The design of a novel tunable filter

A novel tunable RF bandpass filter with a broad tuning range is presented. This tunable filter is realized by hairpin resonators, BaSrTiO₃ (BST) films and MEMS switches. In the proposed design approach, MEMS switches and BST films are combined to achieve a larger tuning range of the central frequency. It is shown that the central frequency of the proposed filter can have a tuning range from 12.45 GHz to 14.74 GHz. Moreover, comparison with the BST filter without MEMS switches, the proposed filter is able to extend the tuning rate from 8.5% to 16.3%. It indicates that this novel design provides more flexible tuning process.