A Horizontally Polarized Omnidirectional Antenna Based On Spoof Surface Plasmons

Spoof surface plasmon is an electromagnetic wave that exists on the surface of subwavelength periodic metal structures.It can be divided into spoof localized surface plasmons and spoof surface plasmon polaritons according to different transmission characteristics.By engraving the periodic grooves or hole rows on the metal surface,the working frequency band can be extended from the far infrared and optical bands to the microwave and terahertz bands,and resonant frequency can be adjusted by changing the physical parameters of the grooves and hole rows.This thesis combines a subwavelength metal spiral structure based on spoof localized surface plasmons with a slow wave transmission line based on spoof surface plasmon polaritons,A horizontally polarized omnidirectional antenna is designed for highly integrated and miniaturized circuit systems.The main work is summarized as follows:1?Through simulation calculations,it is verified that the subwavelength metal spiral structure can support the electromagnetic resonance of spoof localized surface plasmons,the resonance frequency can be adjusted by changing the physical parameters of the spiral groove.2?A slow wave transmission line based on spoof surface plasmon polaritons is designed.The structure consists of a coplanar waveguide matching structure and an spoof surface plasmon polaritons waveguide structure.It is verified that the transmission performance of the transmission line can be adjusted by changing physical parameters such as groove depth and groove width in the structure.By optimizing the physical parameters,the transmission coefficient reaches above 0.9 in the 2.1GHz-5GHz frequency band.Especially in the frequency band of 2.5GHz to 3.1GHz,it has reached above 0.98.In addition,the entire structure does not require the support of a metal ground,This method effectively eliminates the effect of the metal ground on the antenna radiation.3?The magnetic resonance mode of the spoof localized surface plasmons is similar to a magnetic dipole,so the subwavelength metal spiral structure can be used as an antenna for horizontally polarized omnidirectional radiation.The thickness of the sub-wavelength metal spiral structure is only 0.035 mm,which is much smaller than other commonly used horizontally polarized omnidirectional antennas,which is more advantageous in integrated circuits.We use an spoof surface plasmon polaritons transmission line to couple and feed the antenna,and verify the antenna performance through simulation and experiments.