Half-wave dipole anntena using CST program, Study Guides, Projects, Research of Antenna Theory and Analysis

Download Half-wave dipole anntena using CST program and more Study Guides, Projects, Research Antenna Theory and Analysis in PDF only on Docsity! CHAPTER 1 INTRODUCTION 1.1 Introduction The telecommunication is the transmission of signals, signs, writings, words, messages, sounds and images, by radio, wire, optical, or other types of Electromagnetic (EM) systems. Telecommunication happens when there is an exchange of information between participants with the help of technology. It is the lifeblood of our society and has helped make the world a global village with about 98 percent of the world under its network coverage. The importance of telecommunication has been experienced by every sphere of life, some of which we shall learn about right away. Telecommunication plays important roles in many aspects of our lives: Education, health care, business and economic growth. Communications are of two types, wired and wireless, as the wired connection is the one that uses wires to communicate between the sender and the receiver, while wireless communications are those that do not use wires as a medium of transmission, but the communication is done through air or vacuum. A Radio Frequency (RF) signal refers to a wireless EM signal used as a form of communication. Radio waves are a form of EM radiation with identified radio frequencies that range from 3 kHz to 300 GHz. Frequency refers to the rate of oscillation (of the radio waves). RF propagation occurs at the speed of light and does not need a medium like air in order to travel. In the field of communication systems, whenever the need for wireless communication arises, there occurs the necessity of an antenna. Antenna has the capability of sending or receiving the EM waves for the sake of communication, where we cannot expect to lay down a wiring system. Antennas are the most physically visible component of a wireless infrastructure. Whether it be radio, Local Area Network (LAN), or otherwise, an antenna is extremely important. The antennas primary function is to transmit and receive clear signals between multiple 1 wireless points. It is safe to say that an effective and efficient wireless network will require antennas to operate properly. For home, office, or outdoor wireless networks, a good antenna provides a professional solution to wireless connectivity. There exists many different types of antennas with many different specifications. The dipole antenna or dipole aerial is one of the most important forms of RF antenna. Dipole antennas are used in many areas, both on their own and as part of more complicated antennas where they can form the main radiating element. The half-wave antenna is a type of dipole antennas in which the length of the wire is half the wavelength at the operating frequency. Half-wave antenna is used in radio as well as Television (TV) receivers. But mainly these show excellent performance when employed with another type of antenna.""! 1.2 Background of Dipole Antennas German physicist Heinrich Hertz first demonstrated the existence of radio waves in 1887 using what we now know as a dipole antenna (with capacitive end-loading). On the other hand, Guglielmo Marconi empirically found that he could just ground the transmitter (or one side of a transmission line, if used) dispensing with one half of the antenna, thus realizing the vertical or monopole antenna. For the low frequencies Marconi employed to achieve long-distance communications, this form was more practical; when radio moved to higher frequencies especially Very High Frequency (VHF) transmissions for Frequency Modulation (FM) radio and TV it was advantageous for these much smaller antennas to be entirely atop a tower thus requiring a dipole antenna or one of its variations. In the early days of radio, the thus-named Marconi antenna (monopole) and the doublet (dipole) were seen as distinct inventions. Now, however, the "monopole" antenna is understood as a special case of a dipole which has a virtual element "underground".!”! 1- https://byjus.com/jee/communication-systems/ 2- https://www.electronics-notes.com/articles/antennas-propagation/dipole-antenna/dipole- antenna-aerial.php Graham Bell (inventor of the telephone), Edwin Armstrong and Lee de Forest (inventors of radio), as well as Vladimir K. Zworykin, John Logie Baird and Philo Farnsworth (some of the inventors of TV). 