DOCSLIB.ORG

Realization of a Planar Low-Profile Broadband Phased Array Antenna

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Realization of a Planar Low-Profile Broadband Phased Array Antenna REALIZATION OF A PLANAR LOW-PROFILE BROADBAND PHASED ARRAY ANTENNA DISSERTATION Presented in Partial Ful¯llment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University By Justin A. Kasemodel, M.S., B.S. Graduate Program in Electrical and Computer Engineering The Ohio State University 2010 Dissertation Committee: John L.Volakis, Co-Adviser Chi-Chih Chen, Co-Adviser Joel T. Johnson ABSTRACT With space at a premium, there is strong interest to develop a single ultra wide- band (UWB) conformal phased array aperture capable of supporting communications, electronic warfare and radar functions. However, typical wideband designs transform into narrowband or multiband apertures when placed over a ground plane. There- fore, it is not surprising that considerable attention has been devoted to electromag- netic bandgap (EBG) surfaces to mitigate the ground plane's destructive interference. However, EBGs and other periodic ground planes are narrowband and not suited for wideband applications. As a result, developing low-cost planar phased array aper- tures, which are concurrently broadband and low-pro¯le over a ground plane, remains a challenge. The array design presented herein is based on the in¯nite current sheet array (CSA) concept and uses tightly coupled dipole elements for wideband conformal op- eration. An important aspect of tightly coupled dipole arrays (TCDAs) is the capac- itive coupling that enables the following: (1) allows ¯eld propagation to neighboring elements, (2) reduces dipole resonant frequency, (3) cancels ground plane inductance, yielding a low-pro¯le, ultra wideband phased array aperture without using lossy ma- terials or EBGs on the ground plane. The latter, is of course, critical for retaining the aperture's wideband behavior under conformal installations. ii This dissertation focuses on the realization of wideband phased array apertures using tightly coupled dipole arrays. A methodology for designing planar apertures is presented including: element selection, material loading, and unbalanced to balanced conversion for wideband feeding. Multiple solutions and practical design examples are presented to increase bandwidth, reduce height, avoid common mode excitation and retain low-cost planar PCB manufacturability. Using one of these designs, a 64 ele- ment low-pro¯le X-band array prototype is fabricated and measured. The conformal array is capable of scanning up to 70± and 60± in the E- and H-planes, respectively. The active VSWR is less than 2 from 8 to 12.5 GHz (1.6:1) and the array height is only ¸=7 at the lowest frequency of operation. A unique feature of the proposed array is its planar layered PCB construction. Speci¯cally, a single microwave laminate is used for the aperture while another supports all associated baluns and matching net- works. Good agreement between simulations and measurements con¯rm the proposed concepts. iii Dedicated to my family. iv ACKNOWLEDGMENTS I would like to express my sincere appreciation to my advisor, Professor John L. Volakis, for his guidance and advice. Not only has he taught me the academic side of electromagnetics and engineering, but also the importance of communication about what it takes be a successful professional and leader. His guidance and support led me to present at conferences, publish papers and write proposals. I would also like to sincerely thank my Co-Advisor Dr. Chi-Chih Chen for interesting discussions and insight on antenna design, research methodology and measurement techniques. He has been a great friend, mentor and truly is an antenna and electromagnetics expert. Dr. Chen showed me di®erent ways to approach a research problem and the steps necessary to accomplish any goal. His honesty, intelligence and open door policy has made the ElectroScience Lab a wonderful workplace and home for the last four years. I want to thank the other students in the Volakis antenna