Extension of Output Backoff Range in Three-Stage Load Modulated Balanced Amplifier Using Asymmetric Coupling and Non- Z₀ Load

Xie, Jieen1; Cheng, Kwok-Keung Michael1; Fang, Xiaohu2; Yu, Pengyu1

2024-07-01

10.1109/TMTT.2024.3425168

IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES   影响因子和分区

0018-9480

1557-9670

In this article, the extension of the output backoff (OBO) range of the load-modulated balanced amplifier (LMBA) is reported by manipulating the asymmetric output coupling and the non- Z(0 )termination. Closed-form formulas are derived based on the established model. It is demonstrated that by appropriately selecting the relevant parameters, high efficiency can be maintained over a large dynamic power range, such as 11/13/15/17 dB OBO. Furthermore, the strong saturation of the main power amplifier (PA) like the pseudo-Doherty LMBA (PD-LMBA) is circumvented in the proposed LMBA due to the specific scheme of modulation, effectively tackling the stability concerns associated with PD-LMBA and eliminating the linearity concern caused by the over-driven issue of the main PA in PD-LMBA design. The procedure and the graphical illustration are provided in comprehensive detail. For validation, the LMBA with the 15 dB OBO, operating at 1.80-2.05 GHz, is designed and implemented utilizing the gallium nitride (GaN) transistor. Measurements indicate that the prototype offers drain efficiency (DE) of 48.2%-63.2%/50.8%-59.5%/37.9%-49.2% at saturation/7.5 dB OBO/15 dB OBO range with saturation output power of 42-44.4 dBm. Under the excitation of long-term evolution (LTE) signal with bandwidth of 10 MHz and peak-to-average-power-ratio (PAPR) of 10.2 dB, the prototype offers average efficiency of 49.8%-55.5% at the average output power level of 31.8-34.2 dBm, with the adjacent channel leakage ratio (ACLR) of around - 25 dBc.

Modulation Couplers Transistors Power generation Power amplifiers Impedance Couplings Gallium nitride (GaN) high-efficiency load modulated balanced amplifier (LMBA) output backoff (OBO) output power

SCI

英语

其他

Research Grants Council of Hong Kong Special Administrative Region, China[CUHK 14209120]

Engineering

Engineering, Electrical & Electronic

WOS:001273039900001

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC

ENGINEERING

Web of Science

1.Chinese Univ Hong Kong, Dept Elect Engn, Hong Kong, Peoples R China
2.Southern Univ Sci & Technol, Sch Microelect, Shenzhen 518055, Peoples R China

Xie, Jieen,Cheng, Kwok-Keung Michael,Fang, Xiaohu,et al. Extension of Output Backoff Range in Three-Stage Load Modulated Balanced Amplifier Using Asymmetric Coupling and Non- Z₀ Load[J]. IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES,2024.

Xie, Jieen,Cheng, Kwok-Keung Michael,Fang, Xiaohu,&Yu, Pengyu.(2024).Extension of Output Backoff Range in Three-Stage Load Modulated Balanced Amplifier Using Asymmetric Coupling and Non- Z₀ Load.IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES.

Xie, Jieen,et al."Extension of Output Backoff Range in Three-Stage Load Modulated Balanced Amplifier Using Asymmetric Coupling and Non- Z₀ Load".IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES (2024).