Broadband Sequential LMBA with Enhanced Efficiency and Back-Off Range Based on Phase Control
Zeng Yan Chen, Zhi Chang Zheng, Baihua Zeng, Yi-Ming Zhang, Shaoyong Zheng · 2025
This paper presents an efficient broadband sequential load modulated balanced amplifier (SLMBA) with extended output power back-off (OBO) range. The SLMBA utilizes a phase shifter for phase control, thereby achieving efficiency enhancement at different frequencies. The phase shifter is designed based on phase requirements of the carrier and peaking branches of SLMBA, featuring adjustable phase shift slope across the varying frequency. For validation, a broadband SLMBA operating from 2.7 GHz to 3.5 GHz was designed, fabricated, and measured. According to the measurement results, the LMBA achieves 12-dB back-off range, with drain efficiency (DE) ranging from 35.3 % to 43.1 % at OBO and 58.6 % to 74.2 % at saturation, demonstrating the widest OBO range compared with previous works.