One of the frequently asked questions by our customers is: what considerations will be taken into when RF ONE designs a reliable high power attenuator? We would like to share some of our basic practices here.
For a better thermal management in high power attenuators, firstly we need choose the ceramic substrate with low coefficient of thermal expansion (CTE), such as Aluminum Nitride, or 99% Alumina. Also importantly, choosing resistive and insulating materials with a similarly low CTE can reduce the effect of significant reflections due to impedance change at high temperature.
Secondly, in terms of self-cooled attenuators, the convective heat dissipation largely depends on the heat sink’s size and fin spacing. Normally our 5W till 50W attenuators come in annular (round) fin, which could strike a balance between product size and thermal dissipation.
100W till 500W attenuators are generally built in bulky rectangular body in parallel plate fins.
Some customers also ask for flared fin heat sink for improved natural convection cooling ( below picture is cited from internet source) which we will design it in near future.
If customer has their own conduction plate and prefers a more compact size, RF ONE can also offer a solution. Below photo shows one of our latest designs: a 350W DC-8.5 GHz attenuator with both flat body and heat sinks, with the flat bottom mounted onto customer’s conduction plate.
Thirdly surface finishing of the heat sink also plays an effective role. Heat stink is commonly made of black anodized aluminum. The black coating topology enhances the surface emissivity so that the outer heat sinks can more easily radiate the heat from the internal resistive elements. Furthermore the layer of anodization can help increase the surface emissivity.
RF ONE has more than 18 years of experience in designing and building RF attenuators, we offer a broad selection of low power, medium and high power attenuators up to 500W, with highest frequency going up to 50GHZ(Our 67GHz 1.8mm attenuator is going to be released by end of 2019). For more details, please visit
Frequently Asked Questions (FAQ) for Fixed Attenuators. Feel free to contact us at sales@rfone.cn for any of our standard attenuator or customized part.
