Page 128 - Antennas for Base Stations in Wireless Communications

Antennas for Mobile Communications: CDMA, GSM, and WCDMA 101

can be optimized by varying the dimensions of the L-probes and the
patches, which have no effect on the far-field radiation patterns. The
chromosomes are described in the first illustration and the boundaries
of those parameters are shown the second illustration.

h p h lp L p E 1 E 2 E 3 E 4 E 5 E 6 E 7
+
o o o o o o o o
a 1 a 2 a 3 a 4 a 5 a 6 a 7 a 8
+
|a | |a | |a | |a | |a | |a | |a | |a |
2
1
3
4
5
7
6
8
o
h p h lp L p E 1 –E 7 a n a n
o
0.8−1.2l 0− 0.8 − 1.1l 0 0.2 − 0.25l 0 0.6 − 0.9l 0 0 ≤ a n ≤ 360° −1 ≤ a n ≤ 1
o
Phase (a 1 ) 0°
o
o
Phase (a 2 ) −20° ≤ a 2 ≤ −10°
o
o
Phase (a 3 ) −18° ≤ a 3 ≤ −8°
o
o
Phase (a 4 ) −30° ≤ a 4 ≤ −20°
o
o
Phase (a 5 ) −56° ≤ a 5 ≤ −46°
o
o
Phase (a 6 ) 3°≤ a 6 ≤ 13°
o
o
Phase (a 7 ) 10° ≤ a 7 ≤ 20°
o
o
Phase (a 8 ) −2° ≤ a 8 ≤ 8°
Amplitude (a 1 ) 0.3 ≤ a 1 ≤ 0.6
Amplitude (a 2 ) −0.8 ≤ a 2 ≤ −0.5
Amplitude (a 3 ) 0.6 ≤ a 3 ≤ 0.9
Amplitude (a 4 ) −1 ≤ a 4 ≤ −1
Amplitude (a 5 ) 0.4 ≤ a 5 ≤ 0.7
Amplitude (a 6 ) −0.5 ≤ a 6 ≤ −0.2
Amplitude (a 7 ) 0.2 ≤ a 7 ≤ 0.5
Amplitude (a 8 ) −0.6 ≤ a 8 ≤ −0.3
For efficient computation, the step sizes for those parameters can be
different. Each of them induces a quantization error. For the L-probes,
the relative excitation phases (a° ) and relative excitation amplitudes
n

(|a |) induce a quantization error of 1°and 0.01, respectively. The other
n
parameters (h , h , L and E —E ) have a quantization error of approxi-
7
lp
p
p
1
mately 0.01l .
0
GA Parameter Settings The GA parameters are set as follows:
■ The number of chromosomes: 40
■ The number of generations: 100
■ Crossover rate: 0.8
■ Mutation rate: 0.05