Match column A with column B. Column A Column B 1. Point electromagnetic source P. Highly directional 2. Dish antenna Q. End fire 3. Yagi-Uda antenna R. Isotropic
1 – R, 2 – P, 3 - Q
Electromagnetic Source and Antenna Characteristics
The question requires us to match different types of electromagnetic sources and antennas from Column A with their corresponding characteristics in Column B. Understanding the fundamental properties of each item in Column A is crucial for accurate matching.
Point Electromagnetic Source Definition
A point electromagnetic source is an idealized concept in electromagnetism. It represents a source that radiates electromagnetic energy uniformly in all directions in space. This uniform radiation pattern is known as isotropic radiation.
- An isotropic radiator is a theoretical point source that distributes power equally in all directions, having a gain of 1 (or 0 dB).
- Therefore, a Point electromagnetic source matches with Isotropic.
Dish Antenna Directionality
A dish antenna, also known as a parabolic antenna, is a type of high-gain antenna used for radio, television, and data communications. Its distinctive parabolic shape is designed to focus incoming radio waves onto a single receiver or to broadcast radio waves in a narrow, concentrated beam.
- The primary function of a dish antenna is to concentrate the electromagnetic energy, making it suitable for long-distance communication or for receiving weak signals from a specific direction.
- This characteristic of focusing energy into a narrow beam makes it highly directional.
- Therefore, a Dish antenna matches with Highly directional.
Yagi-Uda Antenna Radiation Pattern
The Yagi-Uda antenna is a highly popular directional antenna, commonly used for TV reception and amateur radio communication. It typically consists of a driven element (e.g., a dipole), one or more parasitic reflectors, and one or more parasitic directors.
- The parasitic elements interact with the driven element to shape the radiation pattern, directing most of the power in a specific direction.
- The Yagi-Uda antenna exhibits an end-fire radiation pattern, meaning the main lobe of radiation is along the axis of the antenna, typically in the direction of the directors.
- Therefore, a Yagi-Uda antenna matches with End fire.
Matching Antennas and Sources
Based on the analysis of each item, we can establish the following matches:
| Column A | Column B |
|---|---|
| 1. Point electromagnetic source | R. Isotropic |
| 2. Dish antenna | P. Highly directional |
| 3. Yagi-Uda antenna | Q. End fire |
Analyzing the Options
Comparing our derived matches with the given options:
- Option 1: 1 – P, 2 – Q, 3 - R (Incorrect)
- Option 2: 1 – R, 2 – P, 3 - Q (Correct)
- Option 3: 1 – Q, 2 – P, 3 - R (Incorrect)
- Option 4: 1 – R, 2 – Q, 3 - P (Incorrect)
The correct set of matches is 1 – R, 2 – P, 3 – Q.
Important Questions from Antennas
A device that makes possible the use of the same antenna for transmission and reception both
To match the impedance of a 'ground penetrating radar antenna' to the ground, impedance of ground is given by the expression, (if ϵ r= 14, μ r= 1, σ = 10 −2 ℧/m, operating frequency = 200 MHz)
For an isotropic antenna P n(θ, φ) = 1, D = 1, for all θ and φ. The beam area for the isotropic antenna is given by:
Broadside arrays have
A. Number of dipoles of unequal size
B. Number of dipoles equally spaced
C. Collinear dipoles
D. Dipoles in phase
E. Dipoles are 90 out of phase
Choose the correct answer from the options given below:
Consider the following statements:
(a) Fiber optic cable is much lighter than copper cable
(b) Fiber optic cable is not affected by power surges or electromagnetic interference
(c) Optical transmission is inherently bidirectional.
Which of the statements is (are) correct?
