Page 220 - Antennas for Base Stations in Wireless Communications

Antenna Issues and Technologies for Enhancing System Capacity 193

planar reflector with an angle of 60°. The three rims with a height of
about 0.14l are used to increase the isolation between the antennas as
well as the reflection of radiation. The HPBW of this antenna is 60° for
a six-sector radio zone. The difference between the beam directions of
Antennas #1 and #2 is 60° for service in adjacent zones. To reduce the
space for antenna installation, one radome is used to cover two anten-
nas. The HPBW of the antennas are also controlled using metal con-
18
ductors, as shown in Figure 5.18a. The radiation patterns are shown
in Figure 5.19. This figure shows a 60° HPBW dual-beam antenna
in which the HPBW can be narrowed to 45° using metal conductors.
Figure 5.18b shows a photograph of the antenna prototype shown in
Figure 5.18a.

y

z x

Conductors

Radome
(a) Illustration (b)
Figure 5.18 Dual-beam antenna with parasitic conductors