Pseudo-elliptic side-coupled ring filter miniaturization / Noor Zareena Zakaria

This thesis presents miniature microwave dual-mode pseudo-elliptic filters due to new stringent specification in microwave application. All presented filters are in ring filter topology, known as quarter wavelength side-coupled ring resonator filter and being implemented on FR-4 substrate. There are two miniaturization methods involved which are called miniaturization without topology alteration method and miniaturization alteration topology method. Filters which are designed using the first miniaturization method will maintain the original topology with the size reduce based on the meander line concept. While the original topology of-the second method filter on the other hand, is added by four shunt capacitors at the edge of the ring. The additional capacitors; either in distributed or lumped capacitor are able to shift the filter's resonance frequency to lower value, leading to filter's size reduction. Nevertheless, the presence of these extra shunt capacitances causes in-band matching problem in its passband response which can be improved by modifying the line impedance of the ring. All the filter layouts are presented along with the comparison between the simulation and measured results.