With a fixed antenna gain, what happens to EIRP when the power delivered to the antenna is increased?

With a fixed antenna gain, what happens to EIRP when the power delivered to the antenna is increased?

• A. EIRP decreases.
• B. EIRP stays the same.
• C. EIRP increases quadratically.
• D. EIRP increases proportionally.

Answer: (D)

The main idea is that EIRP scales directly with the transmitter power when the antenna gain is fixed. EIRP is essentially the input power times the antenna gain. If the gain stays the same, increasing the power delivered to the antenna increases EIRP by the same factor—it's a linear relationship. So, doubling the input power doubles the EIRP; halving the input power halves the EIRP. In decibels, the EIRP increases by the same number of dB as you increase the input power, since the gain term is constant. It’s not quadratic, because the dependency is linear with the input power.