Instruments and Systems: Monitoring, Control, and Diagnostics Annotation << Back Principles for designing microwave movement and pressure detectors G.N. AKHOBADZE Principles for designing a microwave translation sensor and a pressure one are proposed on the basis of oscillatory characteristics of the open resonator and the nature of interference of electromagnetic waves. The essence of operation of the microwave resonator translation sensor consists in measuring a resonant frequency of the open resonator with a concave metal plate and a flat one under excitation of electromagnetic oscillations between them. A functional relationship between the resonant frequency and the translation that is applied to the flat metal plate of the open resonator is examined and justified. Error in determination of a translation when it is indirectly measured by the resonant frequency is estimated. The translation sensor which uses the nature of interference of electromagnetic waves under their propagation between the concave plate and the flat one provides for measurement of intensity of an interferential wave that is generated by superposition of a direct wave and a wave that is reflected from the flat plate which meets the effect of the translation. In order to find out a unique relationship between intensity of the interferential wave and the translation, correlations associated with a distance between the concave metal plate and the flat one are analyzed with taking into account a length of the wave propagating between the plates. The principle of operation of the pressure sensor is based on measurement of intensity of an interferential wave that originates between a fixed metal plate and a deformable one. A change in the intensity caused by a bend of a thin metal plate when a pressure object bears on it permits to determine a value of the parameter being controlled in this sensor. Keywords: open cavity, interference, resonance frequency of the plate, wavelength, intensity, bend. Contacts: E-mail: ahogur@yandex.ru Pp. 51-55.