How do I calculate the mismatch loss in dB from a known VSWR value?

Mismatch loss is the power lost due to reflection at an impedance discontinuity. It can be calculated directly from the VSWR value: (1) Formula: first, convert VSWR to reflection coefficient: Gamma = (VSWR - 1) / (VSWR + 1). Then calculate the mismatch loss: ML (dB) = -10 × log10(1 - Gamma²). The mismatch loss represents the fraction of incident power that is reflected back (not delivered to the load). (2) Common VSWR values and their mismatch loss: VSWR = 1.0: Gamma = 0, ML = 0 dB (perfect match). VSWR = 1.2: Gamma = 0.091, ML = 0.036 dB. VSWR = 1.5: Gamma = 0.200, ML = 0.177 dB. VSWR = 2.0: Gamma = 0.333, ML = 0.512 dB. VSWR = 3.0: Gamma = 0.500, ML = 1.25 dB. VSWR = 5.0: Gamma = 0.667, ML = 2.55 dB. VSWR = 10.0: Gamma = 0.818, ML = 4.81 dB. (3) Practical significance: at VSWR = 1.5: only 0.177 dB (4%) of the power is lost. This is generally acceptable for most RF systems. At VSWR = 2.0: 0.512 dB (11%) is lost. This is the typical maximum acceptable VSWR for most designs. At VSWR = 3.0: 1.25 dB (25%) is lost. This is typically unacceptable and indicates a serious mismatch. (4) Relationship to return loss: return loss (dB) = -20 × log10(Gamma). At VSWR = 2.0: RL = 9.54 dB. Mismatch loss can also be calculated from return loss: ML = -10 × log10(1 - 10^(-RL/10)).