Miniaturised zeroth-order antenna on spiral slotted ground plane

Presented is a novel miniaturised zeroth-order resonator antenna on a spiral slotted ground plane. The zeroth resonance property enables the resonant frequency to be independent of the antenna dimension. In addition, the slot on the ground plane makes it feasible to further reduce the overall size. The spiral shape of the slot is properly designed in order not to degrade the radiation efficiency while minimising the antenna size. The proposed idea is explained in terms of circuit parameters and experimentally demonstrated at 2.3 GHz.