Research On Antenna Technology For ESD Protection Effectiveness

Electrostatic discharge(ESD)is a common electromagnetic interference source that causes serious damage to mobile terminals.The damage or failure of electronic products caused by electrostatic discharge has brought great loss to the industry,so the research of electrostatic protection has been explored and paid attention to in the industry.The inner antenna of the mobile terminal is vulnerable to ESD attack.Usually,parallel ESD protection devices are used behind the antenna and in front of the sensitive components to prevent ESD damage,such as parallel ESD protection devices,parallel inductance,series impedance.However,additional components can cause problems such as impedance mismatch,affecting signal transmission and increasing cost.Therefore,a novel protective measure is proposed in this paper: to improve the system’s ability to resist ESD interference by designing the grounding structure of the mobile terminal’s inner antenna.The main principle is that the grounding structure of the antenna can provide a fast path for ESD discharge current and clamp the discharge voltage at a low level.The measure is more efficient,convenient and low-cost.In this paper,relevant verification experiments are designed for the proposed new measures.The test environment is built according to ESD test standards,and the detailed design verification scheme,the test control group and the test circuit board are given.Through the analysis of the measured data,it can be concluded that the printed inverted-F antenna with grounding structure has good ESD protection effectiveness.Based on the structure analysis of printed inverted-F antenna,an antenna design method to improve the ESD protection effectiveness of the system is proposed from two aspects.First,reducing the equivalent inductance of the ground loop of the inverted-F antenna can improve its ESD protection effectiveness.In addition,this paper also studies the influence of improving the ESD protection effectiveness on the radiation performance of the antenna,and puts forward the key points to balance the relationship between the two.The other is to design more grounding structures around the antenna feed branch.Therefore,three new antennas with high ESD protection effectiveness are designed: the Head Feed IFA antenna,the Ground Guarded antenna and the 3D Ground Guarded antenna.This paper makes a detailed theoretical analysis of them.Finally,this paper also uses ANSYS electromagnetic simulation software to simulate ESD protection effectiveness of these new antennas.In order to obtain more real and reliable data,the actual measurement was carried out.Through simulation and measured data analysis,the 3D Ground Guarded antenna has the best ESD protection effectiveness.