A Novel Dielectric Strip Resonator Filter

In this letter, a novel half-wavelength dielectric strip resonator that consists of a thin dielectric strip with high permittivity and a low-permittivity substrate with the bottom ground plane is proposed and theoretically investigated. The dielectric strip is used to replace the metal strip of the traditional microstrip line. Since there is no induced surface current on the dielectric strip, the unloaded quality factor (Q
_u
) of the proposed resonator can be improved significantly, especially at high frequency. Meanwhile, the proposed resonator can be easily excited by the tapped microstrip line for constructing the bandpass filter (BPF), because its E-field distribution is similar to the microstrip counterpart. For demonstration, a third-order dielectric strip resonator BPF centered at 10.5 GHz is designed, implemented, and measured. Good agreement between the simulated and measured results can be observed. The minimum in-band loss is only 0.6 dB.