A compact integrated frequency configurable filter on PCB

A novel design of compact FCEBG (Frequency Configurable Electromagnetic Bandgap) filter is proposed. The filter was manufactured by a conventional 2-layer PCB process in both FR4 substrate and RO4350 substrate with surface mounted lumped capacitors. A specific working frequency of the filter can be selected on demand by changing the lumped capacitors, while the filter's insertion loss and compact design are not compromised. The performance of the filter is dominated by the surface mounted lumped capacitors. As the surface mounted lumped capacitors' values reduce from 5.1pf to 0.2pf, a filter with size of 2.50×3.00×1.00mm³ in PCB operates from 2.60 to 12.0GHz. Specifically, insertion losses of 3.34dB, 1.19dB and 1.48dB were got by the filter at 2.60GHz, 7.71GHz and 12.0GHz respectively, when the surface mounted capacitors' Q factors are 89, 173.5 and 172.9.