Maheerah Hanum Ppkkp 2013

Microwave Probe Inspired By Metamaterial 2014

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CHAPTER 1

INTRODUCTION

1.1 Introduction

This research concerns about developing microwave probe inspired by MTMs

(5.725 5.875 GHz). The term of metamaterial was synthesized by Rodger M. Walser,

University of Texas at Austin, in 1999, which was originally defined as Macroscopic

composites having a synthetic, three-dimensional, periodic cellular architecture designed to

produce an optimized combination, not available in nature, of two or more responses to

specific excitation [1, 2]. The metamaterial is defined as a material which gains its

properties from its structure rather than directly from its composition [2].

The above definitions reflect certain natures of metamaterial, but not all. Actually,

The term metamaterials"(MTMs) had been originally employed to describe any artificial

(engineered) structure possessing effective electromagnetic properties not encountered

among natural materials. The unusual properties and ability to control the electromagnetic

field enabled by MTMs

MTMs gain their properties not from their composition, but from their exactingly

designed structures. The permittivity, permeability and conductivity of a material


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characterize its ability to interact with electromagnetic fields; the magnitudes of these three

quantities are restricted mostly to positive values.

However, MTMs is material with simultaneous negative permittivity () and

negative permeability () would also have a real refractive index, meaning that light waves

could propagate through the material, but would behave as though its refractive index were

negative. The negative refractive index means the wave associated with the antenna is bent

to a sharper angle. As Veselago theorized, if both parameters are negative, then a negative

coefficient must be used.

Beside from that, the probe also plays an important role in this project. Common

types of probes such as waveguide based or coaxial line based probe often operate at 5.725

5.875 GHz or 6GHz to achieve a resolution in the order of millimeters. The high

operation frequency is due to the relatively weak concentration of evanescent fields in the

close proximity of the opening. On the other hand evanescent microwave probes (EMPs)

with sharp tips, such as microstrip resonators utilizing wire tips or loops, cavity resonators

with sharpened tips, and dielectric waveguide sharpened at the end, provide higher

resolutions, and are applied to a wide range of materials.


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1.2 Problem Statement

Too fulfill this project, type of MTMs need to figure out because every size, shape

and design will give impact to the result performance. MTMs have it own classification,

each type have their characteristic need to consider for this project.

1.3 Objectives

The main objective of this project is to design MTMs- split-ring resonator (SRR).

The main objectives for this project are:

1. To analyze the MTMs Split-Ring Resonator.

2. To design and simulate Split Ring Resonance (one port and two ports) using

Computer Simulation Technology (CST).

3. To fabricate design of Split Ring Resonator 1 and 2 ports.

4. To improve efficiency-bandwidth performance of the design by using MTMs.


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1.4 Project Organization

TOPIC DESCRIPTION

CHAPTER 1

Introduction

Introduction to Metamaterials (MTMs)

Objectives and problem statement of the project.

CHAPTER 2

Literature

Review

Discusses the theoretical concepts behind MTMs and design

that need to be considering achieving it.

CHAPTER 3

Methodology

Design of concept will be explains in this chapter.

CHAPTER 4

Result and

Discussion

Shows the results that collected from analytical results and

simulation representation. Made some hypothesis according

to the results.

CHAPTER 5

Conclusion

States the conclusion can be made according to the overall

system that was design in the simulation and also state future

work.


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CHAPTER 2

LITERATURE REVIEW

2.1 Introduction

In this chapter will explain about the project based on previous project as a

reference for better understanding. It will discuss some of the issues that are the most

important in microwave probe inspired by MTMs.

2.2 Metamaterials (MTMs)

MTMs predicated contrivances have received a very vigorous interest in the last

years since the experimental demonstration of a negative refractive index effect.


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Figure 2.1: Metamaterial at atomic structure.

MTMs are artificial materials were introduced by Russian scientist Vesalago in the

year 1960 [3]. In contrast to conventional material, left handed MTMs is designed to

exhibit negative permeability and negative permittivity in the microwave frequency range

of interest. SRR was proposed by Pendry et al., is designed to exhibit negative permeability

[4] and thin wire structure is used to exhibit negative permittivity.

