Broadband GaN Doherty Power Amplifier With Integrated Unequal Wilkinson and λ /4 Phase Network for Midband 5G

This paper presents the design and implementation of a high‐efficiency two‐way Doherty power amplifier (DPA) for sub‐6 GHz 5G New Radio (NR) applications, specifically targeting the n78 band (3.3–3.8 GHz). The proposed gallium nitride (GaN)‐based DPA delivers a peak output power of 42.5 dBm, a gain of 13.3 dB, and a maximum power‐added efficiency (PAE) of 83% at 3.5 GHz with V D D = 28 V under a 50‐Ω matched load. Both amplifier branches employ CG2H40010F GaN HEMTs configured in Class AB (carrier) and Class C (peaking) modes to achieve efficient load modulation across the operating band. A key feature of the proposed design is an integrated input network based on an unequal Wilkinson power divider combined with a λ /4 phase‐delay section, which is system‐level optimized to provide appropriate power division, phase alignment, and impedance matching for Doherty operation without requiring additional hybrid couplers. This compact structure minimizes insertion loss, improves amplitude–phase balance, and enhances Doherty load modulation performance across the 3.3–3.8‐GHz range. The DPA is implemented on a Rogers RO4003C substrate and incorporates λ /4 impedance inverters and a seventh‐order postharmonic suppression network to achieve superior spectral purity, reducing harmonic components below −30 dBc. Full‐wave electromagnetic simulations and experimental validations demonstrate strong agreement between measured and simulated results, confirming the effectiveness of the proposed architecture as a broadband, energy‐efficient, and manufacturable solution for next‐generation sub‐6 GHz 5G base‐station transmitters.