Creating Tuneable Microwave Media from a Two-Dimensional Lattice of Re-entrant Posts

Abstract: The potential capabilities of resonators based on two dimensional arrays of re-entrant posts is demonstrated. Such posts may be regarded as magnetically-coupled lumped element microwave harmonic oscillators, arranged in a 2D lattices structure, which is enclosed in a 3D cavity. By arranging these elements in certain 2D patterns, we demonstrate how to achieve certain requirements with respect to field localisation and device spectra. Special attention is paid to symmetries of the lattices, mechanical tuning, design of areas of high localisation of magnetic energy, which in turn creates unique discrete mode spectra. We demonstrate analogies between systems designed on the proposed platform and well known physical phenomena such as polarisation, frustration and Whispering Gallery Modes. The mechanical tunability of the cavity with multiple posts is analysed and its consequences to optomechanical applications is calculated. One particular application to quantum memory is demonstrated with a cavity design consisting of separate resonators analogous to discrete Fabry-P\'{e}rot resonators. Finally, we propose a generalised approach to a microwave system design based on the concept of Programmable Cavity Arrays.