Filter Mounting Options

In a rush to specify the proper filter for a particular task, an Electrical Engineer may not give much thought to “how am I going to mount this thing”?  Luckily for this Electrical Engineer (or more accurately, the Mechanical Engineer tasked with fitting all of the components into an enclosure) there are many mounting options available.  In this post, I’ll detail a few choices for mounting a simple rectangular shaped filter with connectors.  For the purpose of this discussion, I’ll assume that space is at a premium.


Tapped Holes:  By far, the most common way to mount a filter is by way of tapped holes on the bottom.  There would typically be one hole in each corner using an appropriately sized thread adequately spaced from the corners.  Some factors to think about are the overall size of the filter housing and the tap size – you would not want a tap size so large that the area around the hole would be thin and weak or with so little depth offering only 2 or 3 threads for the screw to attach.  Generally speaking, there is a size from 0-80 thru 6-32 that will provide the best combination of holding power and structural integrity.


Thru-Holes:  For applications where access to the filter’s bottom is not available, a thru-hole is the best option.  Typically, these would be in the corners of the filter and offer a “clearance hole” for the customer’s fastener.  As with tapped holes, thought should be given to select the appropriate fastener size.


Flanges or Plates:  A slight twist to thru-holes, flanges or plates offer the user the ability to use a fastener of any size to mount the filter.  The attachment points are more or less independent of the filter and reside outside of the filter housing.  Typically these options are used when there is an existing grid mounting matrix in the systems chassis and the user would like to take advantage of that grid.


While I only explored the 3 most popular options, many more are available.  If you are interested in a more substantial discussion of filter mounting options, feel free to contact me directly by email at


At Reactel, we manufacture RF & Microwave Filters, Multiplexers and Multifunction Assemblies with satisfied customers across the globe.  If you would like to explore a filter for your requirement, please visit or email me directly at, and if you are interested in reading more blog posts about filters and our industry, please visit