This article is about ISM radio bands. It is not to be confused with Short-range devices.
The ISM radio bands are portions of the radio spectrum reserved internationally for industrial, scientific, and medical (ISM) purposes, excluding applications in telecommunications.[1] Examples of applications for the use of radio frequency (RF) energy in these bands include RF heating, microwave ovens, and medical diathermy machines. The powerful emissions of these devices can create electromagnetic interference and disrupt radio communication using the same frequency, so these devices are limited to certain bands of frequencies. In general, communications equipment operating in ISM bands must tolerate any interference generated by ISM applications, and users have no regulatory protection from ISM device operation in these bands.
Despite the intent of the original allocations, in recent years the fastest-growing use of these bands has been for short-range, low-power wireless communications systems, since these bands are often approved for such devices, which can be used without a government license, as would otherwise be required for transmitters; ISM frequencies are often chosen for this purpose as they already must tolerate interference issues. Cordless phones, Bluetooth devices, near-field communication (NFC) devices, garage door openers, baby monitors, and wireless computer networks (Wi-Fi) may all use the ISM frequencies, although these low-power transmitters are not considered to be ISM devices.
Definition
The ISM bands are defined by the ITU Radio Regulations (article 5) in footnotes 5.138, 5.150, and 5.280 of the Radio Regulations. Individual countries' use of the bands designated in these sections may differ due to variations in national radio regulations. Because communication devices using the ISM bands must tolerate any interference from ISM equipment, unlicensed operations are typically permitted to use these bands, since unlicensed operation typically needs to be tolerant of interference from other devices anyway. The ISM bands share allocations with unlicensed and licensed operations; however, due to the high likelihood of harmful interference, licensed use of the bands is typically low. In the United States, uses of the ISM bands are governed by Part 18 of the Federal Communications Commission (FCC) rules, while Part 15 contains the rules for unlicensed communication devices, even those that share ISM frequencies. In Europe, the ETSI develops standards for the use of short-range devices, some of which operate in ISM bands. The use of the ISM bands is regulated by the national spectrum regulation authorities that are members of the CEPT.
Frequency allocations
The allocation of radio frequencies is provided according to Article 5 of the ITU Radio Regulations (edition 2012).[2]
In order to improve harmonisation in spectrum utilisation, the majority of service allocations stipulated in this document were incorporated in national tables of frequency allocations and utilisations which are within the responsibilities of the appropriate national administrations. The allocation might be primary, secondary, exclusive, or shared.
primary allocation: is indicated by writing in capital letters (see example below)
secondary allocation: is indicated by small letters
exclusive or shared utilization: is within the responsibility of administrations
EARTH EXPLORATION-SATELLITE (passive), FIXED, INTER-SATELLITE, MOBILE, SPACE RESEARCH (passive) & Amateur service
244 GHz
246GHz
245 GHz
2 GHz
A
Subject to local acceptance
RADIOLOCATION, RADIO ASTRONOMY, Amateur & Amateur-satellite service
Type A (footnote 5.138) = frequency bands are designated for ISM applications. The use of these frequency bands for ISM applications shall be subject to special authorization by the administration concerned, in agreement with other administrations whose radiocommunication services might be affected. In applying this provision, administrations shall have due regard to the latest relevant ITU-R Recommendations.
Type B (footnote 5.150) = frequency bands are also designated for ISM applications. Radiocommunication services operating within these bands must accept harmful interference which may be caused by these applications.
ITU RR, (Footnote 5.280) = In Germany, Austria, Bosnia and Herzegovina, Croatia, North Macedonia, Liechtenstein, Montenegro, Portugal, Serbia, Slovenia and Switzerland, the band 433.05–434.79MHz (center frequency 433.92MHz) is designated for ISM applications. Radio communication services of these countries operating within this band must accept harmful interference which may be caused by these applications.
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The ISM bands were first established at the International Telecommunications Conference of the ITU in Atlantic City, 1947. The American delegation specifically proposed several bands, including the now commonplace 2.4GHz band, to accommodate the then nascent process of microwave heating;[3] however, FCC annual reports of that time suggest that much preparation was done ahead of these presentations.[4]
The report of the August 9th 1947 meeting of the Allocation of Frequencies committee[5] includes the remark:
"The delegate of the United States, referring to his request that the frequency 2450 Mc/s be allocated for I.S.M., indicated that there was in existence in the United States, and working on this frequency a diathermy machine and an electronic cooker, and that the latter might eventually be installed in transatlantic ships and airplanes. There was therefore some point in attempting to reach world agreement on this subject."
