I need a single hole tube shape, that I can use up around 500 MHz. I've not found anything beyond 300MHz on Magnetics Inc, Fair-Rite etc. I need a cylinder shape with single central hole, OD <7mm, length non-critical.

I mention the shape because it's important in my application, and I've noticed a given material may only be available in certain shapes.

I remember seeing something like this used in UHF TV applications, probably in matching 300 ohm twinlead, and that would certainly cover the range I need.

  • 2
    \$\begingroup\$ Provide a link to the best you could find and also explain what you are trying to make and in what sort of circuit it goes in. \$\endgroup\$
    – Andy aka
    Nov 20 '19 at 18:12
  • \$\begingroup\$ I can't really, it could be patentable. \$\endgroup\$
    – user121934
    Feb 21 '20 at 17:20

I believe the baluns used in UHF TV applications were actually transmission line transformers. Twisted pair transmission lines, specifically, but you can use coax as well. Bandwidth is high, but available ratios are limited.

For example, using Ferroxcube 4S2 material, it was possible to make a 1MHz to 5GHz 1:4 transformer (Image from Horn, J., & Boeck, G. (n.d.). Ultra broadband ferrite transmission line transformer. IEEE MTT-S International Microwave Symposium Digest, 2003.).

enter image description here


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy