2018/12/14 by Jing Xia, Wenhua Chen, Fan Meng +3 · 143 citations
Engineering · #Adjacent channel #Advanced Power Amplifier Design #Amplifier #Bandwidth (computing) #Broadband #Damping factor #Doherty amplifier #Electrical engineering #Electrical impedance #Electronic engineering #Engineering #Impedance bridging #Impedance matching #Input impedance #Microwave Engineering and Waveguides #Output impedance #RF power amplifier #Radio Frequency Integrated Circuit Design #Telecommunications
paper · doi:10.1109/tmtt.2018.2884404
published in IEEE Transactions on Microwave Theory and Techniques 67(2), 778-786 (IEEE Microwave Theory and Techniques Society)
openalex publication_date 2018/12/14 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/29
This paper presents a broadband three-stage Doherty power amplifier (DPA) using impedance compensation for bandwidth extension. Different from the conventional design, an impedance-compensating load combiner is proposed to broaden the bandwidth of the three-stage DPA by employing the output impedances of the peaking amplifiers. Considering the load impedance of the peaking branch as an independent design variable, the Doherty load modulations are analyzed in theory, pointing out the optimized solution for the load combiner. To achieve the impedance compensation, the peaking output matching networks are deliberately designed with the dual-impedance matching topology. Experimental results show that a three-stage DPA is realized from 1.6 to 2.6 GHz (48% fractional bandwidth) with a measured efficiency of 50%-53% at 9.5-dB back-off and a saturated output power around 45.5 dBm. When stimulated by the 20- and 40-MHz modulated signals at an average output power of around 36.5 dBm, the proposed DPA can achieve the adjacent channel leakage ratio of -50 dBc over the whole frequency band after linearization, with an average efficiency of higher than 50%.