A principle for the invariant measurement of deformation is proposed in the paper; it is based on the use of the resonance frequency of the open resonator and the beat frequency. The analysis of oscillatory characteristics of the open resonator and frequency-modulated oscillations to select information parameters on deformation is given. The necessity of application of invariance to the deformation measurement is explained by the examination of information parameters. The feasible null effect of the height of the unit under control on a deformation measurement result is shown by the conversion of two information signals. A circuit design solution for the implementation of the invariant deformation meter with the feasible application in various industries is given using a microwave technology.