 6 and 10 W. Using a 5G new radio (5G NR) signal with a signal bandwidth of 100 MHz and a peak-to-average power ratio (PAPR) of 7.8 dB, power gain of 8.2 - 9.1 dB, DE of 46.0 - 57.0%, ACLR of better than −45 dBc after DPD linearization at an average power of 35.0 dBm were achieved at the broad frequency range of 3.3 - 4.2 GHz