Uses of Ultrawide Band Antennas
What Are the Benefits of Using Ultrawide Band Antennas?
Ultrawideband has reduced fading from multipath but can suffer from intersymbol interference. In contrast, carrier based systems deal with both problems
Because its signal can pass through doors and walls, it isn’t bound by line of sight. A wireless communication system that covers the next room as readily as the one it is located in is preferred over a system that needs a transmitter in each room subject to interference when the door between them is open.
UWB antennas are increasingly used in wireless communications at short range because they can transmit a great amount of information across a wide frequency range. It gives you a high data rate system at a low cost and with low power. Directional antennas like Vivaldi antennas are not a good choice for indoor or mobile wireless communication. The planar disk version of a UWB antenna is omni-directional and thus better for this type of application.
When signals are sent over ultra-wide band antennas, a low level of signal over a wide frequency band, less power is needed because it suffers from less interference. The means UWB antennas need less energy to provide internet access, digital voice services and video telephony. UWB antennas also don’t interfere with carrier wave transmissions and narrowband signals. The lower power output reduces the risk of eavesdropping, and when communications are key, the fact that UWB is very hard to jam is attractive. This has led to ultrawideband antennas being used in some tactical handheld radios.
Uses of Ultrawide Band Antennas
Ultrawide-band antennas, also known as ultraband and UWB antennas, have long been used in non-cooperative radar imaging. Advantages of its use here include better special resolution, lower probability of intercept signals and detectible materials penetration. The latter is why ultra wide band antennas are used in ground penetrating radar and wall radar.
UWB antennas are regularly used in impulse based technology like locating systems and radar. UWB could be used in public safety and other high precision positioning applications like precision altimetry. It can also be used for location identification of tagged assets, also known as RFID. Or it can be used for personnel localization, such as when the RFID tag in someone’s badge gives an additional level of security by only accepting their login credentials when the person’s badge is next to the computer.
This technology is sometimes used for smart appliances and electronic signs.
The FCC has authorized use of UWB for vehicular radar systems; these systems are used for collision avoidance and airbag activation. These systems operate at the 22 to 29 GHz range.
UWB antennas can be used for surveillance systems. These systems run between 1.99 and 10.6 GHz. Through wall imaging can operate at the same frequency range or at frequencies below 960 MHz.
Ultrawide band antennas are commonly used with software defined radios. The software defined radio or SDR then only needs the one UWB antenna instead of several to cover whatever frequency range it is set for at that moment. Planar disk ultra wide band antennas are ideal for signal generators and SDR since they can receive signals from any direction.
They can be used as a source antenna for signal generators and transmitter testing.
Ultrawide band antennas are used in spectrum analysis.
The high data rate has made UWB increasingly used for UAV and UGV data links.
Ultrawideband antennas can be used for proximity fuses.
UWB is sometimes used for LPI/D wireless intercom systems.
UWB antennas are periodically used for tactical handheld and network LPI/D radios. They’ve also been used for non-LOS LPI/D groundwave communications. Both of these applications are overwhelmingly restricted to military and governmental use.
What Frequency Ranges Are Used for Ultrawideband Applications?
Ultra-wideband technology or UWB exploded after the FCC decided in 2002 to allow the 3.1 to 10.6 GHz frequency range for commercial applications. The FCC range for UWB antennas is actually broader than the EU’s assigned UWB frequency range, 6.0 to 8.5 GHz.
Note: the maximum power emission limit per the FCC is -41.3 dBm/MHz, regardless of the frequencies used. 50 Mhz is the minimum bandwidth for a UWB signal per the FCC.
How Does UWB Differ from Spread Spectrum?
According to “Introduction to Ultra-Wideband Radar Systems” by James D. Taylor, ultrawideband was called by a number of names before 1990 such as impulse, video pulse, super wideband, carrierless signals, nonsinusoidal and baseband. The common term ultrawideband can simply be seen as “wider than wide band”.
Ultrawide band is not spread spectrum, though it operates on a similar concept. Spread spectrum sends a signal over a frequency range wider than the minimum required to actually send the signal, but its baseband signal is only a few kilohertz wide before being encoded and sent over a wider frequency bandwidth. Spread spectrum has a fractional bandwidth but not as low as UWB. Ultra-wideband signals differ from spread spectrum in that their fractional bandwidth is less than 25%, typically far less. The International Telecommunication Union Radiocommunication Sector sets that threshold at 20% of the center frequency or 500 MHz, whichever is less.
The broader frequency range and lower power requirements are why UWB antennas are increasingly used in indoor wireless networks relative to spread spectrum.
Questions & Answers
Have you searched UWB antenna on eBay lately? There is a wide assortment ranging from $12 to several hundred dollars. Also, Johanson Technology and Taoglas are selling them also. Opinion?
I know there are a variety of companies selling UWB antennas. Antennas designed by WA5VJB of Kent Electronics are among the cheapest.
© 2016 Tamara Wilhite