Vivaldi Antenna And PT Symmetric Applications Based On SSPP

Compared to the optical frequencies,at lower frequencies such as microwave or terahertz,spoof surface plasmon polariton is electromagnetic wave that exists on the surface of subwavelength periodic structures.Spoof surface plasmon polariton has attracted the attention of many researchers due to its special properties of short wavelength and high confinement.With the further researches,the applications based on spoof surface plasmon polariton have been emerging.In this paper,we focus on Vivaldi antenna,unidirectional transparent waveguides and ultrasensitive sensors which are all based on spoof surface plasmon polariton,the main contents are summarized as follows:1?We analyze the dispersion relationship of the even and odd modes of spoof surface plasmon polariton,and fast wave mode,Sommerfeld–Zenneck wave mode,and slow wave mode are discussed in detail.Then spoof surface plasmon polariton structure is introduced into the opening of the conventional Vivaldi antenna,which not only keep the ultra-wideband characteristic of the conventional Vivaldi antenna,but also improve the gain and directionality.2?We analyze the method of retrieving the propagation constant and design a spoof surface plasmon polariton structure with equivalent complex refractive index.The real and imaginary parts of the complex refractive index are controlled by adjusting geometric parameters of spoof surface plasmon polariton structure and the loaded electronic components.Based on this method,paritytime symmetric waveguides are achieved,which can realize the unidirectional transparent at a certain frequency point.3?We design a parity-time symmetric coupled system based on spoof surface plasmon polariton resonant structure.In the first method,we only introduce loss into the system.By controlling the electronic components in the system and adjusting spatial position between the two resonant units,the system can reach the exceptional point to improve the sensitivity of detecting perturbations.In the second method,we introduce gain and loss into the system.After reaching the exceptional point,it can further improve the sensitivity of detecting perturbations.