Single down conversion satellite payload with polyphase mixer

A method, comprising:

• sending a command to a mixing circuit of a satellite transponder that indicates for the mixing circuit to adjust respective phases of at least one of first phase shifters or second phase shifters of at least one of a first mixing subcircuit of the mixing circuit, a second mixing subcircuit of the mixing circuit, or a third mixing subcircuit of the mixing circuit;
• amplifying, at a low noise amplifier of the satellite transponder, a first signal;
• generating, at a local oscillator of the satellite transponder, an oscillator signal at an oscillator frequency;
• frequency converting, at the mixing circuit, the first signal to a second signal, wherein the converting comprises:
• dividing, at a splitter circuit of the mixing circuit, the first signal among the first mixing subcircuit, the second mixing subcircuit, and the third mixing subcircuit;
• receiving, from the splitter circuit, the first signal at the respective first phase shifter of the first mixing subcircuit, the respective first phase shifter of the second mixing subcircuit, and the respective first phase shifter of the third mixing subcircuit;
• outputting a first phase shifted representation of the first signal from the respective first phase shifter of the first mixing subcircuit, a second phase shifted representation of the first signal from the respective first phase shifter of the second mixing subcircuit, and a third phase shifted representation of the first signal from the respective first phase shifter of the third mixing subcircuit;
• receiving, from the local oscillator, the oscillator signal at the respective second phase shifter of the first mixing subcircuit, the respective second phase shifter of the second mixing subcircuit, and the respective second phase shifter of the third mixing subcircuit;
• outputting a first phase shifted representation of the oscillator signal from the respective second phase shifter of the first mixing subcircuit, a second phase shifted representation of the oscillator signal from the respective second phase shifter of the second mixing subcircuit, and a third phase shifted representation of the oscillator signal from the respective second phase shifter of the third mixing subcircuit;
• receiving the first phase shifted representation of the first signal and the first phase shifted representation of the oscillator signal at a first mixer of the first mixing subcircuit, the second phase shifted representation of the first signal and the second phase shifted representation of the oscillator signal at a second mixer of the second mixing subcircuit, and the third phase shifted representation of the first signal and the third phase shifted representation of the oscillator signal at a third mixer of the third mixing subcircuit;
• outputting a first component signal from the first mixer, a second component signal from the second mixer, and a third component signal-c) from the third mixer;
• and
• summing, at a summing circuit of the mixing circuit, the first component signal, the second component signal, and the third component signal to obtain the second signal;
• suppressing, at the mixing circuit, one or more harmonics of the oscillator frequency based at least in part on the adjustment of the respective phases;
• and
• amplifying, at a power amplifier of the satellite transponder, the second signal.

A satellite transponder, comprising:

• a low noise amplifier configured to amplify a first signal associated with a first frequency range;
• a local oscillator configured to generate an oscillator signal at an oscillator frequency that corresponds to a difference between a lowest frequency of the first frequency range and a lowest frequency of a second frequency range, and wherein a harmonic of the oscillator frequency is within the second frequency range;
• and
• a mixing circuit coupled with the low noise amplifier and the local oscillator, wherein the mixing circuit is configured to frequency convert the first signal associated with the first frequency range to a second signal associated with the second frequency range, and wherein the mixing circuit comprises:
• a splitter circuit coupled with the low noise amplifier and configured to divide the first signal among a first mixing subcircuit, a second mixing subcircuit, and a third mixing subcircuit;
• the first mixing subcircuit comprising a respective first phase shifter configured to receive the first signal from the splitter circuit and to output a first phase shifted representation of the first signal, a respective second phase shifter configured to receive the oscillator signal and to output a first phase shifted representation of the oscillator signal, and a first mixer configured to receive the first phase shifted representation of the first signal and the first phase shifted representation of the oscillator signal and to output a first component signal;
• the second mixing subcircuit comprising a respective first phase shifter configured to receive the first signal from the splitter circuit and to output a second phase shifted representation of the first signal, a respective second phase shifter configured to receive the oscillator signal and to output a second phase shifted representation of the oscillator signal, and a second mixer configured to receive the second phase shifted representation of the first signal and the second phase shifted representation of the oscillator signal and to output a second component signal;
• the third mixing subcircuit comprising a respective first phase shifter configured to receive the first signal from the splitter circuit and to output a third phase shifted representation of the first signal, a respective second phase shifter configured to receive the oscillator signal and to output a third phase shifted representation of the oscillator signal, and a third mixer configured to receive the third phase shifted representation of the first signal and the third phase shifted representation of the oscillator signal and to output a third component signal;
• and
• a summing circuit configured to sum the first component signal, the second component signal, and the third component signal to obtain the second signal;
• and
• a power amplifier configured to amplify the second signal associated with the second frequency range.