COMPACT BANDSTOP FILTER WITH MULTIPLE REJECTION ZEROS

This paper presents a compact band stop fllter (BSF) based on the dual metal plane conflguration with multiple rejection zeros (RZs). Quasi-lumped technique with novel patch-via-spiral dual mode resonator is applied to the design of the proposed fllter. Multiple rejection zeros are introduced by open-end stubs for high selectivity. Design equations are obtained by using a lossless transmission line model. The calculated results show that the lower and upper rejection zeros can be easily tuned by the coupling capacitor and the open- end stubs respectively. By using the Microstrip-Coplanar-Waveguide (CPW) structure, the size of the proposed fllter can be reduced to 12:8mm £ 9mm (i.e., 0:24‚g £ 0:17‚g), where ‚g denotes the guided wavelength at center frequency.