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Antenna (radio), also known as an aerial, a transducer designed to transmit or receive electromagnetic (e.g. TV or radio) waves. -Wikipedia

The wavelength of the signal doesn't depend on the length of the conductor it's transmitted over. You could say, it's the distance that would be between two maxima if the line was long enough to conta …
answered Jul 7 '15 by The Photon
that apply to our problem. The gaussian beams are a convenient basis set when working with a beam emitted from an aperture. But you might prefer the spherical harmonics if your antenna radiates more … isotropically, for example. TLDR: Gaussian beams are just one choice of how to express the emission from an antenna. The gaussian beams do diverge with an angle, which for the 0th order beam is given …
answered Jan 8 '17 by The Photon
An isotropic antenna would emit power in all directions and have 0 dBi gain (The "i" stands for "relative to isotropic"). Your whip antenna is omnidirectional but not isotropic. It emits power … , it can send more power horizontally. But no receiver will receive even close to 1 W from your transmitter unless it completely surrounds you in all directions. A more directional antenna, like a horn …
answered Aug 20 '18 by The Photon
In order to design the impedance matching, I will need to know the load impedance and the source impedance to begin with. Correct? In most situations you need to know the load impedance and the s …
answered Aug 11 '14 by The Photon
direction) of an antenna when used for receiving is identical to the far-field radiation pattern of the antenna when used for transmitting. This is one consequence of the reciprocity theorem of electromagnetics. The proof is kind of hairy, though. …
answered Aug 20 '13 by The Photon
An antenna's realized gain is the antenna gain reduced by power lost to reflections at the antenna feed. The antenna gain is the product of efficiency and directivity: G_R = \left(1-\left|S_{11 … quite add up. -20 dB is really a very good $S_{11}$ magnitude, indicating a very well matched antenna. And the $D$ term is always greater than 1 (since any change from perfect isotropic radiation …
answered Apr 7 '17 by The Photon
Think about the signal on the transmission line as being made up of a forward-travelling wave and a reverse-travelling wave. At any given point on the line, the ratio of voltage to current in each o …
answered Oct 1 '14 by The Photon
If you want to change the direction of an antenna without physically moving it, you can use a phased-array antenna. This means using several antennas and adjusting the phase of the signal at each one … transmitting. If using a phased array for direction finding, rather than simply sweeping the direction of the antenna, you can use a signal processing algorithm to effectively search all directions simultaneously. Two well-known algorithms for direction finding are MUSIC and ESPRIT. …
answered Jun 28 '16 by The Photon
wavelength associated with the frequencies of the signals present. An antenna, on the other hand, typically must have a dimension that is a substantial fraction of the wavelength, for example 1/4 or 1/2 … wavelength. Therefore an antenna is, practically by definition, not a lumped circuit, so that rule doesn't apply. In fact there will be a potential difference (disregarding the fact that you have …
answered Aug 21 '15 by The Photon
Generally, the directivity of an antenna or array does not depend on $P$ or $P/n$. The main contributor to directivity is $L$, the diameter of the array. The advantage of a phased array is …
answered Oct 7 '16 by The Photon
waveguide in this design is that it allows a narrower trace which matches the pad dimensions better and doesn't need a neck-down before readhing the antenna pad. In other situations, microstrip might …
answered Apr 14 '15 by The Photon
It makes sense that I would want something specialized to transmit data. My question is if I need such an expensive antenna for receiving, The transmit and receive antennas are equally important … world of antennas, "high gain" means that the antenna has a highly directional emission profile. It does not mean that the antenna is able to deliver more power into the transmission than it is provided …
answered Mar 1 '17 by The Photon
feedline to the quarter wave length transformer need to be a certain length too? No. If the 1/4-wave transformer does its job, then the impedance looking in to the transformer (with the antenna … loading the other side) will be matched to the feedline, and there will be no reflection returning to the generator, regardless of the length of the feedline. if I am feeding a dipole antenna, do I …
answered Mar 29 by The Photon
device where $Z$ is purely imaginary with value $\pm 50 j$, and get 100% reflection, meaning VSWR approaches $\infty$. Your actual situation isn't as bad as that, but you don't have a perfectly radiating antenna, so you don't see a perfect VSWR. …
answered Apr 20 by The Photon
Yes, you can run a trace on layer 4 in this scenario. The ground layer on layer 2 means that all field lines from the transmission line are terminated on layer 2, and anything that happens on layer 4 …
answered Dec 18 '17 by The Photon

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