Df
(Dissipation Factor)Measure of signal energy lost as heat in a dielectric material, also called loss tangent.
Definition
Dissipation Factor (Df), also known as loss tangent (tan δ), measures the electrical energy lost as heat when a signal passes through a dielectric material. Lower Df means less signal loss at high frequencies. Standard FR-4 has Df around 0.02 at 1 GHz, while low-loss materials like Rogers RO4003C achieve Df of 0.0027. For high-speed digital (>10 Gbps) and RF applications, low-Df materials are essential to maintain signal integrity.