DOCSLIB.ORG

Analysis and Design of Conformal Array Antennas

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Analysis and Design of Conformal Array Antennas ANALYSIS AND DESIGN OF CONFORMAL ARRAY ANTENNAS Patrik Persson KTH Royal Institute of Technology Division of Electromagnetic Theory Stockholm 2001 P. Persson: Analysis and Design of Conformal Array Antennas ISBN 91-7283-231-2 Akademisk avhandling som med tillstånd av Kungliga Tekniska Högskolan framlägges till offentlig granskning för avläggande av teknisk doktorsexamen i teoretisk elektroteknik, tisdagen den 29 januari 2002, kl. 13.15 i Kollegiesalen, Administrationsbyggnaden, KTH, Valhallavägen 79, Stockholm. Avhandlingen kommer att försvaras på engelska. Copyright 2001 Patrik Persson Printed in Sweden by Universitetsservice US AB, Stockholm December 2001 ii Abstract Abstract Today there is a great need for communication between people and even between things, using systems onboard e.g. aircraft, cars, ships and satellites. As a consequence, these communications needs require antennas mounted on or integrated in the surfaces of different vehicles or platforms, i.e. conformal antennas. In order to ensure proper operation of the communication systems it is important to be able to determine the characteristics of these antennas. This thesis is about the analysis and design of conformal antennas using high frequency asymptotic methods. Commonly used eigenfunction solutions or numerical methods such as FDTD, FEM or MoM are difficult to use for arbitrarily shaped electrically large surfaces. However, the high frequency approximation approach together with an accurate ray tracing procedure offers a convenient solution for these surfaces. The geodesics (ray paths) on the surfaces are key parameters in the analysis and they are discussed in detail. In the first part of the thesis singly and doubly curved perfectly electrical conducting (PEC) surfaces are studied, with respect to the mutual coupling among aperture type elements. A synthesis problem is also considered where the effect of the mutual coupling is taken into account. As expected, the mutual coupling must be included in the synthesis procedure to be able to realize the prescribed pattern, especially in the shaped main lobe. Furthermore, the polarization of the antenna elements is very important when considering antennas on generally shaped surfaces. For such antennas the polarization must most likely be controlled in some way for a proper function. For verification of the results two experimental antennas were built at Ericsson Microwave Systems AB, Mölndal, Sweden. The first antenna is a circular cylinder with an array of rectangular waveguide fed apertures and the second antenna is a doubly curved surface (paraboloid) with circular waveguide fed apertures. It is found that it is possible to obtain very accurate results with the asymptotic method when it is combined with the Method of Moments, i.e. a hybrid method is used. The agreement compared to measurements is good at levels as low as –80 dB in many cases. The second part of the thesis is about the development of a high frequency approximation for surface field calculations on a dielectric covered PEC circular cylinder. When using conformal antennas in practice they have to be covered with a radome for protection and with the method developed here this cover can be included in the analysis. The method is a combination of two different solutions, one valid in the non-paraxial region of the cylinder and the other is valid in the paraxial region. The method is verified against measurements and reference results obtained from a spectral domain moment method code. Keywords: Conformal antennas, conformal arrays, UTD, high frequency method, MoM, hybrid method, mutual coupling, singly curved surface, doubly curved surface, geodesics, dielectric covered circular cylinder, non-paraxial region, paraxial region, waveguide fed apertures, synthesis. iii P. Persson: Analysis and Design of Conformal Array Antennas iv Preface Preface The work of this thesis has been carried out mainly at the Division of Electromagnetic Theory (formerly the Department of Electromagnetic Theory) at the Royal Institute of Technology (KTH). I have spent almost 5 years at KTH (February 1997 to December 2001) working with conformal antennas and it has certainly been an interesting time. I have enjoyed (almost) every day of this part of my life. I will, in particular, remember my visit at the ElectroScience Laboratory, The Ohio State University, Columbus, Ohio during the period September 2000 to March 2001. Thank you Prof. Roberto G. Rojas for your support during this time. Thanks to Prof. Prabhakar H. Pathak as well (I am looking forward to the dinner...). During this period at KTH I have had the honor of working with Adj. Prof. Lars Josefsson, my supervisor. I would like to express my deepest gratitude to you for your excellent guidance and support on this work. Thank you for taking the