Abstract
This brief presents a three-way Doherty power amplifier (DPA) with a symmetric structure in terms of the output power capacities between the carrier and peaking amplifiers for high efficiency and linearity. Based on the analysis for the efficiency peak at the output power back-off, a symmetric structure was adopted to have higher overall efficiency for the modulated signal. Through the optimized bias condition for the two peaking amplifiers, the proposed three-way DPA can be linearized in the wide output power range. To validate the proposed scheme, a three-way DPA was designed and implemented using a 60 W GaN-HEMT for the carrier amplifier and two 30 W GaN-HEMTs for the peaking amplifiers. Using a 2.14 GHz long-term evolution downlink signal with a peak-to-average power ratio of 6.5 dB, the implemented symmetric three-way DPA exhibited a drain efficiency (DE) of 33.7% and an ACLR of -38 dBc at an average output power of 41.4 dBm. Compared to the condition with the same bias for the peaking amplifiers, the DE and average output power were improved by 8.0% and 2.4 dB for the given ACLR of -38 dBc, respectively.
| Original language | English |
|---|---|
| Article number | 7567520 |
| Pages (from-to) | 862-866 |
| Number of pages | 5 |
| Journal | IEEE Transactions on Circuits and Systems II: Express Briefs |
| Volume | 64 |
| Issue number | 8 |
| DOIs | |
| State | Published - Aug 2017 |
Keywords
- Doherty power amplifier (DPA)
- GaN-HEMT
- long-term evolution (LTE)
- output power capacity
- three-way DPA