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.