Comparison Between End and Edge Coupling of Dielectric Resonator Coupled with Microstrip Lines

In this paper, a comparison between two methods of coupling, end coupling and edge coupling, between microstrip line and cylindrical dielectric resonator (CDR) in a microwave integrated-circuit (MIC) environment is presented. The dielectric resonator is coupled to both open-circuited and short-circuited microstrip lines. The analysis is performed using the finite-difference time-domain (FDTD) method. It was shown that the end coupling configuration excites the hybrid electromagnetic modes (HEMmnp) with respect to the axis of rotation of the resonator. The edge coupling configuration also excites these modes at almost the same resonant frequencies in addition to the axis symmetric mode TE01δ. The comparison between end coupling and edge coupling configurations shows that the edge coupling has better values for insertion loss when the ends of the microstrip lines are open-circuited, whereas the end coupling offers better mode separation and sharper resonance curves when the ends of the microstrip lines are short-circuited