Equivalent surface impedance of an infinite array of slot impedance loads designed on the basis of coupled rectangular domains

A 2D design of an infinite array of slot impedance loads (SILs) is considered. Each SIL is designed from two coupled rectangular domains connected through apertures with both each other and free space. The integral equation method is used for determination of the equivalent surface impedance (ESI). Dependences of the ESI value are investigated for different geometric dimensions to wavelength ratios. It is shown that the SILs under study can be used to obtain a reactive component of ESI having either positive or negative sign for the thickness of the impedance structure not exceeding one-quarter the wavelength.