Radio frequencies in the ISM bands have been used for communication purposes, although such devices may experience interference from non-communication sources. In the United States, as early as 1958 Class D Citizens Band, a Part 95 service, was allocated to frequencies that are also allocated to ISM. [1]
In the U.S., the FCC first made unlicensed spread spectrum available in the ISM bands in rules adopted on May 9, 1985.[6] The FCC action was proposed by Michael Marcus of the FCC staff in 1980 and the subsequent regulatory action took five more years. It was part of a broader proposal to allow civil use of spread spectrum technology and was opposed at the time by mainstream equipment manufacturers and many radio system operators.[7]
Many other countries later developed similar regulations, enabling use of this technology. [citation needed]
Applications
Industrial, scientific and medical (ISM) applications (of radio frequency energy) (short: ISM applications) are – according to article 1.15 of the International Telecommunication Union's (ITU) ITU Radio Regulations (RR)[8] – defined as «Operation of equipment or appliances designed to generate and use locally radio frequency energy for industrial, scientific, medical, domestic or similar purposes, excluding applications in the field of telecommunications.»
The original ISM specifications envisioned that the bands would be used primarily for noncommunication purposes, such as heating. The bands are still widely used for these purposes. For many people, the most commonly encountered ISM device is the home microwave oven operating at 2.45GHz which uses microwaves to cook food. Industrial heating is another big application area; such as induction heating, microwave heat treating, plastic softening, and plastic welding processes. In medical settings, shortwave and microwave diathermy machines use radio waves in the ISM bands to apply deep heating to the body for relaxation and healing. More recently hyperthermia therapy uses microwaves to heat tissue to kill cancer cells.
However, as detailed below, the increasing congestion of the radio spectrum, the increasing sophistication of microelectronics, and the attraction of unlicensed use, has in recent decades led to an explosion of uses of these bands for short range communication systems for wireless devices, which are now by far the largest uses of these bands. These are sometimes called "non ISM" uses since they do not fall under the originally envisioned "industrial", "scientific", and "medical" application areas. One of the largest applications has been wireless networking (Wi-Fi). The IEEE 802.11 wireless networking protocols, the standards on which almost all wireless systems are based, use the ISM bands. Virtually all laptops, tablet computers, computer printers and cellphones now have 802.11 wireless modems using the 2.4 and 5.7GHz ISM bands. Bluetooth is another networking technology using the 2.4GHz band, which can be problematic given the probability of interference.[9]Near-field communication (NFC) devices such as proximity cards and contactless smart cards use the lower-frequency 13 and 27MHz ISM bands. Other short-range devices using the ISM bands are: wireless microphones, baby monitors, garage door openers, wireless doorbells, keyless entry systems for vehicles, radio control channels for UAVs (drones), wireless surveillance systems, RFID systems for merchandise, and wild animal tracking systems.
Also in space applications, a helicon double-layerion thruster is a prototype spacecraft propulsion engine which uses a 13.56MHz transmission to break down and heat gas into plasma.
Common non-ISM uses
In recent years ISM bands have also been shared with (non-ISM) license-free error-tolerant communications applications such as wireless sensor networks in the 915MHz and 2.450GHz bands, as well as wireless LANs and cordless phones in the 915MHz, 2.450GHz, and 5.800GHz bands. Because unlicensed devices are required to be tolerant of ISM emissions in these bands, unlicensed low-power users are generally able to operate in these bands without causing problems for ISM users. ISM equipment does not necessarily include a radio receiver in the ISM band (e.g. a microwave oven does not have a receiver).
In the United States, according to 47 CFR Part 15.5, low power communication devices must accept interference from licensed users of that frequency band, and the Part 15 device must not cause interference to licensed users. Note that the 915MHz band should not be used in countries outside Region 2, except those that specifically allow it, such as Australia and Israel, especially those that use the GSM-900 band for cellphones. The ISM bands are also widely used for Radio-frequency identification (RFID) applications with the most commonly used band being the 13.56MHz band used by systems compliant with ISO/IEC 14443 including those used by biometric passports and contactless smart cards.
In Europe, the use of the ISM band is covered by Short Range Device regulations issued by European Commission, based on technical recommendations by CEPT and standards by ETSI. In most of Europe, LPD433 band is allowed for license-free voice communication in addition to PMR446.
ANT / ANT+ (originates from Adaptive Network Topology) is a proprietary (but open access) multicast wireless sensor network technology designed and marketed by ANT Wireless. ANT devices may use any RF frequency from 2400MHz to 2524MHz, with the exception of 2457MHz, which is reserved for ANT+ devices.[11]
IEEE 802.15.4 - Zigbee and other personal area networks may use the 915 MHz and 2450 MHz ISM bands because of frequency sharing between different allocations.
Wireless LANs and cordless phones can also use bands other than those shared with ISM, but such uses require approval on a country by country basis. DECT phones use allocated spectrum outside the ISM bands that differs in Europe and North America. Ultra-wideband LANs require more spectrum than the ISM bands can provide, so the relevant standards such as IEEE 802.15.4a are designed to make use of spectrum outside the ISM bands. Despite the fact that these additional bands are outside the official ITU-R ISM bands, because they are used for the same types of low power personal communications, they are sometimes incorrectly referred to as ISM bands as well.
