International Journal of Engineering Trends and Technology (IJETT) – Volume 32 Number 1- February 2016
Reconfigurability in Antennas by
Incorporation of Metasurface
Anamika Sethi#1, Rajni*2
#
Research Scholar, ECE Department, MRSPTU, INDIA
Associate Professor, ECE Department, MRSPTU, INDIA
*
Abstract- Antennas are the critical components of
modern telecommunication systems and can limit the
system performance because of their inability to
adjust according to the changing environmental
conditions and scenarios. They can be made
reconfigurable so that they can offer important new
capabilities for the next generation applications.
Adapting to changes in requirements and providing
additional functionality, these antennas can tackle
system requirements by changing their functionality
on demand. This paper presents the types of
reconfigurable antennas using metasurface, which is
the two-dimensional equivalent of metamaterial.
Keywords – Reconfigurable antenna, Metasurface.
I. INTRODUCTION
An antenna is a key component of a modern
communication system like mobile phones, laptops,
satellite communication, radio broadcasting, wireless
microphones and wireless computer networks etc. A
good communication system should have the
capability to change its operational characteristics
according to the necessity. Thus, such systems
should be equipped with smart antennas to alter their
operating parameters with the change in the
environmental scenario. These factors encourage the
researchers to look into the new field of antennas
called „Reconfigurable Antenna‟ [1].
Antenna reconfiguration can be done by
changing operating frequency, radiation pattern and
polarization characteristics. This can be done by
many techniques by redistributing the antenna
currents and hence the effective aperture of
electromagnetic fields can be altered. In order to
integrate multiple wireless systems into a single
system, one or more of the operating parameters
need to be reconfigured [2].
Reconfigurable antennas have the ability to
support more than one wireless standard hence they
can minimize cost and volume requirement. They
have good out of band rejection. They have the
capability to learn and can provide multifunctional
capabilities [3].
The reconfiguration of operating frequency,
radiation pattern or polarization of antenna can be
achieved by mechanical or electrical mechanism.
Mechanical reconfigurable antennas (MRA) need to
adjust the movable or rotatable parts in order to
ISSN: 2231-5381
achieve reconfiguration. Electrically reconfigurable
antennas (ERA) use radio-frequency microelectromechanical systems (RF-MEMS), PIN diodes
or varactors to achieve reconfiguration. Biasing
circuits and direct current sources are needed in
design of electrical reconfigurable antenna to bias
the varactor or PIN diodes. The ERA are quite
popular but the electric components can affect the
antenna performance adversely. The movement of
mechanical parts is quite complicated and expensive
in MRA. So to overcome these drawbacks,
metasurface is proposed to design reconfigurable
antennas [2], [3].
Metasurface, a surface equivalent of threedimensional metamaterial, and is extended when
electrically small scatterers or holes are arranged in a
two-dimensional pattern at a surface. Metasurfaces
takes up less physical space as compared to
metamaterials and hence, are less lossy [4].
II. METAMATERIAL
Metamaterials (a Greek word, which means „to
go beyond‟), are intelligent materials which have the
properties that are not found in nature yet. They are
made by assembling multiple elements made from
different materials which can be plastics or metals
etc. These materials are positioned in a repeating
manner at smaller wavelengths. These materials
derive their properties from the newly designed
structures, not from their base materials. The shape,
size, material, positioning, geometry of these
metamaterials make them capable to change
electromagnetic waves, so that they can achieve
some benefits which cannot be achieved by natural
materials. These materials exhibit negative index of
refraction at some particular wavelengths and are
known as negative index metamaterials [5]-[10].
A. Classification of metamaterials
The presence of electromagnetic field affects the
response of the system and can be decided by the
properties of the involved materials. These
properties can be determined by defining some
parameters like permeability and permittivity of
these materials. Figure 1 shows the graphical
illustration of metamaterial classification relative to
the permeability and permittivity [11].
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International Journal of Engineering Trends and Technology (IJETT) – Volume 32 Number 1- February 2016
circular shape and same diameter. The source
antenna is modelled on a double sided substrate and
the metasurface is designed on a single sided
substrate, as shown in Fig. 2(a), 2(b), 2(c). The
design of antenna is carried out on a Rogers
Substrate RO4350B of 1.524mm thickness and
dielectric constant 3.48. The geometrical dimensions
of frequency reconfigurable antenna are given in
Table 1. The antenna is fed by SMA base connector.
The metasurface is rotated around the central point
of patch antenna to achieve frequency
reconfigurability [14].
Fig. 1 Classification of Metamaterials [11]
Double positive medium (DPS) are those
mediums which have both permittivity and
permeability positive, i.e. greater than zero. Most
dielectrics fall under the category of DPS. Epsilon
negative medium (ENG) are those mediums which
have positive permeability and negative permittivity.
