# Dielectrics

## Important Factors[edit]

**Dielectric Strength** (aka **Dielectric Breakdown**, [=] V/m)

The electrical potential per unit dielectric thickness at which the dielectric undergoes electrical breakdown.

The material's dielectric permittivity, expressed as a ratio relative to the permittivity of vacuum; expresses the force between two point charges in a material.

**Dielectric Loss** ([=] unitless)

A measure of a material's tendency to dissipate electromagnetic energy as heat. The **loss angle** describes the angle between the capacitor's impedance vector and the negative reactance axis; the **loss tangent** (aka the **dissipation factor**, the reciprocal of the **quality factor**) is the tangent of the loss angle, and is the ratio of the resistive power loss to the reactive power oscillating in the capacitor.

δ

via: http://www.doitpoms.ac.uk/tlplib/dielectrics/loss.php

"Dielectric loss tends to be higher in materials with higher dielectric constants. This is the downside of using these materials in practical applications."

via: http://www.rfcafe.com/references/electrical/dielectric-constants-strengths.htm

Teflon (PTFE) dielectric constant 2.0 - 2.1 dielectric strength 1000 loss tangent 0.00028 @ 3 GHz

Fused Silica dielectric constant 3.8 dielectric strength loss tangent

dielectric constant dielectric strength loss tangent