Microstrip Plasma Probe

Book excerpt: The report describes a new diagnostic tool-the microstrip plasma probe-which can be used in the laboratory or in a flight payload with little modification. It is rugged in construction, simple in geometric shape, small in frequency operation and low in power requirements. Since the probe is flush mounted and nonradiating, its analytic capability depends on the modification of its electric fringing fields by the outside medium. A measure of standard parameters--that is, reflection coefficient and insertion loss of the probe-can be related back through a series of equations to the parameters of the disturbing medium. Two general models are presented; one with a lossless center conductor, and one with a lossy center conductor. Where possible, theory and experiment are compared. The results are close. A calibration procedure for both models is described. (Author).