initiative to build two experimental conformal antennas at Ericsson Microwave Systems AB (EMW), Mölndal, Sweden. I also owe you a great dept of gratitude for long spent hours reading my manuscripts. It has always been an interesting event reading your comments; how much red ink did you use this time? I also want to thank my colleagues at "TET" for the inspiring atmosphere. In particular Björn Thors for fruitful discussions and for your careful review of my work. In addition to calculated results, this thesis would not have been anything without the measured data obtained at EMW. Thank you Stefan Lindgren for doing the measurements on the circular cylinder (without the dielectric layer). Many thanks to Maria Lanne as well for your patience with the measurements on the doubly curved surface, but also on the circular cylinder (with the dielectric layer). Furthermore, it has been a pleasure to get to know you Dr. Zvonimir Sipus, University of Zagreb, Croatia. I wish to thank you for the calculated reference data and for interesting discussions. Finally, I wish to thank my wife for her patience and sacrifice. Jeanette, this is for you, I love you! Patrik Persson Stockholm December, 2001 v P. Persson: Analysis and Design of Conformal Array Antennas vi Table of contents Table of contents Abstract iii Preface v Table of contents vii List of papers ix Specification of my contributions to the included papers xi 1. Conformal antennas 1 1.1 Introduction 1 1.2 Definition of a conformal antenna 1 1.3 A historical review 1 1.4 Why a conformal antenna? 8 1.5 The challenges 9 1.6 Conformal arrays versus planar arrays 9 1.7 The future 10 2. Analyzing conformal array antennas – an overview 11 2.1 Introduction 11 2.2 Low frequency analysis 11 2.3 High frequency analysis 12 2.4 Final comments 15 3. Development of asymptotic methods 17 3.1 Introduction 17 3.2 Properties of the integrand 18 22− 3.3 Definition of kkz in the complex plane and the 19 determination of the path of integration 3.4 The Watson transformation 20 3.5 The Fock substitution 24 3.6 The polar transformation 26 3.7 The steepest descent representation 27 3.8 The paraxial region 29 4. General smooth convex surfaces 31 4.1 Introduction 31 4.2 Geodesics 31 4.3 The convex cylindrical surface 31 4.4 Generalization to an arbitrary convex surface 32 4.5 Final comments 33 vii P. Persson: Analysis and Design of Conformal Array Antennas 5. Poles and surface waves 35 5.1 Introduction 35 5.2 The dielectric covered PEC circular cylinder 35 5.3 The grounded dielectric slab, planar case 38 5.4 Discussion of the relation between the planar and 40 cylindrical cases 6. Summary of papers 43 6.1 Introduction 43 6.2 Summary of paper I 44 6.3 Summary of paper II 44 6.4 Summary of paper III 44 6.5 Summary of paper IV 45 6.6 Summary of paper V 45 6.7 Summary of paper VI 46 6.8 Summary of paper VII 46 7. References 47 Paper I Calculating the Mutual Coupling between Apertures on a 55 Convex Circular Cylinder Using a Hybrid UTD-MoM Method Paper II The Mutual Coupling between Apertures on Convex Cylinders 71 Paper III Conformal Array Synthesis Including Mutual Coupling 85 Paper IV Calculating Geodesics on Doubly Curved Surfaces: The case 95 of a General Paraboloid of Revolution Paper V Investigation of the Mutual Coupling between Apertures on 119 Doubly Curved Convex Surfaces: Theory and Measurements Paper VI A High Frequency Approximation for Mutual Coupling Calculations 139 between Apertures on a PEC Circular Cylinder Covered with a Dielectric Layer Valid in the Non-Paraxial Region: The Gzz and Gϕϕ cases Paper VII A High Frequency Approximation for Mutual Coupling Calculations 169 between Apertures on a PEC Circular Cylinder Covered with a Dielectric Layer Valid in the Paraxial Region: The Gzz case viii List of papers List of papers I. Patrik Persson and Lars Josefsson, ”Calculating the Mutual Coupling between Apertures on a Convex Circular Cylinder Using a Hybrid UTD-MoM Method”, IEEE Transactions on Antennas and Propagation, Vol. 49, No. 4, pp. 672-677, April 2001. II. Patrik Persson, ”The Mutual Coupling between Apertures on Convex Cylinders”, RVK 99, Karlskrona, Sweden, June 1999. III. Lars Josefsson and Patrik Persson, ”Conformal Array Synthesis Including Mutual Coupling”, Electronics Letters, Vol. 35, No. 8, pp. 625-627, 15th April 1999. IV. Patrik Persson and Lars Josefsson, ”Calculating Geodesics on Doubly Curved Surfaces: The case of a General Paraboloid of Revolution”, Technical report TRITA-TET 00-07, KTH, Stockholm, May 2000. V. Patrik Persson, Lars Josefsson and Maria Lanne, ”Investigation of the Mutual Coupling between Apertures on Doubly Curved Convex Surfaces: Theory and Measurements”, Submitted to IEEE Transactions on Antennas and Propagation. VI. Patrik Persson and Roberto G. Rojas, ”A High Frequency Approximation for Mutual Coupling Calculations between Apertures on a PEC Circular Cylinder Covered with a Dielectric Layer Valid in the Non-Paraxial Region: The Gzz and Gϕϕ cases”.
