Question

Which of the following will increase the antenna radiation efficiency?
$(A)$ Use of a large section of the conductor.
$(B)$ Providing insulation on the conductor.
$(C)$ Top loading of antenna.
$(D)$Any of the above.

Answer 1

Hint:The antenna efficiency is described as the power radiated by the antenna to the power supplied to the antenna.
An ideal antenna has \[100\% \] antenna efficiency; it means it transmits all the power fed to it. But in practice, a good antenna can radiate only \[50\% \] to \[60\% \] only.
We can use the EBG structure or slots to improve radiation efficiency.

Complete step-by-step solution:
The antenna Efficiency is often used to mean the radiation efficiency it is the measure of electrical efficiency. The radiation Efficiency is easy to calculate and it is used to determine by the measurements.
The gain of the antenna is directivity multiplied by the radiation efficiency. The low-efficiency antenna has most of the power absorbed as a loss within the antenna or it is reflected due to the impedance mismatching.
One good property of the antenna is the efficiency is the same when we use the antenna whether to transmit or receive. The antenna efficiency is the ratio of potential power received from all possible angles.
The antenna radiation efficiency can be written as,
\[{\varepsilon _r} = \dfrac{{{P_{radiated}}}}{{{P_{input}}}}\]
\[{\varepsilon _r} = \dfrac{{{P_{radiated}}}}{{{P_{input}}}}\]
The antennas are smaller than the half wavelength at the operating frequency which greatly lowers the antenna efficiency
Hence the answer is Option (C) top-loading antenna.

Note:The high-efficiency antenna has most of the power present at the antenna input radiated away. Here the top loading of the antenna will increase the antenna’s radiation efficiency. The efficiency of the antenna is described as the ratio of the power delivered to the antenna to the power radiated from the antenna.