I intend to build a wireless power charger using the power transmitter design A12 on the WPC manual and having some difficulty. And I need some guidance. Based on the circuit diagram, I will step down the voltage to approx 5V to power the full-bridge inverter. I have never worked with inverters and need some clarification. Based on the attached file, when it states the operating freq for the inverter is 110 - 205KH, how to I design a circuit that will operate within than range? Any thread that could refer me to how to build the inverter? Any guidance will be be greatly appreciated.

 

I suggest you do a Google of "toothbrush charger circuit" and try "Induction Charger Circuits" and look at the images and links. While these circuits are not efficient they do work, well my toothbrush has been working for years.
Some of the links will show you how to wind the coils and give you some dimensions. Just do not expect much as using air for inductive coupling is not going to yield any miracles.

Ron

 

They are not as simple as they sound, but here is a good write up.
http://www.discovercircuits.com/dc-mag/Issue-1/issue-1-receiver-construction.htm