QUESTION

Question

Deas Antenova Team,

I'm matcing a SR4L034-R and I have a question related to the T1 pin, which in the datasheet is coneected to 6.8 nH. Do you have other paper in which this value changes? What's it's purpose? Can I change this value?

Best regards

Samuel

Answer 1

Hi Samuel,

This is the return/ground component and acts like a band selector. In most devices the optimum value is around 6.8nH, however this would depend on bands required, PCB dimensions, mechanical parts, enclosure etc. Matching component values and topology will be specific to your device, as standard we always recommend the values used for the EVB in the data sheet as a starting point, ensuring you implement the complete topology, including 0ohm and not fitted components to give you maximum flexibility for optimal matching. We offer a matching service in our lab, so we can handle the optimisation for you. We provide a full report with matching component values, return loss, efficiency and 2D & 3D radiation patterns. Do you have hardware available or are you at the layout stage?

Many Thanks

Steve

Answer 2

Hi Steve,

Thank for your answer. I'm trying to match an antenna on a PCB for GSM bands but 960 MHz doesn't go bellow -2, -3 dB. Can I put a C in T1 pin instead of a L?

Best regards

Samuel

Comments

Hi Samuel,

Fitting a capacitor will most likely stop the antenna resonating at all in the low bands. Is this a small PCB? What are the dimensions?

Many Thanks

Steve

Answer 3

Hi Steve,

I did some test changing values of the L in T1 pin and without L in the pin, I've gotten a better matching for the band.

It's not perfect, because the extremes of the bands are not bellow -5dB, but I want to try different output matching for fix it. My question now is, can I do this? Or is it mandatory to have a L on T1 pin?

Best regards

Samuel

Answer 4

Hi Steve,

It's a round PCB with almost 80 mm of radius. The antenna is in the right part of the photo. So do you have a specific recomendation for a L in t1 pin to matching it for GSM band?