2.2.1 Metamaterial Clasification

The response of a system to the presence of Electromagnetic field is determined by

the properties of the materials involved. These properties are described by defining the

macroscopic parameters permittivity and permeability of these materials. By using

permittivity and permeability the classification of MTMs as follows, the medium

classification can be graphically illustrated as shown in figure 2.2


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Figure 2.2: MTMs Classification [3]

i. A medium with both permittivity and permeability greater than zero (e > 0, > 0)

are called as double positive (DPS) medium. Most occurring media (e.g. dielectrics)

fall under this designation.

ii. A medium with permittivity less than zero & permeability greater than zero (e < 0,

> 0) are called as Epsilon negative (ENG) medium. In certain frequency regimes

many plasmas exhibit this characteristics.

iii. A medium with both permittivity greater than zero & permeability less than zero (e

> 0, < 0) are called as Mu negative (MNG) medium. In certain frequency regimes

some gyrotropic material exhibits this characteristic.

iv. A medium with both permittivity & permeability less than zero (e < 0, < 0) are

called as Double negative (DNG) medium. This class of materials has only been

demonstrated with artificial constructs.


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2.2.1.1 Single Negative MTMs (SNG)

In single negative (SNG) MTMs either permittivity or permeability are negative,

but not both. Interesting experiments have been conducted by combining two SNG layers

into one MTMs. These effectively create another form of DNG MTMs. A slab of ENG

material and slab of MNG material have been joined to conduct wave reflection

experiments. This resulted in the exhibition of properties such as resonances, anomalous

tunneling, transparency, and zero reflection. Like DNG MTMs, SNGs are innately

dispersive, so their permittivity , permeability , and refraction index n, will alter with

changes in frequency.

2.2.1.2 Double Negative MTMs (DNG)

In double negative MTMs (DNG), both permittivity and permeability are

negative resulting in a negative index of refraction. DNGs are also referred to as negative

index MTMs (NIM).

2.2.1.3 Electromagnetic Band Gap (EBG)

Electromagnetic Band Gap (EBG) based on Frequency Selective Surfaces (FSS) is

one type of MTMs with electrical properties[5][6][7]. Application of truncated frequency

selective surface (FSS) appears as EBG technique. Frequency Selective Surfaces (FSS)

based MTMs have become an alternative to the fixed frequency MTMs.

2.2.1.4 Left-Handed Method (LHM)

The materials with simultaneously negative and are not found in nature. They

were artificially constructed in 2000.[2] Such man-made structures are called MTMs.


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Usually it is an assembly of cell elements. As long as the size and spacing between the

elements are much smaller than the electromagnetic wavelengths of interest, the incident

radiation cannot distinguish the collection of elements from a homogeneous material. The

idea behind making a left-handed MTMs (LHM) is to treat electric and magnetic

properties separately [7][8].

2.2.1.5 Split-Ring Resonator (SRR)

A split-ring resonator (SRR) is a component part of a negative index MTMs (NIM),

also known as double negative MTMs (DNG). They are also component parts of other

types of MTMs such as Single Negative MTMs (SNG). SRRs are also used for research

in terahertz MTMs, acoustic MTMs, and MTMs antennas [7][8]. SRRs are a pair of

concentric annular rings with splits in them at opposite ends. The rings are made of

nonmagnetic metal like copper and have small gap between them.

There are varieties of SRR structures have been reported in literature like square,

circular, triangular, omega, labyrinth resonator. MTMs are used for optical and microwave

applications such as filters, couplers, lenses, and switches etc.. Artificial MTMs structures

are also used in the antenna design to enhance the antenna performance.

The SRR exhibits a large magnetic dipole moment when excited by a magnetic field

directed along its axis. However, the SRR also exhibits an electric response that can be

quite large depending on the symmetry of the SRR and the orientation of the SRR with

respect to the electric component of the field. So, while the SRR medium can be considered

as having a predominantly magnetic response for certain orientations with respect to the

incident wave, it is generally the case that the SRR exhibits magneto electric coupling, and

hence a medium of SRRs arranged so as to break mirror symmetry about one of the axes

will exhibit bianisotropy.


