Dear friend:
I have problem with direction of the antenna and how to miniaturization it.
Then I made a new antenna(2.66 mH 20Ω) and I have tuned the capacitance , It’s work , next step I want to miniaturization it.
So I made another antenna(2.59mH 100Ω, smaller coil diameter ), I tune the best capacitance value with my antenna.
And I got this waveform. I don’t know why TMS37157 ,it’s doesn’t send all of the FSK signal back to the Reader.
At the first , I guess TMS37157 run out of power because of antenna resistance is bigger than original one , so I connect the battery, but it
still doesn’t work. or because of the antenna resistance change too much (20Ω->100Ω) ?
Could anyone give me any suggest to solve this issue? Thank you.