2.2 Importance of Telecommunication Telecommunication plays important roles in many aspects of our lives: education, health care, business and economic growth. Benefits of telecommunication are as follows: e Things are very easy as far as distance learning is concerned, and the only Telecommunication products required is a computer with internet connection, and then the students can start with their course study. ¢ Students need not leave city/country to join an institution of their choice. Many well-known institutions make use of telecommunication to offer a great variety of courses that students can join from the comfort of their own home. This helps them save a lot of money that would otherwise be spent on airfare, hostel rooms, and other charges. Furthermore, you will also save the conveyance charges that you would have to bear to travel to and from your institution every day. ¢ People living in areas that do not have specialist care facility can use telecommunication equipment to get in touch with their healthcare provider without having to travel long distances. ¢ There will be shorter wait times in the clinic as fewer patients will need to visit the doctor physically, and thus the doctors will be able to serve more patients, more effectively. ¢ Telephones are still used by most companies. Owing to call management techniques businesses can handle incoming calls easily. In case other lines are busy in such situation, calls are transferred to other employees who have the skills to manage such calls. e¢ With the help of mobile telecommunication, it becomes easier for employees working from home or from remote locations to communicate effectively. They can use telecommunication devices to receive and send messages, access data, participate in conferences, and work on documents. e It is not possible for all team members to be physically present in important meetings, but collaboration is important for the success of projects. In such situation, telecommunication comes to the rescue. A teleconference of web conferencing can be planned using the best video conferencing software like EZTALKS, and then team members from all over the world can participate in it seamlessly. By having an impact on all spheres of life, telecommunication helps bring big changes in the world. This is in fact why the world is being able to develop and grow at such great pace. Telecommunication offers us not only better social awareness but also a better life at large. As telecommunication keeps on progressing, keeps on growing, human life will also progress, grow, and become a lot easier, a lot better." 2.3 Types of Communications Communication systems can be wired or wireless and the medium used for communication can be guided or unguided. In wired communication, the medium is a physical path like Coaxial Cables, Twisted Pair Cables and Optical Fiber Links etc. which guides the signal to propagate from one point to other. Such type of medium is called guided medium. On the other hand, wireless communication does not require any physical medium but propagates the signal through space. Since, space only allows for signal transmission without any guidance, the medium used in wireless communication is called unguided medium.”! 1- https://www.yourarticlelibrary.com/management/communication/communication-meaning- purpose-importance-and-principles/60291 2- https://en.wikipedia.org/wiki/Wireless If there is no physical medium, then how does wireless communication transmit signals? Even though there are no cables used in wireless communication, the transmission and reception of signals is accomplished with Antennas are electrical devices that transform the electrical signals to radio signals in the form of EM waves and vice versa. These EMs waves propagates through space. Hence, both transmitter and receiver consist of an antenna. 