Forward and reverse VSWR insensitive power detection using quadrature downconversion

A method of detecting output power of quadrature power amplifier circuitry comprising:

• downconverting an in-phase output signal from an in-phase amplifier circuit of the quadrature power amplifier circuitry based on a first local oscillator signal to provide a first downconverted signal;
• downconverting a quadrature-phase output signal from a quadrature-phase amplifier circuit of the quadrature power amplifier circuitry based on the first local oscillator signal to provide a second downconverted signal;
• downconverting the in-phase output signal from the in-phase amplifier circuit of the quadrature power amplifier circuitry based on a second local oscillator signal that is essentially −90 degrees out-of-phase with the first local oscillator signal to provide a third downconverted signal;
• downconverting the quadrature-phase output signal from the quadrature-phase amplifier circuit of the quadrature power amplifier circuitry based on the second local oscillator signal to provide a fourth downconverted signal;
• and
• selectively combining the first, second, third, and fourth downconverted signals to provide one of a group consisting of:
• a signal indicative of forward power and a signal indicative of reverse power.

A power detection system for detecting output power of quadrature power amplifier circuitry comprising:

• a) a forward power detection system having a first input coupled to an output of an in-phase amplifier circuit of the quadrature power amplifier circuitry to receive an in-phase output signal and a second input coupled to an output of a quadrature-phase amplifier circuit of the quadrature power amplifier circuitry to receive a quadrature-phase output signal, and comprising:
• i) phase-shifting circuitry adapted to apply a phase-shift to at least one of the in-phase output signal and the quadrature-phase output signal such that reverse components of the in-phase and quadrature-phase output signals are essentially 180 degrees out-of-phase;
• and
• ii) combiner circuitry adapted to combine phase-shifted in-phase and quadrature-phase output signals from the phase-shifting circuitry such that the reverse components essentially cancel, thereby providing a signal indicative of forward power;
• and
• b) quadrature downconversion circuitry adapted to downconvert the signal indicative of forward power based on quadrature local oscillator signals to provide a quadrature signal indicative of forward power.

A power detection system for detecting output power of quadrature power amplifier circuitry comprising:

• a) downconversion circuitry having a first input coupled to an output of an in-phase amplifier circuit of the quadrature power amplifier circuitry to receive an in-phase output signal and a second input coupled to an output of a quadrature-phase amplifier circuit of the quadrature power amplifier circuitry to receive a quadrature-phase output signal, and adapted to downconvert the in-phase output signal and the quadrature-phase output signal based on a local oscillator signal;
• b) phase-shifting circuitry adapted to apply a phase-shift to at least one of the downconverted in-phase and quadrature-phase output signals such that reverse components of the downconverted in-phase and quadrature phase output signals are essentially 180 degrees out-of-phase;
• and
• c) circuitry adapted to combine the phase-shifted downconverted in-phase and quadrature-phase output signals such that the reverse components essentially cancel to provide a signal indicative of forward power.