A 33-110-GHz Millimeter-Wave Loss Scanner

A broad-band microwave measurement system has been designed to make insertion-loss measurements on a swept basis at millimeter wave frequencies. This instrument covers a frequency range of 33-110 GHz in three waveguide circuits, using WR-22, WR-15, and WR-10 waveguide components. Small variations in loss can be displayed and measured with a resolution of ??0.01 dB and an accuracy of ??0.08 dB while sweeping over frequency ranges as wide as 10 GHz. Insertion losses up to 60 dB can be measured with an accuracy of two percent for losses greater than 10 dB. Straighta way video detection techniques are employed. An interesting feature of the millimeter loss scanner is that random noise is averaged to insignificance and the test-set residual loss or baseline is automatically subtracted. The resultant output display is the actual insertion loss of the network under test along with any calibration lines that may be desired. This stored output can be displayed on an oscilloscope and photographed, read out on an X-Y plotter, or transmitted in either digital or analog form to a computer for further processing or analysis.