Communication at mmWave frequencies is undergoing a kind of renaissance as commercial (e.g. 5G) and military communication systems make use of the combined advantages of operating above 20GHz with small form factor beamforming arrays. One of the main questions left to resolve is around practical ways to implement RF filters that are compact enough to fit inside these systems (components should ideally less than λ/2) while still offering the necessary performance.
Below 6GHz, developers are very familiar with the available filtering technologies that work, such as surface acoustic wave (SAW) and bulk acoustic wave (BAW) filters. These acoustic filters come in small sizes and high volume, and offer a good performance-to-cost tradeoff that makes them a dominant off-chip approach to filtering.
Options for small form factor high performance filters at mmWave are less well known, and the market is still undecided on what filters will be required, where they need to located in the base station, and what performance metrics they need to meet.
In this session, we will provide insights into the key specifications for mmWave filtering and practical options available for teams working on modern mmWave systems. As an illustrative example of the real-world engineering concerns that need to be addressed we take a close look at material and manufacturing tolerance impact on devices in this frequency range.