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A microwave paradigm

Ubiquity, Volume 2007 Issue January | BY Joseph Z. Bih 

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Full citation in the ACM Digital Library


   Microwaves are a form of electromagnetic wave. The range of electromagnetic waves with different wavelengths is called the electromagnetic spectrum - from radio waves to microwaves, infrared and ultraviolet rays, and gamma rays. Microwaves have a much longer wavelength than light - ranging from about a foot to less than half an inch.    The evolution of microwave technology generates the following applications:

  • To generate microwaves and simply heat something with them lead to development of microwave ovens and industrial heating applications.
  • To generate a microwave beam, bouncing it off an object, and receiving the echo lead to the discovery of radars. Developed during World War II, microwave radars today are used to guide missiles, locate storms, and direct airline pilots.
  • To put information onto a microwave beam by satellites, finding applications in wireless communication systems—cell phones, wireless computer networks, and wireless palm pilots.
  • To build sensitive receivers to detect the naturally occurring microwave radiation through radio telescopes to study microwave emissions from stars, galaxies, and even the leftover microwave energy from the Big Bang. The applications foresaw a paradigm in reshaping many industries.

    Microwave Applied in Telecommunications Industry
       CATV systems. Extensively used in the broadcast and cable television industries, as well as in telephony and computer networking, microwave technology has proved to be a superior technology and has been continually generating tremendous values.
       Microwaves are employed by telecommunications industries in the form of both terrestrial relays and satellite communications. Microwave technology was critical to the development of the community antenna television (CATV) [2] industry. Local CATV systems were restricted in channel selection to those stations that could be received over-the-air via tall "master" antennas before the early 1950s. In such situations, a CATV system could flourish only within 100-150 miles of the nearest broadcast television markets. It is the microwave relays that first made it possible for CATV systems to operate miles from TV stations, creating a boon to remote communities, where television was not accessible otherwise. Microwave also introduced the possibility for CATV operators to select which broadcast signals they would carry, allowing them to bypass closer signals in order to provide their customers with more desirable programming—perhaps from well-funded stations in large cities. Microwave technology prompted the earliest efforts by the Federal Communications Commission to regulate CATV [2].
       Two-way wireless microwave system. At Illinois Institute of Technology Microwave Laboratory, scientist Thomas Wong developed a new microwave technology that allows a single device to send and receive multiple signals with a higher carrier density than conventional designs [3]. The patented technology offers the potential for a two-way wireless microwave system to simultaneously transmit video, audio and data. The new applications might include the simultaneous transmission of video conferencing, movies on demand, home shopping, high definition TV (with as many as 500 channels and common carrier telephone service).
       Microwave radios can help establish connections quickly by allowing the options to designing the wireless communication systems to meet very specific requirements. Competitive technologies such as fiber, LEC, T-1s, and xDSL certainly put constraints on users since they require third party service for transmission. The microwave technology help user establish connectivity quickly since users need not rely on the political "right of way" access permission associated with fiber or LEC T-1 connectivity. The new technology creates benefit of relatively low fixed costs associated with constructing the link or links and the rarity of recurring service costs. [4] Cellular operations, CLECs, and ISPs have become strong users of microwave. To provide expanded service to customers and to generate immediate return on investment force cellular carriers to connect cell sites to switching stations quickly and effectively. Carriers often choose microwave for its reliability and quick deployment capabilities.
       Asynchronous Transfer Mode (ATM) traffic over microwave radio links eliminates the hassle of laying cable in large cities. All is done by installing a pizza-size microwave dish atop of the buildings and signing up with a radio frequency service provider for the bandwidth for form the wireless link. Netro Corp. in California pioneered this technology [1] that enables users to connect sides up to five miles apart for high-speed data, video and voice transmission.
       A full-speed Ethernet microwave LAN device made by Microwave Bypass, a 10-year-old wireless microwave pioneer has demonstrated its unique advantageous [5] applications among hospitals and universities with large campus networks, schools districts, military bases, and the government. It saves 50% to 70% cost, compared with leased lines while maintaining the high performance even in adverse weather conditions line rain and dense fog. In addition, using microwave technology to link LANs at native speeds and at distances up to 15 miles needs only one direct line of sight between locations. The one-time capital equipment only involves purchasing the antennae and radio frequency modems for each site.
       Virtually all communications with vehicles for space exploration is carried on with microwaves. Pictures and voice signals from the Space Shuttle, the International Space Station, and exploration spacecraft (the Voyager and Pioneer Programs) are all carried by microwave signals.
       Microwave systems are a low cost, high security alternative to many traditional communications system options.

