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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 .
In the case of purely resistive circuits, the two concepts are identical. Physically realizable sources and loads are not usually purely resistive, having some inductive or capacitive components, and so practical applications of this theorem, under the name of complex conjugate impedance matching, do, in fact, exist.
An L pad used to match a source to a load of a different impedance. If a source and load are both resistive (i.e. Z1 and Z2 have zero or very small imaginary part) then a resistive L pad can be used to match them to each other. As shown, either side of the L pad can be the source or load, but the Z1 side must be the side with the higher ...
Impedances with non-negative resistive components will appear inside a circle with unit radius; the origin will correspond to the reference impedance, Z 0. The Smith chart is plotted on the complex reflection coefficient plane in two dimensions and may be scaled in normalised impedance (the most common), normalised admittance or both, using ...
An antenna tuner, a matchbox, transmatch, antenna tuning unit (ATU), antenna coupler, or feedline coupler is a device connected between a radio transmitter or receiver and its antenna to improve power transfer between them by matching the impedance of the radio to the antenna's feedline.
In electrical engineering, impedance is the opposition to alternating current presented by the combined effect of resistance and reactance in a circuit. [1]Quantitatively, the impedance of a two-terminal circuit element is the ratio of the complex representation of the sinusoidal voltage between its terminals, to the complex representation of the current flowing through it. [2]
Passive, resistive pads and attenuators are bidirectional two-ports, but in this section they will be treated as unidirectional. Z S = the output impedance of the source. Z Load = the input impedance of the load. Z in = the impedance seen looking into the input port when Z Load is connected to the output port.
This is not the same as the actual impedance of the load since the reactive part of the load impedance will be subject to impedance transformer action and the resistive part. Matching stubs can be made adjustable so that matching can be corrected on test. [3] A single stub will only achieve a perfect match at one specific frequency.