Multi-layer multi-permittivity dielectric resonator: A new approach for improved spurious free window

In this paper, a novel approach has been suggested to get spurious free window of dielectric resonator (DR) in MIC environment. In MIC environment, due to smaller thickness of substrate with respect to cavity dimension, the position of DR becomes asymmetric within the cavity. Due to this asymmetry, the field configuration of resonance mode modifies from its symmetry value and mode separation gets reduced. This asymmetry is compensated by introducing the different layers in DR, called as multilayer DR, with each layer having different permittivities. The multilayer makes the DR asymmetric with its axial direction and helps to compensate the asymmetry due to its position, and improves the mode separation. The results shows that multilayer ring DR gives always improved separation over the ring DR for all the range of substrate thickness.