There are many RF communications and sensing applications that are moving to higher frequencies as well as a wealth of new use cases and applications emerging in the millimeter-wave (mmW) spectrum. This obviously includes a variety of 5G use cases and applications, but there are also a variety of automotive, unmanned vehicle, aerospace, satellite communication, and defense use cases benefitting from substantial investment in development.
Some of the drive for developing technologies in the mmW frequencies for RF applications is that at higher frequencies atmospheric attenuation is much higher than at lower frequencies, which aids in both reducing interference as well as reducing the opportunity for detection and interception. Moreover, high speed digital applications are reaching tens of gigabits per second throughput, which equates to tens of gigahertz operating frequencies. These new high-speed digital applications require mmW development tools, test equipment, and design techniques to function optimally and route signals between modules.
Another benefit of operating at mmW frequencies is that the relative size of both passive components and active devices are smaller, as most RF electronics are proportionally sized with the frequency range they are designed to operate in. This allows for much more compact electronics and fabrication methods to be used, for example more surface mount and board-level modules can be used at mmW as opposed to coaxial connectorized or waveguide modules.
To overcome some of the disadvantages of operating at mmW, communication and sensing technology designers are moving to advanced/active antenna systems (AAS) that are composed of antenna arrays with tens to even hundreds of elements. These trends means that the more compact electronics enabled by operating at mmW frequencies are also often accompanied by trends toward much more complex and denser RF systems. Hence, the interconnect for the development and testing of these systems also needs to be extremely compact and suitable for mmW operation.
There are many methods of implementing mmW board level interconnect. However, there are few as high performing and reliable as compression connectors. This is due to the tolerance variations intrinsic to soldered interconnect solutions. In many cases, compression connectors can also be reused many times, which is advantageous for development and testing purposes where it may only be desirable to have a connector attached during testing.
High-speed End Launch Connectors are ideal for mmW system board-to-board or board-to-module interconnect when signals can be routed to the edge of the boards using planar transmission lines (PTLs). There are reusable end-launch connectors available in standard coaxial connector types, including 2.92 mm, 2.4 mm, 1.85 mm, and now even 1.0 mm. All that is needed to use these connectors is a properly designed surface planar transmission line with the correct footprint and a screwdriver with the appropriate allen bit. As the landing zone of the end launch connectors are exposed, it is relatively easy to visually align and assess how well the connection has been made.