The dielectric constant (ε) and dielectric loss (tan δ) are two key parameters that describe the electrical properties of materials, and their relationship can be understood from the following perspectives:

1. Physical definition

Dielectric constant: measures the ability of a material to store charges in an electric field, defined as the ratio of the electric field strength in the medium to the electric field strength in vacuum.

Dielectric loss: characterized by the energy loss of a material converted into thermal energy due to polarization hysteresis or conductivity effect in an alternating electric field, usually quantified by the loss tangent (tan δ).

2. Core relationships

Energy allocation: Part of the energy from the external electric field is stored in polarized form by the material (reflected in dielectric constant), while the other part is lost due to heat generation (reflected in dielectric loss).

Complex dielectric constant: At high frequencies, the dielectric constant exists in complex form, with the imaginary part (ε '') directly reflecting losses and the real part (ε '') corresponding to energy storage capacity.

Frequency dependence: sufficient polarization response and high dielectric constant at low frequencies; Polarization hysteresis intensifies and losses significantly increase at high frequencies.

3. Engineering applications

Material selection: High energy storage capacitors require high ε and low tan δ; High frequency circuit substrates require low ε and low tan δ to reduce signal attenuation.

Measurement method: Simultaneously measure ε and tan δ using parallel plate capacitor method or resonance method to evaluate material properties