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Dielectric Constant, Strength, & Loss Tangent
Can't find what you are looking for - click here for very extensive lists of dielectric constants.
Values presented here are relative dielectric constants (relative permittivities). As indicated by er = 1.00000 for a vacuum, all values are relative to a vacuum.
Multiply by e0 = 8.8542 x 10-12 F/m (permittivity of free space) to obtain absolute permittivity. 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.
The dielectric loss tangent is defined by the angle between the capacitor's impedance vector and the negative reactive axis, as illustrated in the diagram to the right. It determines the lossiness of the medium. Similar to dielectric constant, low loss tangents result in a "fast" substrate while large loss tangents result in a "slow" substrate.
Beware that the exact values can vary greatly depending on the particular manufacturer's process, so you should seek out data from the manufacturer for critical applications.
The dielectric constant can be calculated using: ε = Cs / Cv , where Cs is the capacitance with the specimen as the dielectric, and Cv is the capacitance with a vacuum as the dielectric.
The dissipation factor can be calculated using: D = tan δ = cot θ = 1 / (2π f RpCp) , where δ is the loss angle, θ is the phase angle, f is the frequency, Rp is the equivalent parallel resistance, and Cp is the equivalent parallel capacitance.
Note: All values can vary by very large amounts depending on the specific material.
Check with the MatWeb.com website for more details.
Thanks to Craig B. for correcting the loss tangent for Teflon (0.00028 rather than 0.0028).
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.
The dielectric loss tangent is defined by the angle between the capacitor's impedance vector and the negative reactive axis, as illustrated in the diagram to the right. It determines the lossiness of the medium. Similar to dielectric constant, low loss tangents result in a "fast" substrate while large loss tangents result in a "slow" substrate.Beware that the exact values can vary greatly depending on the particular manufacturer's process, so you should seek out data from the manufacturer for critical applications.
The dielectric constant can be calculated using: ε = Cs / Cv , where Cs is the capacitance with the specimen as the dielectric, and Cv is the capacitance with a vacuum as the dielectric.
The dissipation factor can be calculated using: D = tan δ = cot θ = 1 / (2π f RpCp) , where δ is the loss angle, θ is the phase angle, f is the frequency, Rp is the equivalent parallel resistance, and Cp is the equivalent parallel capacitance.
Note: All values can vary by very large amounts depending on the specific material.
Check with the MatWeb.com website for more details.
| Substance | Dielectric Constant (relative to air) | Dielectric Strength (V/mil) | Loss Tangent | Max Temp (°F) |
| ABS (plastic), Molded | 2.0 - 3.5 | 400 - 1350 | 0.00500 - 0.0190 | 171 - 228 |
| Air | 1.00054 | 30 - 70 | ||
| Alumina - 96% - 99.5% | 10.0 9.6 | 0.0002 @ 1 GHz 0.0002 @ 100 MHz 0.0003 @ 10 GHz | ||
| Aluminum Silicate | 5.3 - 5.5 | |||
| Bakelite | 3.7 | |||
| Bakelite (mica filled) | 4.7 | 325 - 375 | ||
| Balsa Wood | 1.37 @ 1 MHz 1.22 @ 3 GHz | 0.012 @ 1 MHz 0.100 @ 3 GHz | ||
| Beeswax (yellow) | 2.53 @ 1 MHz 2.39 @ 3 GHz | 0.0092 @ 1 MHz 0.0075 @ 3 GHz | ||
| Beryllium oxide | 6.7 | 0.006 @ 10 GHz | ||
| Butyl Rubber | 2.35 @ 1 MHz 2.35 @ 3 GHz | 0.001 @ 1 MHz 0.0009 @ 3 GHz | ||
| Carbon Tetrachloride | 2.17 @ 1 MHz 2.17 @ 3 GHz | <0.0004 @ 1 MHz 0.0004 @ 3 GHz | ||
| Diamond | 5.5 - 10 | |||
| Delrin (acetyl resin) | 3.7 | 500 | 180 | |
| Douglas Fir | 1.9 @ 1 MHz | 0.023 @ 1 MHz | ||
| Douglas Fir Plywood | 1.93 @ 1 MHz 1.82 @ 3 GHz | 0.026 @ 1 MHz 0.027 @ 3 GHz | ||
