The purpose of any antenna, whether in a communica
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Posted On: 04/14/2015 12:25:12 AM
The purpose of any antenna, whether in a communications tower or a mobile phone, is to launch energy into free space in the form of electromagnetic or radio waves, and to collect energy from free space to feed into the device. One of the biggest problems in modern electronics, however, is that antennas are still quite big and incompatible with electronic circuits – which are ultra-small and getting smaller all the time.
“Antennas, or aerials, are one of the limiting factors when trying to make smaller and smaller systems, since below a certain size, the losses become too great,” said Professor Gehan Amaratunga of Cambridge’s Department of Engineering, who led the research. “An aerial’s size is determined by the wavelength associated with the transmission frequency of the application, and in most cases it’s a matter of finding a compromise between aerial size and the characteristics required for that application.”
Another challenge with aerials is that certain physical variables associated with radiation of energy are not well understood. For example, there is still no well-defined mathematical model related to the operation of a practical aerial. Most of what we know about electromagnetic radiation comes from theories first proposed by James Clerk Maxwell in the 19th century, which state that electromagnetic radiation is generated by accelerating electrons.
However, this theory becomes problematic when dealing with radio wave emission from a dielectric solid, a material which normally acts as an insulator, meaning that electrons are not free to move around. Despite this, dielectric resonators are already used as antennas in mobile phones, for example.
“In dielectric aerials, the medium has high permittivity, meaning that the velocity of the radio wave decreases as it enters the medium,” said Dr Dhiraj Sinha, the paper’s lead author. “What hasn’t been known is how the dielectric medium results in emission of electromagnetic waves. This mystery has puzzled scientists and engineers for more than 60 years.”
https://nanotechnologyworld.org/news/details/...-on-a-chip
“Antennas, or aerials, are one of the limiting factors when trying to make smaller and smaller systems, since below a certain size, the losses become too great,” said Professor Gehan Amaratunga of Cambridge’s Department of Engineering, who led the research. “An aerial’s size is determined by the wavelength associated with the transmission frequency of the application, and in most cases it’s a matter of finding a compromise between aerial size and the characteristics required for that application.”
Another challenge with aerials is that certain physical variables associated with radiation of energy are not well understood. For example, there is still no well-defined mathematical model related to the operation of a practical aerial. Most of what we know about electromagnetic radiation comes from theories first proposed by James Clerk Maxwell in the 19th century, which state that electromagnetic radiation is generated by accelerating electrons.
However, this theory becomes problematic when dealing with radio wave emission from a dielectric solid, a material which normally acts as an insulator, meaning that electrons are not free to move around. Despite this, dielectric resonators are already used as antennas in mobile phones, for example.
“In dielectric aerials, the medium has high permittivity, meaning that the velocity of the radio wave decreases as it enters the medium,” said Dr Dhiraj Sinha, the paper’s lead author. “What hasn’t been known is how the dielectric medium results in emission of electromagnetic waves. This mystery has puzzled scientists and engineers for more than 60 years.”
https://nanotechnologyworld.org/news/details/...-on-a-chip
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