Research On Contact And Non-contact Interference Modeling And Testing Methods Of Key Devices In Mobile Phone

With the rapid development of mobile communication technology,the mobile phone is no longer a simple communication device for people.It undertakes most of people's fragmented time leisure and entertainment tasks and even part of work tasks.People's demand for mobile phones is getting higher and higher,which also promotes the continuous development of terminal communication technology.In order to realize users' high demand for audiovisual and performance,the space inside the mobile phone is getting narrower and narrower,which puts forward higher requirements on the electromagnetic compatibility inside the mobile phone.This paper analyzes the electromagnetic interference caused or caused by two key components in the mobile,which are speaker and foam.Through theoretical analysis,simulation modeling,and design test schemes,it finally realizes a scheme that can guide the design of the whole machine.The main research content of this article mainly includes the following two points:1.This paper takes the TDD coupling interference suffered by the speaker and receiver as an example analysis,gradually analyzes the characteristics of the interference source from the interference source,the influence on the interfered device,and analyzes the model of the interfered device;and designs a new set of simulation and testing Scheme,the designed simulation scheme can effectively reduce the simulation time up to 46 h,and the simulation result and the test result are very consistent.In some scenarios where the coupling current is large and easy to measure,it can reach 99% of the simulated test contrast fit.The designed test scheme can accurately measure the ?A-level current coupled to each frequency point of the interfered device due to interference.Finally,based on the acoustic theory,the designed simulation test plan is connected with the auditory experiment,and the loudness value is derived from the simulated coupling current,and then it is determined whether there is a risk of TDD interference with sound,forming a complete plan that can guide the design of the terminal product.2.Aiming at the harmonic interference caused by the non-linearity of the contact between foam and metal,the commonly used gap shielding material in mobile terminals,this paper analyzes the physical effects of the contact step by step from the microscopic model of the metal contact and establishes its equivalent circuit model,and designs a test system for the ”metal-foam-metal” contact structure.The designed system can not change the pressure on the foam when measuring the S11 and harmonic.At the same time,in order to obtain the radio frequency current through the contact structure,this paper innovatively designed an ultra-thin current probe based on FPC,which can be extended into the 0.5mm gap of the ”metal-foam-metal” contact structure for measurement,and can measure the current in the terminal.The designed probe has very good imitation test consistency,and the relative error is only 1.304%.