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2.2.2 Resonant and Non-resonant MTMs

In the rapid design of MTMs, more specifically, the particle design, it is important to

choose the types of particles. Generally, MTMs are classified into two classes: resonant

and non-resonant MTMs. Both resonant and non-resonant MTMs had their own

advantages and disadvantages.[9][10]

Figure 2.3: The constitutive parameters (permeability) of a periodic structure whose

inclusion is SRR. (a) From the DrudeLorentz model under the static and quasi-static limits (above). (b) From the S-parameter retrieval under full-wave simulations (below).[10]

Figure 2.3(b) shows the material properties of a typical resonant MTMs composed of

SRR, as illustrated in the inset of Figure 2.1(a). From Figure 2.3(b), one clearly observes


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that both the permittivity and the permeability have a large dynamic range near the resonant

frequency. When the frequency changes a little bit, and vary a lot. In the other word,

when the size of SRR particle has a small change, the resonant frequency has a small shift,

which results in significant change of and . Hence one can realize large dynamic-range

material parameters using the resonant particle. This is the advantage of resonant MTMs.

However, one also notices from Figure 2.3(b) that and have a narrow bandwidth and

a large loss near the resonant frequency, which are disadvantages of resonant MTMs.

Figure 2.4: The effective constitutive parameters of a non-resonant MTMs whose inclusion is I-shaped.[10]

In fact, non-resonant MTMs have also resonant frequencies, but they are much higher.

Figure 2.4 demonstrates the constitutive parameters of a typical non-resonant MTMs

composed of I-shaped inclusion (see the inset of Fig. 2.4). It is clear that both and vary

slowly with respect to the frequency and have very small loss. Hence the broad bandwidth

and low loss are the big advantages of the non-resonant MTMs. On the other hand, when

the size of I-shaped particle has a small change, and have also small change. Hence one


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can only realize small dynamic-range material parameters using the non-resonant particle,

which is the disadvantage of non-resonant MTMs.[10]

2.2.3 Metamaterial Application

2.2.3.1 Metamaterial Antennas

MTMs antenna are a class of antennas which use MTMs to enhance or increase

performance of the system. The MTMs could enhance the radiated power of an antenna.

Materials which can attain negative magnetic permeability could possibly allow for

properties such as an electrically small antenna size, high directivity, and tunable

operational frequency, including an array system. Furthermore, MTMs based antennas can

demonstrate improved efficiency-bandwidth performance.

2.2.3.2 Superlens

A superlens uses MTMs to achieve resolution beyond the diffraction limit. The

diffraction limit is inherent in conventional optical devices or lenses.

2.2.3.3 Clocking Devices

MTMs are a basis for attempting to build a practical cloaking device. The cloak

deflects microwave beams so they flow around a hidden object inside with little

distortion, making it appear almost as if nothing were there at all. Such a device typically

involves surrounding the object to be cloaked with a shell which affects the passage of light

near it.


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2.2.3.4 Acoustic MTMs

Acoustic MTMs are artificially fabricated materials designed to control, direct, and

manipulate sound in the form of sonic, infrasonic, or ultrasonic waves, as these might occur

in gases, liquids, and solids.

2.2.3.5 Seismic MTMs

Seismic MTMs are MTMs which are designed to counteract the adverse effects of

seismic waves on manmade structures, which exist on or near the surface of the earth.

2.3 Feeding

The most four popular feeding techniques for microstrip patch antenna are coaxial

feeding, microstrip feeding, proximity feeding and aperture feeding.

2.3.1 Coaxial feeding

It is one of the basic techniques used in feeding microwave power. The coaxial

cable is connected to the antenna such that its outer conductor is attached to the ground

plane while the inner conductor is soldered to the metal patch [1, 11-12].

Figure 2.5: Coaxial feeding [1, 11-12]


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Coaxial feeding is simple to design, easy to fabricate, easy to match and have low

spurious radiation [11-12]. But coaxial feeding has the disadvantages of requiring high

soldering precision. There is difficulty in using coaxial feeding with an array since its need

a large number of solder joints. Coaxial feeding usually gives narrow bandwidth and when

a thick substrate is used a longer probe will be needed which increases the surface power

and feed inductance [11-13].

2.3.2 Microstrip feeding

In microstrip feed, the patch is fed by a microstrip line that is located on the same

plane as the patch. In this case both the feeding and the patch form one structure. Microstrip

feeding is simple to model, easy to match and easy to fabricate. It is also a good choice for

use in antenna-array feeding networks. However microstrip feed has the disadvantage of

narrow bandwidth and the introduction of coupling between the feeding line and the patch

which leads to spurious radiation and the required matching between the microstrip patch

and the 50 feeding line. Microstrip feed can be classified into 3 categories: direct feed,

inset feeding and gap-coupled.

