- The short answer is - impedance includes reactance, and reactance includes effects which vary with frequency due to inductance and capacitance.
- Because such a structure will be inherently inductive there will be some inductive reactance opposing current flow.
- It may be expressed as IX, where X, the reactance, is the imaginary part of the impedance.
- A radiating structure involving very low resistance and very high reactance is the definition of a high Q circuit, and such circuits have very narrow bandwidth.
- This can be caused by many contributors such as loaded cables acting as a lowpass filters, and other influences of inductive and capacitive reactance.