Compact dual mode switchable BPF — BSF using RF PIN diodes and DGS

This work presents a novel frequency miniaturized reconfigurable dual-mode stub-loaded resonator switchable from BPF to single/double notched bandpass filter. The proposed filter topology employs RF PIN diodes as the switching device. Based on the odd and even-mode equivalent circuits, the resonant characteristics of the proposed microstrip resonator are investigated. RF PIN diodes are used to switch the passband between GSM (1.83GHz) and BSF to reject much application, and when changing the location of diode, filter could switch its double notched band for 1.77GHz and tuned a second notch. Measured results show a very good agreement with the simulations where a 1.83 GHz center frequency with a 280 MHz bandwidth was obtained for the GSM state. The DGS patterned enhanced the performance such as a 3 dB bandwidth reached 63%, insertion loss of -0.5 dB and great sharpness 351dB/GHz in low frequency edge and 255 dB/GHz in high frequency edge.