Wide Bandwidth and Enhanced Gain of a Low-Profile Dipole Antenna Achieved by Integrated Suspended Metasurface

A low-profile metasurface-based dipole antenna is proposed, analyzed, and implemented for the wideband operation with improved gain. The metasurface is suspended by separating it from the ground plane with an air gap and positioning it right beneath a horizontally oriented dipole. The wide operating bandwidth is attributed to the simultaneous excitation of the transverse electric surface wave resonance of the suspended metasurface (SMS) and the adjacent metasurface-based dipole resonance. The small propagation constant of transverse magnetic surface wave in the operating band enlarges the SMS aperture along the dipole direction for higher gain compared to a conventional low-profile antenna. The proposed antenna design with an overall thickness of 0.07λ (λ is the wavelength in free space at the center operating frequency) shows the realized boresight gain of 8.5-11.5 dBi over |S
₁₁
| ≤ -10 dB impedance bandwidth of 33.6% (or 4.15-5.85 GHz).