Load more

Recommended publications
  • Array Designs for Long-Distance Wireless Power Transmission: State
    INVITED PAPER Array Designs for Long-Distance Wireless Power Transmission: State-of-the-Art and Innovative Solutions A review of long-range WPT array techniques is provided with recent advances and future trends. Design techniques for transmitting antennas are developed for optimized array architectures, and synthesis issues of rectenna arrays are detailed with examples and discussions. By Andrea Massa, Member IEEE, Giacomo Oliveri, Member IEEE, Federico Viani, Member IEEE,andPaoloRocca,Member IEEE ABSTRACT | The concept of long-range wireless power trans- the state of the art for long-range wireless power transmis- mission (WPT) has been formulated shortly after the invention sion, highlighting the latest advances and innovative solutions of high power microwave amplifiers. The promise of WPT, as well as envisaging possible future trends of the research in energy transfer over large distances without the need to deploy this area. a wired electrical network, led to the development of landmark successful experiments, and provided the incentive for further KEYWORDS | Array antennas; solar power satellites; wireless research to increase the performances, efficiency, and robust- power transmission (WPT) ness of these technological solutions. In this framework, the key-role and challenges in designing transmitting and receiving antenna arrays able to guarantee high-efficiency power trans- I. INTRODUCTION fer and cost-effective deployment for the WPT system has been Long-range wireless power transmission (WPT) systems soon acknowledged. Nevertheless, owing to its intrinsic com- working in the radio-frequency (RF) range [1]–[5] are plexity, the design of WPT arrays is still an open research field currently gathering a considerable interest (Fig.
    [Show full text]
  • A Wideband Conformal Antenna with High Pattern Integrity for Mmwave 5G Smartphones
    Progress In Electromagnetics Research Letters, Vol. 84, 1–6, 2019 A Wideband Conformal Antenna with High Pattern Integrity for mmWave 5G Smartphones Gulur S. Karthikeya*,MaheshP.Abegaonkar,andShibanK.Koul Abstract—In this paper, a co-planar waveguide fed circular slot antenna with an operational impedance bandwidth of 20–28 GHz is proposed. In order to reduce the effective occupied volume when the antenna is integrated onto a typical mmWave 5G smartphone, a conformal topology is investigated. Since the radiating aperture is not backed by an electrically large ground plane, it leads to a bidirectional beam resulting in an inherently low forward gain of 4 dBi with a front to back ratio of 1 dB. Hence, a compact exponentially tapered copper film reflector is integrated electrically close (0.046λ at 28 GHz) to the radiating aperture to achieve a forward gain of 8–9 dBi with an effective radiating volume of 0.24λ3. The impedance bandwidth is from 25 to 30 GHz (18.2%) with a 1-dB gain bandwidth of 34.7% indicating high pattern integrity across the band. Since the proposed antenna element offers wideband with high gain, it is a potential candidate for mmWave 5G smartphones. 1. INTRODUCTION The phenomenal growth in the smartphone users over the years has provoked researchers in academia and industry to design future-proof transceivers facilitating high data-rates, which in turn need high carrier frequencies, such as 28 GHz band. The 28 GHz band is projected as a potential candidate for future 5G cellular communication systems. The fundamental challenge for deployment of 28 GHz radios is the inherent high path loss.
