Split-Ring Resonator Loading for the Slotted Waveguide Antenna Stiffened Structure

Slotted waveguide antenna stiffened structure (SWASS) utilizes hat-stiffeners on thin skins or blade stiffeners in sandwich structures as microwave waveguides. By machining slots through the outer skin and into the waveguide, large slotted waveguide antenna arrays may be integrated into a load-bearing structure. However, the slot length is typically resonant with half-wavelength spacing, thereby degrading the load-bearing capacity of the structure. This letter demonstrates a simple method to achieve comparable gain from a slot radiator with subresonant length by means of a single split ring. The adverse structural impact of the individual slot and the slot array may therefore be reduced.