Handheld Communication Products Testing GTEM Cell Design

Now communication products are developing rapidly.The Radio Frequency performance of handheld communication products such as mobile phones and pads are becoming more and more important.GTEM cell is generally used to test communication products Radio Frequency performance.The structure of GTEM Cell is simple and easy to operate,but the size is relatively small and the frequency is usually in the UHF band.However,with the development of wireless communication technology,the working frequency is higher and higher,working frequency band is wider and wider.This topic is to design the space of 600 x310×280mm3,frequency limit of 6 GHz GTEM Cell,this is in order to meet the requirements of high frequency Radio Frequency performance testing for handheld communications products.This paper according to the relationship between the equipment under test and GTEM Cell in the IEC61000-4-20 to determine the overall size of GTEM Cell,then completed the joint design and main part design.The joint part uses different calculation methods according to the cross section shape to determine its structure size.Calculation of characteristic impedance by using characteristic impedance formula of transmission line on circular cross section,Cone structure can effectively reduce reflection.And the characteristic impedance of the rectangular cross section by using dual energy method to calculate,and using axe block structure.Simulation of joint and integral part by CST simulation software,in order to verify the feasibility of the cell size design,and analyze the GTEM Cell field distribution.Finally,testing the GTEM Cell characteristic impedance,standing wave ratio and field distribution The test results show that the frequency ranges from 200 MHz to 300 MHz,standing wave ratio is about 2,this is because the GTEM Cell terminal did not use matching resistance.When the frequency is 0.3 to 6 GHz,the standing wave ratio is less than 1.7.The characteristic impedance of GTEM Cell is about 50?.The terminal part is the core plate directly connected with the bottom board,so the characteristic impedance directly drop to zero.Use the IEC61000-4-20(2010 edition)and(2016 edition)to analyze the result of field distribution.The rectangular region size is 90×80 mm2 and the position is 450 mm away from the terminal,and the distribution is uniform.The design and manufacture process of GTEM Cell shows that dimension design to modeling simulation and then to physical test,and the simulation results and the physical test results are consistent,and verify the rationality of the design.