Coaxial cable is a type of electrical cable with an inner conductor surrounded by an insulating, surrounded by a conducting shield. Coaxial cable is often used for radio frequency signals as it provides more protection from external electromagnetic interference.
Z is the symbol for impedance and is measured in ohm (Ω).
f is the symbol for frequency and is measured in hertz (Hz).
l is the symbol for length and is measured in meter (m).
C is the symbol for capacitance and is measured in farad per meter (F/m).
L is the symbol for inductance and is measured in henry per meter (H/m).
ε r is the dielectric constant.