Page 198 - Antennas for Base Stations in Wireless Communications

Advanced Antennas for Radio Base Stations 171

4.13 Amplifier Integrated Multibeam
Array Antenna
Multibeam array antennas, which employ distributed power amplifi-
ers close to the radiating elements of the antenna array, improve the
radiated power efficiency. An example shown in Figure 4.29 consists of
a dual-polarized antenna array with four columns for the multibeam
radiation patterns and a fifth column for sector coverage. Five ampli-
fiers are mounted for each polarization. Four of these are connected
to the multibeam array whereas the remaining amplifier is used for
sector beam amplification. The antenna unit can be configured both
as a column power amplifier array, as in Figure 4.29a, and as a hybrid
power amplifier array, as in Figure 4.29b.
In the column power amplifier array, a separate power amplifier is con-
nected directly to each column of radiating elements, whereas the hybrid
power amplifier array has a separate amplifier configuration located

Multi-
Sector
beam coverage
array
antenna column

Dx Dx
+45° pol. Dx Dx −45° pol. Dx Dx Dx

Dx Dx Dx

Butler matrix Butler matrix

+45° pol. −45° pol. +45° −45°
Beam ports
(a)
Figure 4.29 Block diagram of an amplifier integrated
multibeam array antenna: (a) column power amplifier
array configuration and (b) hybrid power amplifier array
configuration