Wideband Doherty amplifier

摘要

Embodiments of a low-complexity and potentially physically small wideband impedance transformer that can be used in a combining network of a wideband Doherty amplifier are disclosed. In one embodiment, a wideband Doherty amplifier includes Doherty amplifier circuitry and a wideband combining network. The wideband combining network includes a wideband quarter-wave impedance transformer that includes a quarter-wave impedance transformer and compensation circuitry connected in parallel with the quarter-wave impedance transformer at a low-impedance end of the quarter-wave impedance transformer. The compensation circuitry is configured to reduce a total quality factor of the wideband quarter-wave impedance transformer as compared to a quality factor of the quarter-wave impedance transformer, which in turn increases a bandwidth of the wideband quarter-wave impedance transformer, and thus a bandwidth of the wideband Doherty amplifier.

主权项

1. A wideband Doherty amplifier, comprising:
Doherty amplifier circuitry comprising a main amplifier and a peaking amplifier; and a combining network having a first input coupled to an output of the main amplifier, a second input coupled to an output of the peaking amplifier, and an output, the combining network configured to combine a first amplified radio frequency signal from the output of the main amplifier and a second amplified radio frequency signal from the output of the peaking amplifier to provide a radio frequency output signal of the wideband Doherty amplifier; wherein the combining network comprises a wideband quarter-wave impedance transformer comprising:
a quarter-wave impedance transformer; andcompensation circuitry comprising two open stubs connected in parallel with the quarter-wave impedance transformer at a low-impedance end of the quarter-wave impedance transformer, the compensation circuitry configured to reduce a total quality factor of the wideband quarter-wave impedance transformer as compared to a quality factor of the quarter-wave impedance transformer.