HF Filter Design and Computer Simulation

An electric field is created when a potential difference is applied across conductors separated by an insulator (dielectric). Energy is stored in this electric field. The stored energy is
| (3) | |
where C is the capacitance and E is the potential difference. The capacitor attempts to retain a stored charge and maintain a constant potential difference. The terminal impedance is
| (4) | |
The impedance is purely reactive, negative, and inversely proportional to frequency.