Artificial Materials for High Power Applications

The aim of this research project was to design an "_ Near Zero (EMNZ) Electromagnetic Artificial Material (EAM), optimised to operate in high power microwave environments. This was achieved by manipulating the geometry of sub-wavelength resonant periodic inclusions { unit cells { to create an effective material whose electromagnetic properties could be manipulated to enable high power operation with minimal losses for x-band operation. The optimised unit cell design comprised of a 500_m thick copper double-circular Complementary Split Ring Resonator (CSRR) arrangement with an operating frequency of 10.03GHz. Simulations were conducted in HFSS to determine the electromagnetic characteristics for an infinite array of the unit cell design, optimised to operate as an effective medium with an operating frequency of around 10GHz, demonstrating an absorption coefficient of below 0.1. This was then expanded to simulations where the optimised unit cell design was loaded into a 36x18mm waveguide (x-band waveguide would have only resulted in three of the unit cells being present in the waveguide, thus not adhering to the Effective Medium condition required for this design to be considered an Artificial Material). A comparison of the electromagnetic properties was conducted in COMSOL, with the intention of COMSOL conducting the simulations into the thermal properties of the unit cell design. The COMSOL results suggest that this new design can withstand incident pulsed powers of up to 10kW (a significant improvement on the previous incident power limit of 1W) thus expanding the capabilities of EMNZ materials for use in high power microwave environments.