Flexible cables for massive-parallel high-speed data communications

Abstract: The demand for high-speed data communications has pushed both the wired and wireless technologies to operate at higher and higher frequencies. Classic Kirchhoffs voltage and current laws cannot be directly applied, when entering the microwave spectrum for frequency > 1 GHz. Instead, the transmission line theory should be used. Most of today's wired communication products use bit-serial cables to connect devices. To transfer massive data at high speed, parallel data transfer techniques can be utilized and the speed can be increased by the number of parallel lines or cables, if the transfer rate per line or cable can be maintained. However, the interference between the lines or cables must to be well-shielded so the crosstalk between them can be minimized.Differential lines can also be used to increase the data speed further compared to the single-ended lines, along with saving the power consumption and reducing the electromagnetic interference. However, characterization for the differential lines is not as straight forward as that for the single-ended cases using standard S-parameters. Instead, mixed-mode S-parameters are needed to explain the differential-, common- and mixed-mode characteristics of the differential signal. The mixed-mode S-parameters were first introduced in 1995 and are now widely used. However, improvements of the theory can still be found to increase the accuracy of simulations and measurements.This thesis presents a study of massive-parallel conductors on flexible cables. Furthermore, some connectors in combination with the flexible cable are studies for high-speed data transfer. The conversion method for mixed-mode Sparameters has been reviewed and a new method to improve the conversion accuracy has been proposed.