1. BEAM STEERING TECHNIQUES IN MULTIPLE INPUT MULTIPLE
OUTPUT (MIMO) ANTENNA SYSTEMS TO OVERCOME THE
MULTIPATH EFFECT
OVERVIEW
MIMO systems exploit the multipath
fading effects to turn them into a
valuable way of getting extra
bandwidth instead of it being a
problem.
This project investigated the beam
steering capability of a 2.4 GHz circular
array with six identical elements.
MSc Project by DARWIN ASEKA,
UoB # 04015245
Supervisor: DR. CHAN H. SEE
OBJECTIVE
• A 2.4 GHZ horizontally polarized
antenna was simulated and used as
one of the 6 identical elements of a
circular array antenna.
• The Magnitude and Phase of each
element are to be strategically
altered thereby changing their
radiation pattern.
• The combined radiation of the
element antennas collectively forms
a beam whose direction can be
manipulated based on the
magnitude and phase of each
element.
• Genetic Algorithm Optimisation was
applied in determining the
normalized magnitude and phase
for each element at every angle the
beam was steered to.
• Time switching modulation of each
element was investigated in order to
achieve beam steering.
PROCESS FLOWCHART
CONCLUSION
•Array antenna elements combine their
radiation energy forming a radiation pattern
that can be steered in a chosen direction
given upon altering the magnitude and
phase Components of one or all the array
elements. This process combats the
multipath fading effect.
•MIMO systems exhibit improved spectral
efficiency and achieve higher data rates
without impacting much on power usage.
These features have made MIMO
technology favourable in the development
of future technologies e.g. 4G.
Angles of steering analysed are 0°, 30°, 65°, 170°,
180°, 190°, 290°, 310° and 330°. The table below
shows the angle of steering and the corresponding
element normalized magnitude, phase and the
normalized switch ON/OFF sequence.
ELEMENT
NUMBER
(i)
ELEMENT
ANTENNA
PARAMETERS
BEAM STEERING ANGLE (degrees)
0° 30° 65° 170° 180° 190° 290° 310° 330°
1
Normalized
Magnitude 0.470 0.511 0.853 0.075 0.489 0.295 0.915 0.413 0.501
Phase Shift
(degrees) 354.198° 90.989° 275.165° 72.791° 129.319° 148.835° 258.374° 354.286° 313.934°
Normalized
Switch ON 0.2393 0.0000 0.1990 0.4017 0.2063 0.1898 0.1946 0.6183 0.6401
Normalized
Switch OFF 0.3225 0.2520 0.9231 0.4370 0.4514 0.3764 1.0000 1.0000 0.9765
2
Magnitude 0.786 0.411 0.097 0.614 0.933 0.510 0.453 0.516 0.851
Phase Shift
(degrees) 204.872° 167.863° 229.316° 9.231° 295.470° 187.692° 103.761° 230.769° 216.154°
Normalized
Switch ON 0.4570 0.1810 0.4031 0.1366 0.3020 0.2129 0.1186 0.2644 0.1607
Normalized
Switch OFF 0.6491 0.3799 0.4684 0.4490 1.0000 0.5486 0.3842 0.9105 1.0000
3
Magnitude 0.347 0.982 0.573 0.584 0.559 0.838 0.184 0.326 0.523
Phase Shift
(degrees) 47.121° 346.022° 359.912° 87.033° 36.484° 273.846° 203.429° 35.604° 43.077°
Normalized
Switch ON 0.1821 0.2767 0.5853 0.3004 0.0061 0.2721 0.4225 0.0965 0.0000
Normalized
Switch OFF 0.4952 1.0000 1.0000 0.5949 0.2916 0.9227 0.5263 0.3778 0.3536
4
Magnitude 0.428 0.201 0.932 0.503 0.082 0.290 0.456 0.491 0.144
Phase Shift
(degrees) 319.209° 232.527° 249.846° 182.330° 77.099° 72.703° 235.516° 242.813° 185.407°
Normalized
Switch ON 0.3601 0.3629 0.0000 0.5132 0.2080 0.0000 0.4124 0.3503 0.4728
Normalized
Switch OFF 1.0000 0.4578 0.9838 0.7917 0.2471 0.1833 0.6799 0.8679 0.5446
5
Magnitude 0.498 0.591 0.029 0.971 0.486 0.625 0.389 0.439 0.805
Phase Shift
(degrees) 128.264° 160.352° 91.165° 42.198° 22.505° 346.725° 352.879° 20.044° 227.780°
Normalized
Switch ON 0.0000 0.1167 0.0485 0.0000 0.0000 0.5675 0.6961 0.0000 0.2760
Normalized
Switch OFF 0.6816 0.4140 0.0680 0.7168 0.2435 0.0000 0.9213 0.4185 0.9389
6
Magnitude 0.259 0.906 0.541 0.566 0.793 0.9938 0.199 0.122 0.389
Phase Shift
(degrees) 236.396° 337.407° 188.484° 293.099° 288° 253.978° 16.527° 184.527° 63.648°
Normalized
Switch ON 0.5161 0.3506 0.1303 0.7160 0.4108 0.0949 0.0000 0.4554 0.0979
Normalized
Switch OFF 0.7674 0.8915 0.5181 1.0000 0.8622 1.0000 0.1124 0.5536 0.3516
RESULTS 0.2
0.4
0.6
0.8
1
30
210
60
240
90
270
120
300
150
330
180 0
0.2
0.4
0.6
0.8
1
30
210
60
240
90
270
120
300
150
330
180 0
0.2
0.4
0.6
0.8
1
30
210
60
240
90
270
120
300
150
330
180 0
0.2
0.4
0.6
0.8
1
30
210
60
240
90
270
120
300
150
330
180 0
0.2
0.4
0.6
0.8
1
30
210
60
240
90
270
120
300
150
330
180 0
The 2D Plots of the steered radiation pattern (left)
and their corresponding “Element Switch ON
Time for each Element” (right) are shown below
in the order: 0°, 30°, 65°, 170°, 180°, 190°,
290°, 310° to 330° respectively.
0.2
0.4
0.6
0.8
1
30
210
60
240
90
270
120
300
150
330
180 0
0.2
0.4
0.6
0.8
1
30
210
60
240
90
270
120
300
150
330
180 0
0.2
0.4
0.6
0.8
1
30
210
60
240
90
270
120
300
150
330
180 0
0.2
0.4
0.6
0.8
1
30
210
60
240
90
270
120
300
150
330
180 0
BEAM STEERING PLOTS &
SWITCHING SEQUENCE