Microstrip dual-mode band reject filter

Novel microstrip dual-mode band reject filters using triangular patch resonators are investigated. It is shown that with simple circuit topologies highly selective notch filters can be realized. Full-wave electromagnetic (EM) simulations and circuit modeling are performed in order to understand the operation of this type of filter. Two demonstrators, i.e. single-patch and double-patch dual-mode band reject filters are presented with simulated and measured results.