Research

This article proposes a millimeter-wave wideband power amplifier (PA) featuring an inductive-compensation distributed active transformer (DAT) fabricated using a 90-nm CMOS process. The DAT is designed with a compact size of 0.004 mm2, aiming for high power-combining efficiency (PCEFF) and wideband performance. The PA achieves a saturated output power (PSAT) of 20.6 dBm, a maximum power-added efficiency (PAEmax) of 16.7%, and a 21.1 dB small-signal gain at 60 GHz. A flat 19.6 dBm PSAT with PAEmax exceeding 14.6% is demonstrated within the 32–65 GHz frequency range. The PA exhibits a 3-dB gain bandwidth of 35 GHz (31–66 GHz), and the chip area, excluding pads, is only 0.025 mm2. Notably, according to the author’s knowledge, this PA with a 19.6 dBm PSAT showcases the widest large-signal bandwidth with a flat frequency response compared with previously reported 60 GHz CMOS high-output PAs.

2025_TMTT

This paper presents a 2-6 GHz wideband power amplifier (PA) with a high power density in a 0.25-μm GaN HEMT technology. The design of the wideband PA incorporates an optimal matching network for the output matching and a capacitively and inductively coupled resonator for the interstage matching. This PA achieves a small signal gain ranging from 18.3 to 23.3 dB, and the saturated output power (Psat) and the maximum power-added efficiency (PAEmax) exceed 34.7 dBm and 29.8% across the 2-6 GHz band, respectively. The chip area is only 2.43 mm2, thus the proposed PA exhibits a highly competitive power density (mW/mm2).

2024_AMPC

This paper presents a 28-GHz, 1-W power amplifier (PA) with 41% peak PAE fabricated in a 0.15-μm GaAs pHEMT process. The proposed multi-section low-impedance transmission line matching network can adequately combine the output power and provide a low-loss output matching network in a compact area. The measured small-signal gain is 18.7 dB, and the measured saturated output power (PSAT) is 30.1 dBm with a peak power-added efficiency (PAEMAX) of 41% at 28 GHz.

2024_IMS

This paper presents a millimeter-wave (mmW) bidirectional Gilbert-cell mixer with low conversion loss (CL) and local oscillating (LO) power in a 90-nm CMOS process. The proposed double-balanced mixer provides a wide 3-dB bandwidth from 28 to 43 GHz in transmit (Tx) mode and 24 to 43 GHz in receive (Rx) mode. The compact area is achieved by modifying Marchand balun with compensating capacitors and a band-pass matching network at LO and RF ports. With 3-dBm LO power, the measured peak Tx- and Rx-mode conversion gain (CG) are -3.9 and -2.3 dB under DC power consumption of 11.5 and 8.4 mW, respectively.

2024_IMS

This paper presents an ultra-wideband (UWB) medium power amplifier (MPA) and a broadband high-power power amplifier (HPA) operating at the 5G/6G frequency bands. By using 0.15 µm GaAs pseudomorphic high electron mobility transistor (pHEMT) technology process, the proposed UWB MPA delivers an average small-signal gain of 16.5 dB, a saturation output power (Psat) of 24 dBm, and a peak power-added efficiency (PAE) over 24% from 24 to 38 GHz. The broadband HPA demonstrates a 17-dB average small-signal gain, 29-dBm Psat, and a PAE over 28% from 24 to 32 GHz. The measurement results have demonstrated the great potential of the proposed PA for 5G/6G millimeter-wave applications.

2024_JETCAS

A passive and active wideband reconfigurable power divider (PD)/power combiner (PC) is proposed and realized in 40-nm CMOS for fifth-generation (5G) millimeter-wave (mmW) beamforming systems. 

Based on the conventional Wilkinson PD/PC, the synthesis two-stage LC ladder is used to replace the quarter-wavelength transmission line to save the die area and achieve a wideband design for the passive PD/PC. Besides, the single-pole-double-throw (SPDT) switch function is added to realize the reconfigurable function. Compared with the other reconfigurable PDs/PCs and on-chip PDs, the proposed passive PD/PC demonstrates the widest 3-dB BW and compact area. 

Besides, we propose an active reconfigurable PD/PC. The bidirectional amplifiers (BDAs), based on modified distributed amplifier (DA) architecture, compensate for the loss of the passive elements. The T-type network inductors, equivalent to magnetically coupled resonator (MCR) circuit, replace the artificial transmission lines to avoid the extra dc dissipation on the termination resistor. By controlling switches, the reconfigurable function and bidirectional mechanism can be implemented. Compared with the other active reconfigurable PDs/PCs, our proposed PD/PC demonstrates a broader BW, lower dc power with a compact die area.

2022_TMTT

A bidirectional active mixer based-on Gilbert-cell topology is proposed and realized in 90-nm CMOS at 28 GHz. The offered mixer can achieve both the up and down conversion under 1-dBm LO power by adjusting the Gilbert quad switch's gate bias. An IF bidirectional amplifier is adapted to compensate for the conversion loss of the Gilbert quad switch. The measured peak conversion gain is -2.14/-3.28 dB at 28-GHz, and the 3-dB bandwidth is 7/6 GHz in Tx/Rx mode. Total dc power consumption is only 8.4/6.4 mW for TX/RX mode under 1.2-V supply voltage. Compared with the traditional bidirectional passive mixers, this mixer demonstrates a low conversion loss with a low LO power.

2021_MWCL