Question

Your home Wi-Fi router employs an electrically small antenna (D < λ) and is limited to an effective isotropic radiated power (EIRP) of 4 W at 2.45 GHz. At what free-space distance (r) is the power density guaranteed to be less than 5.3 W/m², the corresponding RF exposure reference level in Canada?

Answer 1

The free-space distance where the power density is guaranteed to be less than 5.3 W/m² for a home Wi-Fi router with an electrically small antenna and an EIRP of 4W at 2.45 GHz is approximately 0.157 meters.

Step-by-step explanation:

To find the free-space distance where the power density is guaranteed to be less than 5.3 W/m², we can use the formula for power density:

Power Density (Pd) = EIRP / (4πr²)

Given that the EIRP is 4 W and the power density should be less than 5.3 W/m², we can substitute these values into the formula:

5.3 = 4 / (4πr²)

Solving for r, we get:

r² = (4 / 4π) / 5.3 = 1 / (π * 5.3)

r = √(1 / (π * 5.3)) ≈ 0.157 meters

Therefore, at a free-space distance of approximately 0.157 meters, the power density is guaranteed to be less than 5.3 W/m².