Gupta, M.P.Kumar, S.Naik Jatoth, D.Gorre, P.Song, H.2026-02-042024AEU - International Journal of Electronics and Communications, 2024, 178, , pp. -14348411https://doi.org/10.1016/j.aeue.2024.155279https://idr.nitk.ac.in/handle/123456789/21145This paper presents a high efficiency Rat-Race Coupler based compact GaN HEMT power amplifier (PA) design over broadband for high power transmitter in wireless communication. The rat-race coupler integrated PA Compact design is proposed for the first time as per author best knowledge. The design methodology used a higher order two open stubs and a rat-race coupler (RRC) at input/output sections to control harmonics impedances. The RRC is used to enhance the i/o power, and efficiency over broadband, which provides a good insertion loss, and consumes the least power and non-crucial impedance bandwidth for the normalized frequency band of interest. As a proof of concept, a PA is fabricated using a monolithic microwave integrated circuit (MMIC) 0.15 µm gallium nitride high electron mobility transistor (GaN HEMT) process. The measured result shows that the designed PA achieves a flat power added efficiency (PAE) of 65 % − 74 %, output power (P<inf>out</inf>) of 44.8 dBm − 46 dBm, and drain efficiency (DE) of 72 % − 85 %, over a record wide frequency of 1.8 GHz − 3.6 GHz, which is the highest one among all reported harmonic tuned PAs. © 2024 Elsevier GmbHBroadband amplifiersEfficiencyElectric connectorsElectric impedanceHarmonic analysisHigh electron mobility transistorsIII-V semiconductorsMicrowave amplifiersMonolithic microwave integrated circuitsPower amplifiersTiming circuitsWaveguide couplersGallium nitride high electron mobility transistorHarmonic networksHigh electron-mobility transistorsMulti-harmonic networkMultiharmonicOpen-stubsPower amplifierPower-efficiencyRat-race couplerGallium nitride