2.3.1 Wirelesses Communication Wireless communication is the fastest growing and most vibrant technological areas in the communication field. Wireless communication is a method of transmitting information from one point to other, without using any connection like wires, cables or any physical medium. Generally, in a communication system, information is transmitted from transmitter to receiver that is placed over a limited distance. With the help of wireless communication, the transmitter and receiver can be placed anywhere between few meters (like a T.V. Remote Control) to few thousand kilometers SC. We live in a world of communication and Wireless Communication (WC), in particular is a key part of our lives. Some of the commonly used wireless communication systems in our day—to— day life are: Mobile Phones, Global Positioning System (GPS) receivers, Remote Controls (RC), Bluetooth Audio and Wireless Fidelity (Wi-Fi) etc. 2.3.2 Importance of Wirelesses Communication When wired communication can do most of the tasks that a wireless communication can, why do we need wireless communication? The primary and important benefit of wireless communication is mobility. Apart from mobility, wireless communication also offers flexibility and ease of use, which makes it increasingly popular day-by-day. Wireless communication like mobile telephony can be made anywhere and anytime with a considerably high throughput performance. Another important point is infrastructure. The setup and installation of infrastructure for wired communication systems is an expensive and time consuming job. The infrastructure for wireless communication can be installed "intellectual" people can feel superior in discussing them), true understanding of these equations is hard to come by. Maxwell's equations are laws - just like the law of gravity. These equations are rules the universe uses to govern the behavior of electric and magnetic fields. A flow of electric current will produce a magnetic field. If the current flow varies with time (as in any wave or periodic signal), the magnetic field will also give rise to an electric field. Maxwell's equations shows that separated charge (positive and negative) gives rise to an electric field, and if this is varying in time as well will give rise to a propagating electric field, further giving rise to a propgating magnetic field. The equations are as follows:""! V°D=p (2.1) V°B=0 (2.2) = —28 VxE=-% (2.3) = 2 VxH= 24] (2.4) Where V ° is refers to the divergence operator, D is the electric flux density, p is the electric charge density, B refers to the magnetic flux density, V x refers to the curl operator, E is the electric field, 0B/Ot is the partial derivative of the magnetic flux density, H is the magnetic field, @D/dt is partial derivative in time of the electric flux density and J is electric current density. The first two equations relate to Gauss's law. equation (2.1) defines that the displacement current through a surface is equal to the encapsulated charge and equation (2.2) states that any magnetic field is solenoid. Equation (2.3) is Faraday's law of induction, which describes that any change of the magnetic field over time causes an electric field. Equation (2.4) is Ampere's law. It basically states that any change of the electric field over time causes a magnetic field. 1- https://www.maxwells-equations.com 10 2.6 Hertz’ s Experiment Hertz built what can be considered to be the first radio system, which included the first dipole antenna and first loop antenna. Hertz showed that oscillating electric charge radiates EM waves. The energy carried by the waves is actually transformed kinetic energy of the oscillating charge. It was found that the distance of oscillation of charge was closely related to wavelength of the radiation. The apparatus used in Hertz experiment is shown in Figure 2.2 given below. LES... Induction plate coil . aS1 Six t YSo Sb Detector or receiver Figure 2.2 Hertz’ s experment Hertz experimental arrangement consists of two square metal plates P1 and P2 made up of either copper or zinc placed at a distance of 60 cm approximately. These plates were connected to two highly polished metal spheres and (separated by 2 — 3 cm) through thick copper wires. An induction coil is used to apply a high potential difference of several thousand volts across the spheres. The detector shown in the figure is in the form of an open metallic coil having small metallic spheres S1’ and S2’ with some gap. This arrangement can produce radiations of wavelength about 6 m. With the help of induction coil a high potential difference across the sphere and is applied, which ionises the air between the spheres thus provides a path for the discharge of the plates. The discharge of metal plates occurs in the form of a spark in the gap between the spheres and EM waves are radiated. The two plates act as a capacitor having a small capacitance C. The resultant electric field induced by the oscillating magnetic 