Question

For an 8 feet (2.4m) parabolic dish antenna operating at 4GHz, the minimum distance required for far field measurement is closest to

(a) 7.5 cm

(b) 15 cm

(c) 15 m

(d) 150 m

Answer 1

The correct option is ( D )

Explanation :

Given,

Parabolic reflector antenna

Diameter (D) = 2.4 m

Frequency (f) = 4 GHz

The measurement of antenna field is considered in Fraunhofer (far field) region. At a distance