Introduction to the Cavity Resonator

Abstract

Resonators are widely used in oscillators, amplifiers, filters, wavemeters, etc. Resonant circuits built up of lumped capacitances and self-inductances, as used in low-frequency applications, cannot always be made in the same way in microwave circuits. As the frequency increases, a lumped capacitance incurs too much self-inductance of its own, often with accompanying high losses. A self-inductance will quickly acquire too high a capacitance between successive windings. However, with modern microminiaturization techniques, even in the microwave area, lumped elements, small compared with the wavelength, can now be used.