Direct feed is where the feeding point is on one edge of the patch. As shown in

Figure 2.6. Direct feed needs a matching network between the feed line and the patch (such

as quarter wavelength transformer). The Quarter wave length transformer compensates the

impedance differences between the patch and the 50 feed line. The quarter wave length

transformer is calculated according to formulas found in [12, 16].

Figure 2.6: Direct microstrip feed line[12, 16]


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Inset feed is where the feeding point is inside the patch. The location of the feed is

the same that will be used for coaxial feed. The 50 feed line is surrounded with an air gap

till the feeding point as shown in Figure 2.7. The inset microstrip feeding technique is more

suitable for arrays feeding networks [11-13].

Gap-coupled is when the feeding line does not contact the patch; there is an air gap

between the 50 line and the patch as shown in Figure 2.8 .The antenna is fed by coupling

between the 50 feed line and the patch.

Figure 2.7: Inset microstrip feed line[12, 16]

Figure 2.8: Gap-coupled microstrip feed line[12, 16]


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2.3.3 Proximity coupled feeding

Proximity coupled feeding consists of two dielectric substrate layers. The microstrip

patch antenna is located on the top of the upper substrate and the microstrip feeding line is

located on the top of the lower substrate as shown in Figure 2.9. It is a non contacting feed

where the feeding is conducted through electromagnetic coupling that takes place between

the patch and the microstrip line. The two substrates parameters can be chosen different

than each other to enhance antenna performance [11, 13]. The proximity coupled feeding

reduces spurious radiation and increase bandwidth. However it needs precise alignment

between the 2 layers in multilayer fabrication.

Figure 2.9: Proximity coupled microstrip feeding[11, 13]

2.3.4 Aperture coupled feeding

Aperture coupled feeding consists of two substrate layers with common ground

plane in-between the two substrates , the microstrip patch antenna is on the top of the upper

substrate & the microstrip feeding line on the bottom of the lower substrate and there is a

slot cut in the ground plane as shown in Figure 2.10. The slot can be of any size or shape

and is used to enhance the antenna parameters. It is a non contacting feed; the feeding is

done through electromagnetic coupling between the patch and the microstrip line through

the slot in the ground plane. The two substrates parameters can be chosen different than

each other to enhance antenna performance [1-2, 11-13]. The aperture feeding reduces

spurious radiation. It also increases the antenna bandwidth, improves polarization purity


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and reduces cross-polarization. But it has the same difficulty of the aperture feeding which

is the multilayer fabrication.

Figure 2.10: Aperture coupled microstrip feed [1-2, 11-13]

2.4 Probe

A probe with a higher sensitivity practically means a higher accuracy for material

characterization schemes, or the ability to detect smaller or deeper objects for detection

schemes. Material characterization refers to the extraction of electrical and magnetic

properties of materials or investigation of physical or chemical properties of materials using

the electrical and magnetic properties. Object detection refers to detecting any geometrical

change in the vicinity of the probe. Which includes detecting objects placed within a

medium or detecting any change in the surface topology of objects.


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2.5 Material

A material is a piece of matter that is made up of a sea of periodically-arranged

atoms and molecules. All materials can be classified into two categories, conductors or

insulators (dielectrics). Conductors are materials that contain free charges (electrons) which

move with applied current, whereas dielectrics consist of bound positive and negative

charges that respond to electromagnetic fields by aligning charge pairs along the direction

of the applied field.

2.5.1 Dielectric Material

A dielectric material (dielectric for short) is an electrical insulator that can

be polarized by an applied electric field. When a dielectric is placed in an electric field,

electric charges do not flow through the material as they do in a conductor, but only slightly

shift from their average equilibrium positions causing dielectric polarization. Because of

dielectric polarization, positive charges are displaced toward the field and negative charges

shift in the opposite direction. This creates an internal electric field that reduces the overall

field within the dielectric itself. If a dielectric is composed of weakly bonded molecules,

those molecules not only become polarized, but also reorient so that their symmetry axis

aligns to the field.[1]

2.6 Resonator Frequency

A resonator is a device or system that exhibits resonance or resonant behavior, that

is, it naturally oscillates at some frequencies, called its resonant frequencies, with

greater amplitude than at others. The oscillations in a resonator can be

either electromagnetic or mechanical (including acoustic). Resonators are used to either

generate waves of specific frequencies or to select specific frequencies from a signal.


