A microwave bandpass filter on dielectric layers with metal grids

A bandpass filter of new design comprising dielectric layers with surface metal grids is developed and studied. Dielectric layers act as half-wave resonators, while metal grids act as mirrors with preset reflectivity and ensure optimum coupling between adjacent resonators and between the boundary resonators and free space. A test prototype of the third-order filter with a central bandpass frequency of $\sim$12 GHz and relative bandwidth $\sim$17% showed good agreement of theory and experiment. The proposed design can be used in making panels radio-transparent within a preset bandwidth for covering microwave antennas.