Benefits of Anti-Cocking and Sandblasting for RF Performance

SAGE Millimeter takes pride in the appearance of our products, but our design philosophy is rooted in our understanding of our customers and the technology. One year ago, SAGE decided to implement the anti-cocking variation of the MIL Spec flanges across our WR-22 and above product lines while also adding sandblasted finishing to our products. The design update and resulting hardware transition is an ongoing project within the organization that has an anticipated end-date in late 2020. The rationale was not merely to differentiate our products in the marketplace but rather to provide customers with a superior hardware experience.

Benefits of Anti-Cocking Flanges

SAGE waveguide products generally span from WR-42 to WR-06. For this core offering, the waveguide flanges we use in our designs is the US MIL Spec design, designated MIL-F-3922. The standard flange names for WR-19 and below is the UG-383 while the flange name for WR-15 and above is the UG-385 and UG-387. At high frequencies, the UG-387 flange type has been shown to be superior to its counterpart, the TRG-714 type from a manufacturing and use perspective. Therefore, it is the most commonly-found flange type amongst millimeter-wave component manufacturing companies. However, flat flanges, also referred to as cover flanges, can be tricky to connect properly and at higher frequencies, the risk of misalignment threatens performance.

Cover Flange (left) vs Anti-cocking Flange (right)

Misalignment can occur in five main ways: 1) flat face misalignment, 2) broad wall, 3) narrow wall, 4) rotational, and 5) diagonal offset. Different levels of severity at various frequency bands can affect the amount of electrical degradation. Larger offsets cause more degradation in performance.

The anti-cocking flange is used to combat the first type of misalignment, also known as cocking. Cocking refers to when two mating surfaces are not touching at all points. There is a risk of cocking when two flat flanges are connected and the four captive waveguide screws are not tightened equally. Unevenness or over-torqueing can result in gaps or deformation of mating surfaces. To avoid this phenomenon, the anti-cocking flange features a raised outer ring that prevents overtightening and improved parallelism of the mating surfaces.   

Anti-cocking Diagram

Benefits of Sandblasted Finishing

While anti-cocking is offered by a few other precision waveguide component manufacturers, sandblasted finishing on hardware seems to be unique to our brand for the time being. We invest in an additional surface treatment process in order to reap a series of benefits. Sandblasting removes surface impurities like dirt, oil, rust, and contaminants that can accumulate from the manufacturing process. A cleaner surface prior to the gold plating process results in a more durable finish. Finally, sandblasted hardware also has the added benefit of ruggedized surfaces during use. This allows customers peace-of-mind to handle SAGE parts without excessive precaution and concern for surface scratches and dents.

Non-sandblasted vs Sandblasted Surface

References:

https://www.microwavejournal.com/articles/19092-article-headline

http://legacy.nrao.edu/alma/memos/html-memos/alma278/memo278.pdf

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