Topic: Electromagnetics
A lossless line of 50 ohms is terminated in a load of 100 ohms resistive. The VSWR is
- A. 1:2
- B. 2:1
- C. 4:1
- D. 1:4
Answer: B. 2:1
Explanation: The reflection coefficient (Gamma) is (ZL - Z0) / (ZL + Z0) = (100 - 50) / (100 + 50) = 50 / 150 = 1/3. The Voltage Standing Wave Ratio (VSWR) is (1 + |Gamma|) / (1 - |Gamma|) = (1 + 1/3) / (1 - 1/3) = (4/3) / (2/3) = 2, which is conventionally written as a 2:1 ratio.