Coaxial‐microstrip transition sections are extensively used in radio frequency (RF) circuits, providing electrical interconnection and signal transmission. However, an antipad used for impedance compensation in the coaxial‐microstrip transition section leads to signal return path discontinuity and radiation emission. Accordingly, in this current work, the impact of impedance compensation structure on the near‐field radiation in the coaxial‐microstrip transition section was investigated by theoretical analysis and experimental testing. A 3D electromagnetic field model of a circuit board with an anti‐pad was developed to calculate the S‐parameters and radiation electric field. Based on the characteristics of the electric near‐field probe, a transfer function model was also developed to convert the radiation electric field obtained by the electromagnetic field model into the output voltage for better comparison with the test results. In addition, the effect of the rise time of the input signal on near‐electric field radiation was also studied in this work. The experimental results are in good agreement with the simulation results obtained from the transfer function model. The results of this study provide a better understanding of the electromagnetic radiation characteristics caused by the impedance compensation structure and theoretical support for compensation optimization strategy in engineering.

Fuzz button connectors are extensively used in vertical interconnection for high‐density integrated circuits. This work studied the impact of fuzz buttons under different compression states on high‐frequency signal transmission using theoretical analysis and experimental testing. The resistance values for fuzz buttons with different heights in compression states were measured. The physical dimensions were obtained for sample fuzz buttons subjected to various compression states. The effects of long‐term compression of fuzz button on the resistance values and S parameters of the device under test (DUT) were analyzed. In addition, the high‐frequency parameters were measured for the DUT with fuzz buttons in various compression states. Both a three‐dimensional (3D) electromagnetic field model and an equivalent circuit model for the fuzz buttons under compression states were developed and the results of these two models show good agreement with experimental results. In the circuit model, a fuzz button connector with a three‐wire transmission line structure was modeled as a π impedance network, composed of equivalent inductances and capacitances. It was found that the proposed 3D electromagnetic field model and an equivalent circuit model can accurately predict the effect of fuzz buttons under different compression states on the signal transmission in the affected frequency band. However, the models cannot evaluate the communication performance of the whole system.