Comparing of Electromagnetic Shielding Structures for SCPW Transmission Line at 5G FR2 Band

With the development of 5G millimeter wave and related technologies, working frequency of transmission lines becomes higher and higher, and the high-frequency electromagnetic radiation is a key factor affecting the working of integrated circuits. Therefore, the method to suppress electromagnetic radiation of high-frequency transmission line has become a research hotspot. Two shielding methods are proposed for a flexible segmented coplanar waveguide (SCPW) transmission line at 5G FR2 band (24.25-52.6 GHz) in this paper, adding copper film or adding copper film and metal vias. Through simulation and optimization of CST, results show that adding copper film can effectively suppress electromagnetic radiation of the SCPW transmission line in available frequency band, the shielding effectiveness of one-unit transmission line can reach 10-25 dB, while that of three-unit transmission line is 35-45 dB. On this basis, punching copper vias can further enhance the electromagnetic radiation suppression capability, the shielding effectiveness of one-unit transmission line can reach 50-60 dB, while that of three-unit transmission line is 50-65 dB. However, copper film will weaken the transmission performance, and metal vias will further affect that of SCPW transmission line. In addition, considering that metal vias will make the processing of transmission lines more difficult, if the shielding effectiveness of transmission lines shielded by copper film meets the requirements, it is not recommended to punch metal vias.