11 field causes sparks to appear in the narrow gap of the detector, as resistance of metal ring is very small. Hence, Hertz demonstrated the production of EM waves owing to spark occurring across the spheres and detected them by the detector coil. 2.7 Antenna An antenna is a device that provides a transition between guided EM waves in wires and EM waves in free space. It is used to radiate EM energy efficiently and in desired directions. Antennas act as matching systems between sources of EM energy and space. The goal in using antennas is to optimize this matching. Figure2.3 below shows the antenna in transmitter. Electric field lines of radiated wave Antenna Generator Guided EM wave ‘Transition region Wave launched into free space Figure 2.3 Antenna in the transmitter Antennas can usually handle this transition in both directions (transmitting and receivinge EM waves). This property is called reciprocity. Figure2.4 below shows the antenna in receiver.'! Antenna Rec a Detector Guided EM wave or receiver Transition region “—" Incident wave Figure 2.4 Antenna in the receiver 1- https://www.usna.edu/ECE/ee434/Handouts/EE302%20Lesson%2013%20 Antenna%20Fundamentals.pdf 12 Table 2.1 Classification of the antennas (cont.) Lens Antennas Convex-plane, Concave-plane, Used for very high frequency Convex-convex, Concave lenses applications Micro-strip Circular-shaped, Rectangular-shaped Air-craft, space-craft, Antennas metallic patch above the ground satellites, missiles, cars, plane mobile phones etc. Array Yagi-Uda antenna, Micro strip patch Used for very high gain Antennas array, Aperture array, Slotted wave applications, mostly when guide array needs to control the radiation pattern 2.7.2.1 Wire Antennas Wire antennas are also known as linear/curved antenna. One of the most commonly used antennas is wire antennas. They can be found in vehicles (automobiles), ships, aircraft, buildings, etc. Wire antennas come in different shapes and sizes like straight wire (Dipole), Monopole, Helix and Loop. e Dipole Antenna A dipole antenna is made up two conductors in the same axis and the length of the wire needs to be small compared to the wavelength. The dipole antenna is consists of two metallic rods through which current and frequency flow. This current and voltage flow created an EM wave and the radio signals get smeared. The antenna consists of a radiation element that slit the rods and makes current flow through the center by using a feeder at the transmitter out that takes from the receiver. The different types of dipole antennas used as RF antennas include half-wave, multiple, non-resonant, and so on. Figure 2.6 shows the dipole antenna. 15 Figure 2.6 Dipole antenna Monopole Antenna A special case of dipole antenna is the monopole antenna i.e. it is half of the dipole antenna. A monopole antenna is half of a simple dipole antenna located regarding a grounded plane. The graphical record on the grounded plane is going to be almost like the half-wave aerial, however the whole power radiated is half that of a dipole the field gets radiated only in the superior hemisphere region. The radial asymmetry of those antennas become double compared to dipole antennas. The monopole antennas are used as vehicle-mounted antennas as they provide the required ground plane for the antennas mounted in the earth. Figure 2.7 depicts the monopole antenna. Monopole for 900 MHz Ground Plane << _ Monopole for 2.4 GHz Feed Figure 2.7 Monopole antenna 16 Helix Antenna Helix antenna is a specialized antenna that emits and responds to EM fields with rotating (circular) polarization. These antennas are commonly used at earth-based stations in SC systems. Figure 2.8 shows helix antenna type. Figure 2.8 Helix antenna Loop Antenna A loop antenna is formed by single or multiple turns of wire forming a loop. The radiation produced by the loop antenna is comparable to a short dipole antenna. The circumference of the loop antenna determines the efficiency of the antenna is similar to that of dipole and monopole antennas. These antennas are two types: electrically small and electrically large based on the periphery of the loop. Figure 2.9 illustrates the loop antenna. 