RF Math

• Watt - energy measurement represents one Joule per second
• Decibel - logarithmic unit used to express the ratio between two values
• dBm- compare the relative power between two signal expressed in mW
○ 0dB = same power as measured
○ 3dB = Twice the power
○ 10dB = 10X the power
○ -3dB = Half the power
○ -10dB = 1/10 of the power

                -dBm = 10*Log10(mW)
                 mW = 10(dBm/10) 



• dBi - decibel in reference to Isotropic antenna
• dBd -  almost the same as dBi, but based on a Dipole antenna. The is a slight math variation
○ dBi = dBd + 2.14
                ○ dBd = dBi – 2.14