A tunable compact bandstop filter using meander spurline and folding open stubs

To achieve compact structure and better frequency characteristics, a tunable bandstop filter is discussed in this paper. Compared to the conventional bandstop filter with open stubs, the proposed filter can obtain a more compact structure by using folding open stubs and can acquire wider rejection bandwidth and deeper maximum rejection by employing the meander spurline slot. Moreover, the frequency characteristics of the proposed filter can be tuned by adjusting the physical size of the meander spurline structure. Measurement results that support the performance of the design concept have also been completed.