4 Foot L-Bracket Storeiar Preamplifier Coax ener Seat Service, a: Rotator RSS (Not Supplied) Cable <Not Supplied) Figure 2.9 Loop antenna 17 e Folded Dipole Antenna This antenna consists of two or more straight electric conductors that are connected in parallel, and each electric conductor is half the wavelength corresponding to the frequency to be used as shown in Figure 2.14. fg Qed) | ——————— Length = 4% Wavelength Figure 2.14 Folded dipole antenna 2.8.1 Half-Wave Dipole Antenna We know that an electric dipole is defined as the separation of charges of opposite polarity (i.e., positive and negative). A dipole as an antenna is a horizontal metallic rod which is excited externally. Generally, the dipole antenna is fed at the center so as to transmit and receive RF energy. It is considered to be as the simplest practical antenna. However, there is a classification of dipole antenna which is usually done on the basis of length of the electric dipole and its orientation. Half-wave dipole antenna is a type of antenna in which the length of the dipole is half the wavelength at the operating frequency is known as a half-wave dipole antenna. It is considered as a very popular form of a dipole antenna and is sometimes known as Hertz antenna. Generally, it is known to be the one with the simplest resonance structure in antennas for the transmission and receptions applications. It is present as the fundamental element of all the antenna shapes, as these are used for constructing various complex antennas. The operating frequency range of the half-wave dipole antennas lies between 3 kHz to 300 GHz and the Maximum gain is 2.15 dB relative to the isotropic antenna. 20 2.8.1.1 Construction of Half-Wave Dipole Antenna A half-wave dipole antenna is an antenna constructed using a conductive tube or metallic element that has a length equal to the electrical half wavelength. The excitation to the half-wave dipole is provided at the center. So, we can say that the feeding to the dipole is present at quarter wavelength point. Figure 2.15 below represents the structure of a half- wave dipole antenna"! +h GD -h Figure 2.15 Construction of half-wave dipole antenna 2.8.1.2 Feeding of Half-Wave Dipole Antenna The feeding of half-wave antenna is in the center, the major concern is related to the way of transferring the power from transmission line to the antenna with the least possible loss. As there are two open ends of the conductor, thus voltage will be maximum but while moving towards the center from the end, voltage starts decreasing. As against though the current was 0 at the ends along the length side of the radiating element, the current increases. Generally current reaches a maximum value at the center which is 0 at the ends. In this way, there is sinusoidal variation in these quantities. So, the external excitation to the antenna is provided at the center, where the current is maximum and 1- https://electronicsdesk.com/half-wave-dipole-antenna.html 21 voltage is minimum. Due to this, there is minimal impedance to the feeder by the antenna. Figure 2.16 shows the working of a half-wave dipole. ) ) Figure 2.16 Working of the half-wave dipole antenna The most common feeder that is used to feed the antenna is coaxial cable or coax cable. It is often referred to as RF cable. A coaxial cable carries current in both the conductors. These currents are equal in magnitude but opposite directions. Due to that, all the radiating fields are linked within the cable and hence they are canceling out each other. Thus, there is no radiating field outside the cable hence it is not affected by nearby any objects. Therefore, it is best suitable as a feeder to the dipole antenna. 2.8.1.3 Working of Half-Wave Dipole Antenna We know that a half-wave dipole is a metallic rod or thin wire having a physical length of half wavelength in free space. We have already discussed that excitation to this antenna is provided at the center where the voltage is minimum while the current is maximum. Thus, the two quantities vary in a sinusoidal manner along the length of the radiating element. So, as the voltage varies sinusoidally, so for the positive half of the voltage, when the amplitude is maximum then the charge carries inside the conductor gets attracted towards the positive applied potential. As against, when the negative half of the sinusoidal signal is provided then the charges present in the conductor experience repulsion. So, every time with the change in 22 G=nxD (2.9) Since the efficiency of an antenna can take on any value between 0 and 1, and the directivity can take on any value greater than or equal to one, the gain can be any positive value. ¢ Radiation Pattern As this antenna is a center fed so, the maximum current offers maximum radiation in the plane which is in perpendicular direction. The radiation pattern of half- wave dipole antenna is omnidirectional and is represented in the Figure 2.17. o° 360° — 30° 300° ep 270° 90° 240° 120° 210° 150° 180° Figure 2.17 Radiation pattern of half-wave dipole antenna 2.10 Advantages of Half-Wave Dipole Antenna The following are the advantages of half-wave dipole antenna: e Input impedance is not sensitive. e Matches well with transmission line impedance. e Has reasonable length. e Length of the antenna matches with size and directivity. 