RuBee is not RFID. It is a long wavelength IEEE (1902.1) wireless peer-to-peer, packet standard, based on magnetic waves, created for harsh environment visibility applications...
RuBee uses low frequencies (131Kz), and has a wavelength of 2,289 Meters or about 1.25 miles. Unlike LF HF or UHF RFID RuBee is an on-demand packet based protocol, similar to WiFi, Bluetooth and Zigbee. All active and passive RFID tags are transponders, they reflect radio signals for data communication, and use the same signal for timing and power. In contrast, RuBee works as a transceiver, similar to a two way walkie-talkie but uses magnetic waves not radio waves (see Maxwell's Equation below). RuBee tags have a crystal and can keep track of time, they also have a battery and static memory. RuBee tags can also have sensors and the ability to data log or store sensor information. Because RuBee uses such a low frequency it does not consume much power (see Planck's Law below) and has a five-year to fifteen-year battery life using simple Li coin size batteries with a range of 1" to 50 feet. RuBee tags overcome many of the technological problems seen with RFID near steel and water, and is field proven in harsh environments. To learn more about the differences between RuBee and RFID see RuBee vs RFID Summary.
Barcodes and RFID are both line-of-sight in harsh environments. RuBee is not line-of-sight in harsh environments; RuBee antennas produce 3D volumetric magnetic waves that go through steel and water. That means RuBee delivers reliable, real-time asset visibility with no Change In Process in any environment.
RuBee has an important advantage over other wireless technologies in that it is not line-of-sight. Plastic, paper, buildings, water, people, steel all block light. If you want to read a barcode you have to take the barcode to the reader. The reader has to have a clear, unblocked view of the barcode. RFID is also blocked by water, people, and steel. Again, if you want to read an RFID tag in a harsh environment you have to take the tag to a reader so it has a clear, unblocked view of the tag. RuBee tags are not blocked by anything read within a large 3D volume, and the signals are not blocked by water or steel (see Tag on I-Beam Underwater Video). RuBee works reliably in harsh environments because it uses magnetic waves no radio waves.
RuBee is unique in that it is the only wireless technology to be approved by the US Department of Energy (DoE) for use in high security, top secret areas where RFID, WiFi, Bluetooth and Zigbee have all been banned. In July 2006, the FDA classified 1902.1 as a Non-Significant Risk (NSR) Class 1 device in medical visibility applications. In April 2007, the FDA issued a warning that HF and UHF RFID may have an untoward effect on implantable devices. In May 2007, a peer-reviewed study was published by the Mayo Clinic showing that RuBee has no effect on pacemakers or ICDs. A second Mayo study has shown RuBee has no EMI or EMC in the operating room (Mayo EMI Study). Visible has started independent laboratory tests and expects its RuBee tags to meet the Intrinsically Safe ANSI 913-88 standard in a Zone 0 or Zone 1 explosive atmosphere as well as the DoD HERO standards. To learn more about RuBee features click on RuBee Fact Sheet or on Whitepaper tab at top of the page.
The Physics of RuBee
Maxwell’s equations quantified the relationship between E the electric field, and H, the magnetic field produced by an electron moving down a conductor. The two photons E and H are linked and impossible to disconnect. A great simplified explanation is found at this URL: Elementary Particles. However, RuBee breaks the rule since it has no significant electric field. RuBee data communication occurs through time varying magnetic fields. RuBee antennas can be designed, and work like light bulbs, to illuminate a 3D volume with “magnetic light”.
A standard RuBee antenna produce about 600 mGauss and the tag produces about 50 mGauss. To put that in perspective, the Earth’s magnetic field is about 500 to 700 mGauss. Magnetic fields from Earth or a permanent magnet do not have any effect on RuBee because they do not vary in time. When a magnetic field does vary in time (possible noise source), it usually has only short range effects on RuBee since signal strength drops off fast (see below). Typical RuBee noise sources are LCD projectors, plasma panel displays, switching power supplies, large transformers and lighting storms. However, RuBee demos and RuBee systems work in the same room with all of these noise sources, because the signal drop off so quickly.
The graphs above plots the RuBee signal in mGauss*100 vs distance from an antenna in feet are important because they show that the RuBee signal drops off 1/R to the 3rd power. In contrast, RF drops off 1/R. That means it is possible to eavesdrop on RF signals many miles away from its source. RuBee signals sink into deep space noise and can not be monitored at a distance. That provides a very high level of security (see Whitepaper, see Slides) over other wireless systems, and also minimizes any tempest or target risks. It also minimizes risk of noise interference. The most serious noise source for RuBee are bolts of lighting since they can transmit electomagnetic signals literally hundreds of miles. However, even the most violent local lighting storm does not compromise RuBee data communication in any serious way, it just slows RuBee down by a few packets.
In 1856 James Clark Maxwell created his equations that described the relationship between the electric field (E) and magnetic field (H) produced by a moving electron. These equations are in effect "Ohms law" for moving electrons and describe the relationship between emitted radio waves (Voltage) and emitted magnetic waves (Current). The impedance or resistance of free space is 377 ohms. This is a universal constant and makes it possible to calculate the electric field (E) from the magnetic field (H) or vice versa. The electric field is given in Volts/meter and the magnetic field is given in Amps/meter and the ratio is E=H*377. This 377 ohm value (Z) is used by the FCC for example to calculate emitted power for all RF systems. The impedance of space Z is the ratio of the electric field to the magnetic field.
However, when emitted energy is measured at a distance of 1/10th of a wavelength or less it is in what is known as the near field and the 377 ohm constant goes out the window. RuBee has a wavelength of 7,511 feet, but tags are typically read in the 10 to 20 foot range or about 1/700th of a wavelength. The impedance of space seen by a RuBee tag is well under 1 ohm not 377 ohms. That is why E becomes so small in near field (E = H * 1). You would have to have a RuBee antenna about ¼ of a mile long and measure E and H about 1,000 feet away, before the impedance gets back up to 377 ohms. In other words, with a RuBee system (or any near field system) you cannot easily calculate E from H; they are decoupled. Good news is magnetic waves, or magnetic photons are not stopped by steel or water.
In 1901 Max Planck (Planck, Max. (1901). "On the Law of Distribution of Energy in the Normal Spectrum". Annalen der Physik, vol. 4, p. 553 ff.) discovered that energy contained in the photons emitted by a moving electron is directly proportional to its frequency. The proportionality constant is known as Planck's constant (E=hv) . Max Planck received a Nobel price in 1918 for this very fundamental discovery and it eventually led to many fundamental discoveries linked to quantum mechanics. Because RuBee uses very low frequency (131 Khz) that means it does not have much energy. That also means it has no known EMI or EMC issues, is intrinsically safe, and has no known human safety issues. Moreover, RuBee signals are so small they do not have any effect on magnetic strip credit cards. RuBee does not erase or affect magnetic cards at all.
