QuinStar Technology’s QMH series harmonic mixers enable down-conversion of millimeter-wave signals using lower frequency (microwave) local oscillator in the 2 to 20 GHz frequency range. The down-converted intermediate frequency (IF) is in the 5 MHz to 3 GHz range. Harmonic mixing is achieved by mixing appropriate harmonic N of the local oscillator, generated by the mixer itself, with the RF signal to produce an IF typically in the 5 MHz to 3 GHz range, such that fIF = |N.fLO–fRF|. The separation of the LO and IF signals is done by an external diplexer. They cover the frequency range of 18 to 110 GHz in seven full waveguide bands. These harmonic mixers are useful for subsystem applications involving frequency sampling such as phase-locked oscillators and frequency linearizers. They are also ideally suited for test and measurement equipment, such as spectrum analyzers, frequency counters and power meters.
Harmonic mixers can be optimized for either odd or even harmonics of the local oscillator (LO). They can also be produced to operate on all harmonics, even or odd. Series QMH harmonic mixers have a common SMA port for LO and IF signals, and hence require an external diplexer. Those mixers can be supplied with external diplexers to combine/separate LO and IF signals. Several choices of LO & IF ranges are offered as standard products. Typical LO ranges from 1.5 GHz to 20 GHz and IF from DC to 2.5 GHz.