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UPRVUNL AE EC 2014 Official Paper

Option 4 : It is independent of angles

CT 1: Engineering Mathematics

565

10 Questions
5 Marks
15 Mins

**The Directive Gain (D):**

**It **is defined as the ratio of radiation intensity due to the test antenna to isotropic antenna (hypothetical antenna that radiates uniformly in all direction)

\(D = \frac{U}{U_0}=\frac{4\pi U}{P_{rad}}\)

Where,

U = radiation intensity due to test antenna, in watts per unit solid angle

U_{0 }= radiation intensity due to an isotropic antenna, in watts per unit solid angle

P_{rad }=total power radiated in watts

Since U is a directional dependent quantity, the directive gain of an antenna depends on the angle θ and Φ. If the radiation intensity assumes its maximum value then the directive gain is called the **Directivity (D _{0}).**

__Power Gain__**:**

The power Gain of an antenna is defined as the ratio of its radiation intensity at a point to the radiation intensity that results from uniform radiation of the same input power.

\(Gain=\frac{4\pi \times radiation \ intensity }{Total \ Input \ power}\)

Whereas, the relative gain is defined as the ratio of power gain of the test antenna in a given direction to a power gain of reference antenna (whose gain can calculate or known). In most of the cases, the reference antenna is a lossless isotropic source.

1. It is the ratio of the radiation intensity in that direction to the average radiated power. (**Statement is true)**

2. It is the function of angles. **(Statement is true)**

3. It is the directivity of an antenna when the directive gain is maximum.(Statement is true)

4. It is independent of angles. (Statement is False)