    Microwave Military Applications
       Microwave Weapon Systems. One typical Ericsson's product is MIDIS [6] -MODULAR, MULTI-FUNCTIONAL DEFENSIVE INFORMATION SYSTEM. MIDIS is a highly modular and multi-functional defensive information system that meets the requirements for situation awareness, survivability and sensor fusion in tomorrow's dense and complex signal environment. MIDIS introduces new principles for signal selection and adaptive processing allied with state-of-the-art technology of Ericsson's in-house integrated Microwave MultiChip Modules (MMCM).
       The interest of U.S. Navy in exploring the use of High Power Microwave (HPM) techniques and technologies for purposes of building anti-ship missile defense (ASMD) and command and control warfare (C2W) would likely encourage joint proposals wherein the project would be executed in a Naval Research Laboratory (NRL)/contractor team format to get the maximum amount of research in the most efficient manner.
       At Los Alamos Laboratory, scientists designed a new high-powered microwave (HPM) weapon system [7]. These weapons, when delivered by a glide bomb or cruise missile, can be flown within yards of a target and exploded to produce a pulse of high-power microwaves that can disable electronic circuitry in computers and communications equipment and perhaps erase software and computer memories. Los Alamos continues the research and its support to military initiatives: high-power microwave and ultra-wideband systems and related technologies including 3-D modeling of microwave sources, effects testing and analysis, and explosive pulsed power.
       According to retired Army Col. John Alexander, the very intense pulse of electromagnetic power [8] can get into the electronic equipment by two paths-front door and back door coupling. The front doors are antennas or other paths open to the outside and lead directly to the targeted equipment. Back door coupling results from a standing wave of energy that may come indirectly into the equipment through wiring, power cables, poorly shielded frames, telephone lines or even holes in the black boxes.
       The phased-array radar [9] was an important development in military microwave technology. To make a very narrow beam with microwaves, an antenna must be very large, tens or hundreds of feet in diameter. In a battle, there may no time to wait for a large, slow dish antenna to move. The idea of a "phased array" came in. A phased array is a set of hundreds or thousands of little radar sets that all emit microwaves so that the peaks all line up in a certain direction. By changing the relative spacing of the peaks electronically, the resulting narrow beam can be steered anywhere in much less than a second, without any mechanical motion. Dozens of these phased-array radars have been built and used for everything from missile tracking to scientific experiments.
       Sophisticated electronic countermeasures or "jamming" systems are used to send out false and misleading signals to confuse enemy radars. Reliable mobile communications can ensure armed forces be able to move quickly. Microwaves transmitted and received via satellites and other means provide much of the increasingly sophisticated communications needed for modern warfare. This has led directly to "eavesdropping" or microwave espionage. Many major nations, including the U. S., have extensive operations that intercept microwave communications and decode them for spying purposes. Echelon [10], a project of the United States' National Security Agency (NSA), is a worldwide network for intercepting communications and the biggest electronic surveillance operation in the world. Echelon involves UK, Australia, Germany, Japan, China, and other countries. Listening stations, including Britain's famous GCHQ, are located in each country to scan the airwaves for all kinds of electronic communications.
       The global positioning system or GPS receivers use microwave beams from satellites to find target position almost anywhere on Earth with an error as small as a few yards, depending on the circumstances. The GPS system was originally designed for military applications, but a wide range of civilian users from trucking companies to surveyors have started to use it as well.

