The resonance method at 5 GHz is used for the characterization of low-loss materials. These materials are non-dispersive, i.e., the properties are frequency-independent. This was verified using DAK-TL2 over 4 MHz  67 GHz (for permittivity only). Hence, in a first approximation, the values provided in the table below can be applied for any frequency. 

Material Relative Permittivity (ε')  Loss Tangent (tan δ)
Alumina 99.5% 9.75±0.1 1.76E-4±2E-5
Ebablock 920 3.18±0.06 1.76E-2±2E-3
Eccostock 0005 2.53±0.02 4.86E-4±6E-5
FR4 4.88±0.2 1.83E-3±2E-4
PA66GF30 3.69±0.1 1.14E-2±4E-4
PEEK 3.27±0.03 2.59E-3±4E-5
Polypropylene 2.54±0.02 1.39E-3±2E-4
POM-C 2.94±0.02 2.98E-2±1E-3
PTFE 2.07±0.02 2.41E-4±5E-5
Rohacell HF51 1.09±0.03 2.68E-3±3E-4

The measurement uncertainties for permittivity and loss tangent for the applied resonance method are:

  • ±1% for relative permittivity (ε')
  • ±3% for loss tangent (tanδ)
The dielectric properties are reported as the average of multiple measurements on different samples for each material.

Electrical conductivity can be calculated from σ=2.π.f.tan(δ).ε'.ε0, where f is the frequency in Hz, ε' is the real part of complex permittivity, tan(δ) is the loss tangent and ε0 is the vacuum permittivity.