Page 153 - Antennas for Base Stations in Wireless Communications

126 Chapter Three

0 0
330 30 330 30

300 60 300 60

270 90 270 90
−35 −30−25−20−15−10 −5 0 −35 −30−25−20−15−10 −5 0

240 120 240 120

210 150 210 150
180 180
(a) (b)
Measured co-pol Measured x-pol
Simulated co-pol Simulated x-pol
Figure 3.24 y-z plane radiation patterns of the single-feed dual-band patch antenna at
(a) 0.89 GHz and (b) 1.94 GHz 10

3.3 Conclusion

Design of base station antennas for mobile communication systems is
very challenging. The required characteristics for bandwidth, gain, pat-
tern shape, beamwidth, and intermodulation level are not easy to achieve.
In this chapter, we have presented the commercial requirements for the
performance of both indoor and outdoor base station antennas for vari-
ous mobile phone systems. Conventional techniques employed to develop
base station antennas are also reviewed. Both directed dipole and aper-
ture-coupled patch antennas are popular choices. The L-probe fed patch
antenna is a wideband patch antenna technology that has attracted
much interest in the antenna community in past years. Through the
study of five different designs, we have demonstrated that this new
antenna structure is highly suitable for the development of base station
antennas for both 2G and 3G mobile communication systems.

3.4 Acknowledgment
Professor K. M. Luk would like to extend his sincere thanks to Dr. Pei Li
and Dr. T. P. Wong for carrying out some of the excellent research works
presented in this chapter.