    Microwave Technology in Network Management
       Natural disaster can wreak havoc on a telephone network and its supporting infrastructure. Utilities often use microwave systems to restore communications while replacing damaged infrastructure.
       Microwave radio links are used to integrate a broad range of networks from fixed and mobile communications networks (e.g. Evolium dedicated to ILECs, CLECs and GSM; DART; ALCATEL [4]) in rural, suburban and urban environments, to corporate and private networks. Microwave technology provides wide bandwidths [3] for transporting crucial voice and data information where network coverage is inadequate or in need of rapid expansion.
       High-speed point-to-point (PtP) microwave wireless networks [4] provide enterprise LAN extension, application sharing between locations, and aggregation and backhaul of IP traffic; with traffic capacities of over 100Mbps and low latency, PtP allows virtually any IP application to be carried, including VLAN data, streaming video, VoIP, and encrypted data.
       IP traffic backhaul [see Figure 1] presents a picture of how the microwave radio systems can be integrated into a network. Building out the networks by aggregating lower-speed data connections to a high-speed PtP microwave radio backhaul network, [4, 5] wireless service providers extend their services as large-scale WISPs or as a wireless carrier's carrier by providing wireless backhaul for local or regional WISPs. The microwave radio IP backhaul network typically connects to a fiber backbone, which in turn connects to an Internet gateway point.
       Microwave radio systems can be fully managed through Simple Network Management Protocol (SNMP) using industry-standard SNMP network management stations such as HP Open View or Castle Rock Computing's SNMPc. [4] SNMP allows service providers to monitor the microwave radio link performance, device performance, and IP traffic statistics, and provides the ability to monitor alarms or traps generated from the microwave radio system.
       A microwave radio system that provides an Ethernet interface can easily connect to a large variety of networking devices such as switches or routers, as shown in Figure 2. The microwave radio system is connected in the same manner as any other networking equipment through a CAT5 Ethernet cable, with options for auto negotiation and for forced 100Mbps full duplex.
    In contrast to WLAN technology, microwave systems offer many security refinements. Since transmitted microwave signal, or beam, is as narrow as 2 degrees or less, a potential eavesdropper must be in line with the signal in order to detect any energy.
       The authentication technique [4] used in microwave radio systems at the endpoints between each other prior to data transmission shows that for authentication failures, such as the case where an eavesdropper tries to communicate with a node, the system can be configured to stop all IP traffic flow until the peer node re-authenticates.
       The advantages of microwave radios—offering continuous wire-speed, low latency, and zero packet loss guarantee the safety of IP applications carried over the link and the performance to meet user expectations. In addition, the security features and network management capabilities augments itself especially appealing to service providers and IT managers.

       Microwave, a low-risk and time proven technology, dispels IS managers fears in the following situations: in major metropolitan areas where carriers cannot easily provide landlines, resulting in high prices; under high ways, bodies of water and in deserts where landlines often cannot run; to remote locations where landlines are not always offered.

    Other Applications
       Radar turned out to have many peacetime applications: Air traffic controllers use radars to locate and guide everything from gliders to jumbo jets along the world's airways; specialized weather radars keep pilots and the general public informed about storms; shipboard and airborne radars aid navigation through the sea and the sky. These applications were explored initially during World War II, and developed commercially in the 1950s.
       Microwave treatment. As many of the medical experiments have been successful, at least one form of microwave treatment (for prostate cancer) has been given to thousands of patients. Before microwaves were used in therapy, high-frequency radio waves produced by diathermy machines were used in the treatment of arthritis and other conditions. The deep heating produced by these waves was believed to be helpful in the treatment of joint and circulatory problems.
       Ozone layer monitoring. Concerns that certain chemicals used in refrigerators (called chlorofluorocarbons) were destroying the ozone layer led to an intensive effort to monitor the layer's thickness. It turns out that observing very short microwaves (millimeter waves) provide accurate information about the condition of the ozone layer, and several microwave monitoring stations around the world constantly keep an eye on this problem.
       Microwave cosmic background radiation. Cosmologists predicted that the Big Bang should have left a small but detectible trace called the cosmic background radiation. Two Bell Telephone Laboratories scientists, A. Penzias and R. Wilson discovered this radiation with a large radio telescope in 1964. The Cosmic Background

       Explorer satellite (COBE), launched in 1989, for the first time detected slight irregularities in the microwave background radiation. These irregularities presents a picture of the universe as it was a very short time after it began, and confirmed or contradicted a number of theories about the universe's early stages.
       The CSIRO SpeedGrader [11] was developed by world acclaimed timber innovator and Wallenberg Prize winner, Dr Bob Leicester. Australian scientists have added a new dimension to the grading of timber with the development of high speed scanning using microwave technology. According to Leicester, SpeedGrader can be used to analyze up to 50 mm thick and measure the presence and size of natural features such as knots, slope of grain and juvenile wood. "Detection of this undesirable wood with microwave scanners helps remove headaches for end users, saving replacement materials and dealing with unhappy customers," Leicester says. SpeedGrader scanners are low-powered, (around 0.15 milliwatts compared with that of the average torch battery) and considerably safer than more expensive alternatives based on x-ray technology.
       A revolutionary new process using microwaves [12] was introduced by BATEMAN to unlock gold, copper and other metals from refractory hard to recover ores. Developed in Canada by EMR Microwave Technologies, this microwave technology is used to breakdown or modify sulphide, carbonaceous and other materials shielding the valuable minerals in ores. When applied to sulphide flotation concentrates, it could replace historic pretreatment processes such as autoclaving, roasting or smelting, resulting in the benefits of cost savings and more effective metal recovery , especially those mineral reserves previously rejected as economically infeasible. In tests on a Mexican ore [12] in which both gold and silver were trapped, 50% of gold unrecoverable by cyanide leach, the microwave treatment resulted in up to 95% gold recovery. The new process promises great commercial potential of microwave technology to the mining industry.