    [Show full text]
  • High Gain Isotropic Rectenna Erika Vandelle, Phi Long Doan, Do Hanh Ngan Bui, T.-P
    High gain isotropic rectenna Erika Vandelle, Phi Long Doan, Do Hanh Ngan Bui, T.-P. Vuong, Gustavo Ardila, Ke Wu, Simon Hemour To cite this version: Erika Vandelle, Phi Long Doan, Do Hanh Ngan Bui, T.-P. Vuong, Gustavo Ardila, et al.. High gain isotropic rectenna. 2017 IEEE Wireless Power Transfer Conference (WPTC), May 2017, Taipei, Taiwan. pp.54-57, 10.1109/WPT.2017.7953880. hal-01722690 HAL Id: hal-01722690 https://hal.archives-ouvertes.fr/hal-01722690 Submitted on 29 Aug 2018 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. High Gain Isotropic Rectenna E. Vandelle1, P. L. Doan1, D.H.N. Bui1, T.P. Vuong1, G. Ardila1, K. Wu2, S. Hemour3 1 Université Grenoble Alpes, CNRS, Grenoble INP*, IMEP–LAHC, Grenoble, France 2 Polytechnique Montréal, Poly-Grames, Montreal, Quebec, Canada 3 Université de Bordeaux, IMS Bordeaux, Bordeaux Aquitaine INP, Bordeaux, France *Institute of Engineering University of Grenoble Alpes {vandeler, buido, vuongt, ardilarg}@minatec.inpg.fr [email protected] [email protected] [email protected] Abstract— This paper introduces an original strategy to step up the capacity of ambient RF energy harvesters.
    [Show full text]
  • Arrays: the Two-Element Array
    LECTURE 13: LINEAR ARRAY THEORY - PART I (Linear arrays: the two-element array. N-element array with uniform amplitude and spacing. Broad-side array. End-fire array. Phased array.) 1. Introduction Usually the radiation patterns of single-element antennas are relatively wide, i.e., they have relatively low directivity. In long distance communications, antennas with high directivity are often required. Such antennas are possible to construct by enlarging the dimensions of the radiating aperture (size much larger than ). This approach, however, may lead to the appearance of multiple side lobes. Besides, the antenna is usually large and difficult to fabricate. Another way to increase the electrical size of an antenna is to construct it as an assembly of radiating elements in a proper electrical and geometrical configuration – antenna array. Usually, the array elements are identical. This is not necessary but it is practical and simpler for design and fabrication. The individual elements may be of any type (wire dipoles, loops, apertures, etc.) The total field of an array is a vector superposition of the fields radiated by the individual elements. To provide very directive pattern, it is necessary that the partial fields (generated by the individual elements) interfere constructively in the desired direction and interfere destructively in the remaining space. There are six factors that impact the overall antenna pattern: a) the shape of the array (linear, circular, spherical, rectangular, etc.), b) the size of the array, c) the relative placement of the elements, d) the excitation amplitude of the individual elements, e) the excitation phase of each element, f) the individual pattern of each element.
    [Show full text]
  • A Conceptual Design for Load Triggering by Extracting Power from the Conventional Wireless Signal with Frequency Matched to Ism Band (2.4 Ghz)
    International Journal of Mechanical Engineering and Technology (IJMET) Volume 9, Issue 5, May 2018, pp. 725–732, Article ID: IJMET_09_05_080 Available online at http://iaeme.com/Home/issue/IJMET?Volume=9&Issue=5 ISSN Print: 0976-6340 and ISSN Online: 0976-6359 © IAEME Publication Scopus Indexed A CONCEPTUAL DESIGN FOR LOAD TRIGGERING BY EXTRACTING POWER FROM THE CONVENTIONAL WIRELESS SIGNAL WITH FREQUENCY MATCHED TO ISM BAND (2.4 GHZ) V. Prabhakaran Research Scholar, Saveetha School of Engineering, Saveetha Institute of Medical and Technical Sciences, Chennai, India Dr. P. Shankar Principal, Aarupadai Veedu Institute of Technology, Chennai, India Dr. P.C. Kishore Raja Professor and Head, Department of Electronics and Communication Engineering, Saveetha School of Engineering, Saveetha Institute of Medical and Technical Sciences, Chennai, India ABSTRACT In recent scenario, the usage of Non-renewable sources is tremendously aggregated to meet the ever increasing load demand. Though renewable sources are used as a supplement, still the load demand cannot be matched. In this paper, a new conceptual inverter design is formulated which powers the load through conventional wireless signals (ISM Band – 2.4 GhZ) by a novel “Rectenna design” with an output amplification factor of (~7 times) than input signal. This design is simulated in MATLAB and the output factors are analyzed for ISM (Industrial, Scientific and Medical Radio) band signals. Keywords: Rectenna Design, Boost Converter, ISM band signals, Inverter Cite this Article: V. Prabhakaran, Dr. P. Shankar and Dr. P.C. Kishore Raja, A Conceptual Design for Load Triggering by Extracting Power from the Conventional Wireless Signal with Frequency Matched to ISM Band (2.4 GHZ), International Journal of Mechanical Engineering and Technology, 9(5), 2018, pp.
