[srijan.rio]

Hi everyone. While going through the wireless charging technology, I saw that the two main competition standards(Qi and Rezence ), the operating frequency are withing 100 kHz and 10 MHz. WPC site tells that other than this frequency, the delivered power isn't constant w.r.t frequency as in this band.
But then new upcoming technologies like Cota are using GHz band.
So what is is the the reason for using the khZ to MHz band by the two standards ? If anyone can throw some light upon this, it will be really great.

[mprinkey]

This isn't what we do here. You will get better responses on RF/Electrical Engineering/General Physics forums.

I don't know any particular design details, but my assumption is that the wireless charging frequencies are going to be highly constrained by absorption spectra of human tissue and common household materials for obvious safety reasons. The lower the frequency, the longer the wavelength and the less likely the EM fields will resonate with tissue, DNA, drywall. There is also the issue of playing nicely with other wireless applications. So, there must be some bands dedicated for this and they are working within those FCC and international RF limitations. In order to drive enough EM energy to charge a battery...even at close distance...the RF power levels must be high. Enough so that the charger could wreak havoc with RF communications on nearby bands. So, these charging frequencies probably have large guard bands to prevent that from happening.

[srijan.rio]

Apologies for posting in the wrong forum. Thank you very much for your reply