Modal Expansion Analysis, Design, and Optimization of Metasurface-Coated Vertically-Polarized Antennas

In this paper, a dual-wideband metasurface-coated vertically-polarized antenna is proposed with a profile of 0.13λ
L
, where λ
L
is the free-space wavelength at the lowest operating frequency. A highly-efficient semi-analytical modal expansion method was developed for calculating the input impedance and radiation properties of the proposed antenna, which greatly reduces the calculation time and consumed memory comparing to commercial full-wave solvers. The measured S
11
of the optimized antenna is smaller than –10 dB from 1.62 to 2.73 GHz and 4.52 to 6.52 GHz. The measured gain varies from 5 to 7.18 dBi in the lower band and changes from 5.66 to 7.85 dBi in the higher band. The antenna has stable omni-directional patterns in both bands.