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The International Journal of Nanoscience is an interdisciplinary peer-reviewed scientific journal published by World Scientific. It covers research in nanometer scale science and technology, with articles ranging from the "basic science of nanoscale physics and chemistry to applications in nanodevices, quantum engineering and quantum computing ".
A short antenna pole next to a house Multiple Yagi TV aerials. Antennas are commonly placed on rooftops and sometimes in attics. Placing an antenna indoors significantly attenuates the level of the available signal. [19] [20] Directional antennas must be pointed at the transmitter they are receiving; in most cases great accuracy is not needed ...
Smart antennas (also known as adaptive array antennas, digital antenna arrays, multiple antennas and, recently, MIMO) are antenna arrays with smart signal processing algorithms used to identify spatial signal signatures such as the direction of arrival (DOA) of the signal, and use them to calculate beamforming vectors which are used to track and locate the antenna beam on the mobile/target.
Log-periodic antennas are arrays invented in 1952 and commonly seen as TV antennas. This was long before Mandelbrot coined the word fractal in 1975. [4] Some authors (for instance Cohen) [5] consider log-periodic antennas to be an early form of fractal antenna due to their infinite self similarity at all scales.
Antenna designs incorporating metamaterials can improve the radiated power of an antenna. The newest metamaterial antennas radiate as much as 95 percent of an input radio signal. Standard antennas need to be at least half the size of the signal wavelength to operate efficiently. At 300 MHz, for instance, an antenna would need to be half a meter ...
A turnstile antenna, or crossed-dipole antenna, [1] is a radio antenna consisting of a set of two identical dipole antennas mounted at right angles to each other and fed in phase quadrature; the two currents applied to the dipoles are 90° out of phase. [2] [3] The name reflects the notion the antenna looks like a turnstile when mounted ...
The system consists of a master antenna and a matching transformer to match the balanced antenna with unbalanced cable and amplifiers. [5] Most antennas have an impedance of around 300 Ω. To convert it to 75 Ω, a matching transformer (or balun) is used. For trunk line isolation, a resistive inductive device known as a splitter is used.
An indoor antenna is a type of radio or TV antenna placed indoors, as opposed to being mounted on the roof. They are usually considered a simple and cheap solution to receive transmissions. An indoor antenna is prone to picking up electrical noise, but digital broadcasts are resistant to this noise.