Question

Mean effective aperture of a \(\lambda/2\) dipole is

• A. \(0.013\lambda^2\)
• B. \(1.3\lambda^2\)
• C. \(0.13\lambda^2\)
• D. \(13\lambda^2\)

Hint:

Half-wave dipole effective aperture ≈ 0.13 λ².

Answer 1

The Correct Option is C

Concept: Effective aperture is related to antenna gain: \[ A_e = \frac{\lambda^2 G}{4\pi} \]

Step 1: Gain of half-wave dipole \[ G \approx 1.64 \]

Step 2: Substitute \[ A_e = \frac{\lambda^2 \times 1.64}{4\pi} \]

Step 3: Numerical approximation \[ 4\pi \approx 12.57 \]

Step 4: Calculation \[ A_e \approx \frac{1.64}{12.57}\lambda^2 \approx 0.13\lambda^2 \]

Step 5: Conclusion \[ \boxed{0.13\lambda^2} \]

Final Answer: \[ \boxed{(C)} \]