    [Show full text]
  • 1- Consider an Array of Six Elements with Element Spacing D = 3Λ/8. A
    1- Consider an array of six elements with element spacing d = 3 λ/8. a) Assuming all elements are driven uniformly (same phase and amplitude), calculate the null beamwidth. b) If the direction of maximum radiation is desired to be at 30 o from the array broadside direction, specify the phase distribution. c) Specify the phase distribution for achieving an end-fire radiation and calculate the null beamwidth in this case. 5- Four isotropic sources are placed along the z-axis as shown below. Assuming that the amplitudes of elements #1 and #2 are +1, and the amplitudes of #3 and #4 are -1, find: a) the array factor in simplified form b) the nulls when d = λ 2 . a) b) 1- Give the array factor for the following identical isotropic antennas with N and d. 3- Design a 7-element array along the x-axis. Specifically, determine the interelement phase shift α and the element center-to-center spacing d to point the main beam at θ =25 ° , φ =10 ° and provide the widest possible beamwidth. Ψ=x kdsincosθφα +⇒= 0 kd sin25cos10 ° °+⇒=− αα 0.4162 kd nulls at 7Ψ nnπ2 nn π 2 =±, = 1,2, ⋅⋅⋅⇒Ψnull =±7 , = 1,2,3,4,5,6 α kd2π n kd d λ α −=−7 ( =⇒= 1) 0.634 ⇒= 0.1 ⇒=− 0.264 2- Two-element uniform array of isotropic sources, positioned along the z-axis λ 4 apart is seen in the figure below. Give the array factor for this array. Find the interelement phase shift, α , so that the maximum of the array factor occurs along θ =0 ° (end-fire array).
    [Show full text]
  • Conformal Microstrip Printed Antenna
    Conformal microstrip printed antenna K. Elleithy H. Bajwa A. Elrashidi ([email protected]) ([email protected]) ([email protected]) University of Bridgeport 126 Park Avenue Bridgeport, CT 06604 Abstract 4. With planer arrays the radiation pattern changes In this paper, the comprehensive study of the with the direction of scan, while conformal arrays conformal microstrip printed antenna is presented. The main with rotational symmetry (cylindrical profile) can advantages and drawbacks of a microstrip conformal have scan-invariant pattern [5]. antenna are introduced. The earlier researches in cylindrical- 5. Cylindrical conformal gives nearly Omni- rectangular patch and conformal microstrip array are directional radiation pattern [6]. summarized. The effect of curvature on the conformal 6. It gives large angle coverage. Microstrip antenna patch on conical and spherical surfaces is studied. Some new flexible antenna is given for different Because of the advantages of conformal antennas, it is very frequencies. Finally, simulation software is used to study the popular in the different flight aircrafts [7]. effect of the curvature on the input impedance, return loss, On the other side, a conformal microstrip antenna has some voltage standing wave ratio, and resonance frequency. drawbacks due to bedding [8], those drawbacks are illustrated below: Keywords: Microstrip antenna, conformal antenna, Printed 1. The dielectric material will undergo stretching and antenna, resonance frequency, curvature, input impedance, compression along the inner and outer surfaces, return loss, and voltage standing wave ratio. respectively. Stretching of copper traces will result in phase, impedance, and resonance frequency 1. Introduction error. 2. Shaping the material can also result in a change in Microstrip antennas have been widely studied in recent both the dielectric constant and material thickness.
