TM mode analysis of a Sievenpiper high-impedance reactive surface

Builds on the published work of King and Park [see IEEE Trans. Ant. Propag., vol AP-31, p. 471-6, 1983] in which they analyze TM modes on a Fakir´s grounded bed-of-nails structure. Sievenpiper´s reactive surface is essentially a Fakir´s structure with the addition of a capacitive FSS loading the ends of the rods. In this analysis, we show that an infinite number of TM modes can exist on this structure, and that the apparent TM mode cutoff, experimentally observed, is a manifestation of the two lowest order modes coalescing, and then being cut off. Furthermore, we show that this apparent TM mode cutoff can be adjusted independent of the +90/spl deg/ reflection phase frequency by controlling the density and diameter of the rods.