title: Reconfigurable ring filter with controllable frequency response.
abstract: Reconfigurable ring filter based on single-side-access ring topology is presented. Using capacitive tuning elements, the electrical length of the ring can be manipulated to shift the nominal center frequency to a desired position. A synthesis is developed to determine the values of the capacitive elements. To show the advantage of the synthesis, it is applied to the reconfigurable filter design using RF lumped capacitors. The concept is further explored by introducing varactor-diodes to continuously tune the center frequency of the ring filter. For demonstration, two prototypes of reconfigurable ring filters are realized using microstrip technology, simulated, and measured to validate the proposed concept. The reconfigured filter using lumped elements is successfully reconfigured from 2 GHz to 984.4 MHz and miniaturized by 71% compared to the filter directly designed at the same reconfigured frequency, while, for the filter using varactor-diodes, the frequency is chosen from 1.10 GHz to 1.38 GHz spreading over 280 MHz frequency range. Both designs are found to be compact with acceptable insertion loss and high selectivity.
authors.affiliation: Microwave Technology Centre, Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40150 Shah Alam, Selangor, Malaysia.
authors.forename: Norfishah
authors.identifier: 0000-0003-4061-785X
authors.initials: N
authors.lastname: Ab Wahab
authors.affiliation: Microwave Technology Centre, Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40150 Shah Alam, Selangor, Malaysia.
authors.forename: Mohd Khairul
authors.identifier: 0000-0001-5136-8532
authors.initials: MK
authors.lastname: Mohd Salleh
authors.affiliation: Microwave Technology Centre, Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40150 Shah Alam, Selangor, Malaysia.
authors.forename: Zuhani
authors.initials: Z
authors.lastname: Ismail Khan
authors.affiliation: Microwave Technology Centre, Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40150 Shah Alam, Selangor, Malaysia.
authors.forename: Nur Emileen
authors.initials: NE
authors.lastname: Abd Rashid
mesh_terms: D025802:Electric Capacitance; D004581:Electronics / Q000295:instrumentation*; D004867:Equipment Design; D013685:Telecommunications / Q000295:instrumentation*