Analytical method for coupling calcula-tions of rotated iris coupled resonator cavity

Abstract

Iris type waveguide to cavity couplers are used to couple power to particle accelerator cavities. Waveguide to cavity coupling for arbitrarily oriented rectangular iris is analyzed using Bethe's small hole coupling theory. Magnetic moment of rotated iris is obtained by defining its dyadic magnetic polarizability. Power radiated by magnetic moment into the incoming waveguide is used for coupling calculations at arbitrary angle. A close agreement is found between the proposed theory, simulations and microwave measurements.