High frequency mixer, method and system

A method of generating a signal, said method comprising:

• supplying a first signal having a first frequency above 1 GHz;
• processing the first signal so as to produce two first output signals that are 180 degrees out of phase relative to each other;
• supplying a second signal having a second frequency above 1 GHz;
• mixing each of the first output signals with the second signal in respective mixers so as to produce two mixer product signals, each mixer product signal having a respective primary output signal with a third frequency, wherein the third frequency=first frequency−second frequency or the third frequency=first frequency+second frequency, and a spur signal having a spur frequency that is a multiple of the second frequency, wherein either the primary output signals or the spur signals are out-of-phase with each other in the mixer product signals;
• combining the mixer product signals such that the spur signals substantially cancel each other out and so as to yield a combined signal comprising a combination of the primary output signals.

A telecommunication system comprising:

• a source of radio-frequency (RF) signal and a source of local-oscillator (LO) signal, both of said signals having respective frequencies in the gigahertz frequency range;
• a light-weight mixer circuit supported within a housing and configured for use on a satellite in space, said mixer circuit comprising:
• a thin-film ceramic substrate;
• a thin film RF balun on the substrate and having an RF signal input connected with the source of the RF signal, said RF balun having first and second RF signal outputs transmitting first and second RF output signals respectively;
• the second RF output signal being substantially 180 degrees out of phase with respect to the first RF output signal, the first and second RF output signals having substantially equal amplitudes;
• first and second thin-film mixer elements on the substrate, each mixer element being a balanced mixer comprising a quad diode formed on said substrate and having two mixer inputs and one mixer output, each mixer element having one of the mixer inputs thereof connected with a respective RF signal output and receiving therefrom the respective RF output signal;
• a thin-film LO transmission structure on the substrate providing electrical communication between the source of the LO signal and each of the mixer elements, receiving the LO signal and transmitting the LO signal as first and second LO input signals to the other of the inputs of the first and second mixers respectively, said LO transmission structure including an LO phase adjuster element adjustable so that the first and second signal inputs are substantially in phase with each other at the inputs of the mixer elements;
• said first and second mixer elements providing first and second mixing output signals, respectively, at the mixer outputs thereof, said first and second mixing output signals including mixer product signals that include an IF signal with a frequency substantially equal to a difference between the frequency of the LO signal and the frequency of the RF signal frequency, and a spur signal having a frequency that is an integral multiple of the frequency of the LO signal,
• said IF signal of the first mixing output signal at the first mixer output being substantially 180 degrees out of phase with said IF signal of the second mixing output signal at the second mixer output, and the spur signal of the first mixing output signal at the first mixer output being substantially in phase with the spur signal of the second mixing output signal at the second mixer output;
• and
• a thin film output balun supported on the substrate and having an output and two inputs, each of said inputs being connected with a respective mixer output and receiving the respective mixer output signal therefrom, said output balun producing a shifted mixer output signal from one of the mixing signal outputs, wherein the IF signal in the shifted signal is substantially in phase with the IF signal of the other of the mixer output signals and the spur signal in the shifted signal is substantially 180 degrees out of phase with the spur signal of the other of the mixer output signals;
• said output balun combining the shifted mixing signal output with the other of the mixing, output signals so as to produce a circuit output signal wherein the spur signals substantially cancel each other out and the IF signals are combined substantially in phase, said circuit output signal being transmitted via the output of the output balun.