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Meandered Inverted F Antenna - Performance at extreme Temperature

Rizwan Hirani
Intellectual 450 points
Other Parts Discussed in Thread: CC2520

Hello There,


I'm using Meandered F Antenna in my design as per application note AN043 along with CC2520. So far multiple board is produced (~50) all are working fine and I'm able to achieve 100meter range using this antenna and things are good.

However - The operating temperature required for my board is -40 to 125 deg C. Our PCB uses IT-180A with maximum operating temperature is 130 degC. Now we want to test the board in chamber - Environment chamber.

Now the question is what would be impact of temperature on PCB antenna ? & What could be tested to measure the performance of antenna at lower and higher temperature. ? We can measure the range - see the impact on range at extreme temperature. But as per my understanding it is not possible to check because if we place one board inside chamber what ever EM waves radiated will be sealed in chamber only. Generaly chamber wall are very thick and metallic.

Thus, I m looking for an idea whereby I can predict more precisely test the performance of RF Antenna at extreme temperature in climate (environment) chamber.

Any suggestions and inputs are welcome.

Thanks

Rizwan Hirani

  • 0
    TI__Guru 56590 points

    Hello Rizwan,

    I do not know how much the antenna characteristics change, but I expect the change would be small. The best would be to connect tour antenna with a coaxial cable (that is rated for high temp) and look at the change in input impedance of the antenna at the different temperatures.

    For example the conductance (G) of the copper in the PCB will decrease slightly (given by the temperature coefficient for copper multiplied with increase in temp). But I believe the effect of this will be very small. I would be more interested in knowing the change in the PCB properties and specially the change in distance between layers at changing temperatures (if there are any). 

    If you have a transmission line of more than 10% of the wavelength for the signals used the characteristic impedance of this line will also affect your performance. To get an idea of how the impedance change according to change in variables you can try out the TXLINE SW tool and change different variables to see how the impedance changes. One of the most sensitive variables I found was  the height between the layers.