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2.7 Computer Simulation Technology (CST)

Computer Simulation Technology (CST) offers accurate, efficient computational

solutions for electromagnetic design and analysis. This software is user-friendly 3D EM

simulation software enables to choose the most appropriate method for the design and

optimization of devices operating in a wide range of frequencies.

The CST Microwave studio is a full-featured software package for electromagnetic

analysis and design in the high frequency range. It simplifies the process of inputting the

structure by providing a powerful solid 3D modeling front end. Strong graphic feedback

simplifies the definition of the device even further. After the component has been modeled,

a fully automatic meshing procedure is applied before a simulation engine is started.

2.8 Parameters Result Analysis

2.8.1 Gain

The power gain and the directivity properties of an antenna are the quantities, which

define the ability of the antenna to concentrate energy in a particular direction and give a

clear view of the antenna radiation performance. The gain of an antenna is a measure of the

ability of an antenna to concentrate power into a narrow angular region of space. The

directivity of an antenna is defined as the ratio of the radiation intensity in a given direction

from the antenna to the radiation intensity averaged over all directions. The ratio between

the amounts of energy propagated in these directions compared to the energy that would be

propagated if the antenna were omni-directional is known as its gain.


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2.8.2 Bandwidth

Bandwidth is the range of frequency that the antenna will properly radiate or receive

energy effectively where the antenna meets a certain set of specification performance

criteria [9]. When antenna power drops to half (3 dB), the upper and lower exterminates of

these frequency have been reached and the antenna no longer performs. An antenna that

operates over a wide frequency range and still maintain satisfactory performance must

compensating circuits switched into the system to maintain the impedance matching.


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CHAPTER 3

METHODOLOGY

3.1 Introduction

This chapter focuses on the method used in this project implementation including a

description of the flow and process. All the relevant experiment, description and work

involve in this project are also discussed. The entire steps are represented by a flow chart

and other related materials that will be discuss further.

3.2 Design Process

Base on Figure 3.1, it shows flowchart to complete this project. The design process

must follow the flowchart. Microwave probe Inspired by Metamaterial project is started by

determining the specification of the antenna. Various of similarly project is been reviewed

to gain more understanding and improvement of the previous project


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Figure 3.1: Project Flow Chart


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3.3 Design Specification

Figure 3.2: Split-ring Design for 1 Port

Table 3.1: Design Specification for Split-ring Design 1 Port.

Specification Value

Substrate FR4

Copper (annealed) Thickness 0.035mm

Ground (width x high) 30mm x 30mm

Feeding Line (width x high) 0.95mm x 15mm

Small Ring Diameter 2.5mm

Big Ring Diameter 4.5mm

Ring Angle 340


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Figure 3.3: Split-ring Design for 2 Port

Table 3.2: Design Specification for Split-ring Design 2 Port

Specification Value

Substrate FR4

Copper (annealed) Thickness 0.035mm

Ground (width x high) 30mm x 30mm

Feeding Line (width x high) 0.95mm x 30mm

Small Ring Diameter 2.5mm

Big Ring Diameter 4.5mm

Ring Angle 340


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Table 3.3: Final Designs

Design 1 Design 2 Design3

Original

shape

After

fabricatio

n

Table 3.3 show design of split-ring resonator for 1 port and 2 ports. SRR is designed

on an FR4 substrate. Split-ring resonator structure is used to exhibit negative permeability.

Microstrip feed is given to both inner and outer rings of split-ring resonator. MTMs

characteristics have been verified by transmission and reflection coefficient of split-ring

resonator. Split-ring resonator structure also satisfies homogeneous condition.


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3.3.1 Feeding Line

A feed line is used to excite to radiate by direct or indirect contact. There are many

different methods of feeding and four most popular methods are microstrip line feed,

coaxial probe, aperture coupling and proximity coupling.

