Question

Find the maximum value of array factor when elements are separated by a λ/4 and phase difference is 0?

(a) θm=cos^-1⁡(4m)

(b) θm=sin^-1⁡(4πm)

(c) θm=cos^-1⁡(4πm)

(d) θm=sin^-1(2m)

I have been asked this question in final exam.

My query is from N-element Linear Array topic in division Antenna Array of Antennas

Answer 1

The correct choice is (a) θm=cos^-1⁡(4m)

To explain I would say: The maximum value of array factor is \(θ_m=cos^{-1}⁡(\frac{λ}{2πd}[-β±2πm]).\)

\(θ_m=cos^{-1}⁡(\frac{λ}{2πλ/d}[0±2πm]).\)

θm=cos^-1⁡(4m).