Home › MCQs › Electronics Engineering › Question #11714
Back to Questions
Electronics Engineering QUESTION #11714
Question 1
A directional coupler has a coupling factor of $-20\,\text{dB}$ and directivity of $30\,\text{dB}$. The isolation between the input and isolated port is:
  • $10\,\text{dB}$
  • $30\,\text{dB}$
  • $50\,\text{dB}$✔️
  • $20\,\text{dB}$
Correct Answer Explanation
Isolation = Coupling + Directivity $= 20\,\text{dB} + 30\,\text{dB} = \mathbf{50\,\text{dB}}$. Coupling factor is the power tapped to the coupled port; directivity is the ability to discriminate between forward and reverse waves at the coupled port; isolation is the total suppression of backward signal at the isolated port.