Given a device with a conventionally optimized P1 dB point, this paper proposes a new theory for feedback amplifiers to optimize gain and improves S22 (ideally resulting in S22 = 0). The design procedure only requires the small-signal S-parameters and the measured load-pull data of the transistor. To verify this theory, two 800-mW 2-GHz GaAs MESFET amplifiers with and without the lossless feedback were implemented and evaluated. The feedback amplifier achieved significant improvement in linear gain (6 dB), reverse isolation (12 dB), and output return loss (5 dB) with the same output P1 dB for both types of amplifiers.
|Number of pages||8|
|Journal||IEEE Transactions on Microwave Theory and Techniques|
|State||Published - 1 Apr 2006|
- Output power 1-dB compression (P)
- Power amplifier (PA)