25 2.11 Disadvantages of Half-Wave Dipole Antenna The following are the disadvantages of half-wave dipole antenna: e Not much effective due to single element. e It can work better only with a combination. 2.12 Applications of Half-Wave Dipole Antenna The following are the applications of half-wave dipole antenna: e Used in radio receivers. e Used in TV receivers. e When employed with others, used for wide variety of applications." 1- https://electronicsdesk.com/half-wave-dipole-antenna.html 26 CHAPTER 3 RESEACH METHODOLOGY 3.1 Introduction This chapter contains information about the project methodology. It starts by the format of the study that summarizes the whole chapters of our project. Then it talks about the plan that explains the components of each chapter. Finally, it shows the timetable that signifies the time that spent to complete each stage of the study. 3.2 Framework of the Study This theme project consists of 5 chapters. Chapter 1 includes the introduction, background, project problem statement, the objectives of the project and the limitations of the project. Chapter 2, talks about the project from the general information to the specific information about the project itself. And in Chapter 3, all the information that related to how the project had been done. Chapter 4, talks about the project implementation, simulation and results. Chapter 5, includes difficulties, facilities, recommendations and suggestions for the future works. 27 Table 3.1 Timetable of the study (cont.) - Get enough Ps knowledge about ZB ° wll cSt Studio working on CST - Executing Plan of a 2 P P 8 . F program. - Microsoft office word 2010. implementation. 2 a - Plan of implementation. - P - . A sg = Simei maaritig - Design the - CST Studio Suite program. - Get results of the simulated a < ° antenna. antenna. -Simulate the antenna. ¢ -Identifying § We P - 4 z | ~ Diiculties and difficulties and - Difficulties and facilities. 3 facilities. facilities. - Recommendations 2 2 - Recommendations. - Identifying - Microsoft office word 2010. Fs " a & . . F - Suggestions. = 50 Suggestions. recommendations 3 and suggestions. 30 CHAPTER 4 IMPLEMENTING & DISCUSSION 4.1 Introduction Chapter four includes the CST Studio Suite program definition, the parameters as well as its theoretical calculation and the antenna design. Then it represents the results from the simulation. Finally, it has mentioned the purpose of this half-wave dipole antenna which is designed. 4.2 CST Suite Studio Designing and simulating antennas using CST Suite Studio is a fully featured software package for EM analysis and design in the high frequency range. It simplifies the process of creating the structure by providing a powerful graphical solid modeling front end. After the model has been constructed, a fully automatic meshing procedure is applied before a simulation engine is started. CST Studio Suite is a high-performance 3D EM analysis software package for designing, analyzing and optimizing EM components and systems. EM field solvers for applications across the EM spectrum are contained within a single user interface in CST Studio Suite. The solvers can be coupled to perform hybrid simulations, giving engineers the flexibility to analyze whole systems made up of multiple components in an efficient and straightforward way. Co-design with other SIMULIA products allows EM simulation to be integrated into the design flow and drives the development process from the earliest stages. Common subjects of EM analysis include the performance and efficiency of antennas and filters, Electromagnetic Compatibility and Interference (EMC/EMI), exposure of the human body to EM fields, electro-mechanical effects in motors and generators, and thermal effects in high-power devices. 