File Name: microwave spectrum and bands .zip
Not a MyNAP member yet? Register for a free account to start saving and receiving special member only perks. The initial surge in microwave technology development was driven by the military needs of the second world war. The tremendous effort that went into development of radar during World War II generated a great body of knowledge on the properties of microwaves and related technologies. A basic understanding of microwaves and their interaction with materials is required to realize the promise, as well as to understand the limitations, of microwave processing. Although there is a broad range of materials that can be processed using microwaves, there are fundamental characteristics and properties that make some materials particularly conducive to microwave processing and others difficult.
The prefix micro- in microwave is not meant to suggest a wavelength in the micrometer range. Rather, it indicates that microwaves are "small" having shorter wavelengths , compared to the radio waves used prior to microwave technology. The boundaries between far infrared , terahertz radiation , microwaves, and ultra-high-frequency radio waves are fairly arbitrary and are used variously between different fields of study. At the high end of the band they are absorbed by gases in the atmosphere, limiting practical communication distances to around a kilometer. Microwaves are widely used in modern technology, for example in point-to-point communication links, wireless networks , microwave radio relay networks, radar , satellite and spacecraft communication , medical diathermy and cancer treatment, remote sensing , radio astronomy , particle accelerators , spectroscopy , industrial heating, collision avoidance systems , garage door openers and keyless entry systems , and for cooking food in microwave ovens. Microwaves occupy a place in the electromagnetic spectrum with frequency above ordinary radio waves , and below infrared light:.
This was based on the considerable interest in the introduction of various services such as fixed wireless access systems, multipoint communication systems, and licence-exempt voice and data equipment. In the spectrum review under Notice DGTP , the Department proposed to designate a modest amount of spectrum in the band 1. The results from the consultation were favourable, and comments indicated that allowing automatic meter reading in this band would facilitate:. Some existing fixed users had concerns over the introduction of telemetry systems in the band 1. Taking into account industry's interest in deploying wireless meter reading services and the increasing competition in the provision of energy distribution services, the Department believes that it is in the public interest to open some spectrum at 1. The Department is fully aware that a number of technologies using both wireline and wireless facilities may be deployed to accommodate automatic meter reading. In terms of wireless facilities, radio facilities for mobile data communication, digital mobile and PCS networks, or licence exempt facilities may prove to be economical solutions.
Microwaves are a type of electromagnetic radiation, as are radio waves, ultraviolet radiation, X-rays and gamma-rays. Microwaves have a range of applications, including communications, radar and, perhaps best known by most people, cooking. Electromagnetic radiation is transmitted in waves or particles at different wavelengths and frequencies.
Microwave and millimeter wave frequency bands are in demand for requirement of more channels in radio communication systems. It has also been recognized that microwave and millimeterwave frequency radiometers on board satellites as promising tools for remote sensing. The frequency more than 10 GHz is affected by rain and cloud. Though the effects of rain on radiowave is more than cloud but the occurence of cloud is more than rain. Cloud has been found to occur for weeks together over this part of the world. It is therefore essential to study cloud morphology over different geographical region.
Dual-feed antennas can be described as a three-port struc-ture, where ports 1 and 2 are the antenna feeds, and port 3 is an invisible radiation port. The first solar collector can be either photovoltaic cells or solar thermal turbine. Bartelmann, P. Starting in the early 's, frequency division multiplex was used to send up to 5, telephone channels on each microwave radio channel, with as many as ten radio channels combined into one antenna for the hop to the next site, up to 70 km away. PDF This paper describes the development of microwave photonic antennas concepts and their Conventional microwave antenna usually has a microstrip.
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