# Antenna and Wave Propagation

**Antenna or aerial**, is an electrical device which **converts electric power into radio waves, and vice versa**. It is usually used with a radio transmitter or radio receiver. The **first antennas** were built in **1888 **by **German physicist Heinrich Hertz** in his pioneering experiments to prove the existence of electromagnetic waves predicted by the **theory of James Clerk Maxwell**.**Wave propagation** is any of the ways in which waves travel.

In **this course** you will learn details of antenna components, their uses, modes of wave propogation and related atmospheric dynamics.

## Overview

Antenna and Wave Propagation

Abbreviation | AWP | ||||
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Course | Third Year, Semester II ENTC | ||||

Credits | |||||

Examination Scheme
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Language | English |

## Table of Contents

## Course Objectives

- To understand the applications of electromagnetic engineering.
- To formulate and solve the Helmholtz wave equation and solve it for Uniform plane

wave - To analyze and understand the Uniform plane wave propagation in various media
- To solve the electric field and magnetic fields for a given wire antenna.

## Course Outcomes

After successfully completing the course students will be able to:

- Formulate the wave equation and solve it for uniform plane wave
- Analyze the given wire antenna and its radiation characteristics
- Identify the suitable antenna for a given communication system

## Syllabus and Notes

### Unit 1: Uniform Plane Waves

- Maxwell Equations in phasor form, Wave Equation, Uniform Plane wave in Homogeneous, free space, dielectric, conducting medium
- Polarization: Linear, circular & Elliptical polarization, unpolarized wave
- Reflection of plane waves, Normal incidence, oblique incidence, Electromagnetic Power and Poynting theorem and vector

### Unit 2: Wave Propagation

- Fundamental equations for free space propagation, Friis Transmission equation
- Attenuation over reflecting surface, Effect of earth's curvature
- Ground, sky & space wave propagations
- Structure of atmosphere
- Characteristics of ionized regions
- Effects of earth's magnetic field
- Virtual height, MUF, Skip distance
- Ionospheric abnormalities
- Multi-hoppropagation
- Space link geometry
- Characteristics of Wireless Channel: Fading, Multipath delay spread, Coherence Bandwidth, and Coherence Time

### Unit 3: Antenna Fundamentals

- Introduction, Types of Antenna, Radiation Mechanism
- Antenna Terminology: Radiation pattern, radiation power density, radiation intensity, directivity, gain, antenna efficiency, half power beam width, bandwidth, antenna polarization, input impedance, antenna radiation efficiency, effective length, effective area, reciprocity
- Radiation Integrals: Vector potentials A, J, F, M, Electric and magnetic fields electric and magnetic current sources, solution of inhomogeneous vector potential wave equation, far field radiation

### Unit 4: Wire Antennas

- Analysis of Linear and Loop antennas: Infinitesimal dipole, small dipole, and finite length dipole half wave length dipole, small circular loop antenna
- Complete Analytical treatment of all these elements

### Unit 5: Antenna Arrays

- Antenna Arrays: Two element array, pattern multiplication N-element linear array, uniform amplitude and spacing, broad side and end-fire array, N-element array: Uniform spacing, non-uniform amplitude, array factor, binomial and DolphTchebyshev array
- Planar Array, Circular Array, Log Periodic Antenna, YagiUda Antenna Array

### Unit 6: Antennas and Applications

[Main Page: Antennas and Applications]

Structural details, dimensions, radiation pattern, specifications, features and applications of following Antennas:

- Hertz & Marconi antennas
- V-Antenna, Rhombic antenna, TW antennas, Loop antenna, Whip antenna
- Biconical, Helical, Horn, Slot, Microstrip, Turnstile, Super turnstile & Lens antennas, Antennas with parabolic reflectors