31 CST Studio Suite is used in leading technology and engineering companies around the world. It offers considerable product to market advantages, facilitating shorter development cycles and reduced costs. Simulation enables the use of virtual prototyping. Device performance can be optimized, potential compliance issues identified and mitigated early in the design process, the number of physical prototypes required can be reduced, and the risk of test failures and recalls minimized. 4.3 The Parameters and Theoretical Calculation A general construction of a half-wave dipole antenna is two monopole wires and a gap between the two arms of half-wave dipole antenna for feeding purpose. Here L refers to the total length of the antenna, D is the thickness of antenna arm and g refers to the feeding gap. Radiation resistance of the half-wave dipole is 50 Ohm which matched with the line impedance. Figure 4.1 shows the parameters that will be used in design the antenna. —— —————e =e f (resonance frequency) , WV (wavelength) Figure 4.1 Parameters of half-wave dipole antenna The parameter and its calculations are: e Resonant Frequency (f) Resonant frequency (f) is the range frequency in which half-wave dipole antenna is operatesed. For the simulation purpose the ranges of frequencies that have been chosen is 2.5 GHz. 32 IB cSTSTLDO SUITE, Create Project Template MW & RF & OPTICAL | Antannas Please select a workflow: Waveguide (Ilcrn, Cone, |_| Planar (Patch, Slot, etc.) ete.) Phased A-ray, Unt Call | Mobile Phone, integrated | Reflecto> om |] each | RE [comes Figure 4.3 Half-wave dipole is a wire antenna The project operates in time domain. Chose “Time Domain” then click “Next” as shown in Figure 4.4. I crsiun sure Create Project Template Mw & RE & OPTICAL | Antennas | Wins | Suluers | Units | Settings | Summary The recommended solvers tor the selected workflow are: Integral Fquation for large or thin wire antennas | a Frequency Domain back (TUNES) concet Figure 4.4 Operation of the project in time domain 35 Determine the units of the parameter as shown in Figure 4.5. El estsinin sun Create Project Template MAW & RE BOPTICAL | Antennas | Wire | Solvers Units | Seztings | Summary Please select une unit Frequency: om ¥ voltage: v ¥ conductance: 5 ¥ anductance: 4 ¥ capacitance: - ¥ Back Figure 4.5 Units of the parameters Determine the minimum frequency value as 2 GHz and maximum frequency value as 3 GHz then click on “Next” as shown in Figure 4.6. est sTUciC SUITE csTsTupio SUITE x Create Project Template MW #1 KOPLICAD | Antennas | Wire | Solvers | Uints | Seftings | ‘suntmary Please select the Settings Frequency Min 2 or Frequency Max.: 3 che Monitors FAE-ficld PIH-fiold 3 Farficld [rower flow power loss befine ar cue, shack Next > cancel Figure 4.6 Determining the frequency range 36 The parameters list that project depends on them is shown in Figure 4.7. Parameter List Yo Name Expression Value a Wy 119.92 119.92 aL Ww/2 59.96 = R Wy/1000, 0.11992 “og L/200 0.2998 Figure 4.7 Parameters list e The First Monopole From “Modeling” click on “cylinder” and press ESC then determine the outer radius as “R”, Wminas “g/2” and Wmax as “L/2” then, click on “Ok” as shown in Figure 4.8. Figure 4.8 First monopole e The Second Monopole Transform the first monopole by side click on monopolel then click on “transform” as shown in Figure 4.9. 37 Final show for the half-wave dipole antenna design is shown in Figure 4.13. Figure 4.13 Final show of the antenna design 4.6 Results and Simulate the Half-Wave Dipole Antenna In this section, the simulation of the designed antenna is explained and results have gotten. 4.6.1 Start the Simulation To start the simulation from “Simulation” then click on “setup solver” and “start” as shown in Figure 4.14. Mesh type: Hexahedral ~ ~ | dB ‘Close (Store result data in cache Apply Stimulation settings Source type: | all Ports ~ Inhomogeneous port accuracy enhancement Par. Sweep... all Calculate port modes only Superimpose plane wave SSS excitation = ‘Specials... S-parameter settings [Normalize to fixed impedance S-parameter symmetries an 50 = Chm S-Parameter List... Help Adaptive mesh refinement CD Adaptive mesh refinement Adaptive Properties... Sensitivity analysis use sensitivity analysis Properties... Figure 4.14 Start the simulation 40 4.6.2 Results The results of the simulation as Scattering Parameters (S-parameter), bandwidth, Voltage Standing Wave Ratio (VSWR), directivity, gain, polarity for directivity, H-Field