Formulas

Attenuation

Voltage: A_V = 20log (V_OUT/V_IN)

Power: A_P = 10log (P_OUT/P_IN)

Impedance

Transmission Line: Z_O = √(L/C)

Where C = capacitance, L = inductance

Reactance

Capacitor: X_C = 1/(2πfC)

Inductor: X_L = 2πfL

Where f = frequency, C = capacitance, L = inductance

Propagation Delay

P_D (nsec/ft) = (√K)/C_o

Where K = dielectric constant and C_o = speed of light » 1 ft/nsec

Velocity of Propagation

V_P (%) = 1/(√K) x 100

Where K = dielectric constant

Electrical Length

L(nsec) = d(ft) x (√K) / C_o

Where K = dielectric constant and C_o = speed of light » 1 ft/nsec

Wavelength

λ = C_o /f (in air)

λ = C_o /(f x √K) (in any dielectric)

Where C_o = speed of light

For example: λ_AIR = (1.18 x 10¹⁰ in/sec)/(5 x 10⁹ Hz) = 2.4 inches @ 5 GHz

λ_FR-4 = (1.18 x 10¹⁰ in/sec)/((5 x 10⁹ Hz)(√4.5)) = 1.1 inches @ 5 GHz