TRF7970A: How to make an antenna narrow band

Hello Abhyuday,

have you already added the antenna tuning and matching components, as described in chapter 3 and 4 in the antenna design guide (https://www.ti.com/lit/pdf/sloa241)?

If yes, could you please share more details?

Best regards,

Andreas.

Hello Andreas,

Yes, I've done the antenna tuning as described in chapter 3 and 4. The strength and range seems fine but, as seen in the above image my antenna is able to detect other frequencies(noise) apart from 13.56MHz which I want to avoid.

Hello Abhyuday,

I'm not sure why your bandwidth is so wide.
Is your antenna inductance in the recommended range of 1...1.5uH?
In general the bandwidth becomes wider with lower Q.
So you would need a higher Q for tighter bandwidth.
With lowering the parallel resistor (R6 in figure 1 of the antenna design guide) you can only lower the Q factor for a given antenna.
Maybe your existing parallel resistor is already too low.
If not, then you would need a higher Q antenna with lower DC resistance as a starting point.
Lower DC resistance can be achieved by wider trace-width on PCB antennas or thicker wires on loop antennas.
Have you measured the impedance of your antenna?
Please share the result.
What type of Antenna have you designed?

Best regards,
Andreas.

Hi Andreas,

Can we change the chat to private as I cannot share the design files on a public channel. It would be a huge help if we can do that.

Regards 

Abhyuday

Hi Abhyuday,

because Andreas is on vacation right now I will send you a friends request to move to a private communication.

Best Regards,

Helfried