ARCHIMEDEAN SPIRAL ANTENNA EMBEDDED WITH
View metadata, citation and similar papers at core.ac.ukbrought to you byCOREprovided by UTHM Institutional RepositoryARCHIMEDEAN SPIRAL ANTENNA EMBEDDED WITH FREQUENCYSELECTIVE SURFACE FOR WIDEBAND APPLICATIONSABDIRAHMAN MOHAMUD SHIREThis thesis is submitted in fulfillment of the requirements for the award of MasterDegree of Electrical EngineeringFACULTY OF ELECTRICAL AND ELECTRONIC ENGINEERING, UNIVERSITITUN HUSSEIN ONN MALAYSIADecember 2014
vABSTRACTThe potential applications such as satellite communication systems, critical militarycommunications, radar warning systems and direction finding systems demand for highgain, uniform unidirectional radiation pattern and wideband antenna ranging from 3.1GHz to 10.6 GHz. An Archimedean spiral antenna is the most potential candidate in theabove mentioned applications as the antenna meets most of the above requirements.However, the practical implementation of spiral antenna is challenged by itsbidirectional patterns, relatively low gain and the need for balanced feeding structures. Amoveable ground plane is proposed as the backing technique of the spiral antenna byplacing it at quarter wavelength behind spiral arms. Despite, the effects of the groundplane on the antenna’s wideband properties, to enable the realization of a conformalantenna without the loss of the antenna’s broadband characteristics, a radian spheretheory is proposed for bandwidth improvement. Microstrip to parallel strip line balun isproposed as the feeding structure of the spiral antenna. This balun has very largebandwidth ranging from 2 GHz to 14 GHz. However, the separation of the ground planeand the spiral arms at quarter wavelength at lower frequencies deteriorate the radiationpatterns at middle and higher frequencies. In order to improve the patterns, frequencyselective structure is proposed to embed in the cavity of the spiral antenna. Theoptimized frequency selective surface improves the radiation pattern while maintainingthe other parameters such as the gain, bandwidth and axial ratio. All the proposeddesigns are fabricated and measured. Both simulated and measured results have showngood agreements. Finally, the results show that the proposed Archimedean spiralantenna is the most suitable candidate for above mentioned applications because goodcircularly polarized unidirectional radiation patterns and high gain of 8 dB to 11.2 dBwith bandwidth of more than 140% is obtained.
ABSTRAKAplikasi berpotensi seperti sistem komunikasi satelit, komunikasi tentera kritikal, sistemamaran radar dan sistem mencari arah mempunyai permintaan untuk keuntungan tinggi,corak sinaran satu arah seragam dan jalur lebar antena daripada 3.1 GHz kepada 10.6GHz. Antena lingkaran Archimedes adalah calon yang paling berpotensi untukmemenuhi sebahagian besar daripada keperluan aplikasi tersebut.Walau bagaimanapun,pelaksanaan prototaip antena lingkaran sangat mencabar disebabkan oleh corak dwiarah,agak keuntungan yang rendah dan keperluan teknik pengujaan yang seimbang. Satahpembunian bergerak dicadangkan sebagai teknik sokongan antena lingkaran ombangdibelakanglingkaran.Kesan penggunaan satah pembumian terhadap ciri-ciri jalur lebar adalah untukmembolehkan antenna komformal direalisasikan tanpa kehilangan ciri-ciri jalur lebaritu,teori sfera radian adalah dicadangkan untuk peningkatan jalur lebar. Mikrojalur kebalun talian jalur selari dicadangkan sebagai teknik pengujaan antena lingkaran. Balunini mempunyai lebar jalur yang sangat besar di antara 2 GHz hingga 14 GHz. Walaubagaimanapun, pemisahan satah pembumian dan lengan antena lingkaran pada panjanggelombang suku pada frekuensi rendah memberi kesan buruk pada corak sinaran padafrekuensi pertengahan dan tinggi.Untuk meningkatkan corak sinaran, struktur frekuensiterpilih dicadangkan untuk menanamkan rongga di dalam antena lingkaran. Nilaioptimum struktur frequensi terpilih memperbaiki corak sinaran sambil mengekalkanparameter lain seperti keuntungan, jalur lebar dan nisbah paksi. Semua reka bentuk yangdicadangkan menjalani proses fabrikasi dan pengukuran. Kedua-dua keputusan simulasidan pengukuran menunjukkan persamaan yang baik. Akhirnya, keputusan menunjukkanantena lingkaran Archimedes yang dicadangkan itu adalah calon yang paling sesuaiuntuk aplikasi yang dinyatakan di atas kerana baik keliling polarisasi corak sinaran satuarah dan keuntungan tinggi 8 dB kepada 11.2 dB dengan lebar jalur lebih daripada 140%diperolehi.
