Why Hermetic Enclosures/Sealing?
A hermetically sealed enclosure, or hermetic packaging, is a method of encapsulating a device or system in an environmentally protected package that prevents the exchange of the inside and outside environment. Hermetic packages are commonly seen in automotive, industrial, naval, military, and aerospace applications where the outside environment may lead to damage, early failure, or derating of internal system components. Many High Reliability (Hi-Rel) applications require hermetic sealing of critical RF/microwave components, devices, and assemblies.
Common environmental contaminants include dust particles, water vapor, salt fog, corrosive chemicals, and other harmful gases and liquids. RF coaxial connectors, waveguide, semiconductors, monolithic microwave integrated circuits (MMIC), microelectromechanical machines (MEMS) devices, and sensors are often hermetically sealed to maintain high performance and reliable operation. In many cases hermetic packaging is chosen as a reliable method of preventing environmental contamination, even though it adds substantial size, weight, and cost to components, devices, and assemblies. It is required by many military, naval, and aerospace standards to use hermetic packaging for certain applications. These standards also include rigorous methods for determining the hermeticity of a seal or enclosure, typically using a helium leak rate as specified in MIL-STD-883C.
There are non-hermetic packaging methods of environmental protection being evaluated to overcome some of the challenges of hermetic packing RF, microwave, and millimeter-wave elements. In the case of extremely harsh environmental factors, hermetic enclosures are often the only method rigorous enough to protect critical electronics. In some cases, it is also important for the enclosure to prevent gases and particles from within a hermetic enclosure from escaping. This is especially true for space systems, such as satellites, where stray gases and particles from can inadvertently lead to system degradation as gases and particles react, deposit, settle, cloud, or otherwise interact with other sensitive systems or interconnect.
Hermetically sealed RF/microwave components and devices can readily be found, or components and devices compatible with hermetic enclosure, such as coaxial connectors and waveguides. In some applications, it may be worthwhile to hermetically enclose each component or device in it’s own package and use an interconnect that is able to maintain the hermeticity of the packages. In other cases, generally to reduce size, weight, cost, and other signal quality degradation factors, several components and devices are placed in a sub-assembly, or assembly, and hermetically enclosed within.
Learn more about Pasternack’s extensive line of hermetically sealed components and devices: https://www.pasternack.com/nsearch.aspx?keywords=hermetic&view_type=grid
Courtesy of Pasternack