Again in search of physics understanding.

If a microwave beam is coming down vertically onto the rectenna,
without much leakage beyond the rectenna boundaries, could we use
the same frequency as that already allocated to cell phones, with
the understanding that there would be no cell phone transmissions
within the rectenna zone.

My gut tells me it's not going to be as simple as that, but I'm not
sure as to the why of it?

Anybody interested in explaining this issue.

> Again in search of physics understanding.
>
> If a microwave beam is coming down vertically onto the rectenna,
> without much leakage beyond the rectenna boundaries, could we use
> the same frequency as that already allocated to cell phones, with
> the understanding that there would be no cell phone transmissions
> within the rectenna zone.
>
> My gut tells me it's not going to be as simple as that, but I'm not
> sure as to the why of it?
>
> Anybody interested in explaining this issue.
>

The answer is, it depends.

Somebody needs to crank the numbers.

The key parameters are as follows:

What is the allowable input sensitivity of the cell phones which the devices
will accept without disprupting the modulated voice signal ?

What is the leakage flux in the sidelobes which are more than, say, 10
kilometres from the rectenna.

To avoid interference, the follwing equations must be satisfied:

leakage flux < cell phone sensitivity.

and

leakage flux < cell tower receiver sensitivity

====

To give it a reality check, there is already interference between terrestrial
systems and cell phones. For example, there were some recently publicised
cases of police emergency communicatiosn being disrupted by leakage from cell
phone traffic.

And both systems met the prevailing FCC standards.

Best regards,

Charles R.