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Reflection Coefficient
In physics and electrical engineering the reflection coefficient is a parameter that describes how much of a wave is reflected by an impedance discontinuity in the transmission medium. It is equal to the ratio of the amplitude of the reflected wave to the incident wave, with each expressed as phasors. For example, it is used in optics to calculate the amount of light that is reflected from a surface with a different index of refraction, such as a glass surface, or in an electrical transmission line to calculate how much of the electromagnetic wave is reflected by an impedance discontinuity. The reflection coefficient is closely related to the ''transmission coefficient''. The reflectance of a system is also sometimes called a reflection coefficient. Different disciplines have different applications for the term. Transmission lines In telecommunications and transmission line theory, the reflection coefficient is the ratio of the complex amplitude of the reflected wave to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Physics
Physics is the scientific study of matter, its Elementary particle, fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge which relates to the order of nature, or, in other words, to the regular succession of events." It is one of the most fundamental scientific disciplines. "Physics is one of the most fundamental of the sciences. Scientists of all disciplines use the ideas of physics, including chemists who study the structure of molecules, paleontologists who try to reconstruct how dinosaurs walked, and climatologists who study how human activities affect the atmosphere and oceans. Physics is also the foundation of all engineering and technology. No engineer could design a flat-screen TV, an interplanetary spacecraft, or even a better mousetrap without first understanding the basic laws of physics. (...) You will come to see physics as a towering achievement of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Impedance Of Free Space
In electromagnetism, the impedance of free space, , is a physical constant relating the magnitudes of the electric and magnetic fields of electromagnetic radiation travelling through free space. That is, Z_0 = \frac, where is the electric field strength, and is the magnetic field strength. Its presently accepted value is : , where Ω is the ohm, the SI unit of electrical resistance. The impedance of free space (that is, the wave impedance of a plane wave in free space) is equal to the product of the vacuum permeability and the speed of light in vacuum . Before 2019, the values of both these constants were taken to be exact (they were given in the definitions of the ampere and the metre respectively), and the value of the impedance of free space was therefore likewise taken to be exact. However, with the revision of the SI that came into force on 20 May 2019, the impedance of free space as expressed with an SI unit is subject to experimental measurement because only t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scattering Parameters
Scattering parameters or S-parameters (the elements of a scattering matrix or S-matrix) describe the electrical behavior of linear electrical networks when undergoing various steady state stimuli by electrical signals. The parameters are useful for several branches of electrical engineering, including electronics engineering, electronics, communications system, communication systems design, and especially for microwave engineering. The S-parameters are members of a family of similar parameters, other examples being: Y-parameters and Z-parameters, Two port#Hybrid parameters (h-parameters), H-parameters, #Scattering transfer parameters, T-parameters and ABCD-parameters. They differ from these, in the sense that ''S-parameters'' do not use open or short circuit conditions to characterize a linear electrical network; instead, impedance matching, matched loads are used. These electrical termination, terminations are much easier to use at high signal frequencies than open-circuit and s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrical Network
An electrical network is an interconnection of electrical components (e.g., batteries, resistors, inductors, capacitors, switches, transistors) or a model of such an interconnection, consisting of electrical elements (e.g., voltage sources, current sources, resistances, inductances, capacitances). An electrical circuit is a network consisting of a closed loop, giving a return path for the current. Thus all circuits are networks, but not all networks are circuits (although networks without a closed loop are often referred to as "open circuits"). A resistive network is a network containing only resistors and ideal current and voltage sources. Analysis of resistive networks is less complicated than analysis of networks containing capacitors and inductors. If the sources are constant ( DC) sources, the result is a DC network. The effective resistance and current distribution properties of arbitrary resistor networks can be modeled in terms of their graph measures and g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Two-port Network
In electronics, a two-port network (a kind of four-terminal network or quadripole) is an electrical network (i.e. a circuit) or device with two ''pairs'' of Terminal (electronics), terminals to connect to external circuits. Two terminals constitute a port (circuit theory), port if the Electric current, currents applied to them satisfy the essential requirement known as the port condition: the current entering one terminal must equal the current emerging from the other terminal on the same port.Gray, §3.2, p. 172Jaeger, §10.5 §13.5 §13.8 The ports constitute interfaces where the network connects to other networks, the points where signals are applied or outputs are taken. In a two-port network, often port 1 is considered the input port and port 2 is considered the output port. It is commonly used in mathematical Network analysis (electrical circuits), circuit analysis. Application The two-port network model is used in mathematical circuit analysis techniques to isol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SWR Meter
