2.71. The far-zone power density radiated by a helical antenna can be approxi- mated by 1 Wrad = Wavear Cocos The radiated power density is symmetrical with respect to 4, and it exists only in the upper hemisphere (0 ≤0л/2, 0 ≤≤2л); C, is a constant. Determine the following: (a) Power radiated by the antenna (in watts). (b) Maximum directivity of the antenna (dimensionless and in dB) (c) Direction (in degrees) along which the maximum directivity occurs. (d) Maximum effective area (in m²) at 1 GHz. (e) Maximum power (in watts) received by the antenna, assuming no losses, at 1 GHz when the antenna is used as a receiver and the incident power density is 10 mwatts/m2.