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

Area of Science:

• Electrical Engineering
• Microwave Engineering
• Telecommunications

Background:

• Fifth-generation (5G) massive multiple-input multiple-output (MIMO) base stations require efficient and compact power amplifiers.
• Existing power amplifier designs may face challenges in meeting the stringent performance demands of 5G systems.

Purpose of the Study:

• To propose and implement a compact, high-performance two-stage Doherty power amplifier (PA) module for 5G massive MIMO base stations.
• To detail the design of a low-loss combiner optimized for Doherty PA modules.

Main Methods:

• Design and implementation of a compact, low-loss combiner.
• Integration of gallium nitride (GaN) transistors and surface-mounted devices (SMDs) into an 8x8 mm^2 Doherty PA module.
• Performance characterization including bandwidth, gain, output power, and efficiency.

Main Results:

• Achieved a 3 dB small-signal bandwidth of 3.1-3.9 GHz.
• Saturated output power ranged from 40.4-41.1 dBm across the 3.2-3.6 GHz band.
• Measured saturated drain efficiency (DE) of 51-56.6% and 8 dB power back-off (PBO) DE of 45.5-48.6%.

Conclusions:

• The proposed Doherty PA module meets the demanding requirements for 5G massive MIMO base stations.
• The compact design and high efficiency demonstrate the viability of GaN technology for next-generation wireless infrastructure.