Search On High-efficiency Power Amplifier Sed On Active Load Modulation Technology

The integration and intelligence development of wireless communication system and the application of broadband muti-mode put forward new requirements for power amplifiers(PAs).Carrying out the study of active load modulation can make PAs have better efficiency at different frequencies or different power region.Based on the LMBA technique,this paper focuses the study of the efficiency enhancement of broadband PAs at power back-off(PBO)region and ultra-broadband PAs at saturation.This paper firstly introduces and analysises the active load modulation PAs,demonstrating the efficiency enhancement technique at PBO and at saturation.Based on the theory of LMBA and Loadpull,the load modulation and design of LMBA are illustrated in detail.The main content and innovation of this paper are as follows:1.To solve the difficulty of load modulation in high-frequency and high-power LMBAs,an 8～12 GHz LMBA with pre-matching networks in main PA based on 0.25μm GaN HEMT process was presented,utilizing the Loadpull of FETs.The continuous wave(CW)test results demonstrate that the saturated power is beyond 20W with DE of 50.5%～55.7%and remain 40%at 6-dB PBO.Compared with the normalized idealistic Class-B PA at 6-dB PBO,15%～17%DE value enhancement of the chip can be achieved,verifying the feasibility of LMBA utilizing pre-matching networks.2.To realize the broadband single-input LMBA MMIC,an 8～12 GHz single-input LMBA MMIC was designed by combining the pre-matching networks,the input phase shift and power division network,and compression characteristics of GaN transistors.The results under CW test demonstrate a peak output power beyond 20W,with DE almost 50%.Moreover,the DE remains 30%～37%at 6-dB PBO,achieving 5%～10%DE value enhancement,compared to the normalized idealistic Class-B PA.3.To solve the imperfection of the output matching networks of ultra-broadband PAs,the design and performance of a 6-18 GHz PA based on 0.20 μm GaN HEMT process utilizing LMBA technique is presented,enhancing the efficiency at saturation.The CW test results demonstrate a peak output power of 41.1 dBm to 43.3 dBm,with PAE of 21.8%～42.7%,3.6%～9.9%higher than the BPA in a control group.Moreover,the PAE is over 40%from 10.5 GHz to 12 GHz in the X band.