3.3.1.1 Microstrip Line Feeding

Microstrip line feed is one of the easier methods to fabricate as it is a just

conducting strip connecting to the patch and therefore can be consider as extension of

patch. It is simple to model and easy to match by controlling the inset position.

Figure 3.4: Standard microstrip feeding line geometry.


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3.3.2 Split-Ring Resonator (SRR) Design

A split-ring resonator (SRR) is an artificially produced structure common

to metamaterials. Split-ring resonator structure is used to exhibit negative permeability.

Their purpose is to produce the desired magnetic susceptibility (magnetic response) in

various types of metamaterials up to 200 terahertz. These media create the necessary strong

magnetic coupling to an applied electromagnetic field, not otherwise available in

conventional materials. For example, an effect such as negative permeability is produced

with a periodic array of split ring resonators. [1]

Figure 3.5: A split-ring resonator. The current, denoted by small letter i, is in the

clockwise direction.

The split ring resonator and the metamaterials itself are composite materials. Each

SRR has an individual tailored response to the electromagnetic field. However, the periodic

construction of many SRR cells is such that the electromagnetic wave interacts as if these

were homogeneous materials.


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3.4 Probe

Figure 3.6: SMA-Right angle probe

Right-angle bends in PC-board traces perform perfectly well in digital designs in

speeds as fast as 2 Gbps. In most digital designs, the right-angle bend is electrically smaller

than a rising edge. For example, the delay through a right-angle bend in an 8-mil-wide, 50

microstrip trace in FR-4 is on the order of 1 psec. Thats less than 1 percent of a 100-psec

rise time.

3.5 Fabrication Process

Fabrication process the design layout printing using Gerber tool and printed on the

PCB inkjet film. It has been printed as a negative layout for FR4 negative board. After

print, the ultraviolet (UV) film need to be stick on the FR4 board by using laminator. Then,

put the film that has been stick on the board into the UV exposure for 120 seconds. After

finish, the board need to be soak on the photoresist chemical to eliminates the UV film that

are not exposed to the UV light and it will show the design shape before the board go

through the etching process. At etching process all the unexposed copper will be removed

and left the copper of the design pattern. After etching process, the feed connector is been

soldered to the feeding line of the design.


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CHAPTER 4

RESULT AND DISCUSSION

4.1 Introduction

Chapter 4 discussed about the simulation result. There are three designs that have

been fabricated. The result for simulation using CST software will be discussed more detail

in this chapter. The result will be compared based on the on the return loss, input

impedance, axial ratio and VSWR.

4.2 Simulation Results and Discussion

Simulation is the process of measuring the antenna by using software to obtain the

behavior of design. The important parameters of design that should be measured are return

loss, voltage standing wave ratio (VSWR), input impedance, axial ratio, and radiation

pattern. These parameters should be at the right value to get the best design with high

performance. Other than that, the design size should be decreased.


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4.2.1 Return Loss

The perfect designs should have a return loss below than -10 dB. It will have a good

performance when the return loss of design is below than -10 dB. The perfect matching of

return loss it means when no power reflected back to the input. In this situation, the return

loss between split-ring resonator 1 port and split-ring resonator 2 port.

4.2.1.1 Split Ring Resonator 1Port

Figure 4.1 : Split Ring 1 Port

Figure 4.2: S-Parameter for Split Ring 1Port


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Based on Figure 4.1, it shows the design of split ring for 1 port and Figure 4.2 show

return loss for split-ring for 1 port. Also the resonant frequency is at 6 GHz at -18.841dB

which is above than -10 dB. This result shows the split ring design had achieved matching

circuit and fall at 6GHz.

4.2.1.2 Split Ring Resonator 2 Port

Figure 4.3: Split Ring 2Port (S1,1)

Figure 4.4: S-Parameter for Split Ring 2Port (S1,1)


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Based on Figure 4.4, it shows the return loss for split-ring for 2 port (S1,1). Also the

resonant frequency is at 6 GHz at -39.243dB which is above than -10 dB.

Figure 4.5: Split Ring 2Port (S2,1)

Figure 4.6: S-Parameter for Split Ring 2Port (S2,1)


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4.2.2 Input Impedance

Input impedance is measured by using Smith Chart. Good input impedance is near

with a value of 50 which is matched with the transmission line of 50 .

Figure 4.7: Input impedance for split-ring 1 port.

