Miniaturized and reconfigurable 2U-shaped DGS based UWB-BPF with notched band

A new compact UWB BPF filter with embedded reconfigurable multiband frequency notch function is presented. The proposed filter consists of compact 2U-shaped DGS resonators shunt connected to the parallel coupled lines. Frequency notch is achieved by using 2U-DGS. To tune the notched band, suitable capacitors within the inner U-DGS and RF PIN diodes within the outer U-DGS are integrated. A curve fitting formula is derived to show the effect of the capacitor value on the center frequency of the notched band, which is decreased by 56.7%. These capacitors improved the quality factor and have the effect of reducing the filter size by 72% as compared to other filters. The RF PIN diode switch in the outer U-DGS either rises the band notch by 27% or remove the band notched according to its positions. In order to validate the feasibility of the proposed structure, UWB BPF with center frequency of 6.85GHz is designed, fabricated, and measured.