Design Fabrication and Analysis of Tunable Planar Microwave Devices Using EBG Structures

Abstract

Microwave tunable devices became very popular in mobile and radio wireless communication. This is because of ease of analysis and fabrication, and their attractive multiband propagation characteristics. However, they have some drawbacks of low efficiency, narrow bandwidth, and surface wave losses. In order to overcome the limitations of microwave tunable devices such as their size, cost, noise, fabrication techniques, high power loss and poor performance etc, a new solution method; using electromagnetic bandgap (EBG) materials, as substrate has attracted increasing attention. Unlike other methods, this new method utilizes the inherent properties of metallo-dielectric materials to enhance microwave tunable device performance. These periodic structures have the unique property of preventing the propagation of electromagnetic waves for specific frequencies and directions which are defined by the shape, size, symmetry, and the material used in their construction. This deal with the design, simulate and fabricate the new Planar Tunable EBG structure , and study the performance of the Honeycomb EBG lattice structure with Hexagonal basis points at Ka frequency band. Those designs were simulated with CST Microwave studio and RSoft Band Solve Software and tested with the Network Analyzer. newlineBoth, simulated and measured data were compared and validated. To achieve precise and controlled tunability was the one of the main objective of the work. To achieve this controlled tuning, thin film of strontium ferrite nano powders were considered. Characterization of these films has been done by the XRD and coupled ring resonator method developed in this thesis. The electromagnetic tuning is achieved by using the sandwich structure of designed EBG structure and Strontium ferrite thin films.