A broad-band low-noise Schottky diode full-height waveguide mixer from 80 to 115 GHz

The RIF matching problem in the input circuit of the mm-wavelength whisker contacted Schottky diode mixer is studied. The experimental results, obtained on the 3mm wavelength mixer mounts in the broad band of frequencies from 80 to 115 GHz are presented. It is shown that advantage in the receiver noise temperature may be realized by the use of a full-height instead of 1/4-reduced-height waveguide because of reduction loss in the mixer input circuit even beginning from the 3mm-wavelength. With a full-height waveguide mixer the double sideband (DSB) receiver noise temperature is 300divided by350K over the 85 to 110 GHz band. Input bandwidth of the full-height waveguide mixer (Delta f(s /) f(s0) >30%) is equal to 1/2-and close to 1/4-reduced-height waveguide mixers.