and E- Field." ¢ S-Parameter After start simulation, to view S-parameter click on ID Results then click on S- parameter. Observe that the curve is not on the required frequency 2.5GHz. Figure 4.15 shows the S-parameter. S-Parameters [Magnitude in dB] dB Frequency / GHz Figure 4.15 S-parameter Because of the curve of S-parameter is not in the required frequency we need for optimization to operate on 2.5GHz. ¢ Optimization A half-wave dipole antenna is not the same length as a half wavelength in free space. End effects mean that the actual length required is slightly shorter. So, we give the value of the total length of the antenna (L) as Wv x 0.4686 as shown in Figure 4.16. Parameter List Vo Name Expression Value = Wy 119.92 119.92 a iL Wv*0.4686 56.194512 mR Wy/1000 0.11992 “og L/200 0.28097256 Figure 4.16 Modify the L parameter 1- Mohammad Tareq , Dewan Ashraful Alam, Mazidul Islam and Razin Ahmed [Simple Half- Wave Dipole Antenna Analysis for Wireless Applications by CST Microwave Studio], International Journal of Computer Applications (0975 — 8887) [PDF] 41 When we modify any parameter a message appears ask if we need to store the last results or not. We select delete current results as shown in Figure 4.17 then start the simulation again. [ss] This operation will change the model and invalidate existing results. Please select one of the following options: @) Delete current results (keep parametric results and cache) Delete all results (current, parametric and cache) (©) Store current results in result cache () Store current results to a new file OK Cancel Help. Figure 4.17 Message of storing the last results After optimization, observe that the S-parameter curve on the required frequency 2.5GHz where the obtained return loss is -15.177628 as shown in Figure 4.18. Parameters [Magntuide n cli] fsa,1 : 5.177628 st a 2 at 22 23 24 25 26 27 28 29 3 Freuency / GHz Figure 4.18 S-parameter after optimization and the return loss ¢ Bandwidth To know how much the bandwidth of the antenna; from “1D plot” file then click on “Measure Lines”. Bandwidth of the designed antenna has found as 0.18426 GHz. Ranges of frequency at -10.105 dB are 2.4149 GHz and 2.5992 GHz as shown in Figure 4.19. 42 Farfield Directivity Abs (Phi=90) 30 phi=270 Phi- 90 30 —— farfield (f=2.5) [1] Frequency = 2.5 GHz Main lobe magnitude = —- 2.15 dBi Main lobe direction = 90.0 deg. Angular width (3 dB) = 78.5 deg. 120 150 150 180 Theta / Degree vs. dBi Figure 4.23 Polar far-field directivity e H-Field Magnetic field density of H-Field shows in Figure 4.24. To view H-Field; from “2D/3D results” then click on “H-Field”. Figure 4.24 Magnetic field density of H-Field e E-Field Electric field density of E-Filed shows in Figure 4.25. To view E-Field; from “2D/3D results” then “E-Field”. 45 Figure 4.25 Magnetic field density of E-Field 4.7 The Summary of the Design The half-wave dipole antenna dimensions are calculated, implemented and designed by CST Suite Studio program depending on the calculated parameters of the antenna then simulated and get results which is summarized as illustrated in Table 4.2. Table 4.2 Simulated results for the half-wave dipole antenna Parameter Value Unit Resonant Frequency (f) 2.5 GHz Return Loss -15.177628 dB VSWR 1.4218856 _ Bandwidth 0.18426 GHz Directivity 2.154 dBi Gain 2.154 dBi 4.8 The Purpose of the Antenna We designed a half-wave dipole antenna that operates on Ultra High Frequency (UHF) at 2.5 GHz to achieve the purpose of it which is applying as a TV receiver antenna. 46 CHAPTER 5 SUGGESTIONS AND RECOMMENDATIONS 5.1 Introduction This chapter will talk about facilities and difficulties that we faced in our academic research. Then it will mention recommendations and suggestions for future work. Finally, it will contain a conclusion about the whole project. 5.2 Academic Facilities The academic facilities get during this study were as follows: ¢ Getting enough time to do the project. ¢ Getting enough explanation from several websites. ¢ Choosing an uncomplicated antenna type. e Pre-study of antennas subject in the college. 5.3 Academic Difficulties The academic difficulties get during this study were as follows: e lack of sufficient knowledge for researchers on the subject of the research. ¢ Unavailability of supervisors in this field to refer to them during the project work. ¢ No enough knowledge about CST studio Suit program. ¢ No books explain some issues briefly. 47