viCONTENTSTITLEPAGECOVER STRACTvABSTRAKviTABLE OF CONTENTSviiLIST OF TABLESxiiLIST OF APPENDICESxiiiLIST OF FIGURESxivLIST OF PUBLICATIONSLIST OF AWARDSCHAPTER IxviiixixINTRODUCTION . 11.1Introduction . 11.2Problems Statement . 21.3 Research Contribution. 4
vii1.4 Objectives of Study . 51.5 Scope of Study . 51.6 Dissertation Overview. 6CHAPTER IILITERATURE REVIEW . 82.1 Introduction . 82.2 Spiral Antenna as a Frequency Independent Antenna . 92.3 Characteristics of Antenna . 102.3.1 Return Loss . 112.3.2 Radiation pattern . 122.3.3 Gain . 142.3.4 Polarization . 142.4 Basic Principles of Operation for Spiral Antenna . 162.5 Techniques for Optimizing Spiral Antenna . 192.5.1 Dielectric Loading Effects . 192.5.2 The Radian sphere concept . 202.5.3 Mutual Coupling . 212.6 Previous Work on the Spiral Antenna . 212.7 Spiral Backing Techniques . 252.7.1 Absorber-filled Cavity . 252.7.2 Lossy Cavity . 262.7.3 Ground Plane. 272.7.4 FSS Embedded between Spiral Antenna and Ground Plane . 282.8 Feeding Systems for Spiral Antenna . 292.8.1 Proposed Microstrip to Parallel Strip lines Balun . 312.9 Overview of Frequency Selective Surface Structures . 32
viii2.9.1 Element Geometry . 342.9.2 Dielectric Substrates . 362.10 Conclusion . 36CHAPTER IIIRESEARCH METHODOLOGY . 373.1 Introduction . 373.2 Methodology. 383.3 Mathematical Formulations of the Spiral Antenna . 403.3.1 Choosing for Suitable Substrate and Backing Technique . 413.4 Feeding Techniques of Spiral Antenna . 423.4.1 Tapered microstrip lines . 433.5 FSS Design and Formulation . 473.5.1Mathematical Formulation of FSS. 473.6 Simulation, Fabrication and Measurement Procedures. 513.7 Measurement Procedures in the Anechoic Chamber . 513.8 Conclusion . 56CHAPTER IVPERFORMANCE INVESTIGATION OF ARCHIMEDEANSPIRAL ANTENNA BASED ON SIMULATION ANALYSIS . 574.1 Introduction . 574.2 Characteristics of Spiral Antenna Feeding with Discrete Port . 574.2.1 Effects of Dielectric Substrate without Air Cavity . 584.2.2 Effects of Dielectric Substrate with Air Cavity . 644.2.3 Effects of the Physical Separation of the Spiral Arms and the Ground Plane. 704.3 Optimization of Archimedean Spiral Antenna . 764.3.1 Effects of Arm Width . 774.3.2 Effects of Arm Spacing . 81
ix4.3.3 Effects of Inner Radius . 854.4 Mathematical Formulation and Analysis of the Active Region of ASA . 894.4.1 Analysis of the Active Region of Spiral Antenna . 934.5 Conclusion . 98CHAPTER VARCHIMEDEAN SPIRAL ANTENNA INTEGRATED WITHBALUN . 995.1 Introduction . 995.2 Characteristics of Spiral Antenna Feeding with Balun . 995.2.1 Microstrip to parallel strip balun design . 985.2.3 Back to Back Balun design . 1035.2.4 Measurement of Back to Back Balun Design . 1055.3 Integration of the Spiral Antenna with Balun . 1075.3.1 Spiral Antenna on a Moveable Ground plane . 1095.3.2 The Polarization of the Antenna . 1155.4 Measurement of Spiral Antenna with Balun . 1185.5 Conclusion . 127CHAPTER VISPIRAL ANTENNA EMBEDDED WITH FREQUENCYSELECTIVE SURFACE . 1286.1 Introduction . 1286.2 Physical Parameters of Frequency Selective Surface . 1286.2.1 FSS Shapes. 1296.3 Square Loop FSS Design Parameters . 1326.3.1 Dielectric Substrate . 1326.3.2 Square Loop Length . 1346.3.3 Square Loop Width . 1356.4 Archimedean spiral antenna embedded with Frequency selective surface . 136
