Topology Optimization and Cooling System Design For Functionally Graded Patch Antenna Substrates
ME, Master’s Thesis, 2016
Thesis Supervisor: Assoc. Prof. Gullu Kiziltas Sendur
Keywords: Topology optimization, patch antennas, genetic algorithm, functionally graded materials, freeze casting, low temperature cooling system
In parallel to current important developments in electronics and communication technologies, needs on wireless systems have become more popular yet stringent. In order to meet that demand, development of novel technologies and materials has become crucial. Patch antennas are widely used in the radio frequency (RF) industry. This is due to their simple shape, easy and low cost manufacturing capability and their suitability for conformal applications. However, most of current patch antenna designs rely on efforts puts towards their geometrical parameters with limited available dielectric materials in the market.
This thesis mainly focuses on the topology optimization of polymer- ceramic composite substrates. These substrates allow for spatial dielectric permittivity variation via their functionally graded multilayer configuration with the objective to achieve minimization of reflected power at desired frequency values. Towards this goal in the proposed optimization study, Comsol Multiphysics 5.2 software was integrated with Matlab 2014b software and genetic algorithm was used as the optimization solver.
In addition to the design study, in the second part of the thesis, a cooling system which allows for the adjustment of temperature values between 0℃ and -100℃ was designed to control the substrate properties of functionally graded materials (FGM) of ceramic-polymer antenna substrates, similar to those designed in the first part of the thesis. These substrates were produced via a novel manufacturing method based on freeze casting process. A new test platform was developed in order to investigate the effect of cooling rate and temperature on microporosity and permittivity of these substrate materials.