Design of a Compact Genetic Microstrip Antenna with improved performance

In this paper the design issues of compact genetic microstrip antennas for mobile applications has been investigated. The antennas designed using Genetic Algorithms (GA) have an arbitrary shape and occupies less area (compact) compared to the traditionally designed antenna for the same frequency but with poor performance. An attempt has been made to improve the performance of the genetic microstrip antenna by optimizing the ground plane (GP) to have a fish bone like structure. The genetic antenna with the GP optimized is even better compared to the traditional and the genetic antenna.

APSYM 2014

14th Biennial International Symposium on Antennas and propagation Department of Electronics, Cochin University of Science & Technology, Cochin 682022, INDIA

Comparison of Microwave and Electrical Properties Selected Conducting Polymers

Microwave properties of conductive polymers is crucial because of their wide areas of applications such as coating in reflector antennas, coating in electronic equipments, firequenry selective .surfaces, EMI materials, satellite communication links, microchip antennas, and medical applications. This work involves a comparative study of dielectric properties of selected conducting polymers such as polyaniline. poly(3,4-eth),lenedio.syt2iophene), polvthiophene, polvpvrrole. and pohparaphenylene diazomethine (PPDA) in microwave and DC,fields. The inicrowave properties such as dielectric constant, dielectric loss. absorption coefficient, heating coefficient, skin depth, and conductivity in the microwave frequency (S hand), and DC fields were compared. PEDOT and polccuiiline were found to exhibit excellent properties in DC field and microwave frequencies, which make thein potential materials in many of the alorenientioned applications

Enhancement of Microwave Properties of Planar Filters and Antennas using Photonic Bandgap (PBG) Structures

In this thesis, we explore the design, computation, and experimental analysis of photonic crystals, with a special emphasis on structures and devices that make a connection with practically realizable systems. First, we analyze the propenies of photonic-crystal: periodic dielectric structures that have a band gap for propagation. The band gap of periodically loaded air column on a dielectric substrate is computed using Eigen solvers in a plane wave basis. Then this idea is extended to planar filters and antennas at microwave regime. The main objectives covered in this thesis are:• Computation of Band Gap origin in Photonic crystal with the abet of Maxwell's equation and Bloch-Floquet's theorem • Extension of Band Gap to Planar structures at microwave regime • Predict the dielectric constant - synthesized dieletric cmstant of the substrates when loaded with Photonic Band Gap (PBG) structures in a microstrip transmission line • Identify the resonant characteristic of the PBG cell and extract the equivalent circuit based on PBG cell and substrate parameters for microstrip transmission line • Miniaturize PBG as Defected Ground Structures (DGS) and use the property to be implemented in planar filters with microstrip transmission line • Extended the band stop effect of PBG / DGS to coplanar waveguide and asymmetric coplanar waveguide. • Formulate design equations for the PBG / DGS filters • Use these PBG / DGS ground plane as ground plane of microstrip antennas • Analysis of filters and antennas using FDID method