Updated July 4,
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Why all the interest in sub-harmonic
mixers (SHM) these days? Because millimeterwave is where all the
growth is, and sub-harmonic mixers are often cheaper and more convenient
than fundamental mixers.
Sub-harmonic mixers are usually
accomplished buy using an anti-parallel Schottky
diode pair, either in shunt or in series. The three ports are
tapped off using filter
structures, the RF and LO could be bandpass, while the IF is usually
One characteristic of SHM is
that the mixer loss is quite sensitive to drive level. There is
an optimum drive level, below or above it the loss increases. If
you plot this it looks like an upside down parabola.
us if you want us to work on posting an example to this page,
or even better, if you want to contribute one!
More to come!