Concept and method of high efficiency in a precision Ka-band subminiature coaxial connector

This article presents the design approach and test results of a Ka-band narrow flange receptacle (NFR), subminiature version A (SMA) connector based on transmission line theory, involving multi-step impedances and air-layer characteristics to increase its maximum frequency of operation. In order to increase its frequency performance, the connector is designed with a dual outward form (a hook structure), a thick outer conductor wall and a very thin inner pin. The return loss increment due to the hook and multi air-layer structures is minimized to 2 and 1.5 dB, respectively. A VSWR of less than 1.2 is obtained from DC to 30 GHz, and the connector performance is stable from room temperature to 120 degrees C.