x6.5 Optimization of Spiral Antenna with FSS . 1426.6 Measurement Results . 1516.7 Conclusion . 154CHAPTER VIICONCLUSION AND RECOMMENDATION . 1557.1 Conclusions . 1557.2 Future work . 1587.2.1 WAVES Concept Applications on Spiral Antenna . 1597.2.2 Low Q Antenna Designs . 160REFERENCES 161
xiLIST OF TABLESNO. OF TABLETITLEPAGE2.1Comparison between previous works252.2Comparison between the Baluns322.3Performances of FSSs shapes353.1The dimensions of the balun463.2Loop parameters at 5GHz514.1Physical thickness for variation of substrate594.2Size Increment of the spiral antenna894.3Details position of the active region954.4The maximum current distribution965.1Comparison of the balun with previous baluns1067.1Summary of the performance of the ASA1597.2Comparison of ASA and the previous works159
xiiLIST OF APPENDICESAPPENDIXATITLEAwardsPAGE170
xiiiLIST OF FIGURESNO. OF FIGURETITLEPAGE2.1Examples of two arm Spiral Antenna102.3The return loss of Wideband antenna112.3Radiation Patterns122.4Linear Polarization152.5Circular Polarization162.6Band theory for mode 1 excitation172.7Cut open FVTD model of the spiral antenna232.8ASA with ring absorber material242.9Spiral antenna on absorber-filled cavity262.10Spiral Antenna on lossy cavity272.11Wideband antenna on ground plane282.12Antenna with FSS layers292.13Schematic for unbalanced to balanced302.14A single microstrip to parallel strip lines balun312.15Four basic FSS332.16Common FSS element Shapes34
xiv2.17The frequency response353.1Flow chart of the design393.2Schematic view of the ASA413.3Spiral antenna with discrete port423.4Configuration of a balun453.5Square loop FSS schematic483.6S-parameter Measurement set up523.7Gain Measurement set up554.1Configuration of two arm ASA without air cavity584.2Comparison of S11 on different permittivity604.3Comparison of AR on a different permittivity604.4Comparison of gain on a different permittivity614.5Comparison of radiation pattern on different permittivity634.6Comparison of radiation pattern on different permittivity634.7Configuration of two arm ASA with air cavity644.8Comparison of S11 on different substrates654.9Comparison of axial ratio on a different permittivity664.10Comparison of gain on a different permittivity674.11Comparison of S11 on different substrate thicknesses684.12Comparison of axial ratio on different thicknesses684.13Comparison of gain on different substrate thicknesses69
xv4.14Comparison of S11 at GP different positions724.15Comparison of gain at GP different724.16Comparison of axial ratio734.17Radiation patterns at 3.1GHz, 6.85GHz and 10.6GHz754.18Radiation patterns at 3.1, 6.85 and 10.6GHz754.19Comparison of Radiation Efficiency774.20Effects of Arm width794.21Effects of Arm spacing834.22Effects of inner radius874.23Active region of ASA based on Radiation band theory904.24Current distribution of two arms ASA954.25Calculation and simulation results of active region of ASA 964.26Calculation and simulation results of active region of ASA 974.27Phase current flowing on ASA985.1Designed Balun1015.2S-parameter (return loss) of single balun1015.3S-parameter (Impedance) of single balun1025.4Back to back balun design1035.5Simulation of return loss and insertion loss1035.6S-parameter (impedance matching)104
