LOW-LOSS MATERIALS V2.0

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-2±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.