Browsing by Author "Sharma, Satyam Kumar"
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- ItemVariable bandwidth planar coupled resonator filters utilizing tunable non-resonant node inverters(Stellenbosch : Stellenbosch University, 2018-12) Sharma, Satyam Kumar; Meyer, Petrie; Stellenbosch University. Faculty of Engineering. Dept. of Electrical and Electronic Engineering.ENGLISH ABSTRACT: This dissertation presents a novel design technique for designing microstrip staircase and pedestal substrate integrated waveguide (SIW) filters with tunable bandwidth. The design technique utilizes non-resonant nodes as inverters, allowing the inter-resonator coupling to be varied by varactor diodes. For the microstrip implementation, a circuit model of the proposed tunable nonresonant node inverter (NI) to be implemented in parallel coupled line staircase filter is presented. Generalized synthesis design equations are formulated and dimensional design charts are presented to aid designers in designing tunable staircase filters using NI. Reconfigurable second order and third order parallel coupled line staircase filters with constant absolute bandwidth are designed and measured. For the substrate integrated waveguide (SIW) implementation, the proposed tunable non-resonant node inverter is implemented in a T-ridge pedestal SIW resonator based filter topology. A detailed dimensional analysis for integrating NI in T-ridge SIW filters is presented and design charts are formulated. A design procedure is proposed to design NI based T-ridge SIW filters with bandwidth control for a given filter specification. A second order T-ridge SIW filter with tunable bandwidth is designed and simulated. The designed reconfigurable filters using NI offer significant advantages over most of the other reconfigurable filter designs. The proposed synthesis method comprising of design equations and design charts presents an insight into the dimensional information required to design these filters for a given specification. Further, it reduces the reliance on full wave optimization and thus results in reduced computational cost and design time. The designed and measured prototype filters based on NI demonstrate negligible centre frequency deviation as the bandwidth is tuned. The use of spatial biasing mechanism reduces the complexity of the filter designs as additional biasing circuit is not required to bias tuning elements