WT4 millimeter waveguide system: Electrical transmission measurement system

An electrical transmission measurement system which measures the TE
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loss characteristics of the millimeter waveguide medium is described in this paper. This computer-controlled system operates from 33 to 117 GHz with fully automated measurements over 10-GHz frequency intervals after several preparatory manual adjustments. The measurement signal is a pulse which is reflected from the end of the test waveguide line and detected in a calibrated receiver. The transmitter and receiver are both located at one end of the test line. The measuring range is 50 dB and the systematic error and random uncertainty are less than ±0.3 dB and ±0.1 dB respectively for any test line longer than 100 meters. The minimum line length is determined by the spatial duration of the signal pulse. The system can also be used to measure the reflected signal from a piston moving in the waveguide. This technique is useful for measuring loss and mode conversion effects in a local region of the transmission medium.