Hello everyone!
I'm building a bifilar coil to transfer power wirelessly. to generate the signal for transmitter coil, I'm building my own function/signal generator with this youtube video -
. but it doesn't work well with higher frequencies (1-10MHz) . So my question is how can I lower the resonance frequency of my bifilar coil by changing its diameter, windings, winding direction, length? is there a equation for calculating the resonance frequency of a bifilar coil with factors like its windings, diameter, length, direction? I'd like to keep the resonance frequency as low as possible and love to transmit a considerable amount of power with this. the coil setup is similar to this except there is no mobile phone and permanent magnet. Please explain your answer in simple words, I don't have a lot of knowledge in Mathematics or advanced electrical engineering ( I'm 16
) Thank you!

I'm building a bifilar coil to transfer power wirelessly. to generate the signal for transmitter coil, I'm building my own function/signal generator with this youtube video -
