High frequency performance, measurement and modelling of simple mechanical ground contacts used in mobile phones

In this paper a test method is proposed to assess the performance, characterise, measure and then model the high frequency impedance of simple mechanical ground contacts that are used within mobile phones. A simple test fixture is defined that allows the ground contact attenuation performance between 2 ports to be measured over a wide frequency range. A simulation model for the test fixture and ground contact is modelled using a 3D EM simulation solver. The 3D model for the ground contact contains variable parameters that can be adjusted for each type of ground contact used within the test fixture. A comparison and good correlation between the 3D EM solver results and the actual test fixture results is completed. The test fixture allows varying mechanical ground contacts [design, material etc] to be evaluated and the simulation allows a 3D model of the mechanical ground contact to be modelled which can then be utilised in full phone 3D EM simulations.