Simulation of PCB Enclosure with Aperture for Shielding 5G High Frequency

Abstract

5G frequency is a new area of research, with minimal rollout in many countries. It can be sectioned into low band frequency, sub-6 GHz, and millimeter wave (mm Wave). Millimeter wave deals with frequency ranging from 24 GHz to 100 GHz. Such signals do not travel very far despite having a high transmission rate. Due to this most objects placed far away do not face electromagnetic interference (EMI) from 5G frequencies. However, the object most likely to be in danger of EMI from 5G frequencies are integrated circuit chips (ICs) on printed circuit boards (PCBs) that are found in 5G cell phones. As they are packed close to the 5G frequency source, the implementation of PCB shielding becomes imperative. In an ideal world, a perfect shield will have no aperture or defects, and shall have a very high shielding effectiveness of 100 dB. Yet, apertures are needed for thermal ventilation, inserting input or output ports, inserting microstrips as well as for visibility. Therefore, having a PCB shield with apertures and good shielding effectiveness is needed for the functionality of wireless communication technology. Recent studies have shown advances in frequency selective surface (FSS) materials, where certain frequency bands are filtered off, allowing certain bands to pass through. This paper analyzes different aperture shapes and sizes of frequency selective surfaces (FSS) to mitigate the EMI from the 5G 28 GHz high frequency range. It was found that a 1mm x 1mm size aperture in Christian cross shape provided shielding effectiveness of 33.7 dB at 28 GHz frequency range.