A standing wave ratio meter, SWR meter, ISWR meter (current "" SWR), or VSWR meter (voltage SWR) measures the standing wave ratio (SWR) in a transmission line. The meter indirectly measures the degree of mismatch between a transmission line and its electrical load, load (usually an antenna (radio), antenna). Electronics technicians use it to adjust radio transmitters and their antennas and feedlines to be impedance matching, impedance matched so they work together properly, and evaluate the effectiveness of other impedance matching efforts. Directional SWR meter A directional SWR meter measures the magnitude of the forward and reflected waves by sensing each one individually, with directional couplers. A calculation then produces the SWR. Referring to the above diagram, the transmitter (TX) and antenna (ANT) terminals connect via an internal transmission line. This main line is electromagnetically coupled to two smaller sense lines (directional couplers). These are terminate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Antenna
In radio-frequency engineering, an antenna (American English) or aerial (British English) is an electronic device that converts an alternating electric current into radio waves (transmitting), or radio waves into an electric current (receiving). It is the interface between radio waves propagating through space and electric currents moving in metal conductors, used with a transmitter or receiver. In transmission, a radio transmitter supplies an electric current to the antenna's terminals, and the antenna radiates the energy from the current as electromagnetic waves (radio waves). In reception, an antenna intercepts some of the power of a radio wave in order to produce an electric current at its terminals, that is applied to a receiver to be amplified. Antennas are essential components of all radio equipment. An antenna is an array of conductor segments ( elements), electrically connected to the receiver or transmitter. Antennas can be designed to transmit and receive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Impedance Mismatch
In electrical engineering, impedance matching is the practice of designing or adjusting the input impedance or output impedance of an electrical device for a desired value. Often, the desired value is selected to maximize power transfer or minimize signal reflection. For example, impedance matching typically is used to improve power transfer from a radio transmitter via the interconnecting transmission line to the antenna. Signals on a transmission line will be transmitted without reflections if the transmission line is terminated with a matching impedance. Techniques of impedance matching include transformers, adjustable networks of lumped resistance, capacitance and inductance, or properly proportioned transmission lines. Practical impedance-matching devices will generally provide best results over a specified frequency band. The concept of impedance matching is widespread in electrical engineering, but is relevant in other applications in which a form of energy, not n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Standing Wave Ratio
In radio engineering and telecommunications, standing wave ratio (SWR) is a measure of impedance matching of loads to the characteristic impedance of a transmission line or waveguide. Impedance mismatches result in standing waves along the transmission line, and SWR is defined as the ratio of the partial standing wave's amplitude at an antinode (maximum) to the amplitude at a node (minimum) along the line. Voltage standing wave ratio (VSWR) (pronounced "vizwar" ) is the ratio of maximum to minimum voltage on a transmission line . For example, a VSWR of 1.2 means a peak voltage 1.2 times the minimum voltage along that line, if the line is at least one half wavelength long. A SWR can be also defined as the ratio of the maximum amplitude to minimum amplitude of the transmission line's currents, electric field strength, or the magnetic field strength. Neglecting transmission line loss, these ratios are identical. The power standing wave ratio (PSWR) is defined as the square o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nomogram
A nomogram (), also called a nomograph, alignment chart, or abac, is a graphical Analog computer, calculating device, a two-dimensional diagram designed to allow the approximate graphical computation of a Function (mathematics), mathematical function. The field of nomography was invented in 1884 by the French engineer Philbert Maurice d'Ocagne (1862–1938) and used extensively for many years to provide engineers with fast graphical calculations of complicated formulas to a practical precision. Nomograms use a parallel coordinate system invented by d'Ocagne rather than standard Cartesian coordinates. A nomogram consists of a set of n scales, one for each variable in an equation. Knowing the values of n-1 variables, the value of the unknown variable can be found, or by fixing the values of some variables, the relationship between the unfixed ones can be studied. The result is obtained by laying a straightedge across the known values on the scales and reading the unknown value fro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrical Length
In electrical engineering, electrical length is a dimensionless parameter equal to the physical length of an electrical conductor such as a cable or wire, divided by the wavelength of alternating current at a given frequency traveling through the conductor. ANSI (American National Standards Institute) accredited definition In other words, it is the length of the conductor measured in wavelengths. It can alternately be expressed as an angle, in radians or degree (angle), degrees, equal to the phase shift the alternating current experiences traveling through the conductor. Electrical length is defined for a conductor operating at a specific frequency or narrow band of frequencies. It is determined by the construction of the cable, so different cables of the same length operating at the same frequency can have different electrical lengths. A conductor is called ''electrically long'' if it has an electrical length much greater than one; that is it is much longer than the waveleng ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