    [Show full text]
  • A Dual-Port, Dual-Polarized and Wideband Slot Rectenna for Ambient RF Energy Harvesting
    A Dual-Port, Dual-Polarized and Wideband Slot Rectenna For Ambient RF Energy Harvesting Saqer S. Alja’afreh1, C. Song2, Y. Huang2, Lei Xing3, Qian Xu3. 1 Electrical Engineering Department, Mutah University, ALkarak, Jordan, [email protected] 2 Department of Electrical Engineering and Electronics, University of Liverpool, Liverpool, United Kingdom. 3 Department of Electronic Science and Technology, Nanjing University of Aeronautics & Astronautics, Nanjing, China. Abstract—A dual-polarized rectangular slot rectenna is they are able to receive RF signals from multiple frequency proposed for ambient RF energy harvesting. It is designed in a bands like designs in [4-7]. In [4], a novel Hexa-band rectenna compact size of 55 × 55 ×1.0 mm3 and operates in a wideband that covers a part of the digital TV, most cellular mobile bands operation between 1.7 to 2.7 GHz. The antenna has a two-port and WLAN bands. Broadband antennas. In [7], a broadband structure, which is fed using perpendicular CPW and microstrip line, respectively. To maintain both the adaptive dual-polarization cross dipole rectenna has been designed for impedance tuning and the adaptive power flow capability, the RF energy harvesting over frequency range on 1.8-2.5 GHz. rectenna utilizes a novel rectifier topology in which two shunt (2) antennas for wireless energy harvesting (WEH) should diodes are used between the DC block capacitor and the series have the ability of receiving wireless signals from different diode. The simulation results show that RF-DC conversion polarization. Therefore, rectennas have polarization diversity efficiency is greater 40% within the frequency band of like circular polarization [7]; dual polarization [8] and all interested at -3.0 dBm received power.
    [Show full text]
  • Design and Analysis of Microstrip Patch Antenna Arrays
    Design and Analysis of Microstrip Patch Antenna Arrays Ahmed Fatthi Alsager This thesis comprises 30 ECTS credits and is a compulsory part in the Master of Science with a Major in Electrical Engineering– Communication and Signal processing. Thesis No. 1/2011 Design and Analysis of Microstrip Patch Antenna Arrays Ahmed Fatthi Alsager, [email protected] Master thesis Subject Category: Electrical Engineering– Communication and Signal processing University College of Borås School of Engineering SE‐501 90 BORÅS Telephone +46 033 435 4640 Examiner: Samir Al‐mulla, Samir.al‐[email protected] Supervisor: Samir Al‐mulla Supervisor, address: University College of Borås SE‐501 90 BORÅS Date: 2011 January Keywords: Antenna, Microstrip Antenna, Array 2 To My Parents 3 ACKNOWLEGEMENTS I would like to express my sincere gratitude to the School of Engineering in the University of Borås for the effective contribution in carrying out this thesis. My deepest appreciation is due to my teacher and supervisor Dr. Samir Al-Mulla. I would like also to thank Mr. Tomas Södergren for the assistance and support he offered to me. I would like to mention the significant help I have got from: Holders Technology Cogra Pro AB Technical Research Institute of Sweden SP I am very grateful to them for supplying the materials, manufacturing the antennas, and testing them. My heartiest thanks and deepest appreciation is due to my parents, my wife, and my brothers and sisters for standing beside me, encouraging and supporting me all the time I have been working on this thesis. Thanks to all those who assisted me in all terms and helped me to bring out this work.
