Dielectric Losses

Dielectric loss quantifies a dielectric material's inherent dissipation of electromagnetic energy. It loss of energy that goes into heating a dielectric material in a varying electric field.

For example, a capacitor incorporated in an alternating-current circuit is alternately charged and discharged each half cycle.

During the alternation of polarity of the plates, the charges must be displaced through the dielectric first in one direction and then in the other, and overcoming the opposition that they encounter leads to a production of heat through dielectric loss, a characteristic that must be considered when applying capacitors to electric circuits, such as those in radio and television receivers.

Dielectric losses depend on frequency and the dielectric material.

Dielectric Loss is measured using the Loss of tangent which is also commonly referred to as tan delta (tan δ). The value of tan delta is high means Dielectric Loss is also high.

Loss Tangent

Loss Tangent or tan δ is a dimensionless quantity. Loss Tangent tends to calculate the estimated Loss of signal because of the fundamental dissipation of electromagnetic energy that takes place in the substrate of the printed circuit board.


D = tanδ = cotθ = 1/(2πRpCp)


tanδ = The Loss angle

θ = The phase angle

f = The frequency

Rp = Equivalent parallel resistance

Cp = Equivalent parallel capacitance

The Loss Tangent has a vital part in extremely high frequencies above 1 GHz, The analog signals to decide the signal attenuation.

Radiation and Induction Losses

RADIATION and INDUCTION LOSSES are similar in that both are caused by the fieldssurrounding the conductors.

Induction losses occur when the electromagnetic field about a conductor cutsthrough any nearby metallic object and a current is induced in that object.

As a result, power is dissipatedin the object and is lost.

Radiation losses occur because some magnetic lines of force about a conductor do not return to theconductor when the cycle alternates.

These lines of force are projected into space as radiation and thisresults in power losses.

That is, power is supplied by the source, but is not available to the load.