04-05-2012, 05:04 PM
On Applications of Self-Phased Array Antennas to Mobile Communications
[attachment=21316]
Introduction
Widespread utilisation of mobile communications
systems which has lead to concentration of their
transmitters over the limited territories (large populated
and industrial areas) has dramatically aggravated
electromagnetic and ecological compatibility problems.
The radiated power of these systems’ base stations can
reach 5-10 kW (up to 320-350 W per channel), which
can be ecologically dangerous in case their antennas are
installed in residential districts as well as in the vicinity
of industrial premises. Because of their comparatively
large power, portable (0.5-5W) and mobile (5-50 W)
units represent significant danger to their users. [1-3].
Approximately half the radiated power of a hand-held
mobile phone is absorbed in a person’s head [4].
According to certain data, the radiated power level of
portable units which is acceptable from the medical
point of view is 100-300 mW [5].
The Use of a Self-Phased Array Antenna
The above-mentioned problems can be fully solved
by substantial reduction of the power radiated by mobile
communications system transmitters. In this case the
service areas of these systems may retain their size if a
transition to the microcellular level is made as well as if
sensitivity of the receivers is increased or antennas gain
is expanded.
Conclusion
A self-phased array antenna is very promising for
the use in mobile communications. Its design is very
simple: it performs self-phasing without phase shifters
and adaptive control electronics. The large progress in
the field of microwave IC technology makes its
production very simple and cheap.
[attachment=21316]
Introduction
Widespread utilisation of mobile communications
systems which has lead to concentration of their
transmitters over the limited territories (large populated
and industrial areas) has dramatically aggravated
electromagnetic and ecological compatibility problems.
The radiated power of these systems’ base stations can
reach 5-10 kW (up to 320-350 W per channel), which
can be ecologically dangerous in case their antennas are
installed in residential districts as well as in the vicinity
of industrial premises. Because of their comparatively
large power, portable (0.5-5W) and mobile (5-50 W)
units represent significant danger to their users. [1-3].
Approximately half the radiated power of a hand-held
mobile phone is absorbed in a person’s head [4].
According to certain data, the radiated power level of
portable units which is acceptable from the medical
point of view is 100-300 mW [5].
The Use of a Self-Phased Array Antenna
The above-mentioned problems can be fully solved
by substantial reduction of the power radiated by mobile
communications system transmitters. In this case the
service areas of these systems may retain their size if a
transition to the microcellular level is made as well as if
sensitivity of the receivers is increased or antennas gain
is expanded.
Conclusion
A self-phased array antenna is very promising for
the use in mobile communications. Its design is very
simple: it performs self-phasing without phase shifters
and adaptive control electronics. The large progress in
the field of microwave IC technology makes its
production very simple and cheap.