| Enamel | 5.1 | 450 | ||
| Epoxy glass PCB | 5.2 | 700 | ||
| Ethyl Alcohol (absolute) | 24.5 @ 1 MHz 6.5 @ 3 GHz | 0.09 @ 1 MHz 0.25 @ 3 GHz | ||
| Ethylene Glycol | 41 @ 1 MHz 12 @ 3 GHz | -0.03 @ 1 MHz 1 @ 3 GHz | ||
| Formica XX | 4.00 | |||
| FR-4 (G-10) - low resin - high resin | 4.9 4.2 | 0.008 @ 100 MHz 0.008 @ 3 GHz | ||
| Fused quartz | 3.8 | 0.0002 @ 100 MHz 0.00006 @ 3 GHz | ||
| Fused silica (glass) | 3.8 | |||
| Gallium Arsenide (GaAs) | 13.1 | 0.0016 @ 10 GHz | ||
| Germanium | 16 | |||
| Glass | 4 - 10 | |||
| Glass (Corning 7059) | 5.75 | 0.0036 @ 10 GHz | ||
| Gutta-percha | 2.6 | |||
| Halowax oil | 4.8 | |||
| High Density Polyethylene (HDPE), Molded | 1.0 - 5.0 | 475 - 3810 | 0.0000400 - 0.00100 | 158 - 248 |
| Ice (pure distilled water) | 4.15 @ 1 MHz 3.2 @ 3 GHz | 0.12 @ 1 MHz 0.0009 @ 3 GHz | ||
| Kapton® Type 100 Type 150 | 3.9 2.9 | 7400 4400 | 500 | |
| Kel-F | 2.6 | |||
| Lexan® | 2.96 | 400 | 275 | |
| Lucite | 2.8 | |||
| Mahogany | 2.25 @ 1 MHz 1.88 @ 3 GHz | 0.025 @ 1 MHz 0.025 @ 3 GHz | ||
| Mica Mica, Ruby | 4.5 - 8.0 5.4 | 3800 -5600 | ||
| Micarta 254 | 3.4 - 5.4 | |||
| Mylar® | 3.2 | 7000 | 250 | |
| Neoprene | 6 - 9 | 600 | ||
| Neoprene rubber | 6.26 @ 1 MHz 4 @ 3 GHz | 0.038 @ 1 MHz 0.034 @ 3 GHz | ||
| Nomex® | 800 | 450 | ||
| Nylon | 3.2 - 5 | 400 | 280 | |
| Oil (mineral, squibb) | 2.7 | 200 | ||
| Paper (bond) | 3.0 | 200 | ||
| Paraffin | 2-3 | |||
| Phenolica (glass-filled) | 5 - 7 | |||
| Phenolics (cellulose-filled) | 4 - 15 | 0.03 @ 100 MHz | ||
| Phenolics (mica-filled) | 4.7 - 7.5 | |||
| Plexiglass® | 2.2 - 3.4 | 450 - 990 | ||
| Polyethylene LDPE/HDPE | 2.26 @ 1 MHz 2.26 @ 3 GHz | 450 - 1200 | 0.0002 @ 100 MHz 0.00031 @ 3 GHz | 170 |
| Polyamide | 2.5 - 2.6 | |||
| Polycarbonate, Molded | 2.8 - 3.4 | 380 - 965 | 0.000660 - 0.0100 | 239 - 275 |
| Polypropylene | 2.2 | 500 | 250 | |
| Polystyrene | 2.5 - 2.6 | 500 | 0.0001 @ 100 MHz 0.00033 @ 3 GHz | |
| Polyvinylchloride (PVC) | 3 | 725 | 140 | |
| Porcelain | 5.1 - 5.9 | 40 -280 | ||
| Pyrex glass (Corning 7740) | 5.1 | 335 | ||
| Quartz (fused) | 4.2 | 150 - 200 | ||
| RT/Duroid 5880 (go to Rogers) | 2.20 | |||
| Rubber | 3.0 - 4.0 | 150 - 500 | 170 | |
| Ruby | 11.3 | |||
| Silicon | 11.7 - 12.9 | 100 - 700 | 0.005 @ 1 GHz 0.015 @ 10 GHz | 300 |
| Silicone oil | 2.5 | |||
| Silicone RTV | 3.6 | 550 | ||
| Soil (dry sandy) | 2.59 @ 1 MHz 2.55 @ 3 GHz | 0.017 @ 1 MHz 0.0062 @ 3 GHz | ||
| Soil (dry loamy) | 2.53 @ 1 MHz 2.44 @ 3 GHz | 0.018 @ 1 MHz 0.0011 @ 3 GHz | ||
| Steatite | 5.3-6.5 | |||
| Strontium titanate | 233 | |||
| Teflon® (PTFE) | 2.0 - 2.1 | 1000 | 0.00028 @ 3 GHz | 480 |
| Tenite | 2.9 - 4.5 | |||
| Transformer oil | 4.5 | |||
| Vacuum (free space) | 1.00000 | |||
| Valox® | 1560 | 400 | ||
| Vaseline | 2.16 | 0.00004 @ 0.1 GHz 0.00066 @ 3 GHz | ||
| Vinyl | 2.8 - 4.5 | |||
| Water (32°F) (68°F) (212°F) | 88.0 80.4 55.3 | 80 | 0.04 @ 1 MHz 0.157 @ 3 GHz | |
| Water (distilled) | 76.7 - 78.2 | 0.005 @ 100 MHz 0.157 @ 3 GHz | ||
| Wood | 1.2 - 2.1 | 0.04 @ 0.1 GHz 0.03 @ 3 GHz |
Related Pages on RF Cafe
- Coaxial Cable Specifications
- Capacitor Dielectrics & Descriptions
- Dielectric Constant, Strength, & Loss Tangent
- Conductor Bulk Resistivity & Skin Depths
- Coaxial Cable Equations
- Coaxial Cable Specifications
- Coaxial Cable Vendors
- Skin Depth Calculator
Note: Thanks to Gareth for correcting the omission of a square root sign in the dielectric equations.- Coaxial Cable Specifications
- Capacitor Dielectrics & Descriptions
- Dielectric Constant, Strength, & Loss Tangent
- Conductor Bulk Resistivity & Skin Depths
- Coaxial Cable Equations
- Coaxial Cable Specifications
- Coaxial Cable Vendors
- Skin Depth Calculator
Thanks to Craig B. for correcting the loss tangent for Teflon (0.00028 rather than 0.0028).
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