Previously available elastomeric EMI gaskets provided for multiport RF connector assemblies have performance limiting drawbacks. Consequently, EM isolation provided by a previously available elastomeric EMI gasket is often inadequate. Various implementations disclosed herein include multiport RF connection arrangements that use a metal gasket arranged within at least a portion of an isolation space provided by a multiport RF connector. In some implementations, a multiport connection arrangement includes a substrate, a multiport RF connector and a fitted metal gasket. The substrate includes a first surface and a first plurality of connection ports. The multiport connector has a body that includes a second surface, a second plurality of connection ports, and includes an electromagnetic isolation boundary that defines an isolation space between at least two of the second plurality of connection ports terminating at the second surface. Mechanical fasteners are optional and are included to merely provide engagement, without substantial compressive force.