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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.
Lossy dielectric equation for real and imaginary parts
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.
          "Q" from dielectric loss equation       Dielectric complex loss tangent

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.
Dielectric loss equation
RF Cafe - Dielectric loss tangentThe 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.

Dielectric complex conductivity

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  
Glass (lead silicate) 7 - 14   (Table 2: LS30-LS32)  
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
Tefzel® (1 kHz - 3 Ghz) 2.6 - 2.3   0.0007 - 0.0119 300
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
 
 

Note: Thanks to Gareth for correcting the omission of a square root sign in the dielectric equations.

          Thanks to Craig B. for correcting the loss tangent for Teflon (0.00028 rather than 0.0028).

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