3-D-Printed CRLH Metamaterial-Enabled Electrically Small Antenna

This letter presents a 3-D-printed composite right/left-handed (CRLH) metamaterial-enabled electrically small antenna (ESA) in the 300 MHz band. A 3-D conical helix strip is loaded by surrounding an electrical small monopole antenna, with a length of 0.02λ₀ (free space wavelength), which is vertically placed over a finite ground plane. The proposed ESA is based on the 3-D realization of an open-ended CRLH resonator, of which the electrical size is ka = 0.11. An equivalent circuit model is provided with corresponding circuit parameters to derive the frequency response of the proposed 3-D-CRLH ESA. A prototype is fabricated using a widely available 3-D print technology, fused filament fabrication, combined with copper electro- and electroless plating. Experimental verification of the antenna demonstrates a monopole-like radiation pattern with a peak measured gain of −5 dBi, which is suitable to be integrated into compact wireless systems.