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Parametric Synthesis of 3D Structure of SRR Element of the Metamaterial

Authors:
  • Central Scientific Research Insitute of Armaments and Military Equipment of Armed Forces of Ukraine
  • Полтавская государственная аграрная академия, Poltava, Ukraine

Abstract and Figures

Variants of split ring resonators (SRR) models are proposed. They are considered as unit cells of DNG metamaterials. The synthesized SRR variants are based on the implementation of 3D geometry. Efficiency assessment is carried out on the base of determination of the relative bandwidth δ fDNG, in which the DNG properties are observed. Since metamaterials are complex composite structures, instead of analytical calculations, the Finite Element Method (FEM) is used to estimate the electromagnetic properties of SRR. The adequacy of the proposed SRR model is confirmed by the coincidence of the obtained results in the particular case with the corresponding estimates of the base model. At the same time, the influence of the geometric parameters of the SRR components (orientation and size of the conductor; axial rotation of the rings, subtract material) on the effectiveness of the decisions was investigated. The use of 3D-based constituent elements in SRRs allowed us to achieve a 10 times increase in δ fDNG compared to the base prototype.
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Problems of Infocommunications. Science and Technology
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978-x-xxxx-xxxx-x/20/$31.00 ©2020 IEEE
Parametric synthesis of 3D structure of SRR
element of the metamaterial
Ihor Sliusar
Department of information systems and technologies
Poltava State Agrarian Academy
Poltava, Ukraine
islyusar2007@ukr.net
Vadym Slyusar
Central Research Institute of Armaments and Military
Equipment of Armed Forces of Ukraine
Kyiv, Ukraine
swadim@ukr.net
Yurii Utkin
Department of information systems and technologies
Poltava State Agrarian Academy
Poltava, Ukraine
1008utkin@gmail.com
Olena Kopishynska
Department of information systems and technologies
Poltava State Agrarian Academy
Poltava, Ukraine
17elenak@gmail.com
AbstractVariants of split ring resonators (SRR) models
are proposed. They are considered as unit cells of DNG
metamaterials. The synthesized SRR variants are based on
the implementation of 3D geometry. Efficiency assessment is
carried out on the base of determination of the relative
bandwidth δ fDNG, in which the DNG properties are observed.
Since metamaterials are complex composite structures,
instead of analytical calculations, the Finite Element Method
(FEM) is used to estimate the electromagnetic properties of
SRR. The adequacy of the proposed SRR model is confirmed
by the coincidence of the obtained results in the particular
case with the corresponding estimates of the base model. At
the same time, the influence of the geometric parameters of
the SRR components (orientation and size of the conductor;
axial rotation of the rings, subtract material) on the
effectiveness of the decisions was investigated. The use of 3D-
based constituent elements in SRRs allowed us to achieve a
10 times increase in δ fDNG compared to the base prototype.
Keywordsdouble negative; metamaterial; split ring
resonator
I. INTRODUCTION
Telecommunication miniaturization trends have
intensified the search for approaches to the creation of
Eletrically Small Antennas (ESA) [1]. At the same time,
the technologies of microstrip antennas have reached their
limits in terms of reducing the dimensions of microwave
devices. As a result, one of the promising areas of ESA
design is the use of metamaterials.
As is known [2, 3], metamaterials as substrates for
printed miniature antennas can reduce the size of the
emitters, increase their passband and radiation efficiency.
Metamaterials that contain only one negative
electromagnetic parameter (εr or μ) are called Single
Negative (SNG). However, the greatest interest is shown in
the creation of metamaterials with a negative refractive
index of electromagnetic waves, which are characterized
simultaneously by negative values of the dielectric constant
and magnetic permeability (εr < 0, µ < 0) [2, 3]. Such
materials are called Double Negative (DNG) [2, 3].
At the same time, the main task of improving of the
metastructures is the synthesis of such environment that
would have minimal losses and almost insignificant
dispersion properties, as well as provide a wide frequency
band corresponding to DNG.
