Synthesis and Design of Microwave Wideband Filters and Components

Abstract

In the development of modern communication systems, various stringent requirements are imposed on the hardware components to support emerging applications. There is broad interest in developing wideband microwave passive components that enable the successful building and integration of wideband communication systems.

The main objective of this dissertation is the development of exact synthesis techniques for wideband microwave filters, based on proposed equivalent circuit models. In the conventional narrowband approach, the multiple resonators are arbitrarily coupled by frequency independent couplings, which do not accurately represent very wideband frequency responses. By replacing the frequency independent couplings by the frequency dependent coupling model in the equivalent circuit, the synthesis techniques are re-developed by: (i) coupling matrix approach and (ii) cascade synthesis approach.

Coupling structures in LTCC (Low Temperature Co-fired Ceramic) technology that can provide very wide coupling bandwidth and are suitable for the developed synthesis technique are analyzed. Various wideband microwave filters realized in LTCC technology which utilize the proposed synthesis approaches are demonstrated by design examples. High performance microwave transitions that can be used for integration of the LTCC broadband filters in wideband communication systems are also investigated.