RF and Microwave Electromagnetism

Pierre Jarry, Jacques N. Beneat

• Publisher: Wiley-ISTE
• Year: 2014
• ISBN:
  9781118985106
• Edition: 1
• Topic: Technology & Engineering
• Subtopic: Microwaves
• Index: Technology & Engineering

Microwave and radio frequency (RF) elements play an important role in communication systems, and, due to the proliferation of radar, satellite and mobile wireless systems, there is a need for the study of electromagnetism.

Each of the nine chapters of this book provides a complete analysis and modeling of the microwave structure used for emission or reception technology, providing students with a set of approaches that can be used for current and future RF and microwave circuit designs. The authors emphasize the practical nature of the subject by summarizing the analysis steps and giving numerous examples of problems and exercises complete with solutions, making this book theoretical, but also experimental, with over 16 microwave problems. This approach has produced a coherent and practical treatment of the subject.

The book has grown out of the authors' own teaching and, as such, has a unity of methodology and style. It provides basic knowledge of microwave and RF range and is intended for microwave engineers and for advanced graduate students.

PART 1

Transmission Lines

1

Electromagnetic of TEM Transmission Lines

1.1. General waves

Generally, electromagnetic waves are given by the solution of well-known Maxwell–Faraday formulas. These formulas give electric and magnetic fields (

) .In the case without charges we have the following expressions:

1.2. Transverse electromagnetic (TEM) waves

The waves are propagating in a medium which is

– linear;

– homogeneous;

– isotropic;

– without loss.

The medium being linear means that the permittivity constant ε and the permeability constant μ are independent of the frequency.

In the case of a harmonious state, the electric and magnetic fields are of the form:

where the propagating constant is:

α is the attenuation and β is the propagation.

When we consider only positive propagating waves, we have a solution in –γ, and the resulting electric and the magnetic waves are:

The amplitude decreases by the factor e^–αz. Also, phase is constant if:

This means that:

And we have the phase speed:

Now we decompose the electromagnetic wave (Figure 1.1) with:

– a part parallel to the propagating way z : E_z (x, y)

;

– a part perpendicular to the propagating way z :

(x,y).

Figure 1.1. Decomposition of the EM field

In the case of transverse electromagnetic (TEM) fields, the waves are transversal; then:

which means that:

And the transversal fields satisfy the following group of equations:

To ensure the compatibility of these equations, we must have

And the TEM fields are lossless

From the quantity

This gives

The TEM fields are propagating at the same speed as the uniform plane waves c .

From these equations...

Table of contents

• Cover
• Contents
• Title Page
• Copyright
• Preface
• Introduction to Microwaves
• Part 1: Transmission Lines
• Part 2: Guides
• Part 3: Cavities
• Index