ENGI 7811/9816 Winter 2017 FEKO Simulation Assignment 3 Due: Monday, Mar 27, 2017

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1 ENGI 7811/9816 Winter 2017 FEKO Simulation Assignment 3 Due: Monday, Mar 27, STANDING WAVE ANTENNA (DIPOLE) 1. Using FEKO, provide plots for the current distribution and the 3-D far-eld electric-eld pattern of a dipole antenna with length l = 7λ/2. In your simulation, consider frequency=300 MHz, wire radius=0.001λ. Comment on the result (see slide 100 of Unit 3). Figure 1: Current distribution for antenna in 1-1.

Figure 2: 3-D far-eld electric eld pattern for antenna in 1-1. 2. TRAVELING WAVE ANTENNA (YAGI-UDA ANTENNA) 1. Read section 7.3 of our FEKO reference book. 2. Using FEKO, simulate a simple three-element Yagi-Uda dipole array consisting of one driven element and two parasitic elements.

The reector and director elements have a length of 0.49λ and 0.45λ, respectively. Consider a frequency of 300 MHz.

2 Figure 2: 3-D far-eld electric eld pattern for antenna in TRAVELING WAVE ANTENNA (YAGI-UDA ANTENNA) 1. Read section 7.3 of our FEKO reference book. 2. Using FEKO, simulate a simple three-element Yagi-Uda dipole array consisting of one driven element and two parasitic elements. The dipoles are spaced at a distance of 0.04λ apart and all have a wire radius of 0.001λ. The driven element has a length of λ. The reector and director elements have a length of 0.49λ and 0.45λ, respectively. Consider a frequency of 300 MHz. Provide plots for the current distribution and the 3-D far-eld electric-eld pattern. Comment on the result and compare it with the results pertaining to the standing wave antenna in Problem 1-1.

3 Figure 3: Current distribution of 2-2.

4 Figure 4: 3-D eld pattern of problem LINEAR AND PLANAR ARRAYS 1. Review Chapter 11 of our FEKO reference book. 2. Two-Element Uniform Half-Wave Dipole Array Placed Along the X-Axis: Using FEKO, verify the broad-side and end-re modes of a two-element half-wave dipole array as discussed in Unit 3 of the class notes (see Figure 5). Use a frequency of 300 MHz, wire radius= 0.001λ, and consider array spacing of d = λ/2, d = 0.7λ, and d = λ. For all cases, provide plots for the 3-D far-eld electric-eld pattern, phi cuts at phi =0 and phi = 180 degrees and a theta cut at theta = 90 degrees (i.e., superimpose the three cuts on a single plot). Compare the cuts obtained with the corresponding resultant patterns in slides 46/47 and 49/50 of Unit 3, and comment on the eect of increasing the array spacing.

5 Figure 5: Two-element dipole array of Problem 3-2.

6 (a) 3-D far-eld pattern of 3-2. (b) Phi and theta cuts superimposed (for 3-2). Figure 6: β = 0 (broad-side mode), and d = 0.5λ [Problem 3-2].

7 (a) 3-D far-eld pattern. (b) Phi and theta cuts superimposed. Figure 7: β = 180 (end-re mode), and d = 0.5λ [Problem 3-2].

8 (a) 3-D far-eld pattern. (b) Phi and theta cuts superimposed. Figure 8: 0 (broad-side mode), and d = 0.7λ [Problem 3-2].

9 (a) 3-D far-eld pattern. (b) Phi and theta cuts superimposed. Figure 9: 180 (end-re mode), and d = 0.7λ [Problem 3-2].

10 (a) 3-D far-eld pattern. (b) Phi and theta cuts superimposed. Figure 10: 0 (broad-side mode), and d = λ [Problem 3-2].

11 (a) 3-D far-eld pattern. (b) Phi and theta cuts superimposed. Figure 11: 180 (end-re mode), and d = λ [Problem 3-2]. 3. Five-Element Uniform Dipole Array Placed along the X-Axis (slide 61 of Unit 3): Using FEKO, simulate the broad-side and end-re modes of a 5-element uniform linear half-wave dipole array placed as shown in Figure 12. Use a frequency of 300 MHz, wire radius=0.001λ, and array spacing d = λ/2. Provide plots for the 3-D far-eld electric-eld pattern, and phi and theta cuts similar to Problem 3-2.

12 Figure 12: Five-element dipole array of Problem 3-3.

13 (a) 3-D electric-eld pattern. (b) Phi and theta cuts superimposed. Figure 13: Five-element array (broad-side mode) of Problem 3-3.

14 (a) 3-D electric-eld pattern. (b) Phi and theta cuts superimposed. Figure 14: Five-element array (end-re mode) of Problem Five-Element Binomial Array Placed Along the X-Axis (slide 83 of Unit 3): Using FEKO, simulate a 5-element binomial half-wave dipole array. Use amplitude distribution of 1/6, 4/6, 6/6, 4/6, 1/6, a frequency of 300 MHz, wire radius=0.001λ, and array spacing d = λ/2. Provide plots for the 3-D far-eld electric-eld pattern. Compare the 3-D eld pattern with that obtained for the ve-element uniform dipole array in Problem 3-3 (i.e., broad-side and end-re modes).

15 (a) 3-D electric-eld pattern. (b) Phi and theta cuts superimposed. Figure 15: Five-element binomial array of Problem A 3 by 3 Uniform Planar Dipole Array: Using FEKO, simulate a 3 3 uniform planar half-wave dipole array arranged as shown in Figure 16. Use a frequency of 300 MHz, wire radius=0.001λ, and β = 0. Provide a 3-D far-eld electric-eld pattern plots for the following cases (comment on the result and compare it with the simulations of the linear array considered in Problem 3-3): dx = 0.5λ and dy = 0.5λ,

16 dx = 0.5λ and dy = λ, dx = λ and dy = 0.5λ, and dx = λ and dy = λ. Figure 16: A 3 3 planar dipole array of Problem 3-5. Figure 17: Plot for Problem 3-5 (dx = 0.5λ and dy = 0.5λ).

17 Figure 18: Plot for Problem 3-5 (dx = 0.5λ and dy = λ).

18 Figure 19: Plot for Problem 3-5 (dx = λ and dy = 0.5λ).

19 Figure 20: Plot for Problem 3-5 (dx = λ and dy = λ).

RADIATING ELEMENTS MAY BE: DIPOLES, SLOTS, POLYRODS, LOOPS, HORNS, HELIX, SPIRALS, LOG PERIODIC STRUCTURES AND EVEN DISHES Dipoles simple structures,

RADIATING ELEMENTS MAY BE: DIPOLES, SLOTS, POLYRODS, LOOPS, HORNS, HELIX, SPIRALS, LOG PERIODIC STRUCTURES AND EVEN DISHES Dipoles simple structures, ANTENNA ARRAYS Array - collection of radiating elements An array may be: 1D (linear), 2D (planar), 3D (frequency selective) structure of radiating elements Purpose More directivity, Steereable beams Radiation