Here are some physical constants and other data in the MKS system which are useful in microwave engineering.
Sources: NIST website and the CRC Handbook of Chemistry and Physics
| Constant |
Description |
Value |
Units |
| k |
Boltzmann's constant |
1.38065030E-23 |
Joule/Kelvin |
| c |
Velocity of light in free space |
2.99792458E+08 |
meters/second |
| e |
Base number of natural logarithms |
2.71828183E+00 |
none |
| h |
Planck's constant |
6.62606876E-34 |
Joule-second |
| Z0 |
Impedance of free space |
3.76730313E+02 |
Ohms |
| ε |
Permittivity of free space |
8.85418782E-12 |
Farad/meter |
| me |
Electron mass |
9.10938188E-31 |
kilogram |
| N |
Avagadro's constant |
6.02214199E+23 |
mol-1 |
| π |
Pi |
3.14159265E+00 |
none |
| q |
Electron charge |
1.60217646E-19 |
Coulombs |
| μ0 |
Permeability of free space* |
1.25663706E-06 |
Henry/meter |
* exact value is 4πx10-7