The Study Of Microwave And Millimeter-wave Circuits Based On Low Loss COC Material

Cyclic Olefin Copolymer(COC)is a novel high molecular flexible transparent polymer,showing stable relative permittivity and extremely low dielectric loss factor in radio frequency,microwave,millimeter wave and even THz region(0.1 THz-10 THz),which makes it especially suitable for the application requirements of millimeter wave and even terahertz circuits with large electromagnetic wave transmission loss.This thesis is mainly based on the novel COC materials to carry out microwave and millimeter-wave circuit designs and application researches.The main research contents are as follows:1)Research on the basic characteristics of the novel transparent low-loss material COC,including the research and analysis of COC molding technology,electromagnetic properties,optical absorption spectrum and surface metal circuit manufacturing methods.A COC-based printing plate preparation technology was proposed,and the corresponding electromagnetic properties,peel strength,water absorption,thermal stability,surface resistivity,dynamic mechanics,specific heat capacity,thermal expansion coefficient,and thermal conductivity were evaluated.2)Deeply studied the electromagnetic characteristics of the COC materials.Based on the orthogonal resonance ring method,the dielectric constant and isotropic characteristics of the COC substrate are tested and verified.Based on the proposed COC substrate and RT/duroid5880 circuit board,the loss comparison with a fabricated microstrip transmission line proves the low loss characteristics of the COC material.3)Research on the adaptability of circuit technology based on low-loss COC substrate.Develop low-loss balun circuits based on substrate integrated waveguide and half-mode substrate integrated waveguide,and respectively study the adaptability of inkjet printing,laser composite cladding and laser processing on the printing plate on COC substrates,and perform comparative analysis of various processes through actual production and testing.The work submitted a paper in the IEEE Transactions on Components,Packaging and Manufacturing Technology journal and was granted an invention patent.4)Research on low-loss dielectric waveguide windows based on COC materials.A concept of a COC-based compact waveguide window is proposed,which realizes impedance matching through a double-tapered structure to meet its application in the full frequency band.The feasibility of the proposed COC-based compact waveguide window in Ka-band(26.5GHz-40GHz),V-band(50GHz-75GHz),W-band(75GHz-110GHz)and terahertz frequency(325-500GHz)is proved through simulation verification,and the waveguide windows in Ka-band,V-band and W-band are processed and measured.This work has published one paper respectively in IEEE Microwave and Wireless Components Letters,Journal of Microwaves,etc,and one conference paper in the 2020 China Microwave Annual Conference,and one invention patent is granted.5)Flexible transparent antenna technology based on COC.For the new hybrid energy transmission system for broadcasting and television,a transparent antenna used for solar panels is proposed,and two different forms of transparent antennas are conducted.The first flexible transparent microstrip antenna utilizes the flexible and transparent characteristics of the COC substrate and method of the surface metal grid to make it have the characteristics of flexibility and transparency;the second type of four-arm helical antenna uses a small proportion of the helical antenna metal to achieve a transparent effect.