       One possible future use of microwaves that has yet to prove popular is the transmission of large amounts of electric power. The postwar high-power microwave transmitters became efficient enough to send thousands of watts over distances of a mile or more. Engineers have calculated that if several large solar-powered satellites were placed in orbit, the energy collected could be beamed to earth and gathered by arrays of receiving antennas covering many square miles.

       The industrial applications of microwave technology are commonly found in ceramics, pharmaceutical and chemical synthesis, glue and rubber curing and the sterilization and incineration of hazardous materials.

       Conclusion
    The discovery of microwave, initially applied for military purposes, led to its early significant applications—radar and microwave oven. Microwave oven has revolutionized the food industry, creating a paradigm that changed our life styles. Today, most Americans consider microwave oven the most important technological breakthrough since 1969, according to a study conducted by the inventors of the Seiko kinetic watch.

       Microwave technology finds its ways into numerous military applications. Wherever armed conflicts exist, radars, communications systems on the ground and in the air, and guidance systems for sophisticated weapons all use microwaves. The emerging technologies in microwave have altered course of the future war. HPM technology used in developing intelligent and sophisticated modern weapon systems and radar systems has created tremendous advantages on the war.

       The superiority of the microwave technology has demonstrated its power and commercial values in telecommunications and computer networks.

       Microwave, as a well-established technology, and like any other high technology, continues playing a significant role in shaping the world in which we live. The social, economic and cultural ramifications it has produced as a new wave further testifies the powerful paradigm.

    References:
    [1] Wallace, Bob. Start-up cooks up ATM over microwave. Computer Networks, January, 1997
    [2] CATV Operator's Handbook. Editors of BM/E Magazine. Blue Ridge Summit, Pennsylvania: TAB Books, 1973.
    [3] Zeyher, Allen. "Microwave invention opens up broadband communications". Catalyst, summer 1998
    [4] Aurimpex Technologies Inc. Product Profile, Spectrum - Microwave Radio http://www.aurimpex.com/products.html
    [5] Dido, Laura. "Microwave technology lures new users". Computer Networks, August 1995
    [6] ERICSSON MICROWAVE SYSTEMS AB DEFENSE ELECTRONICS AND MICROWAV COMMUNICATIONS. Microwave Systems. www.ericsson.com/microwave
    [7] Los Alamos National Laboratory http://www.lanl.gov/orgs/dod/
    [8] Fulghum, David A. "Microwave Weapons Await a Future War". Aviation Week & Space Technology. June 1999.
    [9] IEEE Microwave Theory and Techniques Society Postwar Applications: Military http://www.mtt.org/old/miscellany/fiftyanniv/
    [10] Echelon (bless you!) http://www.tinhat.com/surveillance/echelon
    [11] "New electronic timber grading - by microwave" http://www.globaltechnoscan.com/archive.htm
    [12] "Microwave Technology Unlock Refractory ores" http://www.batemanbv.com/pdfs/

    Author's Biography
       Joseph Bih has been teaching and researching for more than 5 years. Since completing his graduate studies at the University of North Texas, he has been teaching undergraduate courses at Jarvis College and Tyler Junior College and he is actively involved in research, with many publications through professional journals and technical conferences. His work resulted in grants that helped upgrading computer lab facilities and software, directly benefited the students. He owns MCSE, MCSD, CCNA and OCP other IT certification titles and is actively involved in the industry. His research interests focus on secure networks, information systems management and new technology applications. Joseph Bih is an IEEE Senior Member. He can be reached at [email protected]org.

    COMMENTS

    Have need of 2 ton per day microwave equipment.

    — K Richards, Mon, 14 Apr 2014 04:41:12 UTC

    Interested to know the names and contact details of industrial/commercial size microwave furnace manufacturers for ore processing. Are pictures of ore treatment microwave furnaces/kilns available? What's the largest throughput rate possible for different max processing temperatures?

    — Dr. Karl Cherian, Mon, 08 Oct 2012 03:51:21 UTC

    Comment: --------- 1)Which companies manufactures/assemble, industrial size microwave system, for refractory ore treatment In USA-CHINA - OR ELSEWHERE ? 2) Processing 200 tons of ore concentrate per day. Wilson

    — Wilson Hatanaka, Thu, 20 Sep 2012 18:32:00 UTC

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