Abstract
This paper presents a high-efficiency continuous class B power amplifier MMIC (Monolithic Microwave Integrated Circuit) from 8 GHz to 10.5 GHz, fabricated with 0.25 μm GaN-on-SiC technology. The Pedro load-line method was performed to calculate the optimum load of the GaN field-effect transistor (FET) for efficiency enhancement. Optimized by an output second-harmonic tuned network, fundamental to second-harmonic impedance, mapping was established point-to-point within a broad frequency band, which approached the classic continuous class B mode with an expanded high-efficiency bandwidth. Moreover, the contribution to the output capacitance of the FET was introduced into the output second-harmonic tuned network, which simplified the structure of the output matching network. Assisted by the second-harmonic source-pull technique, the input second-harmonic tuned network was optimized to improve the efficiency of the power amplifier over the operation band. The measurement results showed 51–59% PAE (Power Added Efficiency) and 19.8–21.2 dB power gain with a saturated power of 40.8–42.2 dBm from 8 GHz to 10.5 GHz. The size of the chip was 3.2 × 2.4 mm2.
Highlights
The efficiencies of transmitters widely applied in radars, communication satellites, and base stations are predominantly determined by the efficiencies of applied power amplifiers (PAs) [1]
Based on the bandwidth limitation of traditional harmonic-controlled PAs, Cripps proposed the continuous class B mode PA according to the method of waveform engineering [6]
This work presented an X-band high-efficiency power amplifier MMIC implemented in 0.25-μm
Summary
The efficiencies of transmitters widely applied in radars, communication satellites, and base stations are predominantly determined by the efficiencies of applied power amplifiers (PAs) [1]. To further improve the efficiency and extend the bandwidth of the power amplifier, the value of C in the input second-harmonic tuned network is calculated to achieve the smallest quality factor of the fundamental source impedances when the Electronics 2019, 8, 1312 second-harmonic source impedances are moved into the high-efficiency regions over the operation band. The desired fundamental and harmonic load impedances at the current source node of the FET to expand the high-efficiency bandwidth. High-efficiency regions of the second-harmonic source in continuous class B mode are given as follows (shown in Figure 1b): impedance based on continuous class B mode are obtained through a second-harmonic source-pull simulation. The desired fundamental and harmonic load impedances at the current source node of the FET in continuous class B mode are given as follows (shown in Figure 1b): ZL, f = Ropt (1 + jα),. The efficiency of a continuous class B mode PA in all solutions is 78.5%, which is the same as class B mode
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
