A Compact Multimode Antenna Design Based on Metasurface for Wideband Applications

This communication presents a novel approach to design a compact wideband metasurface (MS) antenna with multimode resonance for the Internet of Things (IoT) applications. The proposed antenna incorporates an aperiodic MS structure and an aperture-coupled feeding structure, operating within the frequency range of 2.15–3.84 GHz, covering n7, n38, n41, and n78 frequency bands. Initially, an MS resonant antenna is designed based on the left-handed dispersion characteristics of metamaterials, generating TM(-10) and TM(-20) modes, which are then merged. Subsequently, the unit structure is adjusted to transform the antenna into an aperiodic structure, resulting in the generation of the TM(-21) mode. The working frequency is from 2.15 to 3.84 GHz with 56% fractional bandwidth. The three negative resonant modes are cleverly combined to enable broadside patterns with a maximum realized gain of 4.22 dBi. Besides that, its simultaneous wideband operation and miniaturized form factor makes this design unique compared to previously reported literature.