Impedance matching


Also found in: Dictionary, Medical, Wikipedia.
Related to Impedance matching: Impedance mismatch

Impedance matching

The use of electric circuits and devices to establish the condition in which the impedance of a load is equal to the internal impedance of the source. This condition of impedance match provides for the maximum transfer of power from the source to the load.

The maximum power transfer theorem of electric network theory states that at any given frequency the maximum power is transferred from the source to the load when the load impedance is equal to the conjugate of the generator impedance. When these conditions are satisfied, the power is delivered with 50% efficiency; that is, as much power is dissipated in the internal impedance of the generator as is delivered to the load. In general, the load impedance will not be the proper value for maximum power transfer. A network composed of inductors and capacitors may be inserted between the load and the generator to present to the generator an impedance that is the conjugate of the generator impedance (see illustration).

References in periodicals archive ?
However, as aforementioned, it remains a critical task in LNA designs to realize impedance matching at the input port by presenting a resistive impedance (e.g., 50 [OMEGA]).
Its initial value is ~0.8, but it rapidly decreases to ~0.45, showing that the tuning process (including both the impedance matching (loop[C]) and the resonance condition finding loop (loop[C])) are properly working.
Indeed, optimization on the parameters of the ELC unit may could further improve the bandwidth, impedance matching, and realized gain over a wider scan angle.
By comparing the three different algorithms of reflection coefficient magnitude, the particle swarm optimization combined with simulated annealing algorithm is a new type of impedance matching algorithm, and the reflection coefficient tends to zero to achieve impedance matching finally, which is better than the improved particle swarm algorithm in speed.
Third Setup: General Impedance Matching. Mechanical impedance is defined as the ratio between the amplitudes of force and speed in a vibration movement.
In order to better match the fundamental, we need to compromise on the lower frequency harmonics impedance matching. The second and the third harmonic suppression levels are maintained at -16 to -36 dBc and -16 to -33 dBc, respectively.
The feedline is tapered for optimum impedance matching the antenna's fractal tree patch.
And the most difficulty issue for such an antenna design lies on the fact that these variables in the antenna structure working together to determine the impedance matching and circular polarization performance.
Stacked structures are usually used to broaden the axial-ratio (AR) bandwidth and horizontally strip feed technique in [5,6] is proposed to achieve good impedance matching. For the single-port and double-feed antennas, modifications are not required on the radiated patch and the approach of 90[degrees] hybrid or power splitter can obtain wide AR bandwidth but has the disadvantages of complicated structure and large antenna size [7].
1 shows few conventional LNA for input impedance matching. In Fig.
In the following, we simply indicate with impedance matching the receiver design that enables the maximum power transfer.