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G: the antenna gain; is the magnetic constant; is the electric constant; For antennas which are not defined by a physical area, such as monopoles and dipoles consisting of thin rod conductors, the effective length (units: meter) is used to measure the ratio between voltage and electric field.
To perform the test a number n statistically independent runs of the model are conducted and an average or expected value, E(Y), for the variable of interest is produced. Then the test statistic, t 0 is computed for the given α, n, E(Y) and the observed value for the system μ 0
It is an empirical formulation based on the data from the Okumura model, and is thus also commonly referred to as the Okumura–Hata model. [1] The model incorporates the graphical information from Okumura model and develops it further to realize the effects of diffraction, reflection and scattering caused by city structures. [ 2 ]
The Numerical Electromagnetics Code, or NEC, is a popular antenna modeling computer program for wire and surface antennas. It was originally written in FORTRAN during the 1970s by Gerald Burke and Andrew Poggio of the Lawrence Livermore National Laboratory .
Electromagnetic fields are excited in the cavity by coupling in an RF source with an antenna. When the RF fed by the antenna is the same as that of a cavity mode, the resonant fields build to high amplitudes. Charged particles passing through apertures in the cavity are then accelerated by the electric fields and deflected by the magnetic fields.
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The Foltz drawing pin like antenna from 1998 size 0.62 and 22% bandwidth. The Rogers cone from 2001 is size 0.65 and right on the limit. Lina and Choo planar spirals in size ratios range from 0.2 to 0.5; The fractal Koch curve antenna approaches the limit. [5] A meander line antenna optimizes the size for narrower bandwidths of the order 10%. [11]
Human-based computation (HBC), human-assisted computation, [1] ubiquitous human computing or distributed thinking (by analogy to distributed computing) is a computer science technique in which a machine performs its function by outsourcing certain steps to humans, usually as microwork. This approach uses differences in abilities and alternative ...