Study and Design of Tunable Filters Based on Planar Technology

Abstract

The objective of this thesis is the design and synthesis of tunable bandpass filter at microwave frequencies using planar patch resonators. The characteristics of the designed filter, such as center frequency, bandwidth, and/or selectivity, are electronically adjusted by a DC voltage control.A design and synthesis of tunable patch filters is developed and applied to circular filter topologies. The complete simulations combine the results of the 3D electromagnetic (EM) simulation of the filter layout with the results of the electrical stimulation of the tuning devices was presented. This allows the correct model of the tuning effect and the definition of the tuning possibilities and limits. The minimum dimensions are greater than 0.5 mm, ensuring a low cost fabrication process. The filter is a tunable triple-mode patch filter using a circular resonator with four slots, across which the varactor diodes are connected