I have seen a few articles that show efficiencies greater than 100% for a power harvester using a zero bias diode and sometimes without a voltage multiplier.
If the efficiency is Pin/Pout how can we have more than 100% efficiency without an active component?
Of course you can never get with passive structure more than 100 % conversion efficiency. However this may come in via the antenna cross section (which can become quite large for resonant structures) compared with the real physical size of the receiving element. Thus if you have an antenna of say 5 cm length one may assume that the antenna cross section is 25 cm^2 but of the the antenna is resonant or has many elements the effective receiving area can be considerably larger.
Thank you Nasr Alkhafaji
but I mean Pout/Pin, and as I said sometimes in people's publications it shows 100% efficiency !!!- Badges
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