Several brands of radio control equipment use the 2.4 GHz band range for low power remote control of toys, from gas powered cars to miniature aircraft.
Worldwide Digital Cordless Telecommunications or WDCT is a technology that uses the 2.4 GHz radio spectrum.
Google's Project Loon used ISM bands (specifically 2.4 and 5.8GHz bands) for balloon-to-balloon and balloon-to-ground communications.
Pursuant to 47 CFR Part 97 some ISM bands are used by licensed amateur radio operators for communication - including amateur television.
Digital Enhanced Cordless Telecommunications, usually known by the acronym DECT, is a standard used for creating cordless telephone systems and for IoT systems. It originated in Europe, where it is the common standard, replacing earlier cordless phone standards, such as 900 MHz CT1 and CT2. The IoT usage relies on the new DECT-2020 standard.
Ultra high frequency (UHF) is the ITU designation for radio frequencies in the range between 300 megahertz (MHz) and 3 gigahertz (GHz), also known as the decimetre band as the wavelengths range from one meter to one tenth of a meter. Radio waves with frequencies above the UHF band fall into the super-high frequency (SHF) or microwave frequency range. Lower frequency signals fall into the VHF or lower bands. UHF radio waves propagate mainly by line of sight; they are blocked by hills and large buildings although the transmission through building walls is strong enough for indoor reception. They are used for television broadcasting, cell phones, satellite communication including GPS, personal radio services including Wi-Fi and Bluetooth, walkie-talkies, cordless phones, satellite phones, and numerous other applications.
Wireless local loop (WLL) is the use of a wireless communications link as the "last mile / first mile" connection for delivering plain old telephone service (POTS) or Internet access to telecommunications customers. Various types of WLL systems and technologies exist.
The S band is a designation by the Institute of Electrical and Electronics Engineers (IEEE) for a part of the microwave band of the electromagnetic spectrum covering frequencies from 2 to 4 gigahertz (GHz). Thus it crosses the conventional boundary between the UHF and SHF bands at 3.0 GHz. The S band is used by airport surveillance radar for air traffic control, weather radar, surface ship radar, and some communications satellites, especially those satellites used by NASA to communicate with the Space Shuttle and the International Space Station. The 10 cm radar short-band ranges roughly from 1.55 to 5.2 GHz. The S band also contains the 2.4–2.483 GHz ISM band, widely used for low power unlicensed microwave devices such as cordless phones, wireless headphones (Bluetooth), wireless networking (WiFi), garage door openers, keyless vehicle locks, baby monitors as well as for medical diathermy machines and microwave ovens. India's regional satellite navigation network (IRNSS) broadcasts on 2.483778 to 2.500278 GHz.
Code of Federal Regulations, Title 47, Part 15 is an oft-quoted part of Federal Communications Commission (FCC) rules and regulations regarding unlicensed transmissions. It is a part of Title 47 of the Code of Federal Regulations (CFR), and regulates everything from spurious emissions to unlicensed low-power broadcasting. Nearly every electronics device sold inside the United States radiates unintentional emissions, and must be reviewed to comply with Part 15 before it can be advertised or sold in the US market.
The radio spectrum is the part of the electromagnetic spectrum with frequencies from 3 Hz to 3,000 GHz (3 THz). Electromagnetic waves in this frequency range, called radio waves, are widely used in modern technology, particularly in telecommunication. To prevent interference between different users, the generation and transmission of radio waves is strictly regulated by national laws, coordinated by an international body, the International Telecommunication Union (ITU).
A cordless telephone or portable telephone has a portable telephone handset that connects by radio to a base station connected to the public telephone network. The operational range is limited, usually to the same building or within some short distance from the base station.
The 33-centimeter or 900 MHz band is a portion of the UHF radio spectrum internationally allocated to amateur radio on a secondary basis. It ranges from 902 to 928 MHz and is unique to ITU Region 2 (Americas). It is primarily used for very local communications as opposed to bands lower in frequency. However, very high antennas with high gain have shown 33 centimeters can provide good long-range communications almost equal to systems on lower frequencies such as the 70 centimeter band. The band is also used by industrial, scientific, and medical (ISM) equipment, as well as low-powered unlicensed devices. Amateur stations must accept harmful interference caused by ISM users but may receive protection from unlicensed devices.
The Unlicensed National Information Infrastructure (U-NII) radio band, as defined by the United States Federal Communications Commission, is part of the radio frequency spectrum used by WLAN devices and by many wireless ISPs.