II. ANALYSIS OF RECENT STUDIES AND PUBLICATIONS,
WHICH DISCUSS THE PROBLEM
To identify a metamaterial as a DNG, it is necessary to
evaluate its electromagnetic properties. Such an estimate
comes down to an analysis of the sign of the real part of the
quantities εr and µ. The following relations should be used
[4]:
εr = n / z и µ = n z, (1)
where n is the refractive index; z is the wave impedance.
In turn, to obtain the values of n and z, you can use the
formulas [5]:
, (2)
, (3)
where k0 = f/c, с speed of light, f frequency, d
linear size of the metamaterial unit cell, Sxy S-parameters
of dispersion matrix [5].
As a classic example of the metastructure unit cell, on
the basis of which a negative refractive index can be
achieved (accordingly, a DNG frequency range can exist),
the Split Ring Resonator (SRR) should be mentioned [2, 3].
Such a structure is described more in detail in [6].
The systematization of existing sources related to this
topic indicates that the studies of the joint use of microstrip
or patch antennas and metamaterials are dominant [4, 7-
11].
Unfortunately, metamaterials based on circular or
rectangular SRRs are characterized by a narrow DNG
frequency band, high level of electromagnetic losses, etc
[6]. To make up for flaws, it is possible to form structures,
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in which perpendicular arrangement of metamaterial cells
based on printed SRRs is used [12] or several layers based
on them [6] are implemented.
However, to reveal all the possibilities for integrating
ESA technologies and metamaterials, it is advisable to
conduct an open optimization of the parameters of SRR
structural elements, for example, through the use of 3D
geometry. A similarity of such structures may be a design
option from [13].
Considering that metamaterials are complex composite
structures, analytical solutions to assess their properties
become inapplicable. As a result, the role of fixed assets in
the process of metamaterials designing is assigned to
numerical modeling. In this case, the most common is the
use of the Finite Element Method (FEM), successfully
tested by the authors, for example, in [14-16].
III. THE AIM OF RESEARCH
Thus, the aim of the work is to increase the efficiency
of metamaterial using SRR by modifying its geometry.
IV. THE MAIN RESULTS OF THE STUDY
In this paper, a printed SRR [7] was used as a
prototype, the model of which is presented in HFSS [7,
17] Fig. 1.
Fig. 1. Printed SRR as a base model.
The indicated SRR variant contains a composite epoxy
material substrate (in HFSS this material is FR4). On one
of its surfaces there are metal split “rings”, and on the
other conductor. Since the model of such an SRR is one
unit cell, which should be in a multi-element system, the
formation of limit conditions in the form of a “Master /
Slave” boundary on the x- and y-edges of the model will
be most acceptable (Fig. 2.a) [7]. This area is very critical
for determining the correct location of the excitation ports,
which should be located quite far from the near fields
induced on the SRR structure. This ensures that the
dispersion parameters are calculated correctly. Since the
exact calculation of the S-parameter phase is important for
an efficient parameter estimation [7], the ports are
displayed on the inner surface of the box describing the
boundary conditions (blue arrows in Fig. 2.b). Herein, a
modification of wave ports is used, which is called
“Floquet Ports” [7], since in these ports the harmonicа of
Floquet with zero indices propagates (it is often called the
main harmonicа). It has a field structure that matches the
field of the incident wave. In this case, higher order
harmonics are not excited.
а)
b)
Fig. 2. Formation of the calculation area: a) “Master / Slave” boundary
conditions; b) Floquet Ports [7].
Based on the considered model, the authors
synthesized the SRR variant based on the implementation
of 3D geometry (Fig. 3). The following situations were
considered as introduced assumptions:
SRR “rings” and conductor made of copper; the
orientation of the wire and the cuts of the “rings” of the
SRR are identical to the base model;
the geometric dimensions of the SRR components
according to Ox and Oz coincide with the same parameters
of the base model;
subject to change the dimensions of the SRR
components along the Oy axis;
to correctly compare the properties of the basic and
synthesized SRR models, its dimensions should not extend
beyond the figure (parallelepiped) describing the boundary
conditions of the basic model;
analysis is carried out in the range 0.1 ÷ 20 GHz;
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conditions for the calculations coincide with the
base model;
performance assessment is based on determining the
relative bandwidth, for which the conditions εr < 0, µ < 0
are valid.
