Research On Terahertz Waveguide And Microwave Filter Based On 3D Printing Technology

With the rapid development of communication technology,the market demand for waveguides and filters is increasing,and the quality requirements are also increasing.Technology upgrade supports product innovation,and the future of the waveguide and filter industry is promising.At present,coaxial cavity filters are still widely used in China's major base stations.Cavity filters have many advantages such as low loss,high stability,high temperature resistance etc.and thus have become the mainstream equipment in the current base station filter industry.Since the sealing structure between the cavity filter channels is limited by the machining accuracy and structural stress of the parts,the cavity filter also has certain limitations.In addition,the size,cost and performance of the filter are key factors to consider in practical applications.In recent years,with the rapid development of 3D printing technology and the optimization of the performance of printing raw materials,the use of 3D printing technology to make microwave or even terahertz band devices has become a new research idea.Communication devices fabricated by 3D printing technology are comparable in performance to devices fabricated by conventional computer numerically controlled machining techniques.The three-ball topology band-pass filter,one maximum insertion loss is 2.25 dB/cm with a working band of 0.17?0.22 THz and a passband bandwidth of 26.1-27.8 GHz is designed and printed by DLP-3D.The main research work includes design optimization of waveguide and filter design?fabrication of devices based on DLP-3D printing technology?metallization of devices by electroless plating process?analysis and testing by vector network?analysis and discussion of research results.The specific research work is as follows:First of all,we have developed a 3D printing system based on digital light processing technology.The projection format is 131.2 mm×82 mm,and the projection accuracy in the XY direction is 200?m.The DLP-3D printing system has high printing precision and a smooth printing surface.The advantages of almost no polishing except for local support provide technical guarantee for making terahertz waveguides and microwave filters.Secondly,we use HFSS electromagnetic simulation software to design and simulate a 0.17-0.22 THz terahertz waveguide and a passband filter with a passband of 26.1-27.8 GHz according to the waveguide and filter working theory.We use a self-made DLP-3D printer for 3D fabrication and metallization of non-metallic devices by non-metal nickel plating plus copper plating for better electromagnetic wave transmission.Finally,the devices fabricated through the above process are tested for transmission characteristics by a vector network analyzer,and the RF performance of these devices is studied based on a comparative analysis of simulation and test results.In the end,the maximum return loss S11 is 13.8 dB,the insertion loss is 2.3dB,S21 satisfies the out-of-band rejection at DC-26.47 GHz,27.8-30 GHz,and the S-parameter curve of the simulation results is well fitted,which proves DLP-3D printing technology is feasible in the production of communication devices such as waveguides and filters,and also prospects for the application of 3D printing technology in the production of communication devices.