What is impedance?
Impedance is the opposition to current flow and
contains both a real and an imaginary component, in the form of (Real +/- j*Imaginary). In the case of a
pure resistance, the imaginary component is 0, and in the case of a pure reactance, the real component
Why does it matter so much in RF?
Impedance is important because mismatch between
connected components causes poor efficiency (DC to RF conversion) and causes a perfectly level input to
exhibit rippling and/or slope at the output.
What is impedance matching?
Impedance mismatch is
when the output impedance of one component does not exactly equal the input impedance of the next
component in line. Theoretically, maximum power transfer between two components is achieved when the
load impedance is the complex conjugate of the source impedance. For instance, if the source impedance
is 25+j10 ohms, then the load impedance must be 25-j10 ohms.
You can poke around on the RF Cafe
website and other websites for more detail.
- Kirt Blattenberger