Fig. 3. Synthesized model No. 1 of metamaterial cell.
There are several options for interpreting of the concept
of “relative bandwidth”. Following [14, 15], we further use
the definition that corresponds to the expression:
, (4)
where f1 and f2 are the limit values of the frequencies of the
range characterized by the condition: {Re(εr) < 0 and
Re(µ) < 0}, Δf = f2 f1.
To check the adequacy of the proposed model No. 1
(Fig. 3) with respect to the base, the substrate material
“FR4 epoxy (εr = 4.4) was selected and the first
calculation was carried out with the values of the variables:
t_copper = Wide = 0,017 mm. The results obtained
coincided with the corresponding estimates of the base
model (δ fDNG = 0.19). At the same time, a new graph
(Fig. 4) was formed as the result, which shows the
frequency dependences of Re(εr) and Re(µ.
Fig. 4 Evaluation of the characteristics of model SRR No. 1: a) Re(εr);
b) Re(µ).
Further, the dependence of δ fDNG on the geometric
dimensions of the conductor and SRR rings along the Oy
axis was studied. First, the situation of a synchronous
increase in their size was considered (Table I), and then the
size of the SRR rings was fixed and the dimensions of the
conductor were changed along the Oy axis. The
corresponding results are presented in Table II. The
greatest effect is observed at t_copper = Wide = 1 mm, for
which δ fDNG = 0.335 was obtained (Fig. 5). It can be
assumed that a further increase in the size of the cell will
lead to the expansion of the DNG region.
Fig. 5. DNG SRR estimate at t_copper = Wide = 1 mm: a) Re(εr);
b) Re(µ).
The analysis indicates an increase in the width of the
DNG frequency range as the dimensions of the SRR
constituent elements along the Oy axis increase.
TABLE I. DNG BANDWIDTH ESTIMATION
Variable structures,
mm
Boundary
frequencies, GHz
Bandwidth
Wide
f1
f2
f, GHz
δ fDNG
0.017
12.32
14.30
1.98
0.149
0.0358
12,32
14.30
1.98
0.149
0.1
12.17
14.70
2.53
0.19
0.2
11.92
14.89
2.97
0.222
0.3
11.73
14.89
3.16
0.237
0.4
11.51
14.86
3.35
0.254
0.5
11.34
14.86
3.52
0.269
0.6
11.21
14.92
3.71
0.284
0.7
11.04
14.89
3.85
0.297
0.8
10.92
14.97
4.05
0.313
0.9
10.78
14.97
4.19
0.325
1
10.67
14.97
4.3
0.335
TABLE II. THE RESULTS OF CALCULATIONS OF THE FREQUENCY
DOMAIN DNG WHEN CHANGING THE SIZE OF THE CONDUCTOR AND
FIXING THE SIZE OF THE SRR RINGS ALONG THE AXIS OY
Variable structures,
mm
Boundary
frequencies, GHz
Bandwidth
t_copper
Wide
f1
f2
f, GHz
δ fDNG
0.1
0.7
11.33
12.22
0.89
0.076
0.2
11.26
12.96
1.7
0.14
0.4
11.20
14.13
2.93
0.213
0.6
11.10
14.86
3.76
0.29
The next step in the study was to assess the effect of the
substrate material. In addition to the classic FR4, several
material options were considered: Rogers RO3003 (εr = 3);
Rogers RO3006 (εr = 6.15); Rogers RO3010 (εr = 10.2);
and vacuum. By the way, using of vacuum as the substrate
material allows us to transform model No. 1 to the variant
shown in Fig. 6.
Herein, the values of the variables
t_copper = Wide = 0.2 mm were taken. Corresponding
estimates of the length of the DNG frequency domain are
shown in Fig. 7-10 and are presented in Table III.
The obtained results suggest the possibility of a slight
decrease in the frequency range of the DNG domain due to
the use of a substrate material with a higher εr value.
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Fig. 6. Version of the model SRR without substrate.
