In this paper, we present a design approach for broadband harmonic-tuned monolithic microwave integrated circuit (MMIC) power amplifiers (PAs). Two harmonic matching networks are proposed for the realization of continuous class-B and class-F modes in an integrated PA. A design procedure is developed for integrated PAs using these matching networks to achieve high linearity, broadband operation, and compact chip area, in the presence of parasitic components and the physical limitations of the MMIC process. Two proof-of-concept fully integrated PAs are implemented in a 0.25-µm GaN-on-SiC process. Output power of 34.2-36.4 dBm with 40% to 49% power-added efficiency (PAE) is achieved in 4.2-7.0 GHz (51.6% fractional bandwidth), from the continuous class-B PA with only 1.5-mm 2 chip area. Furthermore, the continuous class-F PA achieves 36.2 dBm output power and 52% PAE at 5.0 GHz. The PAs are also characterized using QAM signals with wide bandwidth, in order to evaluate their performance for 5G wireless applications. For a 64-QAM signal with 100-MHz bandwidth and 8 dB peak-to-average power ratio (PAPR), the continuous class-B PA achieves 29.3 dBm average output power, 28% average PAE, and −25 dB (5.5%) error vector magnitude (EVM). The continuous class-F PA, tested using a 200 MHz 256 QAM signal with 8.5 dB PAPR, provides an average output power of 28.5 dBm, average PAE of 27%, and −28 dB (4%) EVM, without any pre-distortion. INDEX TERMS 5G, broadband amplifier, continuous mode, GaN, harmonic tuned, monolithic microwave integrated circuit (MMIC), power amplifier (PA).
In this paper, we present a design technique for broadband fully integrated GaN power amplifiers (PAs), with merged bandpass filter (BPF) and AM-PM compensation. The minimum-inductance BPF structure is used as the output matching network of the PA. A new theory of the minimum-inductance BPF is developed and it is shown that, compared to the standard BPF, it can be implemented using lower total inductance and provide higher out-of-band attenuation. Furthermore, using a twotransistor architecture, an AM-PM compensation technique is proposed where compressive and expansive nonlinearity profiles of the transistors' transconductance and gate-source capacitance are combined to achieve a linear total transconductance and input capacitance, over a wide power range. A fully integrated PA prototype, implemented in a 0.25-µm GaN-on-SiC process with 28-V supply, provides 35.1-38.9 dBm output power, 45-61% drain efficiency (DE), 40-55% power-added efficiency (PAE), and 11.3-13.4 dB power gain, across 2.0-4.0 GHz. For a 256-QAM signal with 7.2-dB PAPR and 100-MHz bandwidth at 2.4 GHz, it achieves 2.5% (−32.0 dB) rms error vector magnitude (EVMrms) and −37.5/−37.6 dBc adjacent channel leakage ratio (ACLR), while average output power and DE/PAE are respectively 30.1 dBm and 20.6/19.5%, without predistortion. EVMrms and ACLR can be improved to 0.5% (−46 dB) and −46.4/−46.8 dBc by using digital predistortion (DPD).
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.