Coupling system for the selective excitation of the te - fundamental wave in the shielded dielectric resonators

摘要

A TE fundamental wave is selectively energised in a screened dielectric resonator. The excitation of the TE fundamental wave takes place at several points on the resonator front side, the points being uniformly distributed along a field line of an azimuth E-field. The mean dia. of the circle, on which the coupling loops are arranged, corresponds approximately to the nodal circle dia. of the H component of the first harmonic radial TE wave. For decoupling of the TM oscillations in radial and axial direction the electric length of the coupling loop is pref. selected such that the centre of the loops approximately coincide with a voltage node. The coupler may have a coaxial feed, e.g. in strip technique. If a dielectric disc resonator is used, the coupler is accommodated inside a coaxial line. The arrangement may be used in a bandpass filter.