Figure 4.8: Input impedance for split-ring 2 port.


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Figure 4.7 it shows the input impedance value for split-ring 1 port is 62 Ohm while

figure 4.8 shows the value for split-ring 2 ports is 49 Ohm. Which mean from the

simulation result, design split-ring 1 port is better for input impedance value.

4.2.3 Voltage Standing Wave Ratio (VSWR)

VSWR is a function of the reflection coefficient, which describes the power

reflected from the design. The VSWR is always a real and positive number for design. The

smaller the VSWR is, the better the design is matched to the transmission line and the more

power is delivered to the design. The minimum VSWR is 1.0. In this case, no power is

reflected from the design which is ideal.

Figure 4.9: VSWR for Split-ring 1 port


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Figure 4.10: VSWR for Split-ring 2 port

Figure 4.9 show the VSWR for MTMs Split-ring 1 port is 1.2580 and 4.10 show

the VSWR result for MTMs Split-ring 2 port is 1.0220. Both of the value is below 2 which

means that both of this design is at the best performance.


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4.2.4 Radiation Pattern


Table 4.1: Radiation Pattern for Split-Ring Resonator 1 Port

Plane Phi Theta

E-Plane

H-Plane


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Table 4.1 shows radiation pattern of Split-Ring Resonator 1 Port. Based on the

result of simulation, the main lobe magnitude in E-plane (phi) for split-ring resonator is

9.5dBV/m.


Table 4.2: Radiation Pattern for Split-Ring Resonator 2 Port

Plane Phi Theta

E-Plane

H-Plane


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Table 4.2 shows radiation pattern of Split-Ring Resonator 2 Port. Based on the

result of simulation, the main lobe magnitude in E-plane (phi) for split-ring resonator is

2.6dBV/m.

4.2.5 Gain, Directivity and Efficiency

Gain is defined as the ratio of the power produced by the antenna from a far-field

source on the antennas beam axis to the power produced by a hypothetical lossless

isotropic antenna, which is equally sensitive to signals from all directions. Directivity

measures the power density the antenna radiates in the direction of its strongest emission,

versus the power density radiated by an ideal isotropic radiator radiating the same total

power. Efficiency is defined as the ratio of the total power radiated by an antenna to the net

power accepted by the antenna from the connected transmitter.

Table 4.3: Gain, directivity and efficiency of design

Design Gain (dB) Directivity (dBi) Efficiency (%)

Split-Ring 1Port 2.231 4.914 44.8

Split-Ring 2 Port 1.231 5.367 25


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CHAPTER 5

CONCLUSION

5.1 Introduction

This final chapter discusses about two important parts. The first part is about overall

summary of the project whether this project achieved the objective and for the second part

is about recommendation to improve the performance of the antenna for future work.

5.2 Summary

The MTMs field is a very challenging from all aspects, in this paper, the analysis

and design of MTMs Inspired by Microwave Probe were presented. Motivated by the

challenge of enhancing the penetration of MTMs-related applications into commercial

products, low cost, easily deployable MTMs structures were proposed. Such MTMs

structures were employed for the design of easily fabricated.

For this project, 3 designs of split ring resonator has been design, simulate and

fabricate. This design were simulate using CST and result that have to be seen are return

loss, input impedance, VSWR, radiation pattern and efficiency. From simulation results, the

best split-ring resonator design has return loss below than -10dB, input impedance equal to

50 Ohm and VSWR in range between value 1 to 2.


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At the end of this project, it can be concluded that the objective of this project is

achieved. The split-ring resonator 1 port were designed and operate at 6 GHz with return

loss of -18.841 dB, input impedance of 62 and VSWR equal to 1.2580 while split-ring

resonator 2 port with return loss of -39.243,imput impedance of 49 and VSWR equal to

1.0220.

5.4 Recommendation

Recommendation for the future work is to do the measurement for this design and

compare with simulation result, from there can be seen the difference between the both

result and therefore able to see whether the design is a good.

Apart from that, Antenna systems and communications electronics in satellites can

incorporate MTMs as well. The payload size is minimized, making it easier to launch a

smaller satellite, and less expensive to design and build it. Applications of MTMs also

include smaller security equipment and devices used by the military. So far, as of 2011,

engineers have been able to cloak one wavelength at a time, but have theorized on

applications of MTMs for improving the performance of wireless devices, memory

storage, and optical lenses.


