# Total power output from dual-band antenna

#### Afabiani

Joined Jul 4, 2020
4
Hi! I have calculated the power output for a receiving dual-band antenna at 2.4 and 5.8 GHz. Obviously the power received for each frequency is different. What I would like to know is te total power output of both frequencies. Is it as simple as to add the powers? Thank you

#### DickCappels

Joined Aug 21, 2008
6,532
What would be the reason for combining the measurements?

#### Afabiani

Joined Jul 4, 2020
4
What would be the reason for combining the measurements?
Hi! Thanks for your reply. I would like to know what is the total power fed to a rectifying circuit. I think that maybe this might not make sense since the signals are not rectified yet they still Are two ”separated powers”. if this is the case, how do I find the power delivered from both frequencies at the rectifier output. I’m fairly new with this and I’m probably not expressing myself right, if you could dumb-it-down a bit for me I would appreciate. Thanks

#### DickCappels

Joined Aug 21, 2008
6,532
I'm sorry I forgot that you are making a radiated energy harvesting device. Since there is a large frequency difference between the two frequencies the efficiencies of the circuits that turn the AC into (presumably) DC will probably have much different efficiencies and based on this I would calculate the power of the two inputs separately and then after conversion to DC (?) add them together.

If there is only one circuit making the conversion of both of the signals you will still have different conversion factors (watts out divided by watts in) for different frequencies, so a useful measure of power can be made by adding the two outputs together.

I've never done that but the above makes sense to me.

Incidentally, we will be very interested in how much power you expect to be received and the amount actually converted.

#### Afabiani

Joined Jul 4, 2020
4
I'm sorry I forgot that you are making a radiated energy harvesting device. Since there is a large frequency difference between the two frequencies the efficiencies of the circuits that turn the AC into (presumably) DC will probably have much different efficiencies and based on this I would calculate the power of the two inputs separately and then after conversion to DC (?) add them together.

If there is only one circuit making the conversion of both of the signals you will still have different conversion factors (watts out divided by watts in) for different frequencies, so a useful measure of power can be made by adding the two outputs together.

I've never done that but the above makes sense to me.

Incidentally, we will be very interested in how much power you expect to be received and the amount actually converted.
Hi Dick! Thank you for your answer, it has been really helpful. I expect to harvest very low power, also I don’t think the harvester is going to be really efficient as my knowledge of the subject is very little. I aim to harvest a total power of around 18mW, i don’t have to do it with only one harvesting circuit, I don’t have a limit for that.

• DickCappels