Characterization of triplate strip resonators with a loading capacitor

The influence of loaded capacitance on the resonant frequency of a triplate -type strip resonator is investigated through numerical simulations by mean s of the finite-difference time-domain (FDTD) method. This type of resonato r is one of the basic components of very small high-dielectric stripline fi lters, named laminated planar filters. Numerical results of resonant freque ncies are compared with experimental results and found to be in excellent a greement, which circumstance ensures that the FD TD method can be applied t o the characterization of a wide range of laminated planar microwave device s including resonators and filters. It is also found that the resonant freq uency is directly related to the square root of its line capacitance when t he resonator is regarded equivalently as a series LC circuit.