Antenna and Base-Station Diversity for WSN Livestock Monitoring
Diversity Antenna
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1 ©Kathrein/Scholz 03/0 Diversity Multipath propagation Diversity principle Space diversity Polarization diversity
description
Description ab antenna Di
Transcript of Diversity Antenna
Nokia Antenna SeminarDiversity / Multi Path Propagation
signals especially in cities consists of the direct wave and a lot of reflections
the reflections differ in amplitude, phase and polarization
summarized signal level varies a lot within short distances
Rx1
Rx2
downlink (BTS) : high power, high antenna gain
Consequence : Diversity
the diversity concept bases on the idea to have two independent signals available at the base station (two Rx antennas)
considering both signals results in avoiding nulls and improving the average signal level (diversity gain)
©Kathrein/Scholz 03/03
Diversity / Principle
Diversity / Space Diversity
space diversity uses two vertical polarized Rx antennas (Rxa and Rxb) with a horizontal spacing of 12-15
Omni base station
- 3 omni antennas
> to reach the required isolation
between Rx and Tx (>30 dB)
3m
3m
- 3 directional antennas per sector
- all antennas at the same level due to better isolation compared to omnis
©Kathrein/Scholz 03/03
expensive support structures
duplexers reduces the number of antennas but not the applied spacing
raising problems to receive permissions from the land lords to install antenna systems
Without Duplexer
With Duplexer
©Kathrein/Scholz 03/03
polarization diversity uses two antennas of orthogonal polarization
horizontal and vertical radiating elements are combined in a common radome
interlocked dipoles, same size of a single antenna
Disadvantages :
horizontal polarization cannot be used for Tx
Without Duplexer
With Duplexer
©Kathrein/Scholz 03/03
Diversity / X Polarization Diversity
instead of horizontal and vertical polarization the dipoles are slanted +/- 45°
identical situation for both terminations
equivalent diversity results compared to space diversity either in cities or in rural areas
both terminations are suitable for Rx and Tx
Xpol is the technology for future systems !!
Without Duplexer
With Duplexer
©Kathrein/Scholz 03/03
Diversity / X Polarization Diversity
instead of 9 resp. 6 antennas per base station, only 3 Xpol antennas are required
extremely reduced size
due to exellent isolation (> 30 dB for any possible port combination), mounting on a single pole mast with minimum spacing
specific 3-panel brackets available
Diversity with two antennas
signals especially in cities consists of the direct wave and a lot of reflections
the reflections differ in amplitude, phase and polarization
summarized signal level varies a lot within short distances
Rx1
Rx2
downlink (BTS) : high power, high antenna gain
Consequence : Diversity
the diversity concept bases on the idea to have two independent signals available at the base station (two Rx antennas)
considering both signals results in avoiding nulls and improving the average signal level (diversity gain)
©Kathrein/Scholz 03/03
Diversity / Principle
Diversity / Space Diversity
space diversity uses two vertical polarized Rx antennas (Rxa and Rxb) with a horizontal spacing of 12-15
Omni base station
- 3 omni antennas
> to reach the required isolation
between Rx and Tx (>30 dB)
3m
3m
- 3 directional antennas per sector
- all antennas at the same level due to better isolation compared to omnis
©Kathrein/Scholz 03/03
expensive support structures
duplexers reduces the number of antennas but not the applied spacing
raising problems to receive permissions from the land lords to install antenna systems
Without Duplexer
With Duplexer
©Kathrein/Scholz 03/03
polarization diversity uses two antennas of orthogonal polarization
horizontal and vertical radiating elements are combined in a common radome
interlocked dipoles, same size of a single antenna
Disadvantages :
horizontal polarization cannot be used for Tx
Without Duplexer
With Duplexer
©Kathrein/Scholz 03/03
Diversity / X Polarization Diversity
instead of horizontal and vertical polarization the dipoles are slanted +/- 45°
identical situation for both terminations
equivalent diversity results compared to space diversity either in cities or in rural areas
both terminations are suitable for Rx and Tx
Xpol is the technology for future systems !!
Without Duplexer
With Duplexer
©Kathrein/Scholz 03/03
Diversity / X Polarization Diversity
instead of 9 resp. 6 antennas per base station, only 3 Xpol antennas are required
extremely reduced size
due to exellent isolation (> 30 dB for any possible port combination), mounting on a single pole mast with minimum spacing
specific 3-panel brackets available
Diversity with two antennas
