A new compact microstrip slow wave open loop resonator filter with improved spurious-free band

摘要

In this paper, a new microstrip slow wave open loop resonator is proposed. This resonator improves the spurious-free band up to 5.1 times of the fundamental frequency which is more than 2 times of the conventional slow wave open loop resonators. Based on the proposed resonator, two three-pole filters are designed and one of them is fabricated. Simulation and measurement results are reported which are in good agreement. Designed filters provide 75% and 83% of footprint reduction in comparison with the conventional open loop resonator filters.