Compact high impedance surface based on interdigital capacitors

This paper proposes a compact high impedance surface based on interdigital capacitors. Compared with another surface which follows a similar compacting principle, the new structure increases the interdigital capacitance and obtains a lower resonance frequency. This performance is confirmed using several measurement methods, involving plane-wave incidence, coupling between small monopoles and suspended microstrip lines. An equivalent circuit of the proposed structure is also presented, which models its frequency behaviour for design purposes.