Question

Name: Problem 2. (Option # 1 ) Five half wavelength dipole antennas are used as sources to form a linear phased array antenna, as shown below. These elements are all excited by sinusoidal current source of equal amplitude and phase followed by phase shifters. (9 pts.) a) If d 2, write the expression for array factor of the linear array. (9 pts.) b) Find total field at observation point P: (r, 0, 6) at far-field (i.e., kr>1). (8 pts.) c) How much progressive phase shift is required for beam pointing in broadside, end-fire, and the 0-60°? Discuss how to achieve this required phase shift in the end-fire case. (12 pts.) d) Show radiation pattern of array factor using CAD array program for end-fire and show the number of nulls and side-lobe levels in the visible space. (12 pts.) e) Show the overall radiation pattern of end-fire phased array and calculate its maximum gain using pattern multiplication principle. P: (r, 0, 6) i=1 i-2 i-2 i--1 j-0 ridga i -2, -1, 0, 1, 2

Answer 1

Ans dive half wevelengt. Siven de- /2 Af=Σ jAF1+ 24 et Af= 1-6 15kdceso 1- AF= 1- C 5 4Kncusig e

tielel ou obsevatho The ElectlC N=5 J4-3K Gin ニ Io e .esoh-) 1nle ddo

Se 2. AFニ 1- -e / K 2リ .n 1- e 2- Jo ーレす 1 e T こ(aS ) JSIのㄏ -1+0 1

Το 1 71 Ε. 1-1) 1-3 2 E.J= len= Γ.+1. S Γ -Τo HR Τ F,Τ ηΣ νT Qυ

B h Prograsive phase Shift B=-kd coso = Condl k2 Acosco - IT 2. 2- The nuu AF ca kdse 44 70 S M Cestoz 22

: kdes8 p fers endl tre ao Oo The man sodahon,at = 0, 1 0ニ 幻 when pニ pd cs1so tβニ 272 (-)tB