Some plasmas at certain frequencies exhibit this
property. Mu negative medium (MNG) are those
mediums which have positive permittivity and
negative permeability. Some gyrotropic materials at
certain frequencies exhibit this property. Double
negative mediums (DNG) are those mediums which
have both permeability and permittivity negative.
This type of medium can only be demonstrated by
artificial structures [11].
Fig. 2 (a) Patch antenna , (b) Metasurface and (c)
Unit cell of frequency reconfigurablity [14]
TABLE I
GEOMETRICAL PARAMETERS OF
FREQUENCY RECONFIGURABLE ANTENNA
B. Metasurface
Metasurface is a surface version of threedimensional metamaterial, and can be extended by
arranging electrically small scatterers or holes are
arranged in a two-dimensional pattern at a surface.
Metasurfaces takes up less physical space as
compared to metamaterials and hence, are less lossy
[12]. Metasurfaces are used instead of metamaterials
for many applications. Some potential applications
of metasurfaces are: (a) novel wave-guiding
structures, (b) biomedical devices, (c) controllable
intelligent surfaces, (d) terahertz switches, etc [13].
S.No.
Parameter
1
2
3
4
5
6
7
8
9
10
11
Pa
Pb
a
b
W
Lp
Wp
Wf
Pf
Pe
RD
Value
(in mm)
12.4
5.4
10
3
1
16
12
2
11
2
40
B. Polarization Reconfigurable Antenna
III. TYPES OF RECONFIGURABLE
ANTENNA
Classification of reconfiguration antennas can be
done in the following three ways:
A. Frequency Reconfigurable Antenna
Frequency reconfigurable antennas are those
which can reconfigure their operating frequency. A
frequency reconfigurable antenna is depicted in
Fig.2, by incorporating a metasurface. It is
comprised of a patch antenna and a metasurface. The
metasurface consists of rectangular looped unit cells.
The source antenna and the metasurface are of
ISSN: 2231-5381
The polarization reconfigurable antennas are
those which have the capability to change their
polarization.
A
Polarization
reconfigurable
metasurface antenna is depicted in Fig. 3. It is
comprised of a slot antenna and a metasurface. The
metasurface is designed on a single sided substrate
and consists of truncated square unit cells as shown
in Fig. 3(a).
The antenna is fabricated on Rogers Duroid
substrate RO4350B and fed from the base with SMA
connector and through the substrate material of the
slot antenna. In order to achieve polarization
reconfigurability, the metasurface is rotated around
the central position with respect to the slot antenna.
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International Journal of Engineering Trends and Technology (IJETT) – Volume 32 Number 1- February 2016
It has been shown that with
= 0± and 90±, the
antenna operates in left hand circular polarization
and right hand circular polarization, respectively.
The design dimensions of the antenna are listed in
Table 2 [15].
Fig. 4 (a) Patch antenna, (b) Metasurface and (c)
Unit cell of Pattern reconfigurability [16]
Fig. 3 (a) Metasurface and (b) Slot antenna for
polarization reconfigurability [15]
TABLE III
GEOMETRICAL PARAMETERS OF PATTERN
RECONFIGURABLE ANTENNA
TABLE II
GEOMETRICAL PARAMETERS OF
POLARIZATION RECONFIGURABLE
ANTENNA
S. No.
Parameter
1
2
3
4
5
6
7
8
9
10
a
B
C
sw
sl
fw
fl
fy
P
t
Value
(in mm)
18.5
5.3
1
3
20
2.5
24.5
2
2
78
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Parameter
1
2
3
4
A
G
Pr
T
Value
(in mm)
6
0.35
18
70
IV. CONCLUSION
Three different types of reconfigurable antennas,
namely, frequency, polarization and pattern
configurations, designed using metasurfaces have
been presented in this paper. The source antennas of
these reconfigurable antennas have circular shapes.
By using different metasurfaces underneath the
source antennas, the operating frequency,
polarization and radiation pattern of the source
antennas can be reconfigured by simply rotating the
MS around the centre of the source antenna.
C. Radiation Pattern Reconfigurable Antenna
The radiation pattern reconfigurable antennas are
those which can change their radiation pattern
according to the demand. A radiation pattern
reconfigurable antenna is depicted in Fig. 4. It is
comprised of a patch antenna and a metasurface. The
patch antenna is of circular shape whereas the
metasurface is semicircular, having the same
diameter. The metasurface consists of square patches
as unit cells.
The substrate, Rogers Substrate RO4350B, used
for the antenna is of 1.524mm thickness, and
dielectric constant of 3.48. A tilted beam is
generated because of the semicircular shape of the
metasurface. The pattern reconfigurability is
achieved by the rotation of metasurface around the
patch antenna from the centre point. The design
dimensions of the antenna are enlisted in Table
3[16].
S. No.
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International Journal of Engineering Trends and Technology (IJETT) – Volume 32 Number 1- February 2016
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