xvi5.7Surface Currents at 2.5 GHz1045.8Fabrication and Measurement of Balun1065.9Configuration of the balun with a SMA connector1075.10Configuration of the Spiral antenna with the balun1085.11Return loss1085.12Impedance views at (r1 0.7mm, w s 2mm and N 8)1085.13Comparison between S11 at GP different positions1105.14Comparison between gain at GP different positions1115.15Radiation patterns for 3.1GHz at GP infinite1125.16Radiation patterns at (a) 3.1GHz, (b) 4GHz and (c) 6GHz1145.17Comparison of axial ratio (r1 0.7mm w s 2mm and N 8) 1165.18Comparison of co and cross polarization1175.19Fabricated Spiral antenna on a moveable ground plane1195.20Comparison between measurement and simulated S111225.21Comparison between measurement and simulated Gain1245.22Effects of different GP position on the return loss1265.23Effects of different GP position on the gain1266.1The structures; SL FSS, Dipole and Cross Dipole FSSs1306.2FSS responses on different shapes1316.3SL FSS parameters analysis133
xvii6.4Substrate thickness on FSS1346.5The effect of varying element length1356.6The effect of varying element width1366.7Schematic view of the ASA embedded with FSS1376.8Comparison of S11 Spiral only and with FSS-1 design1386.9Comparison of pattern spiral only and spiral with FSS1406.10Comparison of gain of spiral only and spiral with FSS1406.11Comparison of axial ratio of spiral only and spiral with FSS 1416.12FSS structures1436.13Different Periodicity1446.14Comparison of S11 Spiral with different FSS periodicity1456.15Comparison of pattern of spiral with and without FSSs1476.16Comparison of gain of spiral only and spiral with FSS1476.17Comparison of axial ratio1486.18Comparison of RHCP and LHCP for spiral with FSS-31516.19Fabricated structures1526.20Comparison of the simulated and measured return loss1536.21Comparison of the simulated and measured gain1547.1Planar arrays based on WAVES concept160
xviiiPublicationsProceedingsi.A. M Shire and F. C. Seman “Effects of dielectric substrate on performance ofUWB Archimedean Spiral Antenna” Space Science and Communication(IconSpace), 2013 IEEE International Conference Pages 412-415.ii.Abdirahman Mohamud Shire and Fauziahanim Che Seman “Analysis of theActive Region of Archimedean Spiral Antenna” Chapter 25, Notes ElectricalEng., Vol. 315, et al: Advanced Computer and Communication EngineeringTechnology.iii.Abdirahman Mohamud Shire and Fauziahanim Che Seman “Parametric Studiesof Archimedean Spiral Antenna for UWB Applications” PRESENTED at ApaceConference, 10 December 2014.Journalsiv.F. B. Zarrabi, A. M. Shire, M. Rahimi and N. P. Gandji “Ultrawideband taperedpatch antenna with fractal slots for dual notch application” Microwave OpticalTechnology Letters, Vol. 56, 2014, Pages:1344-1348.v.F. C. Seman and A. M Shire “Archimedean Spiral Antenna on Moveable GroundPlane for UWB Applications” (Under Review at APRN Journal; indexed inSCOPUS).vi.A. M Shire and F. C. Seman “Numerical Analysis of Frequency SelectiveSurface Using Equivalent Circuit Method” (Under Review at electronic letters)
xixList of Awardsi.GOLD PRIZE “Archimedean Spiral Antenna on Moveable Ground Plane”Exhibited at the Seoul International Invention Fair (SIIF) 2014, in Seoul, SouthKorea.ii.SILVER MEDAL “Archimedean Spiral Antenna on Moveable Ground Plane”Invention and Innovation Awards for Malaysia Technology Expo (MTE) 2014, inKuala Lumpur, Malaysia.iii.BRONZE MEDAL “Archimedean Spiral Antenna on Moveable Ground Planefor UWB Applications” Exhibited at Research and Innovation Fest (R & I) 2013,in University Tun Hussein Onn Malaysia (UTHM).
