Compact hollow-core photonic band gap resonator with optimised metallic cavity at microwave frequencies

A report is presented on the improvement by an optimised hexagonal metallic cavity of the electromagnetic field confinement in a hollow-core resonator based on out-of-plane two-dimensional photonic band-gap crystal cladding. A resonator was constructed with silica rods to prove the concept at frequencies around 30 GHz. It is shown that the technique can reduce the resonator size by 8.1 times without loss in quality.