Antenna, impedance matching

[PaoloDellaVedova]

Hello,

I have to match the impedance of an homemade loop antenna to 50 ohm.
The antenna has to work in the range 2-4 GHz.
Can you explain me what i need to do that? and how?
Thank you very much.

as you can guess I´m not an expert, so, be patient ;-)

 

[paujuan]

Hi Paolo,
You'll better give us more information about your antenna. To begin with, to match the impedance to 50 ohm you will need a matching network. If your antenna is a narrow-band antenna, this network can be made with a RC circuit, commonly built using parallel stubs. If otherwise your antenna is a wide-band antenna, covering from 2 to 4 GHz, then a wideband matching network is needed (a bit more complex and less efficient). Tapered lines are the most common options.
I hope it will help you, and if you need more help, simply ask!

 

[spid3rx]

hello Paolo,
let us know how are you planning to match the loop antenna. There is a certain size of the loop
antenna. Last time I tried making a loop antenna with a copper tape, but I wasn't able to use it
because the antenna was matching at 2.4GHz with a relative big area size and had problem fitting
into the housing.

 

[PaoloDellaVedova]

Hello,

Thank you very much for the reply.
So, the antenna is supposed to be a circular loop antenna. The idea was to solder the antenna directly to the connector:
**broken link removed**
,that is attached to my system (rf generator, amplifier and circulator).
I would like to have more narrow bands antenna at the beginning, because I heard that is rather simpler to build the matching circuits.
Can you explain me ho to build it?
Thanks again

 

[paujuan]

Hello,
If you want to make a narrow-band antenna, you can adapt it using stubs matched at the central frequency of your antenna. Firstly, you need to know the input impedance of your antenna. Then, you can design a LC matching network (usually by means of a Smith Chart) with inductors and capacitors, and finally, implement them using a \lambda/4 line and a parallel stub.
This document can help you: **broken link removed**