Power ofElectromagnetic waves

[rpayne88]

Its been awhile since I've been here.  

I've been planning to do an expirament to see if I could transfer small amounts of power via microwaves.  I've just have a few questions:

1  How can I calculate the power, in watts, of an electromagnetic wave given frequency?

2. Does doubling the amplitude double the power?

3. Do I need shielding if I'm only using a 1w microwave source.  If I do, what should I make it out of?

 

I've been having some technical difficulties with my Physic Fourms account and thought I would drop this in the Science Lounge.

[YNM]

1. Use E = hf , where E is the energy of individual photons, h is planck constant, f is the frequency.

2. According to the equation above, what you will have is more photons, more intensity. Needs someone else to back this up though.

3. I don't think so. 90 W is the smallest amount used in microwave oven. 1W is just a thousandth of that. I do not know the amount used in WiFi but it should be less than 10 W (just looked that up on my WiFi transmitter, which says a power input of 12 W and I believe most is used for transmitting).

Also, what's the purpose of your experiment ? Wireless charging already demonstrates it well - unless you want to make one yourself...

[QuesoExplosivo]

57 minutes ago, YNM said:

1. Use E = hf , where E is the energy of individual photons, h is planck constant, f is the frequency.

2. According to the equation above, what you will have is more photons, more intensity. Needs someone else to back this up though.

While this is technically true, electromagnetic power transfer for microwaves is not usually calculated by this method. Instead, it's calculated by classical electrodynamics, using the Poynting vector: https://en.wikipedia.org/wiki/Poynting_vector

[YNM]

Hmm... Is that because we're measuring something very close to the source ? Near-field ? I haven't learned near-field properly so, if you want to correct things, please do it.