# A 3.2–3.6 GHz GaN Doherty Power Amplifier Module Based on a Compact Low-Loss Combiner

## TL;DR

This paper presents a compact and efficient GaN Doherty power amplifier module for 5G MIMO base stations, operating in the 3.2–3.6 GHz range.

## Contribution

The novel contribution is a compact low-loss combiner design for a two-stage GaN Doherty PA module optimized for 5G applications.

## Key findings

- The module achieves a 3 dB small-signal bandwidth of 3.1–3.9 GHz with a peak gain of 31.7 dB.
- It delivers a saturated output power of 40.4–41.1 dBm from 3.2 to 3.6 GHz.
- Measured drain efficiencies are 51–56.6% at saturation and 45.5–48.6% at 8 dB power back-off.

## Abstract

In this paper, a 3.2–3.6 GHz two-stage Doherty power amplifier (PA) module is proposed for fifth-generation (5G) massive multiple-input multiple-output (MIMO) base stations. A detailed design method and procedure for a compact and low-loss combiner suitable for the Doherty PA module are introduced. Based on the proposed combiner, a Doherty PA module is implemented using gallium nitride (GaN) transistors and surface-mounted devices (SMDs) with a packaged size of 8 × 8 mm2. The proposed two-stage Doherty PA module achieves a 3 dB small-signal bandwidth of 3.1–3.9 GHz and a peak gain of 31.7 dB. From 3.2 to 3.6 GHz, the saturated output power is 40.4–41.1 dBm. Moreover, the measured saturated drain efficiency (DE) and 8 dB power back-off (PBO) DE reach 51–56.6% and 45.5–48.6%, respectively.