Measurement of microwave characteristics of helix traveling wave circuits

A measurement technique has been developed for accurately and rapidly measuring phase velocity, loss profile, and Pierce impedance in helix traveling wave circuits. This technique employs an Automatic Network Analyzer to control a perturbation measurement sequence which generates amplitude and phase information on the microwave signals in the circuits. These data are statistically reduced in the computer and hard copy of the results is produced automatically in the form of graphs and tables. Phase velocity measurements are repeatable to within ± 0.05% and Pierce impedance to within ± 5%. Loss profiles are typically tracked down to the -20 dB level. Dispersion characteristics are measured over wide frequency ranges including the stopband regions of lossless circuits. Resonant loss profiles have been successfully measured. All these measurements can be made on production helix circuits which typically are one-port devices.