Abstract
This brief presents an active second-harmonic injection technique to improve the efficiency and bandwidth for high-efficiency power amplifiers (PAs). An optimum third-harmonic termination condition was examined for higher efficiency after the second-harmonic injection using a multiharmonic load-pull simulation. It was determined that the optimum third-harmonic termination is the same as that of the inverse class-F PA. Based on this result, a high-efficiency PA with an optimized third-harmonic termination for the second-harmonic injection was designed for a center frequency of 1 GHz as a main amplifier. The overall system requires an auxiliary second-harmonic amplifier and a diplexer between the main and auxiliary PAs. The PA with an optimized third-harmonic termination for the second-harmonic injection was implemented using a 10-W GaN high-electron-mobility transistor for both the main and auxiliary power stages. Compared with the PA without second-harmonic injection, the bandwidth with a power-added efficiency of more than 80% is extended from 60 (960-1020 MHz) to 180 MHz (880-1060 MHz) after the second-harmonic injection.
| Original language | English |
|---|---|
| Article number | 6823125 |
| Pages (from-to) | 549-553 |
| Number of pages | 5 |
| Journal | IEEE Transactions on Circuits and Systems II: Express Briefs |
| Volume | 61 |
| Issue number | 8 |
| DOIs | |
| State | Published - 1 Aug 2014 |
Keywords
- High-efficiency power amplifier (PA)
- inverse class-F PA
- second-harmonic injection