Questions and discussions about the antennas for the TD RF modules.
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Joined: Thu May 07, 2015 12:50 pm

Customization of TD1205 antenna

by jean Mon Jun 22, 2015 5:11 pm


I am currently developing an hardware based on TD1205.
Is it possible to have more information on the design of the RF antenna deployed on the TD1205? What is the material used? The antenna impedance?

I am considering twisting it, would it be possible?

Could you provide on-demand design for this antenna?


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Re: Customization of TD1205 antenna

by mstempin Fri Jul 03, 2015 7:52 am

The RF signal should have a 50 ohms impedance to match the RF chip impedance and thus get the best power transfer.

In order to get the maximum RF power transfer, an antenna should have dimensions related to the signal's wavelength.

The best possible antenna would be a full wave antenna made up of a straight cable the same length as the wavelength. In practice, if you have a ground plane, it can act as a "mirror" and you only need a 1/2 wave antenna. A 1/4 wave antenna is possible, but only if you have a very large ground plane, which is kind of a problem if your goal is to reduce the overall size of your device.

It is possible to bend the straight antenna or "screw" it like a pig tail in order to reduce their length: this last solution is what is done inside the black swivel antennas delivered with our TD1208 or TD1204 EVB boards.

Be careful however that every time you bend an antenna, you get worse RF performance.

Once the design of the antenna performed, you will have to match it to the standard 50 ohms impedance. This is generally done using a "Pi" network at the base of the antenna, and this matching requires specific RF test equipment called VNA (Vector Network Analyzer) to plot the complex impedance of your antenna.

For antenna design / matching, please contact our commercial team!
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