Experimental implementation of a large scale multipost re-entrant array

We demonstrate possibilities of a large scale multi-post re-entrant cavity with two case studies implemented with the same physical structure. The first demonstration implements two discrete Fabry-Perot cavities crossing at the centre. The configuration allows the control not only of the resonance frequencies, but also a whole band gap and transmission band of frequencies between the directly excited diagonal and a higher frequency band. The second experiment demonstrates appearance of discrete whispering gallery modes on a circle of re-entrant post. With the introduction of an artificial "scatterer", we demonstrate control over the doublet mode splitting. (C) 2019 The Japan Society of Applied Physics