Experimental verification of two kinds of transmission resonance phenomena for a narrow slot in thick conducting screen

A microwave waveguide setup is used for the experimental verification of the presence of two kinds of transmission resonance phenomena; that are observed to occur in the case of the three-dimensional narrow rectangular slot problem in an infinite conducting screen of finite thickness under an incident electromagnetic plane wave. This presence of two kinds of transmission resonance phenomena is different from the case of the two-dimensional infinitely long slit problem in a thick conducting screen in which only the Fabry-Perot(FP) resonator type occurs. The first type of resonance phenomenon occurs near (slightly higher than) the cutoff frequency of the lowest TE10 mode and mainly depends on the transverse length of the slot region inside the thick conductor irrespective of the longitudinal length of the narrow rectangular waveguide (corresponding to the thickness of the slotted thick conductor). The second is the Fabry-Perot(FP) type, which occurs at particular longitudinal lengths of the rectangular slot region inside the thick conductor.