Conductor disc used to suppress spurious mode and enhance electric coupling in a dielectric loaded combline resonator

The effects of conductor disc in a dielectric loaded combline resonator on its spurious performance, unloaded quality factor (Q_u), and coupling coefficients are analysed using a commercial electromagnetic software package CST Microwave Studio (CST MWS). The disc improves the spurious free band but simultaneously deteriorates the Q_u. The presence of the disc substantially improves the electric coupling by 1.891 for an aperture opening of 12 mm, while it has insignificant effect on the magnetic coupling.