1CHAPTER IINTRODUCTION1.1IntroductionWide band is a transmission technology in which information is transmitted overlarge operating bandwidth. Such technology has been utilized for decades mostly formilitary related systems because more information and applications can be carriedthrough the radio frequency channels with a high data rate and accuracy [1]. Widebandapplications are numerous including ground penetrating radar systems, militarycommunications, satellite communications, direction finding systems, vehicular radarsystems and wireless communications [2].In order to make the transmission andreception of an wide band system over the frequency range of 3.1 GHz to10.6 GHz; it isrequired to have a high gain antenna, with good impedance matching and VSWR lessthan 2 throughout the entire band [2-3]. Therefore, Archimedean spiral antenna is goodcandidate to be used in wideband applications since it has met the above mentionedrequirements. Archimedean spiral antenna has received huge interest over the last twodecades due to its wide impedance bandwidth, high efficiency, nearly unidirectional
2radiation pattern, low profile, stable impedance characteristic and circular polarizationover the last two decades [4].There are three different designs of spiral antennas. The first design of spiralantenna is by shaping it as a single arm spiral antenna, which is designed for somenarrow-band applications. The second design is the two arm case, which is the minimumnumber of arms needed for single-mode broadband operation. The third design is themulti arm case, which is designed when two broadband modes are needed. This means,in order to achieve two broadband modes at least three arms are required. Therefore, inthis research the second design which is the two arm case is discussed due to itsadvantages over the other two cases. It is because the two arm Archimedean spiralantenna has better axial ratio than the single arm Archimedean spiral antenna, whichmeans the two arm case has better circular polarization compared to the single arm case.The two arm spiral antenna has a simple feed (e.g. Microstrip to parallel strip balun) andless complex geometry design compared to the multi arm spiral. It is because the multiarms spiral has complex geometry design and feeding systems such as a beam feedingnetwork.In summary, several optimizations techniques are proposed in this study such asloading lower permittivity dielectric substrate, radian sphere concept, reducing mutualcoupling, moveable ground plane and embedding frequency selective surface structurein the cavity of the spiral. Therefore, these five optimization techniques leads to theinvention of a new design of two arm Archimedean spiral antenna backed by cavity withlarge bandwidth, high gain, unidirectional pattern with circular polarization and withhigher efficiency.1.2Problems StatementA common approach used to cover a large frequency range which encompassesmany different communication systems is to employ a separate antenna for each system.
