An antenna is a device used to propagate, receive, and/or transmit electromagnetic waves which can have information embedded within them. The antenna creates an electromagnetic wave that carries the original embedded sound information through the atmosphere/space around it. An antenna at a different location, receives the electromagnetic wave, sending it to circuitry (your radio) that then translates it to an electronic signal and then back to a sound wave.
Radio waves are used for wireless transmissions (such as from cell phone towers to the cell phone and wireless internet connections). The radio wave is created by an accelerated charge. This can be done using an alternating current circuit, which forces the electrons in the electrically conducting antenna (a transmitter or receiver) to move back and forth along the antenna. As they move back and forth they speed up and slow down and create an electromagnetic wave. One of the important requirements of an antenna is that the antenna’s length be related to the wavelength of the electromagnetic wave that it is trying to transmit or receive.
The shrinking of mobiles and other communication devices is demanding miniaturization of the antenna as much as possible while preserving the efficiency. “We identified ultra-compact antennas as the critical last step in true device miniaturization. Researchers had successfully shrunk most electronic components, but the true miniaturization of antennas was still a missing piece,” said Howe.
The miniaturization is also needed because it will enable to integrate multiple antennas in a device to support MIMO schemes. Multiple transmit and multiple receive (MIMO) antennas has emerged as one of the most significant technical breakthroughs in next generation wireless communications. MIMO is the use of multiple antennas at both the transmitter and receiver to improve communication performance.
In the future, networks of nano-devices will be a key component of almost every field of our society, with applications in biomedicine, environmental protection, entertainment, and homeland security, and beyond. In order to enable nano-devices to communicate with each other, many fundamental challenges need to be addressed. Electromagnetic (EM) communication in the Terahertz (THz) band (0.1–10 THz) enabled by graphene-based plasmonic nano-transceivers and nano-antennas has been suggested as one of the possible approaches for communication among these devices.
The development of ultra-compact antennas has great significance to military as it leads to miniaturization of military and commercial communication systems. The miniaturization of military electronics is of significant benefit to the warfighter, not only in terms of device size, but in transportability, space requirements, weight, and many factors,” said Dr. Brandon Howe, a materials scientist with the AFRL. “It can allow us to fit more into a given space, whether that be in a field pack or on an aerial platform. It gives us greater capability in a smaller space.
Vast amounts of data zip across the Internet each day in the form of light waves conveyed by optical fibers. But our computers still rely on electrical signals traveling through metal wires, which have much lower bandwidth. Optical interconnects that could guide light through the labyrinth of a circuit board would increase computing speed and save power, but so far they haven’t made it out of the lab. Now researchers are devising new techniques that may may enable engineers to build nanoscale antennae that turn light into a different sort of wave that can move through metal; the result could be data transmission speeds that are orders of magnitude higher than today’s.
Nano means one billionth. A nanoantenna is an antenna that is very, very small, and It is used to gain understanding about what is happening on an atomic scale. An image of a gold nanoantenna created by the Paul Alivisatos group at Lawrence Berkley National Laboratory, along with researchers at the University of Stuttgart in Germany, is shown below. Above the gold nanoantenna is a palladium nanoparticle. The purpose of their research is to figure out a way to measure interactions on the atomic scale so that an extremely sensitive gas sensor – one that might be able to detect a single particle – may be created. The optical properties of palladium are altered when hydrogen atoms are nearby and this should be detectable, but the effect is so small that it is hard to measure. Measuring the presence of hydrogen gas with more commonly used techniques can be dangerous because hydrogen is very explosive.
Hydrogen can be absorbed into palladium. The hydrogen atoms situate themselves between the palladium atoms rather easily. When the hydrogen atoms sit between the palladium atoms in this way the substance is called palladium hydride. The hydrogen atoms can also easily leave the palladium. Each time hydrogen enters or leaves the palladium structure, a change in how the palladium nanoparticle interacts with electromagnetic waves occurs.
Researchers measured how an incoming electromagnetic wave in the visible region was scattered off of the palladium nanoparticle. Each time hydrogen atoms were absorbed or released from the palladium the light scattered in a different way, however the measurements were not so obvious, as shown in the first image below. Researchers tried to enhance the signal to improve their measurements. A gold antenna, of just the right dimensions to make it resonant with the electromagnetic waves involved, was brought nearby. The antenna’s sharp tip is strongly affected by the scattered electromagnetic waves causing an oscillation of the electrons within the gold antenna tip that travels down the antenna. The detected signal is increased, becoming very clear as shown below, and this is music to any researcher’s ear.
Nano-antennas are useful for converting solar radiation into electricity. Adamant supplies of clean energy result in the growth of economic prosperity, global stability and quality of life. A nano-antenna is a type of solar cell that makes use of infrared radiation to create electricity instead of harnessing visible light to create electricity where infrared radiation is often believed as heat and exists beyond the visible range for humans. Infrared light is emitted from the Earth and also from various industrial processes like waste energy and coal-fired power plants. One version of the nano-antenna takes the shape of a microscopically small gold square or spiral of metal wire about 1/25th the diameter of a human hair that is embedded in a flexible polyethylene plastic sheet. In researches, the devices have been shown to be as high as 92% efficient at converting the frequencies of infrared light which they capture and convert into electrical energy.
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