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REFERENCES

[1] Weiglhofer,W.S., Lakhtakia, A.: Introduction to complex mediums for optics and

electromagnetics. SPIE Press, Bellingham, WA, USA (2003)

[2] http://en.wikipedia.org/wiki/Metamaterial

[3] Veselago, V.G. The electrodynamics of substance with simultaneously negative

values of and . Sov. Phys. Usp. 1968, 10, 509514.

[4] Pendry, J.B.; Holden, A.J.; Robbins, D.J.; Stewart, W.J. Magnetism from conductors

and enhanced nonlinear phenomena. IEEE Trans. Microw. Theory Tech. 1999, 47,

20752084.

[5] Shelby, R.A.; Smith, D.R.; Schultz, S. Experimental verification of a negative index

of refraction. Science 2001, 292, 7779.

[6] Pendry, J.B. Negative refraction makes a perfect lens. Phys. Rev. Lett. 2000, 85,

39663969.

[7] Jacob, Z.; Alekseyev, L.V.; Narimanov, E. Optical hyperlens: Far-field imaging

beyond the diffraction limit. Opt. Express 2006, 14, 82478256.

[8] Liu, Z.; Lee, H.; Xiong, Y.; Sun, C.; Zhang, X. Optical hyperlens magnifying sub-

diffraction-limitted object. Science 2007, 315, 16861687.

[9] Smolyaninov, I.I.; Hung, Y.J.; Davis, C.C. Magnifying superlens in the visible

frequency range. Science 2007, 315, 16991701.

[10] Tie Jun Cui, Ruopeng Liu and David R. Smith : Introduction to MTMs.

[11] J. L. Volakis, Antenna Engineering Handbook 4th edition, McGraw-Hill, 2007.

[12] A. Milligan, Modern Antenna Design 2nd edition, John Wiley & Son Inc, 2005.

[13] R. Garg, P. Bhartia, I. Bahl , A. Ittipiboon, Microstrip Antenna Design Handbook,

Arteck House, 2001.


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[14] C. A. Balanis, Antenna Theory Analysis and Design 3rd edition, John Wiley &

Sons, Inc., 2005.

[15] Y. T. Lo, S. W. Lee, Antenna Handbook, Van Nostrand Reinhold, 1993.

[16] A. Y. Simba, M. Yamamoto, T. Nojima, K. Itoh, Circularly Polarised Proximity-

Fed Microstrip Antenna with Polarisation Switching Ability, IET Microwaves

Antennas & Propagation, Vol.1, Issue. 3, 2007, pp. 658 665.

[17] Y.-L. Kuo, Kin-Lu Wong, A Circularly Polarized Microstrip Antenna with a

Photonic Band Gap Ground Plane, in proceedings of Microwave Conference,

AMPC, Asia-Pacific , vol. 2, 2001 , pp. 647-650.

[18] D. M. Pozar, Microwave Engineering 2nd edition, John Wiley & Son, Inc.1998

[19] D. R. Smith, W. J. Padilla, D. C. Vier, S. C. Nemat- Nasser, and S. Schultz.

Composite medium with simultaneously negative permeability and permittivity,

Phys. Rev. Lett., vol. 84, no. 18, pp. 41844187, May 2000.

[20] C. Caloz, T. Itoh. Electromagnetic Metamaterials: Transmission Line Theory and

Microwave Applications, Wiley-IEEE Press, 2006


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APPENDICES

Appendix A

Final Year Project Progress Gantt Chart Part 1


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Final Year Project Progress Gantt Chart Part 2


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Appendix B

Fabrication process

Print layout

design on the

PCB inkjet film.

Cut it according

to the design

size.

Prepare

FR4 board.

Stick the PCB

inkjet film on the

FR4 board.

Put it into the UV

exposure for 120

seconds.

Soak the board

with photoresist

chemical.

Soldier the

connector into it

feeding line.

Clean and cut

into it proper

shape.

Put it into etching

machine to

eliminate

unwanted copper.

Clean it.

Finally, finish fabrication

process and can continue

to measure with

VNA(Vector Network

Analyzer).

Maheerah Hanum Ppkkp 2013

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