TABLE III. ESTIMATION OF THE DNG FREQUENCY DOMAIN WHEN
THE SRR SUBSTRATE MATERIAL CHANGES
Material
(εr)
Variable
structures, mm
Boundary
frequencies,
GHz
Bandwidth
t_copper
Wide
f1
f2
f, GHz
δ fDNG
Vacuum (1)
0.2
0.2
14.10
17.59
3.49
0.22
RO3000
(tm) (3)
0.2
0.2
12.61
15.71
3.1
0.22
FR4_epox
y (4.4)
0.2
0.2
11.92
14.89
2.97
0.22
RO3006
(tm) (6.15)
0.2
0.2
11.45
14.22
2.77
0.22
RO3010
(tm) (10.2)
0.2
0.2
10.63
12.94
2.31
0.2
Fig. 7. Estimation of the DNG frequency domain for the Rogers RO3003
substrate material: a) Re(εr); b) Re(µ).
Fig. 8. Estimation of the DNG frequency domain for the Rogers RO3006
substrate material: a) Re(εr); b) Re(µ).
Considering the presence of an SRR modification
without a substrate (see Fig. 6), it is advisable to analyze
the influence of the angle of inclination of the SRR rings
around the Ox axis on the frequency properties of the
metamaterial unit cell model (Fig. 11) for the same
variables: t_copper = Wide= 0.2 mm. It is significant that
an increase in these values may lead to contact between the
SRR rings, which is unacceptable. The research results
were systematized and summarized in Table IV. Thus, the
inclination of the SRR rings around the Ox axis did not
give a significant improvement in the properties of the
metamaterial cell according to the maximum criterion
δ fDNG.
Fig. 9. Estimation of the DNG frequency domain for the Rogers RO3010
substrate material: a) Re(εr); b) Re(µ).
Fig. 10. Estimation of the DNG frequency domain for the model shown
in Fig. 6: a) Re(εr); b) Re(µ).
Fig. 11. Model No. 2, with AN option of independent selection of the
angle of inclination of the outer and inner rings of the SRR.
TABLE IV. RESULTS OF CALCULATIONS OF THE FREQUENCY AREA
DNG WHEN CHANGING AN ANGLE OF THE RINGS SRR AROUND THE OX
AXIS
Angles of
inclination,
deg
Variable
structures, mm
Boundary
frequencies,
GHz
Bandwidth
A1
A2
t_copper
Wide
f1
f2
f
δ fDNG
0
0
0.2
0.2
13.92
18.06
4.14
0.259
4
0
0.2
0.2
13.47
17.52
4.05
0.261
5
0
0.2
0.2
13.96
18.19
4.23
0.263
10
0
0.2
0.2
14.07
18.15
4.08
0.253
0
-5
0.2
0.2
14.03
17.99
3.96
0.247
0
5
0.2
0.2
14.03
17.99
3.96
0.247
5
5
0.2
0.2
14.16
17.99
3.83
0.238
15
-15
0.2
0.2
15.31
17.61
2.3
0.14
-15
15
0.2
0.2
15.51
17.07
1.56
0.096
5
-5
0.5
0.2
13.86
18.12
4.26
0.267
A further area of research was the determination of the
influence of the orientation of the conductor relative to the
SRR rings. At the same time, it was located in the xOy
plane, and it rotated around the Oz axis by 90 degrees
(Fig. 12). This approach has led to an expansion in
bandwidth in the DNG region (Fig. 13), which indicates its
effectiveness. In this case, the value f = 8.64 GHz
(δ fDNG = 1.13) was achieved. For a given SRR arrangement
in Fig. 14 shows the frequency dependence of Re(n).
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Fig. 12. Model SRR No. 3.
Fig. 13. Assessment of the DNG frequency domain for model No. 3:
a) Re(εr); b) Re(µ).
Fig. 14. Evaluation of the real component of the refractive index Re(n)
for model No. 3.
Hereinafter, we analyzed the influence of changes in
the dimensions of the conductor, its placement in relation
to the center of the SRR, as well as the previously
considered versions of the SRR models, but taking into
account the changed spatial orientation of the conductor.
