Artificial Structure Surface Plasmon Polaritons Terahertz Power Divider

Terahertz radiation is electromagnetic radiation in the frequency band of 0.1~10THz with wavelength of 0.03 mm ~ 3mm.Officially named terahertz band from the late 19 th century,results and data of the terahertz band research are very scarce.With the breakthrough of new technology and material,efficient terahertz radiation source and detector have come out.Research and application of terahertz technology have rapid development and a good application prospect in the civil and military fields.Surface Plasmon Polaritons(SPPs)are electromagnetic waves propagating along the surface of metal when the electromagnetic waves are incident on the interface between metal and dielectric,resulting in collective oscillation of free electrons on the metal surface.Because of the ohmic effect in metal,SPPs travel along the surface within a limited distance and gradually run out of energy.Only when the size of the structure can be compared with the propagation distance of SPPs,SPPs characteristics and effects will be revealed.SPPs can break through the diffraction limit and have strong local field enhancement,which can realize the transmission and processing of nano-scale optical information.In this paper,we propose a double-layer rectangular slotted plasma waveguide structure.We find that the dispersion curve of the two-layer structure deviates more significantly from the light line than the traditional one-layer plasma waveguide structure does,which means the two-layer structure is more bound to electromagnetic waves.After that,we analyze the transmission characteristics of the transmission line based on the two-layer structure,and conclude that the S21 parameter exceeds-1dB in the broadband frequency band of 0.2-0.4THz,reflecting the excellent transmission characteristics of this transmission line in terahertz frequency band.On this basis,we put forward a two-layer artificial structure power divider,whose reflection coefficient is less than-10 dB in the frequency band of 0.2THz-1THz,and the transmission coefficient is close to-5dB in the frequency range of 0.25THz-0.45 THz,which can achieve good electromagnetic energy distribution.We scale up 100 times the geometric parameters of the designed power divider to make it operate in microwave frequency,and the simulation result shows that S11 is less than-10 dB in the range of 4-8.5 GHz,implying the reflection at the input of the device is very small.The parameters of S21 and S31 are close to the-3dB line and more than-5dB line within the range of 2-10 GHz,which shows the EM energy coupled from port1 can be divided equally to the two output ports.Finally,the proposed wave divider is drawn by engineering drawing software,and the device is processed.The transmission parameters are tested and analyzed by the vector network analyzer.