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When a receiving antenna picks up a signal, a current flows. This current acts as a secondary "transmission", and this will partially cancel out the electromagnetic field that is incident - this is how you get power from the EM field into the antenna. If you look "slightly downstream" from the antenna, you will see a reduction in the EM field (assuming for a ...


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A radio wave may "bend" due to diffraction or scattering off objects, but it will not "bend" just because a receiving antenna exists.


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Under the vast majority of practical circumstances, there would be no difference between the blocks of metal and layers of metal. The reason is that only the surface of the metal (more precisely, a thin layer with a thickness on the order of a few microns for milimeterwaves/microwaves e.g Wifi frequencies) interacts with the EM wave. If the metal is roughly ...


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The skin depth of a good conductor is given by the expression $$ d = \sqrt{\frac{2}{\mu_r \mu_0 \sigma \omega}},$$ where $\omega$ is the angular frequency of the EM wave and $\sigma$ is the conductivity. Using this we can say that the electric field strength penetrating a conductive material decays as $E = E_0 \exp(-x/d)$ and of course the penetrating power ...


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If you are willing to walk around a bit, you can triangulate a radio source. It helps to have the frequency (wavelength is just $\frac{c}{\lambda}$) to tune your receiver. This is the principle behind the avalanche beacon A directional antenna will help you pick the direction of the source; moving at right angles to the direction you will get a different ...


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First off, detecting the wavelength and the frequency is redundant (assuming free space propagation) these are related by $c=f \lambda$ (speed of light = frequency times wavelength). Single Site Measurement If you know the absolute intensity of the signal that the object is emmitting, and you are dealing with (essentially) free space propagation, then you ...


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How thick should the conducting layer be? The conductive layer can be very thin because of something known as the skin effect. That term describes the tendency of current to flow primarily on the skin of a conductor. As long as the conducting layer is greater than the skin depth, it will provide excellent shielding because the absorption loss will be large. ...



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