3An advantage of this approach is that it meets the specific needs of each communicationsystem. However, when a platform such as an airplane, ship or automobile requires theuse of many communication systems, this approach has several problems such as space,payload, cost and electromagnetic compatibility/interference (EMC/EMI). Therefore,there is a significant interest in antennas which possess compact size, have multifunctional characteristics, have large bandwidth ( 20%) and have high gain.In the design of an antenna that meets the above requirements, there are severalchallenges that must be taken into account. First of all, the antenna must have sufficientbandwidth to facilitate the integration of multiple antennas into a single aperture. Sincethe applications of interest require bandwidths in excess of 10:1, this work focuses onwide-band antenna such as the Archimedean spiral antenna. Since the spiral antennabelongs to the class of frequency independent antennas, it is easily capable of bandwidthgreater than 10:1 [5]. Such antennas are considered frequency independent because theirpattern, impedance and other parameters vary little with frequency as compared to amulti-band antenna which can exhibit considerable variation. These characteristics makethe spiral an ideal candidate for replacing a variety of antennas. Apart from theadvantages of spiral antenna, there are disadvantages in spiral antenna, such as the spiralantenna has a low gain and bidirectional radiation pattern. There are several techniquesto get rid of the bidirectional radiation pattern, such as by using an absorber-filledcavity, a lossy cavity, and conducting ground plane.Therefore, in this project a technique is proposed to get rid of this problem,which is to construct a moveable ground plane, which maintains quarter wavelengthspacing between the spiral and the ground plane in the vicinity of the active region of thespiral. However, by introducing this technique; antenna’s patterns at higher frequenciesdeteriorate. In order to improve the patterns and to minimize the splitting of the patternsat higher frequencies; a frequency selective surface structure is embedded between thespiral antenna and the ground plane. This new design can substantially enhances theradiation pattern properties of the antenna since the reflected field is in phase with thatdirectly radiated by the antenna itself. In addition, by embedding the FSS structure in the
4design minimizes the gain fluctuations caused by the ground plane. However, FSSstructure together with the ground plane reduces the antenna’s bandwidth. One way tominimize the FSS reduction of the bandwidth is applying the radian sphere theory inorder to make the antenna electrically larger and to obtain larger bandwidth.As a result of the optimized techniques such as the ground plane (forunidirectional radiation pattern), radian sphere theory (for maintaining widebandbandwidth) and embedding FSS in the cavity of the spiral antenna (for betterperformance of radiation pattern), it is expected to come up with new spiral antennaprototype, which has enhanced unidirectional radiation pattern, wide bandwidth (at least100% of bandwidth of return loss better than -10dB) and high gain which enables theantenna to detect the enemy radar in a large range of distance compared to the presentradar systems.1.3 Research ContributionThroughout this research work several major contributions have been achieved forArchimedean spiral antenna performance. In this section a summary of these majorcontributions are presented:1. A prototype of wideband Archimedean spiral antenna has been designed withenhanced performance based on Radian sphere theory.2. Universal design of spiral antenna has been used which leads to the eliminationof multiple antennas configurations on wideband systems.3. A tapered microstrip to parallel strip lines balun is proposed with new tapereddesign based on mathematical formulation is proposed as a feeding technique forwideband antennas.4. Comprehensive study is carried out for different structures of frequency selectivesurface in order to improve the antenna’s performance.
