A diplexer is a dual filter, designed to have a common input with dual outputs. (3 ports total). The typical diplexer has a lowpass & a highpass filter designed to match properly to give no amplitude distortion while maintaining a good passband VSWR (or return loss). Sometimes bandpass filters are used as well. The region in between the lowpass & the highpass edge frequencys is called the transition region. There is normally no spec in this region.

The power levels for each band are usually different (although they can be the same). The environmental requirements are usually not an issue they tend to be rather ruggedized with our normal designs.

Connectors can be different if required. We have made some with pins instead of connectors but could be a problem above 500 Mhz.

To date we have made diplexers from 1Mhz to 2.5Ghz. 3Ghz is our current limit.

The analyzer plot on the next screen is one example of a production diplexer P/N 53193