LOADED MICROSTRIP DISK RESONATOR EXHIBITS ULTRA-LOW FREQUENCY RESONANCE

In this paper a novel method of generation of ultra- low resonance in a microstrip disk resonator is presented. The disk resonator is loaded with series L-C circuit across a selective location in the disk via a thin shorting pin. It is shown that in loaded disk resonator, the lowest resonance observed is in VHF range whereas the unloaded disk had a fundamental resonance at 1.76 GHz. This resonance is slightly offset from the series resonant frequency of L- C circuit. and it depends on the disk radius as well. Using IE3D, a commercial MoM solver, the said structure is simulated. The experimental results agree well with the simulated results. A closed form expression for computing the resonant frequency is given.