Return loss is a ratio of the reflected wave and the incident wave power of the power transmission line ports, an absolute value of logarithmic expressed in units of dB, is generally a positive value.
Reflection coefficient (r) is the ratio of reflected voltage and incident voltage wave logarithmic, and return loss (rL) as the ratio of reflected power to the incident power. When taking the operands can be pushed to the mutual relationship between the two is as follows:
rL=20|lg(r)|
For example: if r = 0.1 when the callback loss of 20dB can be obtained; i.e., the reflected power was 1% of the incident power.
Annex: VSWR (voltage standing wave ratio) = 1 + r / 1-r.