Board-to-Board RF Connector Solution: SMP spring bullet


What is it for?

With the rapid development of science and technology, equipment has increasingly higher requirements for device integration and performance indicators.


Due to machining and final integration tolerances in board to boards interconnection, the distance between the electrical reference planes vary in different locations. Excessive axial offset may lead to poor electrical performance or even break down while limited axial distance may cause damage in stackup. This calls for an adapter that can float axially to ensure that the electrical reference plane fits closely.


It maintains consistent RF connection under offset up to 0.25mm radially and  4° misalignment axially. A typical application is for board to board connector in phased array radar. One end board is with fixed SMP shroud, the other is board active. The spring adapter eliminate the gap between the shrouds at both ends.  



The first part is the SMP female end, and its interface size meets the requirements of the MIL-348 standard; the second part is the main part of the adapter - the axial length floating part; the third part is the SMP female end, and the interface size also. The floating part is realized by a spring. As the spring stretches or compresses, the outer guide

Body 1 and outer conductor 3, inner conductor 1 and inner conductor 2 can slide relative to each other, making the axial length of the connector longer or shorter.



All elastic parts in the product are made of beryllium bronze that features good elastic properties and fatigue resistance. After the parts are closed or recovered, they are aged to enhance their elasticity, and hardness and strength improved as well. The insulating material is PTFE with excellent high-frequency performance and manufacturability. While rigid shell options can be passivated stainless steel or gold-plated copper alloy to meet varied environment application. The former excels in strength and resistance to harsh environments. While the latter provides Lower contact resistance and meets general salt spray resistance.


SMP bullet is suitable for floating blind mating for large scale arrays application in particular.

It level down dimensional tolerance for board spacing, which greatly reduces module processing costs and. It is doomed to be prospective in compact and modular integration. 

Longtrox is proud to offer ready-to- use spring bullet and develop solution of customized length. 

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