Progress in Compact Antennas

212 Pages·2014·23.98 MB·English

by  Huitema L.

Progress in Compact Antennas

Edited by Laure Huitema
Progress in Compact Antennas

D3pZ4i & bhgvld, Dennixxx & rosea (for softarchive)
Edited by Laure Huitema
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Published by AvE4EvA
Copyright © 2014
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Published: 10 September, 2014

ISBN-10 9535117238
ISBN-13 978-9535117230

C ontents

Preface

Chapter 1 Compact Antennas — An overview
by L. Huitema and T. Monediere
Chapter 2 Anten nas for Body Centric Wireless Communications at
Millimeter Wave Frequencies

by Nacer Chahat, Maxim Zhadobov and Ronan Sauleau

Chapter 3 Low Cost Compact Multiband Printed Monopole Antennas
and Arrays for Wireless Communications
by Qi Luo, Jose Rocha Pereira and Henrique Salgado

Chapter 4 Miniature Antenna with Frequency Agility
by L. Huitema and T. Monediere
Chapter 5 Active Compact Antenna for Broadband Applications
by Y. Taachouche, M. Abdallah, F. Colombel,

G. Le Ray and M. Himdi

Chapter 6 All-Dielectric Optical Nanoantennas
by Alexandr E. Krasnok, Pavel A. Belov,

Andrey E. Miroshnichenko, Arseniy I. Kuznetsov,
Boris S. Luk’yanchuk and Y uri S. Kivshar

Chapter 7 Building Partial Discharge Signal Wireless Probes
by Fabio Viola and Pietro Romano

Preface

Compact antennas are a subject of growing interest from industry
and scientific community to equip wireless communicating objects.
The need for high performance small antennas and RF front ends is
the challenge for future and next generation mobile devices.
This book brings the body of knowledge on compact antennas into
a single comprehensive volume. It is designed to meet the needs
of electrical engineering and physics students to the senior
undergraduate and beginning graduate levels, and those of
practicing engineers.

Chapter 1
Compact Antennas — An overview
L. Huitema and T. Monediere
Additional information is available at the end of the chapter
1. Introduction
Antenna size reduction is restricted by fundamental physical limits [1-3], in terms of trade-off
between radiation performances and impedance bandwidth. Miniaturization of devices leads
to the reduction of antennas which becomes one of the most important challenges [4]. Limi‐
tations in terms of bandwidth and efficiency suggest an analysis with respect to fundamental
limits [5]. Although interests are often focused on the impedance bandwidth, many studies
deal with the radiation quality factor Q. Some papers [6] have been concluded that the
impedance bandwidth BW equals 1/Q. The minimum Q value reachable by an infinitesimal
electric dipole, or similarly by the azimuthally symmetric TM spherical mode, has been
10
investigated thoroughly.
Hansen and Best [7] have shown that the lower bound on Q, deriving from Chu’s analysis, is
depending on the expense of efficiency as shown by the equation:
( 1 1 )
Q =η +
lb (ka)3 ka
where a is the minimum radius of the sphere enclosing the antenna and k is the wave number
(k=2π/λ).
The Figure 1 shows that it is very difficult to have a wide bandwidth (low Q-factor), while
reaching a good efficiency for miniature antennas (k.a around 0.2). Thus, the miniaturization
of antennas implies them to suffer of both limited efficiency and low bandwidth.
Since many years the scientific literature addresses some approaches concerning miniaturiza‐
tion techniques. The goal is to decrease the electrical size of the radiating element. This chapter
will draw up a survey of compact antennas in practical settings and the most common
miniaturization techniques listed below:
2 Progress in Compact Antennas
105
 = 100%
antenna
104 antenna = 50%
 = 20%
antenna
103  = 2%
antenna
Q
r
o
t102
c
a
f
y
tila101
u
Q
100
10-1
10-2
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
k.a
Figure 1. Quality factor according to the antenna dimensions and efficiencies
• Folded configurations [8-10]
• Surface etching techniques [11-14]
• Shorting walls or pins [15-16]
• The use of high dielectric constant materials or magneto-dielectric materials [17-22].
• Loading the radiating element with active components [23-26].
• Creation of hybrid modes with particular boundary conditions in dielectric resonator
antennas. It allows choosing their resonance frequencies (for multiband or wide impedance
bandwidth) [27].
We will start this chapter by detailing wire antennas. Indeed, after explaining the classical
dipole antenna, we will show how to miniaturize this kind of antennas based on shape design
such as bending, folding and meandering. The second part will detail planar antennas. We
will see the impact of materials properties under the patch antenna hat, i.e. dielectric or
magneto-dielectric materials. Then, planar miniature antennas will be shown, e.g. Planar
Inverted F Antenna (PIFA) and monopolar wirepatch antenna. The third part will exhibit
Dielectric Resonator Antennas and how to use this kind of antennas for low frequency band
application while having compact sizes. Finally, the last part will summary all the antennas
presented in this chapter, while showing their main settings.