Triple Band Filter Based on Double Periodic CRLH Resonator

A triple band filter based on double periodic composite right and left handed (DPCRLH) is designed, modeled, simulated, and tested. A DPCRLH resonator can be formed from symmetric DPCRLH unit cell with the ends open circuited. The designed open circuit DPCRLH resonator has five resonant points at 1.574, 2.05, 3.24, 6, and 9 GHz, and it is verified by simulation and experiment. This DPCRLH resonator can be used to from a triple band filter using the last three resonant points at 3.3, 6, and 9 GHz. The triple band filter is of third order and has three independent fractional bandwidths. The simulated and measured S-parameter responses match quite well.