A novel periodic electromagnetic bandgap structure for finite-width conductor-backed coplanar waveguides

The one-dimensional (1-D) periodic electromagnetic bandgap (EBG) structure for the finite-width conductor-backed coplanar waveguide (FW-CBCPW) is prop osed. Unlike the conventional EBG structures for the microstrip line and th e coplanar waveguide (CPW), which are typically placed on one of the signal strips and the ground plane, this EBG cell is etched on both the signal st rip and the upper ground plane of FW-CBCPW, resulting in a novel circuit el ement. The equivalent circuit is also used to model the EBG cell. Measured and full-wave simulated results show that the cell exhibits remarkable stop band effect. The low-pass filter with lower cutoff frequency and wider reje ction bandwidth is constructed from a serial connection of the EBG cells. T he effect of back metallization on guiding characteristic is also discussed . Compared to the published EBG cells, the proposed structure has the advan tages of relative flexibility, higher compactness, lower radiation loss, an d easier integration with the uniplanar circuits.