Notch Filters based on Multilayer Ring Resonators (MRR)

Notched band filters are proposed based on multilayer ring resonator (MRR) structures. Three methods are introduced to obtain notch response for both forward-coupling and reverse-coupling configurations. In the first technique, an extra loop is employed on the top or bottom layer of MRR filters and a stop band is generated. This is applied to both forward coupling and reverse coupling. In the second method, a complementary ring resonator which is connected to the ground plane is used to reject undesired frequency and generate bandstop region. The third method, which is used for forward-coupling, the complementary ring is not connected to the ground plane and a dual-notch response is achieved within the passband. Second order and fourth order MRR bandpass filters are used to develop notched band. The simulated scattering parameters are obtained and the results are demonstrated.