In addition, the SRR model was investigated with rings
rotated by 90 degrees around the Oy axis (Fig. 15), with
sections of the SRR frames located on the Oz axis. This
allowed us to obtain f = 10.78 GHz and δ fDNG = 1.9
(Fig. 16).
Fig. 15. Model SRR No. 4.
Fig. 16. Assessment of the frequency domain DNG for model No. 4: a)
Re(εr); b) Re(µ).
Considering an obtained effect, the SRR layout option
was studied in the most detail, which differed by the
deviation of the rings section in relation to the Oz axis by
angles of up to ± 30 degrees (Fig. 17). In this case,
fluctuations in the value of δ fDNG occurred. As a result, the
maximum effect was observed at the deviation angle of 20
degrees (Fig. 18).
Fig. 17. Model SRR No. 4 (with variation of the inclination angle of the
rings rupture in relation to the axis Oz).
Fig. 18. Assessment of the DNG frequency domain for model No. 4 with
an inclination angle of the cut of rings 20 degrees: a) Re(εr); b) Re(µ).
To increase ∆f, it is possible to introduce mutual
rotation of SRR rings around the Oz axis. For instance, for
the model shown in Fig. 19, this made it possible to
provide an additional increment of f at 0.5 GHz.
Fig. 19. SRR with mutual rotation of the rings around the axis Oz (top
view).
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In general, the estimates of the synthesized SRR
models allow us to conclude that for the expansion of the
DNG frequency regions and their simultaneous shift down
in frequency, it is advisable to perform mutual
displacement between the SRR rings. However, it should
be considered that such a shift is acceptable only within
certain limits.
V. PERSPECTIVES OF FURTHER RESEACH
It is advisable to focus further research on studying of
the electromagnetic parameters of SRR structures, in which
the constituent elements are modeled on the basis of
fractals [18] or antifractals.
Another direction of designing such SRRs may be the
combination of square frames and round rings, as well as
the introduction of various types of dielectric inserts into
the SRR, which are based on dielectric resonator antenna
technologies [16].
VI. CONCLUSIONS
The study of the electromagnetic properties of the
synthesized SRR variants was carried out taking into
account the influence of geometric parameters (orientation
and size of the conductor; axial rotation of the rings,
substrate material).
Compared with the prototype [7], the synthesized SRR
models allow one to obtain a 10-fold increase in δ fDNG с
0.19 to ≈1.9.
SRR with the conductor placed in the xOy plane and its
axis oriented perpendicular to xOz is an effective solution
that has led to the expansion of the DNG bandwidth in the
low frequency region.
The use of a conductor with a rectangular cross section
is advisable if its larger side is oriented perpendicular to the
Floquet Ports.
When determining the optimal angle of inclination of
the section plane of the SRR frames in relation to the yOz
plane, it is advisable to choose it within the range of 0 ÷ 90
degrees.
If we consider the synthesized SRR model as a
template for creating a metastructure, then the cut width of
the frames should be equal to the double thickness of the
rings.
To expand the frequency domain of the DNG and
simultaneously shift it down in frequency, it is advisable to
perform a mutual offset between the SRR rings. However,
it should considered that it only makes sense to do this
within certain limits.
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... Among these works, the concept of 3D Split Ring Resonator (SRR) structures based on square split frames deserves attention [14]. In contrast to the classical prototype [15], the 3D square SRR models synthesized in [14] made it possible to expand the relative frequency band δ f DNG by approximately a factor of 10 (from 0.19 to ≈1.9), within which negative values of the relative permittivity and permeability simultaneously occur. ...
... Among these works, the concept of 3D Split Ring Resonator (SRR) structures based on square split frames deserves attention [14]. In contrast to the classical prototype [15], the 3D square SRR models synthesized in [14] made it possible to expand the relative frequency band δ f DNG by approximately a factor of 10 (from 0.19 to ≈1.9), within which negative values of the relative permittivity and permeability simultaneously occur. (ε < 0, µ < 0) [2]- [5]. ...
... One of the important innovations in the 3D design of SRRs proposed in [14] was the orientation of a straight conductor in the direction perpendicular to the plane of placement of square frames. It was this solution that made it possible to expand the binegative zone in the lowfrequency region. ...
