A New Isolation Structure of Pogo Pins for Crosstalk Reduction in a Test Socket

A new isolation structure is integrated in the test socket to reduce the crosstalk between pogo pins with various pin patterns and different signal to ground (S/G) ratios. It comprises inserted vias to shield the signal coupling and two metal planes to connect the inserted vias with the ground pogo pins. The crosstalk between pogo pins with and without the isolation structure is simulated and investigated by 3-D full wave analysis. A systematic design methodology is established to determine various structural parameters. It is found that the optimal pin radius to pitch ratio is about 0.2, thereby achieving crosstalk and reflection both smaller than -20 dB for all considered patterns from dc to 10 GHz. Experimental results are in good agreement with the simulation and both validate the proposed design.