High-speed multimedia radio (HSMM) is the implementation of high-speed wireless TCP/IP data networks over amateur radio frequency allocations using commercial off-the-shelf (COTS) hardware such as 802.11 Wi-Fi access points. This is possible because the 802.11 unlicensed frequency bands partially overlap with amateur radio bands and ISM bands in many countries. Only licensed amateur radio operators may legally use amplifiers and high-gain antennas within amateur radio frequencies to increase the power and coverage of an 802.11 signal.
IEEE 802.11y-2008 is an amendment to the IEEE 802.11-2007 standard that enables data transfer equipment to operate using the 802.11a protocol on a co-primary basis in the 3650 to 3700 MHz band except when near a grandfathered satellite earth station. IEEE 802.11y is only being allowed as a licensed band. It was approved for publication by the IEEE on September 26, 2008.
Dynamic Frequency Selection (DFS) is a channel allocation scheme specified for wireless LANs, commonly known as Wi-Fi. It is designed to prevent electromagnetic interference by avoiding co-channel operation with systems that predated Wi-Fi, such as military radar, satellite communication, and weather radar, and also to provide on aggregate a near-uniform loading of the spectrum. It was standardized in 2003 as part of IEEE 802.11h.
The 5-centimeter or 5 GHz band is a portion of the SHF (microwave) radio spectrum internationally allocated to amateur radio and amateur satellite use on a secondary basis. In ITU regions 1 and 3, the amateur radio band is between 5,650 MHz and 5,850 MHz. In ITU region 2, the amateur radio band is between 5,650 MHz and 5,925 MHz. The amateur satellite service is allocated 5,830 to 5,850 MHz, for down-links only on a secondary basis, and it is also allocated 5,650 to 5,670 MHz, for up-links only on a non-interference basis to other users. Amateur stations must accept harmful interference from ISM users operating in the band. The band is within the IEEE C Band spectrum.
LDMOS is a planar double-diffused MOSFET used in amplifiers, including microwave power amplifiers, RF power amplifiers and audio power amplifiers. These transistors are often fabricated on p/p+ silicon epitaxial layers. The fabrication of LDMOS devices mostly involves various ion-implantation and subsequent annealing cycles. As an example, the drift region of this power MOSFET is fabricated using up to three ion implantation sequences in order to achieve the appropriate doping profile needed to withstand high electric fields.
The 13 centimeter, 2.3 GHz or 2.4 GHz band is a portion of the UHF (microwave) radio spectrum internationally allocated to amateur radio and amateur satellite use on a secondary basis. The amateur radio band is between 2300 MHz and 2450 MHz, and thereby inside the S-band. The amateur satellite band is between 2400 MHz and 2450 MHz, and its use by satellite operations is on a non-interference basis to other radio users. The license privileges of amateur radio operators include the use of frequencies and a wide variety of modes within these ranges for telecommunication. The allocations are the same in all three ITU Regions.
There are several uses of the 2.4 GHz ISM radio band. Interference may occur between devices operating at 2.4 GHz. This article details the different users of the 2.4 GHz band, how they cause interference to other users and how they are prone to interference from other users.
The 1-millimeter band is a portion of the EHF (microwave) radio spectrum internationally allocated to amateur radio and amateur satellite use. The band is between 241 GHz and 250 GHz.
The 2.5-millimeter or 122 GHz band is a portion of the EHF (microwave) radio spectrum internationally allocated to amateur radio use between 122.250 GHz and 123.000 GHz.
The C band is a designation by the Institute of Electrical and Electronics Engineers (IEEE) for a portion of the electromagnetic spectrum in the microwave range of frequencies ranging from 4.0 to 8.0 gigahertz (GHz). However, the U.S. Federal Communications Commission C band proceeding and auction, designated 3.7–4.2 GHz as C band. The C band is used for many satellite communications transmissions, some Wi-Fi devices, some cordless telephones, as well as some radar and weather radar systems.
References
↑ "ARTICLE 1 - Terms and Definitions"(PDF). life.itu.ch. International Telecommunication Union. 19 October 2009. 1.15. industrial, scientific and medical (ISM) applications (of radio frequency energy): Operation of equipment or appliances designed to generate and use locally radio frequency energy for industrial, scientific, medical, domestic or similar purposes, excluding applications in the field of telecommunications.
1 2 ITU Radio Regulations 2020, CHAPTER II – Frequencies, ARTICLE 5 Frequency allocations, Section IV – Table of Frequency Allocations
↑ ITU Radio Regulations, Section IV. Radio Stations and Systems – Article 1.15, definition: Industrial, scientific and medical (ISM) applications (of radio frequency energy) / ISM application
In the US, CFR07/47cfr18 07.html Title 47 Part 18 describes the regulation of the ISM bands. contains some of the regulations for wireless LAN devices operating in three of the low power communication, Part 15, bands.
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