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The paper proposes variants of 3D models of split ring resonators (SRR) based on ring structures as unit cells of doubly negative (DNG) metamaterials. Evaluation of the efficiency of the synthesized 3D SRR variants is based on determining their relative bandwidth, for which the real part of permittivity and permeability are negative. To analyze the electromagnetic properties of the proposed 3D SRR structures, numerical simulation in Ansys EM Suite was used. In the course of the research, an available set of geometric parameters that affect the width of the binegative zone in the low-frequency region of the spectrum was analyzed: the angles of deviation of the cuts in the rings from the vertical, the width of these cuts, variations in the cross-sectional dimensions of the perpendicular conductor and its displacement relative to the center of the rings. Non-traditional types of conductors were also studied, in particular options for the form in the form of a dumbbell and the use of a fractal tree. At the final stage of research, the main efforts were focused on the analysis of the influence on the frequency properties of the metamaterial unit cell model of the mutual displacement of the SRR rings relative to the middle of the conductor length and their inclination angles. As a result, the maximum relative frequency band of the binegative zone was reached, which is equal to 1.99995. This is superior to the previously obtained result for 3D SRR with square frames, for which this value corresponds to 1.9.
... Presently, most metamaterials are being designed with two basic types of structures: dense arrays of thin wires (the electric dipoles) and arrays of split-ring resonators (SRRs) (the magnetic loops), which are metallic rings etched onto a dielectric substrate in a concentric pattern [27,28]. According to the authors in [29], SRRs are considered as unit cells of DNG metamaterials. In order to attain DNG mediums, ENG and MNG mediums are combined, as shown in Figure 3. ...
Article
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... The engineered material, metamaterial are found very effective in improving the performance of the microstrip antennas [18]. Among different metamaterial structures, the split-ring-resonator (SRR) are popular due to its stable performance and ease of designs [19]. In [20], electronic band-gap structure is used to minimize the mutual couling. ...
Conference Paper
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... On the other hand, also in the frequency band from 2.5 GHz to 2.8 GHz, an operating frequency band with a width of more than 297 MHz was obtained (Fig. 17). The closeness of the shape of the split outer frame of the reference frame in the patch antenna design to the SRR element used in metamaterials [17,18] makes it possible to hypothesize about the possibility of using such a cell of the metamaterial as an element of the MicroQR code. The corresponding modification of the MicroQR code picture was successfully tested on a smartphone scanner, however, provided that the color of the printed element was changed to black. ...
Conference Paper
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The paper proposes a new type of broadband patch antennas based on MicroQR codes. To synthesize them, the word “antenna” was used. In this research, several design options were considered that used the variation of the antenna's feeder parameters. For their analysis, the Numerical modeling methods were used due to the complexity of describing the interaction of antennas of non-Euclidean geometry with radio waves. Evaluation and comparison of proposed antennas held by the following characteristics: amplitude-frequency response and voltage standing wave ratio. To expand the frequency band of the synthesized antenna was implemented the split square marker that is the element of MicroQR.
Poster
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The poster presents the results of the study combined antennas developed on the basis of dielectric resonator elements and a fractal approach. This approach allows to achieve a broadband and multi-band antenna systems. As a basic structure is considered, composed of a recursive tree and passive dielectric resonators. To simplify the analysis of the characteristics of the proposed antennas, their arrangement is limited by the fractal on the level of the first three iterations, and the number of dielectric resonators does not exceed four. Due to the complexity of describing the interaction of the antennas of non-Euclidean geometry with radio waves for their synthesis and analysis selected methods for the numerical simulation. An evaluation of the spatial-frequency characteristics of the designed antenna solutions used indicators such as return loss, beam pattern and voltage standing wave ratio.
Conference Paper
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The article considers the variants of models quasi-fractal antennas. Their synthesis suggested the vector description of the fractal transformation of individual segments of the primary geometric shape. The combination of the decomposition of the geometric shape and multi-dimensional fractal approach allows to simplify the synthesis of fractal 3D structures and/or to use several types of fractals, including with a different number of iterations. This approach allows achieving broadband and multi-band antenna systems. Thus the influence of the segmentation level and the power scheme on the spatial-frequency characteristics of the antenna. Due to the complexity of describing the interaction of the antennas of non-Euclidean geometry with radio waves for their synthesis and analysis taken methods of numerical simulation. Evaluation and comparison of antennas held by the following characteristics: amplitude-frequency response, beam pattern and voltage standing wave ratio.
