Dr. Mahmoud. A. Abdalla Electronics and Communication Department

EC750 Course Assignment 1/2 Fall 2013

Assignment #1 (Array Antennas)

(Should be submitted by 5th week) Part (1): Uniform Array 1) 4.1 Use Eq. (4.14) and MATLAB and plot the array factor in rectangular

coordinate form for the following broadside array cases

(a) N = 4, d = /2 (b) N = 8, d = /2 (c) N = 8, d = 2) 4.2 For the three arrays given in Prob. 4.1, calculate null and s for each of

the arrays given above.

3) 4.4 Use MATLAB and the command trapz( ) to calculate the maximum directivity for the following two arrays:

(a) Broadside with N = 8, d = /2 (b) End-fire with N = 8, d = /2 4) 4.5 Use MATLAB and the command trapz( ) to calculate the maximum

directivity for the beamsteered array where d = /2, N = 8.

(a) 0 = 30 (b) 0 = 45 5) 4.6 What is the beamwidth for the following array parameters? (a) 0 = 0, N = 8, d = /2 (b) 0 = 45, N = 8, d = /2 (c) 0 = 90, N = 8, d = /2 Part (2): Non Uniform Array 6) 4.7 For an N = 6, d = /2 uniformly weighted broadside array, plot the array

factor. Superimpose plots of the same array with the following weights.

(Create one new plot for each new set of weights) (a) Kaiser-Bessel for = 2 using kaiser(N, ) (b) Blackman-Harris using blackmanharris(N) (c) Nuttall using nuttallwin(N) (d) Chebyshev window for R = 30 dB using chebwin(N, R)

Dr. Mahmoud. A. Abdalla Electronics and Communication Department

EC750 Course Assignment 2/2 Fall 2013

7) 4.10 Using MATLAB, create and superimpose three normalized array factor plots using the chebwin( ) function for R = 40 and beamsteer the array to three angles such that 0 = 0, 30, 60. N = 9, d = /2.

8) 4.12 For d = /2, use MATLAB and plot the N = 8 element array beamwidth for a range of steering angles such that 0 < 0 < 90.

Part (3): Planar Uniform Array 9) 4.15 Design and plot a 5 5 element array with equal element spacing such

that dx = dy = .5. Let the array be beamsteered to 0 = 45 and 0 = 90. The element weights are chosen to be the Blackman-Harris weights using the blackmanharris( ) command in MATLAB. Plot the pattern for the range 0 pi/2 and 0 2pi.

Part (4): Fixed Beam Array 10) 4.16 Using Buttler matrix (Eq (4.56)), create scalloped beams for the N =

6-element array with d = /2.

(a) What are the l values? (b) What are the angles of the scalloped beams? (c) Plot and superimpose all beams on a polar plot similar to Fig. 4.29

11) For the shown 4x4 Butler matrix with 3 dB / +90 coupler, find the magnitudes of the excitation angles

of the four elements array antenna

and their crosssponding maximum

angles, assuming the distance

separation between elements is

d=/2.

12) 4.17 For the fixed beam sidelobe canceller with N = 3-antenna elements, calculate the array weights to receive the desired signal at D = 30, and to

suppress the interfering signals arriving at 1 = 30 and 2 = 60.