A 28 GHz Linear Power Amplifier Based on CPW Matching Networks with Series-Connected DC-Blocking Capacitors

Abstract

In this paper, the influence of the DC-blocking capacitors leveraged in coplanar waveguide (CPW) matching networks is studied. CPW matching networks with series-connected DC-blocking capacitors are less sensitive to capacitance and are adopted in a 28 GHz power amplifier (PA). The PA targeting fifth-generation (5G) phased array is developed in 90 nm silicon-on-insulator complementary-metal-oxide-semiconductor (SOI CMOS) technology. A stacked field-effect-transistor (FET) architecture is elected in the output stage to boost the output power and reduce the die area. The PA with a core area of 0.31 mm2 demonstrates a maximum small signal gain of 13.7 dB and a −3 dB bandwidth of 6.3 GHz (22.9–29.2 GHz). The PA achieves a measured saturated output power (Psat) of 14.4 dBm and a peak power added efficiency (PAE) of 25% for continuous wave signals. At 24/25.6/28 GHz, the PA achieves +7.87/+9.16/+10.7 dBm measured output power and 6.21%/8.11%/10.17% PAE at −25 dBc error vector magnitude(EVM) for a 250 MHz-wide 64-quadrature amplitude modulation (64-QAM). The developed linear PA provides a great potential for low-cost 5G phased array transceivers.