The generalized multiprobe reflectometer and its application to automated transmission line measurements

The multiprobe reflector can perform the measurements usually performed with the slotted line without the need for mechanical adjustment, thus making it ideal for automated systems. Theory is presented showing how impedance data may be obtained from three or more arbitrarily placed probes; the spacing need not be at any particular fraction of a wavelength thus permitting very wide band operation. The use of additional probes permits measurement of frequency and also self checking of the system, thus providing accuracies comparable with the best slotted lines available. The simplicity of the hardware makes it easy to install in both standard and non-standard waveguides and transmission lines thus avoiding the use of adaptors with their attendant errors. A brief error analysis is included. Measurements of antenna impedance and wall loss, using a nonstandard size of waveguide, are presented and show an accuracy comparable with the best slotted lines.