Abstract
This letter presents an optimized load trajectory for symmetrical Doherty power amplifiers (DPA) with finite peaking off-state output impedance. This presented architecture uses the transistor's nonlinear phase distortion (NPD) to enhance the average drain efficiency (DE) of the DPA with the proper choice of carrier and peaking power amplifier (PA) load trajectories. A gallium nitride (GaN)-based DPA operating at 2.2 GHz has been designed and fabricated using the presented design methodology. The DPA delivers 43 dBm of output power at 3-dB compression (P-3 dB) and exhibits a DE of 55.5% at 9-dB OBO under continuous wave (CW) excitation. The DPA achieves average DE of 55% with linearized adjacent channel power ratio (ACPR) of -56.0 dBc with a 20-MHz LTE signal. This letter demonstrates that NPD in a DPA with finite peaking off-state impedance can be used to achieve excellent back-off efficiency and linearity.
| Original language | English (US) |
|---|---|
| Article number | 8721226 |
| Pages (from-to) | 486-488 |
| Number of pages | 3 |
| Journal | IEEE Microwave and Wireless Components Letters |
| Volume | 29 |
| Issue number | 7 |
| DOIs | |
| State | Published - Jul 2019 |
Keywords
- Doherty power amplifier (DPA)
- gallium nitride (GaN)
- load trajectory
- off -state impedance
- phase distortion
ASJC Scopus subject areas
- Condensed Matter Physics
- Electrical and Electronic Engineering