Whispering gallery modes of planar dielectric resonators in LTCC technology

In this paper, Planar Dielectric Resonator (PDR) with large Q value in Low Temperature Co-fired Ceramic (LTCC) technology employing the whispering gallery modes (WGMs) has been designed and simulated for millimeter-wave applications. The design consists of two different dielectric constant (k) LTCC substrates, ground plane with circular hollow patch at the center each on top and bottom of the high-k LTCC substrate, two metal plates for shielding and two 50 Ohm strip lines for coupling. The present study shows that the resonance in the proposed PDR is due to the excitation of WGMs which gives a relatively high quality factor (Q) and ease of integration into MICs compared to conventional TE_01δ mode dielectric resonators at higher microwave frequencies. The loaded quality factor obtained for the designed PDR is about 1000 at 28 GHz.