Study Of Broadband High-efficiency Continuous Modes Power Amplifiers

Continuous modes power amplifiers(PAs) are new types of harmonic-tuned broadband high-efficiency PAs. This dissertation focuses on the studies of the theory and design methodology of the broadband high-efficiency continuous modes PAs. The main contents and contributions are summarized as follows:Firstly, the typical modes of high-efficiency and broadband PAs are summarized in the time and frequency domains. A 3.0-3.8 GHz wide-band high-efficiency PA is designed based on load-pull/source-pull techniques, increasing the drain voltage to boost the amplifier gain and output power. The broadband high efficiency PA achieves a small signal gain of 15.7±0.7 dB from 2.95-3.75 GHz, and delivers the output power of 45.32-46.33 dBm with the drains efficiency(DE) of 56.06%-64.56%. A new Doherty structure with high-gain, wide-band and high-efficiency based on cascaded peaking PAs is proposed. A 3.6-3.9 GHz wide-band Doherty PA is simulated to test the feasibility. The small signal gain of 13.9-14.9 dB is realized, saturated output power of 49.3-51.1 dBm with power-added efficiency(PAE) of 56%-62.6% is also achived, and PAE is higher than 50% at the back-off lever of 7-8 d B.Secondly, the theory of the continuous modes PAs such as continuous Class-B/J and continuous Class-F are systematically researched. Besides, the continuous mode concept is extended and the broadband high-efficiency hybrid continuous modes PAs are proposed. The impedance solutions space based on the hybrid continuous modes offer a greater freedom for realizing broadband high-efficiency PAs. To verify the feasibility and superiority, a broadband high-efficiency PA based on hybrid continuous modes over a 54.5% relative bandwidth from 1.6 to 2.8 GHz is designed. The simulated results show that the fundamental impedances in this PA are found to be in or near the scope of the calculated ones. Moreover, this PA delivers the measured saturation output power of 8.1-17.8 W with the DE of 67.5%-81.9% in the target band.Thirdly, the optimal impedances transformation of the hybrid continuous modes PAs between the current generation plane and the package plane is deduced theoretically. The optimal impedances at package plane can be directly used for output impedance matching. Using the optimal impedances at the package plane, combinating with Load-pull technology to determine the high-efficiency and high output power harmonic impedances regions, a 1.5-2.7 GHz broadband high-efficency PA based on the hybrid continuous modes is designed. The simulated fundamental impedances are found to be in good agreement with the calculated ones, and the second fundamental impedances are almost close to the edge of the Smith chart and in the high-efficiency and high output power harmonic impedances regions. The experimental results reveal that the saturation output power of 10.7-16.6 W with the DE of 70.4%-78.3% across the band from 1.4-2.7 GHz are achieved. Tested by a 5 MHz WCDMA signal with 6 dB peak-to-average power ratio(PAPR), the measurements reveal that an average output power of 35.2-38.1 dBm with an average DE of 42.2%-50.8% at an adjacent channel leakage ratio(ACLR) of-30 dBc are obtained.