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Molecular aggregates are a fascinating and important class of materials, particularly in the context of optical (pigmented) materials. In nature molecular aggregates are employed in photosynthetic light harvesting structures, whilst synthetic aggregates are employed in new generation molecular sensors and magnets. The roles of disorder and symmetry are vital in determining the photophysical properties of molecular aggregates but have been hard to investigate experimentally, owing to a lack of sufficient structural control at the molecular level and the challenge of probing their optical response with molecular spatial resolution. We present a new approach using microwave analogues of molecular aggregates to study the properties of both individual meta-molecules and 1D molecular chains. We successfully replicate J- and H-aggregate behaviour, and demonstrate the power of our approach through the controlled introduction of structural symmetry breaking. Our results open a new area of study, combining concepts from molecular science and metamaterials.
Conference Paper
Full-text available
The paper presents the results of the study combined antennas developed on the basis of dielectric resonator elements and a fractal approach. This approach allows to achieve a broadband and multi-band antenna systems. As a basic structure is considered, composed of a recursive tree and passive dielectric resonators. To simplify the analysis of the characteristics of the proposed antennas, their arrangement is limited by the fractal on the level of the first three iterations, and the number of dielectric resonators does not exceed four. Due to the complexity of describing the interaction of the antennas of non-Euclidean geometry with radio waves for their synthesis and analysis selected methods for the numerical simulation. An evaluation of the spatial-frequency characteristics of the designed antenna solutions used indicators such as return loss, beam pattern and voltage standing wave ratio.
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In this work we have proposed a CAD model for metamaterial unitcell synthesis. The purpose of the synthesized unitcell is to improve performance of a microstrip antenna designed for TCAS (Traffic Collision Avoidance System) antenna. EM device Synthesis process generally requires high computational resources because of its inherent natures like complex, non-convex and continuous. Soft computing based techniques are very much convenient for these type of EM device based problems. Initially, Genetic Algorithm and Differential Evolution based CAD Models are developed to synthesize of a rectangular patch antenna having microstrip feed-line. TLM analysis is used to develop the proposed CAD model for Microstrip Patch Antenna. In the proposed CAD models the input parameters are the design/operating frequency, thickness of the substrate used and permeability of the substrate material. Whereas, the outputs are structure design dimensions of the radiating patch and the microstrip feed-line. CST MWS EM Tool has also been used here to design the antenna and to validate the synthesized antenna parameters. A comparison between both the CAD models is presented. After the successful design of CAD model for microstrip antenna, we applied the technique for Metamaterial synthesis. After that, a metamaterial lens is designed with the help of the proposed CAD model and used for antenna performance improvement for TCAS application. The comparison of the performance improvement is given in a tabular form towards the end of the paper. The comparison includes both simulated and measured result.
Conference Paper
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The paper considers the models quasi-fractal dielectric resonator antenna (DRA) based on a hemispherical. Thus, the influence of the depth of the overlap of the constituent elements in the spatial-frequency characteristics DRA. The interaction of the antennas of non-Euclidean geometry with radio waves is described difficult. It is therefore advisable to perform the synthesis of these antennas by mathematical modelling using the Ansoft HFSS package. To simplify the analysis of the characteristics of the antennas, their arrangement is limited geometrical structure, which has five elements on one horizontal surface. Evaluation and comparison of antennas held by the following characteristics: amplitude-frequency response, beam pattern and voltage standing wave ratio
Conference Paper
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This report describes the theory of metamaterials and its utilization for antenna's techniques. Metamaterials exhibit qualitatively new electromagnetic response functions that can not be found in the nature. The present report reviews basic historical aspects of the meta-environments theory development. Also the role of Veselago, the well-know theorist of negative refraction index metastructures whose 80 anniversary is celebrated in present year is emphasized as well as the role of other scientists.