group for their challenging questions, interesting discussions and sharing their research during our weekly meetings. In addition, I want to speci¯cally thank my colleges and close friends; Kenneth E. Browne, Mustafa Kuloglu, Brandan T. Strojny and Orbay Tuncay for their collaboration, proof reading, support and suggestions. v VITA September 2, 1984 . Born - Gillette, Wyoming May, 2006 . B.S. Electrical and Computer Eng., South Dakota School of Mines and Technology, Rapid City, SD August, 2009 . M.S. Electrical and Computer Eng., The Ohio State University, Columbus, OH September, 2006 - present . Graduate Research Fellow, The Ohio State University, Columbus, OH PUBLICATIONS Journal Publications 1. Kasemodel, J.A.; Chen, C.-C.; Volakis, J.L., \Wideband Planar Array with Integrated Feed and Matching Network for Wide-Angle Scanning," Under review: Trans. Antennas and Propagation, IEEE. 2. Kasemodel, J.A.; O'Brien, A.; Gupta, I.J.; Chen, C.-C.; Volakis, J.L., \Small, Conformal Adaptive Antenna of Spiral Elements for GNSS Receivers," Under review: Trans. Antennas and Propagation, IEEE. 3. Kasemodel, J.A.; Volakis, J.L., \A Planar Dual Linear Polarized Antenna with Integrated Balun," To appear in Antennas and Wireless Propagation Letters, IEEE. 4. Kasemodel, J.A.; Chen, C.-C.; Gupta, I.J.; Volakis, J.L., \Miniature Continuous Coverage Antenna Array for GNSS Receivers," Antennas and Wireless Propagation Letters, IEEE, vol.7, no., pp.592-595, 2008. vi Conference Publications 1. Kasemodel, J.A.; Chen, C.-C.; Volakis, J.L., \Low-pro¯le Wideband Phased Array Antenna with Integrated Balun," Submitted to: Phased Array Symposium, IEEE, Baltimore, MD, Nov., 2010. 2. Kasemodel, J.A.; Chen, C.-C.; Volakis, J.L., \Low-Cost, Planar and Wideband Phased Array with Integrated Balun and Matching Network for Wide-Angle Scan- ning," in Proc. Antenna and Propagation International Symposium, IEEE, Toronto, Ontario, Canada, July 2010. 3. Volakis, J.L.; Kasemodel, J.A.; Chen, C.-C.; Sertel, K.; Tzanidis, I., \Wideband Conformal Metamaterial Apertures," in Proc. Antenna Technology (iWAT), 2010 International Workshop on , vol., no., pp.1-4, 1-3 March 2010. 4. Kasemodel, J.A.; Chen, C.-C.; Volakis, J.L., \Wideband Conformal Array with Integrated Feed and Matching Network for Wide-angle Scanning," in Proc. URSI National Radio Science Meeting, Boulder, CO, January, 2010. 5. Kasemodel, J.A.; Chen, C.-C.; Volakis, J.L., \A Novel Non-symmetric Tightly Coupled Element for Wideband Phased Array Apertures," in Proc. Antennas Appli- cations Symposium, Allerton, IL, Sept. 2009. 6. Kasemodel, J.A.; Chen, C.-C.; Volakis, J.L., \A Miniaturization Technique for Wideband Tightly Coupled Phased Arrays," in Proc. Antennas and Propagation Society International Symposium, Charleston, SC, June 2009. 7. Kasemodel, J.A.; Chen, C.-C., \A Measurement Setup for Characterizing An- tenna on an In¯nite Ground Plane from 1 to 18 GHz," in Proc. Antenna Measurement Technique Association Symposium, Boston, MA, November 2008. 8. Kasemodel, J.A.; Chen, C.-C.; Gupta, I.J.; Volakis, J.L., \Miniature Continu- ous Coverage Wideband GPS Antenna Array," in Proc. Antennas and Propagation Society International Symposium, San Diego, CA, July 2008. 9. Kasemodel, J.A.; Chen, C.-C.; Gupta, I.J.; Volakis, J.L., \Compact Wideband Antenna Array for GNSS Receivers," in Proc. Antenna Measurement Technique As- sociation Symposium, St. Louis, MO, November 2007. FIELDS OF STUDY vii Major Field: Electrical Engineering Studies in: Applied Electromagnetics Antenna Design and Measurement Techniques viii TABLE OF CONTENTS Page Abstract . ii Dedication . iv Acknowledgments . v Vita . vi List of Tables . xi List of Figures . xii Chapters: 1. Introduction . 1 1.1 Motivation, Challenges and Objective . 1 2. Broadband Phased Array Aperture using Tightly Coupled Dipoles . 5 2.1 Introduction . 5 2.2 Planar Phased Array Antenna Comparison . 6 2.2.1 Input Impedance . 7 2.2.2 Scan Element Pattern . 13 2.3 Equivalent Circuit . 17 2.4 Linear and Dual Linear Polarization Properties . 23 2.5 Feeding Network Consideration . 27 2.5.1 External 180± