High-frequency transmission lines crosstalk reduction using spacing rules is treated in this paper. Two of the most popular planar transmission line configurations, namely microstrip and stripline, commonly used in printed circuit boards and radio frequency/microwave integrated circuits, are considered in this work. The trace separation between two adjacent transmission lines of each type is stepwise increased as function of the trace width. The single-ended transmission line structures are numerically investigated by a frequency-based 3-D full-wave electromagnetic analysis tool. A particular case using coated microstrip transmission lines has been fabricated, along with some calibration structures, to allow direct measurement and experimental analysis of crosstalk between the single-ended transmission lines. The test structures are characterized at high-frequency (up to 20 GHz) with scattering parameters using a vector network analyzer. The experimental results are compared with the simulation data, and some conclusions and suggestions on the impact and use of spacing rules for high-frequency crosstalk reduction between single-ended transmission lines are presented. These investigations emphasize the necessity of reevaluating classical design rules for their suitability in high-frequency applications.Index Terms-Far-end crosstalk (FEXT), high-frequency crosstalk, near-end crosstalk (NEXT), -parameter measurement, spacing rules.

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A new cable connector for twisted pair cable usable for high frequency applications is presented in this paper. An elastic conductive matrix as an interface between cable and printed wiring board (PWB) is pressed against the ends of the copper wires of the cable, and a land grid array on the PWB, thereby making the connections. The shielding braid of the cable is lengthened by a tube structure up to the same plane as the end of the copper wires, where the shielding is connected to an earth plane on the PWB. This not only gives a sound basis for good electromagnetic interference (EMI) behavior, but can also serve as an adequate structure for a dc barrier of common-mode currents in the shielding of twisted pair cables. A washer-formed capacitor between the earth of the PWB and the shielding tube structure would probably be the only addition needed.Measurements, performed on two connectors and the connected twisted pair cable, confirmed the hypothesis of how the performance of the new cable would be improved in the high frequency range compared to the SOFIX cable connector.Index Terms-Elastomer interconnect, high frequency, MPI, signal connector, twisted pair cable.

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