Hi,
please be informed power is in watts and NOT in volts. Fine, if you want to take 4to6V DC at say 1Amp, why not use two wires of at least single strand 18swg insulated copper wires, as it is cheapest mode.
maybe if you put your question in more words?
do you need wireless transfer of energy? do you have any ideas how would you do it? What is the V*I you need on the other end? What efficiency ratio is good enough? You can do a simple "focused light bulb" on one end and solar panel on other end solution if the efficiency ratio is not issue. You can google for microwave power transmission, you can try to build Tesla amplifier...