Forward magneto-inductive wave propagation in planar magnetically coupled capacitor grids

Abstract

One-, two- and three-dimensional arrays of magnetically coupled resonant loop circuits have been shown to support propagating waves and are known as Magneto-Inductive waveguides (MIW). Planar configurations of such circuits exhibit negative mutual inductance and support backward waves. Here, we consider a similar planar structure in which the individual resonators have coalesced forming a planar 1D ladder circuit which we call a CapGrid. These structures’ cells now couple by both magnetic and electric interactions and exhibit positive coupling and forward wave propagation. The bandwidth and group velocity available for signals is then greater than that possible for planar MIW with similar dimensions whilst offering similar characteristic impedances. A simple demonstration device has been fabricated and tested and found to match very well to a simple model based only on first-order interactions and circuit theory.