US Patent 7616009 Method for microwave measurement, measuring device and oscillator

An object to be measured is measured using microwave radiation. Oscillation energy is generated by means of a feedback coupled active unit. The solution involves generating resonance into at least one oscillator, each oscillator comprising at least one open resonator, each resonator being coupled to at least one active unit, by using the object to be measured as a functional part of the resonator, the object to be measured causing a resonance frequency dependent on the location of a surface of the object to be measured to be generated in each oscillator. A measurement part determines at least one characteristic of the object to be measured on the basis of the resonance frequency of each oscillator.