Chapter 14, Problem 14.20P

A two-element dipole array is configured to provide zero radiation in the broadside $(\varphi =\pm 90°)$ and endfire $(\varphi =0,180°)$ directions, but with maxima occurring at angles in between. Consider such a setup with $\psi =\pi$ at $\varphi =0$ and $\psi =-3\pi$ at $\varphi =\pi$, with both values determined in the H plane. (a) Verify that these values give zero broadside and endfire radiation. (b) Determine the required relative current phase, $\xi$. (c) Determine the required element spacing, d. (d) Determine the values of $\varphi$ at which maxima in the radiation pattern occur.