Question

The S-parameters are used at microwave frequencies because of the following reasons, except

• A. Equipment is readily available to measure total voltage and total current
• B. Short and open circuits are difficult to achieve over a broad band of frequencies
• C. Logical variables to use at the microwave frequencies are travelling waves
• D. More stable Active devices are used at short or open circuits

Hint:

At microwave frequencies: \[ \text{Wave quantities} \rightarrow \text{S-parameters} \] instead of \[ V,\;I \] based measurements.

Answer 1

The Correct Option is A

Concept: At microwave frequencies, voltages and currents cannot be measured conveniently. Therefore scattering parameters (S-parameters) based on incident and reflected waves are used.

Step 1: Recall the advantages of S-parameters.
S-parameters are preferred because:
• Travelling waves are easy to measure.
• Open and short circuits are difficult to realize.
• Microwave devices are naturally characterized using wave quantities.

Step 2: Check the incorrect statement.
Option (A) states that total voltage and current are readily measurable. This is exactly the opposite of the reason S-parameters are used. Hence Option (A) is incorrect.

Step 3: Final Answer.
\[ \boxed{\text{Correct Option (A)}} \]