Interim Report of Ammar Ghazal

Added on - 23 Sep 2019

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1AbstractThe antenna in which we will be talking about in this report will be the stub feed dipole slot antenna. It is used a lot inthis industry. This is because of its easiness to make and its brilliant transmission distances. When you’re creating something likethis, the length, width and placement of the port can affect the antenna. So those dimensions need to be correct. The software thatis used to perfect this is CST. The CST software is used to prototype the work. The CST software assesses the information wehave created using that the S-parameter results are also analyzed. So every time the parameters are changed the information thatwas made also changes. However they both need to be in agreement with each other that is when the design is made. The CSTsoftware have an analyzer called the S11 analyzer, this tool helps the source transmit information to the antenna. If analysis isgood enough the design is made.Keywords— Stub fed, antenna, CST, feed impedance..I.INTRODUCTION1hen a wire goes through a magnetic field an electriccurrent is transferred to the wire inductively.anelectromagnetic wave is now created which now movesback and forth. An antenna is a part of cable. The cable ismoving through the magnetic field. This transfers a verytiny current in the antenna. This is then amplified to a levelthat can then be used, for example can be used as atransistor. The transmitter converts an electrical signal intoradio wave then back to an electrical signal. A traditionaltransmitting circuit is observe in figure: 1WWhat does feed impedance mean?It is define as characteristics of transmission line i.e. theratio between the load impedance and impedance. Themagnitude of antenna’s feed impedance is changeaccording to overall volume, shape and size of antenna.Additionally, its depend on applied frequency andsurrounding. In this case, the impedance has resistive andreactive functions. By using that, the individualtransmission can enhance overall antenna impedance andthat must equal to the antenna load, that result is signaltransmitted individually. This situation occurs due torelation between impedance and power transmission. Thefollowing figure demonstrates the response of impedance.Figure 11Z = Za + ZbjWhere, Za- for real life andZb- for the imaginary.The unreal element of the aerial is related to the powerstorage around the field. The real life part is theimpedance controls the power that is absorbed or radiatedin transmission process. Another way this can berepresented is Za = Rs + R1.The following equation provides the power inducefrom the electric circuit asThe power generated from this circuit isFor full power dissipationIf you combine the first equation and the last Rr = R1.System doesn’t generate anything because of the reflectedpower. This measure is known as the feed impedance of theantenna.Working of dipole antenna :Interim ReportAmmar Ghazal E
2In figure 3 dipole antenna consists of two conductivepoles between insulated materials. Which has the sameobjective as a half wave antenna? This means that half ofthe pole is a district wavelengths long as seen in the figurebelow. The half wave dipole is fed using a broadcast line.Which has a input impedance of 60-70 ohms. The feedlineis identical and have the same but opposite transmissionvoltages. In a dipole each end has an open end circuit. Thismeans an infinite resistance and a coefficient of 1. Thesignal in the front reflected back at the open source and isout of phase the open ends give out high voltages and themiddle reaches a high currentBabinet’s PrincipleBabinets’s principle is the principle of diffraction patternsmade by screens are exactly the same. In this case, theseparate screens make balancing in case the opaque partsare one that reporter to the transparent ones. Additionally,the conductor having thin slot may induce equal amount ofenergy that induce without metal slot. This is beneficial byconsidering engineering aspect that consist slot antenna.With that being said the impedance of the a slot can also beseen asConverting antenna dipole into a slot dipole:The slot antenna is emerge radiation that is produce throughcutting the thin slot through considerable large metal area.This slot length is considerable half wavelength at theoperational frequency and the antenna length is considerablesmall area through antenna. The slot antenna is generallycompared with partial wave dipole antenna which consisttwo flat metal strips. In this case, the metal strip requiresassembling in area of slot which was cut out by the metalsurface. In this case, the slot antenna and balancing dipolehave induced equal radiation outline. Still, there areconsiderable variation by considering slot antenna andbalancing antenna. From both of this, the electric andmagnetic fields can manage anyone of this. The followingfigure.4 indicates the dipole antenna. In this case, the dipoleantenna lines are zero degree by considering ground surfaceand magnetic lines are 180 degree by considering groundsurface. Additionally, it is require providing smalldimensional electric line due to polarization of the radiationdeveloped through 0 to 180 degree. In case, the vertical slotis uses the polarization should be zero degree with referenceof ground surface. When the current is flow through slotantenna, the current release across the sheet and radiationinduce over the both side of the sheet. The result is morepowerful and compact of current.What is a stub and how can a stub match impedances?The stub can be the described as a look like the half ofdipole antenna and its placed vertically or by an angle closeto the ground. Ground is also known as earth stub antennasare very useful as normally sold with a connector andFigure 2Figure 3Figure 4
3comes with a casing of rubber or plastic. Then you plug itinto your device whether a receiver or transmitter that’s upto you. The stub can be used for RF measurement devicesor calibration in RF lines. For calibration to be achievedfully you need 50 0hms. 0 ohms and infinite impedanceusing an open circuit. The magnitude of impedance ischange as the transmission line dimensions change andconnected such as the minimum voltage occurs. Ensure thatthe how much the antenna transmission needs to preserve.When you look at a quarter waves. The reflected wavesform a normal wave which can create unwanted results. Thereflected impedance can be so big however this can cause abreakdown of dielectric material. it is observe that, therewas change in overall performance as the wave affect togenerator. In this case, there was no reflected wave producewhich is beneficially completely. That will ensure that thepriority of stub matching for operation. The line needsmatch in case, the load have similar approach forimpedance. The front wave is generated through the loadreleasing and there was not observing the wave generation.The wave generation is depends on the main impedance andcharacteristic impedanceand the load impedance which isZL.The basic designs of stub feed dipole antenna.The design have on the CST software. We were given aspecification we had to follow. The dimensions we had tofollow the maximum dimensions couldn’t exceed 32x32mm this was including the substrate.Simulation and optimizationFigure 5. The stub demminsions were 12.93 and the slot for port is 3.5mm.This is the S parameter for figure 5S11 results using the these dimensions are the length of theslot will be 23.00, the width of slot and the stub together is3.5mm and finally the length of the stub is 12.925. Withthese dimensions being changed the resonant frequency wasnow 5.61 and magnitude of the S11 was -14.63Db.S11 results using the these dimensions are the length of theslot will be 22.50mm, the width of slot and the stubtogether is 3.5mm and finally the length of the stub is10.50mm. With these dimensions being changed theresonant frequency was now 5.60 and magnitude of the S11was -15.34dB
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