Study On New Type Terahertz Waveguide Filters

Terahertz radiation is a kind of electromagnetic radiation whose radiation area between the infrared light and millimeter wave. Compared with microwave communication, Terahertz communication has a larger transmission capacity; Terahertz beam is narrow so it can be applied in precise positioning. What’s more, the characteristics of short wavelength of Terahertz makes Terahertz devices smaller and lighter, which make it suitable for the miniaturization and precision requirements of modern communication equipment. Filter is one of the key devices in electronic system which can remove interfering signals mixed in electromagnetic spectrum and improve the performance of the system. In the terahertz band, the small physical size of terahertz filter restricts its development. Therefore, fabrication difficulty of terahertz filter has become an important consideration. In many types of terahertz filter, the waveguide filter is a metal-enclosed structure. Compared with other forms of terahertz filter, terahertz waveguide filter can avoid electromagnetic radiation, so it has large power capacity. Terahertz waveguide filter structure also has repeatability and simple characteristics, make it has the advantage of performance and cost. Therefore, we focus on our researches on the terahertz waveguide filters, and discuss the design method of terahertz filter and its new structure.The state of art and prospects of the development of terahertz filter is firstly described, and then the analysis methods of basic theory and the waveguide filter equivalent circuit is introduced in this text. Secondly, an inductive iris coupling waveguide with 220 GHz frequency center and 5.5% relative bandwidth was given. How converting the low-pass prototype into an actual band-pass filter and replacing iris with lumped element was described. Then, the result though the 3D software simulation and optimization are met bandpass filter design index. In addition, we design a E plane iris coupling waveguide filter with 148 GHz center frequency and 13% bandwidth. Compared with inductance iris structure waveguide filters, E plane coupled waveguide filters have more bandwidth. At the end of the paper, we focuses on the analysis of the parallel plate slotted waveguide and rectangular E plane slotted waveguide as a transmission characteristic of band stop filter. We analyze the influence of different groove shape on the properties of the transmission, and analyze the impact of changes in the number and position of groove on filter performance.