antenna-theory.com

[gthill]

I'm a Wi-Fi guy, not an antenna designer. I am a Wi-Fi consultant and I use metal business cards to promote my business. I'm in the process of a card redesign and I thought it would be super cool if the card was an actual antenna. I don't actually expect it to be used other than for fun, but I want it to be designed correctly.

In order to do that, it has to be small like a business card (3.5" x 2" max) and must have a resistance of 50 Ohms.

I've searched the site and it appears that it is possible, but the shape of the antenna and where and how the connector (something small like MMCX) would actually work.

Any help you can provide would be much appreciated!

GT Hill

[admin]

Thank you for the cool post.

Making an antenna work at 5 GHz in the dimensions you provided would be no problem. You could make a simple fat planar dipole and that would work and fit the profile of your business card. For 50 Ohms, you'll need to trim the length until it's resonant (no imaginary resistance component). You probably won't get exactly 50 Ohms but it will be a great antenna. It will only be 50 Ohms at a single frequency though by the way. And if you want to have acceptable performance over the entire 5 GHz band (5-5.8 GHz I believe?) it would be a little trickier.

You could make the above antenna with any sturdy piece of plastic (business card sized) and copper tape.

I am not real familiar with the connector you specified. Another way I would recommend having your antenna port be a female SMA connector, because this can be plugged directly into most Network Analyzers, which is what antenna designers use to check performance. Here's a link to a page showing a female SMA connector:
http://www.surplussales.com/connectors/SMA-2.html

Basically, this is a 5 minute task if you have the right equipment and a bunch of experience making antennas. If not it can seem harder than it is. I like the idea though.