    [Show full text]
  • Antenna Arrays
    ANTENNA ARRAYS Antennas with a given radiation pattern may be arranged in a pattern line, circle, plane, etc.) to yield a different radiation pattern. Antenna array - a configuration of multiple antennas (elements) arranged to achieve a given radiation pattern. Simple antennas can be combined to achieve desired directional effects. Individual antennas are called elements and the combination is an array Types of Arrays 1. Linear array - antenna elements arranged along a straight line. 2. Circular array - antenna elements arranged around a circular ring. 3. Planar array - antenna elements arranged over some planar surface (example - rectangular array). 4. Conformal array - antenna elements arranged to conform two some non-planar surface (such as an aircraft skin). Design Principles of Arrays There are several array design var iables which can be changed to achieve the overall array pattern design. Array Design Variables 1. General array shape (linear, circular,planar) 2. Element spacing. 3. Element excitation amplitude. 4. Element excitation phase. 5. Patterns of array elements. Types of Arrays: • Broadside: maximum radiation at right angles to main axis of antenna • End-fire: maximum radiation along the main axis of ant enna • Phased: all elements connected to source • Parasitic: some elements not connected to source: They re-radiate power from other elements. Yagi-Uda Array • Often called Yagi array • Parasitic, end-fire, unidirectional • One driven element: dipole or folded dipole • One reflector behind driven element and slightly longer
    [Show full text]
  • Army Phased Array RADAR Overview MPAR Symposium II 17-19 November 2009 National Weather Center, Oklahoma University, Norman, OK
    UNCLASSIFIED Presented by: Larry Bovino Senior Engineer RADAR and Combat ID Division Army Phased Array RADAR Overview MPAR Symposium II 17-19 November 2009 National Weather Center, Oklahoma University, Norman, OK UNCLASSIFIED UNCLASSIFIED THE OVERALL CLASSIFICATION OF THIS BRIEFING IS UNCLASSIFIED UNCLASSIFIED UNCLASSIFIED RADAR at CERDEC § Ground Based § Counterfire § Air Surveillance § Ground Surveillance § Force Protection § Airborne § SAR § GMTI/AMTI UNCLASSIFIED UNCLASSIFIED RADAR Technology at CERDEC § Phased Arrays § Digital Arrays § Data Exploitation § Advanced Signal Processing (e.g. STAP, MIMO) § Advanced Signal Processors § VHF to THz UNCLASSIFIED UNCLASSIFIED Design Drivers and Constraints § Requirements § Operational Needs flow down to System Specifications § Platform or Mobility/Transportability § Size, Weight and Power (SWaP) § Reliability/Maintainability § Modularity, Minimize Single Point Failures § Cost/Affordability § Unit and Life Cycle UNCLASSIFIED UNCLASSIFIED RADAR Antenna Technology at Army Research Laboratory § Computational electromagnetics § In-situ antenna design & analysis § Application Examples: § Body worn antennas § Rotman lens § Wafer level antenna § Phased arrays with integrated MEMS devices § Collision avoidance radar § Metamaterials UNCLASSIFIED UNCLASSIFIED Antenna Modeling § CEM “Toolkit” requires expert users § EM Picasso (MoM 2.5D) – modeling of planar antennas (e.g., patch arrays) § XFDTD (FDTD) – broadband modeling of 3-D structures (e.g., spiral) § HFSS (FEM) – modeling of 3-D structures (e.g.,
    [Show full text]
  • Design of Narrow-Wall Slotted Waveguide Antenna with V-Shaped Metal Reflector for X
    2018 International Symposium on Antennas and Propagation (ISAP 2018) [ThE2-5] October 23~26, 2018 / Paradise Hotel Busan, Busan, Korea Design of Narrow-wall Slotted Waveguide Antenna with V-shaped Metal Reflector for X- Band Radar Application Derry Permana Yusuf, Fitri Yuli Zulkifli, and Eko Tjipto Rahardjo Antenna Propagation and Microwave Research Group, Electrical Engineering Department, Universitas Indonesia Depok, Indonesia Abstract - Slotted waveguide antenna with wide bandwidth match to side lobe level requirement. Later, two metal sheets characteristics is designed at the 9.4-GHz frequency (X-band) as metal reflector are attached to the SWA edges to focus its for radar application. The antenna design consists of 200 narrow-wall slots with novel design of V-shaped metal reflector azimuth plane beam. The reflection coefficient, radiation to enhance side lobe level (SLL) and gain. New optimized slot pattern plots, and gain results of the antenna are reported. design results in SLL of -31.9 dB. The simulation results show 36.7 dBi antenna gain and 780 MHz bandwidth (8.67-9.45 GHz) for VSWR of 1.5. 2. Antenna Configuration Index Terms — slotted waveguide antenna, X-band, narrow- The 3-D view of the proposed antenna configuration is wall slots, high gain, metal reflector, radar shown in Fig 1. The antenna configuration consists of narrow wall slot waveguide with V-shaped metal reflector. The target frequency is 9.4 GHz. The slot antenna dimension 1. Introduction with its parameters is shown in Fig. 2. The antenna radiates Radar is essential component used for detecting hazards horizontal polarization and determines the parameters w = (such as coastlines, islands, icebergs, other objects or ships), 1.58 mm and t = 1.25 mm.
    [Show full text]