Topic: Electromagnetics
A transmission line having characteristic impedance '$Z_{1}$' of varying length in series with a load impedance '$Z_{L}$' appears in a Smith Chart on
- A. Constant Resistance Circle
- B. Constant VSWR Circle
- C. Constant Reactance Circle
- D. All of the above
Answer: B. Constant VSWR Circle
Explanation: Varying the length of a lossless transmission line changes the phase of the reflection coefficient but keeps its magnitude constant. Since the VSWR depends only on the magnitude of the reflection coefficient, the locus of impedance points maps onto a constant VSWR circle on the Smith Chart.