55. Band stop frequency selective surface design based numerical synthesis isdeveloped.1.4 Objectives of StudyThis project has the following objectives:i.To design wideband Archimedean spiral antenna on a moveable ground planeplaced at a quarter wavelengths for selected design frequencies in order toachieve high gain antenna with circularly polarized unidirectional radiationpattern.ii.To design and embed frequency selective surface structure in the Archimedeanspiral antenna cavity in order to improve antenna’s radiation patternperformance.1.5 Scope of StudyThis project focuses on the performance investigations of Archimedean spiralantenna based on radian sphere theory, FSS structures and microstrip to parallel stripbalun within wideband frequency range (3.1-10.6GHz). The effects of the dielectricmaterials (free space εr 1, Rogers RT 5870 εr 2.33, FR-4 εr 4.3 and Rogers RO3030εr 10.2) and moveable ground plane placed at quarter wavelengths for selected designfrequencies including 2GHz, 3.1GHz, 5GHz, 6.85GHz and 10.6GHz on the performanceof the spiral antenna are investigated, in order to achieve a bandwidth of 100% at thereturn loss of the antenna; which below -10dB, high gain of up to 10dB andunidirectional radiation pattern with circular polarization using discrete port as the
6feeding of the antenna. Wideband balun such as microstrip to parallel strip lines balunover the frequency range of 2 GHz to 14 GHz as the feeding network of the antenna isdesigned. Square loop of FSS structures with reduced periodicity are designed.Commercially available computer model of CST microwave studio 2012 has been usedfor simulation and investigations for the performance of spiral antenna, balun and FSSstructures. In order to validate the theoretical analysis, the antenna, FSS and balunstructures are fabricated on dielectric substrate; Rogers RT 5870 with permittivity ofεr 2.33 and thickness of 1.57mm. Finally, the measurements of the requiredcharacteristics such as S11, S21 and gain are carried out using vector network analyzer.1.6 Dissertation OverviewThis thesis is divided into 7 main chapters and a reference section
2.7 Cut open FVTD model of the spiral antenna 23 2.8 ASA with ring absorber material 24 2.9 Spiral antenna on absorber-filled cavity 26 2.10 Spiral Antenna on lossy cavity 27 2.11 Wideband a
A self-complementary Archimedean spiral antenna is shown in Fig. 2.1. A spiral antenna is self-complementary if the metal and air regions of the antenna are equal. The input impedance of a self-complementary antenna can be found using Babinet’s principle, giving 4 η2 Zmetal Zair (2.1)File Size: 716KB
Random Length Radiator Wire Antenna 6 6. Windom Antenna 6 7. Windom Antenna - Feed with coax cable 7 8. Quarter Wavelength Vertical Antenna 7 9. Folded Marconi Tee Antenna 8 10. Zeppelin Antenna 8 11. EWE Antenna 9 12. Dipole Antenna - Balun 9 13. Multiband Dipole Antenna 10 14. Inverted-Vee Antenna 10 15. Sloping Dipole Antenna 11 16. Vertical Dipole 12 17. Delta Fed Dipole Antenna 13 18. Bow .
Random Length Radiator Wire Antenna 6 6. Windom Antenna 6 7. Windom Antenna - Feed with coax cable 7 8. Quarter Wavelength Vertical Antenna 7 9. Folded Marconi Tee Antenna 8 10. Zeppelin Antenna 8 11. EWE Antenna 9 12. Dipole Antenna - Balun 9 13. Multiband Dipole Antenna 10 14. Inverted-Vee Antenna 10 15. Sloping Dipole Antenna 11 16. Vertical Dipole 12 17. Delta Fed Dipole Antenna 13 18. Bow .
DESIGN OF ARCHIMEDEAN SPIRAL ANTENNA FOR RADAR APPPLICATIONS S.RAJESH KUMAR 1, E.JEEVITHA 2, V.KEERTHI 3, S.KIRUTHIKA 4, V.MANIMEKALAI 5 1Assistant Professor, Department of Electronics and Communication Engineering , V.S.B Engineering College Karur, India rajesh26july@gmail.com 2,3,4,5 Departme
Wire-Beam Antenna for 80m. 63 Dual-Band Sloper Antenna. 64 Inverted-V Beam Antenna for 30m. 65 ZL-Special Beam Antenna for 15m. 66 Half-Sloper Antenna for 160m . 67 Two-Bands Half Sloper for 80m - 40m. 68 Linear Loaded Sloper Antenna for 160m. 69 Super-Sloper Antenna. 70 Tower Pole as a Vertical Antenna for 80m. 71 Clothesline Antenna. 72 Wire Ground-Plane Antenna. 73 Inverted Delta Loop for .
spiral antenna with a balanced feed. Two forms of this antenna have been used, the plane conductor antenna, ie., metallic arms suspended in free space, and the slot antenna, which consists of spiral slots cut in a large con- ducting she
The first very wide-band antenna using spiral topology was invented by Ed Turner in 1950s. Rumsey advanced the equiangular spiral theory in 1954 and then, Burdine and Jones, et al. helped explain its performance in 1960s. [6] The spiral antenna can be left-hand or right-hand circularly polarized. The advantage of
Automotive EMI/EMC Pre-compliance Tests - Tektronix RF Automotive Test Solution Summary EMI compliance testing for automotive components and subsystems is an important part of the design process, and it usually occurs quite late. Pre-compliance testing can take help mitigate stress on your project and by taking the right steps, you can have higher confidence that your design will pass at the .
