Antenna tuning with chipset antenna

[vidal]

Hello,

I developed a Nordic board with 2450AT18B100 chipset antenna. I follow the design of Solar Powered Sensor Beacon.

infocenter.nordicsemi.com/index.jsp I test it and it works fine, but I want to tuning the antenna in order to get minimum return lose in signal.

So, I implement this antenna circuit in my board.

From johanson technology values are:

I suppose that from C3 and L1 you have to modify some references values of johanson chip antenna.

In general, my questions are:

Can you explain me each part of this circuit?.

Can you explain me why do you change this values and how do you calculated?.

Can you explain me how tuning the antenna?. Because your reference document for that do not explain how to do it in this case.

infocenter.nordicsemi.com/.../nwp_017.pdf

Thanks in advance.

Jose.

Others attached files. Conductor Impedance

Trace Lenght Solar Beacon

[vidal]

Hello Kristin,

Thanks a lot for your swift reply. I have a new questions...

How can I measure the output power?.

About VNA I suppose that the signal of VNA is in C13 and the GND of VNA in L4 (GND), that is right?. About this process...that means that doing that we will be sure about the impedance adaptation between all parts but...what about the frequency resonance?. Imagin that impedance is right but frequency resonance is wrong... I suppose that you make some calculations to do that. Can you shared with us this calculations.

Thanks in advance.

Jose.

[vidal]

Hello Kristin, Right now I can not do it, so I will try to measure the impedance with VNA. To do that I have to cut off the track in the same way of tuning antenna process????.

Also I was doing some math. According to “nRF52 matching network.pdf” document shown that trace has 10nH/cm and I did some simulation and that trace has around 4nH/cm there are a lot of difference… do you know why???. Conductor Width is 9 mils. Also I was checking the distance. In Solar Beacon board, the distance is 1.694mm and in “nRF52 matching network.pdf” document is 0.9mm, do you know why???. I suppose that you are taking other reference. You can see in the picture below my reference of 1.694mm because I think that GND is the thermal/ground PAD of the nRF52.

Thanks.