A Multiport Coaxial Interconnection for MTCA.4 Based High-Frequency Instrumentation Applications

This article describes a radio frequency (RF) interconnection for the micro telecommunication computing architecture (MTCA) open standard published by the PCI Industrial Computer Manufacturers Group. The interconnection is capable of transmitting signals with frequencies ranging from dc to 3 GHz from the rear transmission module (RTM) to the advanced mezzanine card (AMC, IEEE1386.1). The existing connection is based on differential connectors and suffers from strong crosstalk between the pairs. The main motivation behind our research is to develop a new connection with high isolation between the ports that can transmit RF signals up to 3 GHz. A new MTCA.4 interconnection class RF1.0 based on two improved single-ended multiport coaxial connectors with up to 12 contacts is introduced. This could open a new field of MTCA-based modular high-frequency instrumentation, e.g., for beam diagnostics in particle accelerators, RF preconditioning in radar systems, or in 5G telecom wireless networks. A sophisticated through-hole technology (THT) and surface-mounted device (SMD) footprint pattern with very-low crosstalk, down to −90 dB between the connector pins, is presented. The new broadband connection between the AMC and the RTM allows the use of modern direct-sampling digitizers [analog-to-digital converter (ADC)] and fast digital-to-analog converters (DACs) on MTCA.4 AMCs, while maintaining the high spectral purity of the converters. This allows omitting large mixer circuits on the RTM, which were needed to reduce the signal frequency due to insufficient isolation of the current differential Zone 3 connector. The RF1.0 interconnection class presented in this article could enable a highly modular instrumentation platform for processing of RF signals.