MMCX to SMA Cable Selection and Routing Guide
In many RF designs, cable selection happens after the radio and antenna are already chosen. At that stage, the link normally works and early measurements are acceptable. A common case is a module with an MMCX connector that needs to connect to an SMA antenna port on the enclosure. The typical solution is to use an mmcx to sma cable. From that point on, the cable is part of the RF path. It adds loss, adds connector interfaces, and introduces mechanical load that was not present during early testing. In compact products such as GNSS trackers, LTE modules, Wi-Fi devices, drones, and wearables, these factors often affect long-term stability more than initial link margin. This document focuses on practical selection and routing of an mmcx to sma cable in production hardware.
