What is PCB Dk and Df?

Abstract: Substrate effective dielectric constant (DK) and dissipation factor (DF) are important parameters for the printed circuit board (PCB) design. A novel algorithm based on the Wheeler incremental inductance method for extracting the dispersive material properties on rough conductor PCBs are proposed.

What is DF and DK?

Df is the material loss tangent. Dk is the material relative permittivity.

What is DK PCB?

A key starting point in sorting through printed circuit board (PCB) materials is usually the dielectric constant, or Dk, one of the essential characteristics of a laminate material and one that is subject to many comparisons among different suppliers of PCB materials.

What is DF PCB?

εr = dielectric constant of pcb material. df: The dissipation factor (df) is a measure of loss-rate of energy of a mode of oscillation in a dissipative system.

What is DK Electrical?

Dielectric constant (Dk or relative permittivity) is a parameter that design engineers use constantly, often without fully understanding it. Every material has a dielectric constant, even air (slightly more than unity).

Understand How Circuit Materials and Fabrication Can Affect PCB Dk Variation and Phase Consistency

What is DK DF value?

The term "Dk" refers specifically to the real part of the dielectric constant (i.e., the refractive index), while the term "Df" refers to the imaginary part. Note that the imaginary part of the dielectric constant only determines losses, while the real and imaginary parts collectively determine dispersion.

What is DF capacitor?

Dissipation factor (DF or tan δ) is the electrical property of plastics and other electrical insulating materials. It is defined as the reciprocal of the ratio between the insulating materials' capacitive reactance to its resistance (Equivalent Series Resistance or ESR) at a specified frequency.

What is DK in material?

DK represents a dielectric' capacity to store electrical energy and hinder signal transmission. High-frequency/high-speed PCBs function as antennas to generate and receive high-frequency/high-speed signals and signal delay on the circuit board is not expected. So a high-frequency PCB should use material of low DK.

What is tan d in capacitor?

Loss tangent definition:

The value δ (Greek letter delta) is also known as the loss angle. Capacitor loss tangent. From the diagram and definition of the capacitor loss tangent it can be seen that the following equation can be derived. tanδ=DF. tanδ=1Q.

What is dissipation factor and quality factor?

In physics, the dissipation factor (DF) is a measure of loss-rate of energy of a mode of oscillation (mechanical, electrical, or electromechanical) in a dissipative system. It is the reciprocal of quality factor, which represents the "quality" or durability of oscillation.

What is substrate dielectric constant?

Dielectric constant is a measure of the charge retention capacity of a medium. In general, low dielectric constants (i.e., Polypropylene) result in a "fast" substrate while large dielectric constants (i.e., Alumina) result in a "slow" substrate.

How do I choose a PCB material?

When it comes to PCB layers, you are looking for a material that has low Dk values to act as insulation for the copper traces and power planes. In addition, the chosen material should also maintain as much of a constant Dk as possible during its lifecycle for different frequency ranges.

What is loss tangent in PCB material?

A material's loss tangent gives a measure of power lost due to the material. The lower a material's loss tangent, the less power lost. The Tan δ of most PCB materials range from 0.02 for most commonly used materials to 0.001 for very low-loss high-end materials.

What is dielectric constant in PCB?

The dielectric constant (Er) or relative permittivity (Dk) of a PCB material is generally between 3.5 and 5.5. A material's Er level depends on frequency and will usually drop as the frequency rises. The Dk level changes less on certain PCB materials than on others.

What is dielectric dissipation factor?

Dissipation factor is defined as the reciprocal of the ratio between the insulating materials capacitive reactance to its resistance at a specified frequency. It measures the inefficiency of an insulating material.

How is dissipation factor measured?

Dielectric constant (relative permittivity) and dissipation factor can be measured using a HP 4284A LCR meter with a HP 1645B test fixture. The frequency range is 20 Hz to 1 MHZ. The dissipation factor is a measure of energy lost during the reversal of electric polarization. It is expressed as a fractional energy loss.

What is ESR for a capacitor?

Equivalent series resistance (ESR), also known as internal resistance, is a value representing the loss of useful energy in a simple electronic circuit consisting of a resistor and an ideal (perfect) capacitor. Technically speaking, the energy is not lost, but is usually dissipated as undesirable heat.

Why is tangent loss important?

In short, the dielectric loss tangent will limit the useful length of a transmission line on a PCB as it causes the signal level to decrease during propagation.

Why is tan delta important?

The main purpose of the tan delta test is to make sure of maintaining a secure and reliable functioning of the transformer. With the calculation of dissipation factor and capacitance values, it provides the result of insulation behavior of bushings and in windings too.

What is dielectric constant unit?

The Dielectric constant (K) of the medium is the ratio of the permittivity of the substance (\varepsilon) to permittivity of the free space (ε0). i.e K=ε/ε0. As Permittivity of medium and permittivity of free space both have same units(F/m ie Farad/meter) dielectric constant becomes dimensionless quantity.

What is the minimum value of dielectric constant?

The value of the dielectric constant at room temperature (25 °C, or 77 °F) is 1.00059 for air, 2.25 for paraffin, 78.2 for water, and about 2,000 for barium titanate (BaTiO₃) when the electric field is applied perpendicularly to the principal axis of the crystal.

How is dielectric constant calculated?

What is PF and DF?

Dissipation Factor

With the exception of electrolytic and large power capacitors, most wound dielectric type units utilize a ratio figure known as the "dissipation factor" (OF) instead of the Power Factor (PF). By definition, this DF is the ratio of the equivalent series resistance to the reactance.

What is dielectric loss tangent?

The dielectric loss tangent (tan δ) of a material denotes quantitatively dissipation of the electrical energy due to different physical processes such as electrical conduction, dielectric relaxation, dielectric resonance and loss from non-linear processes [4].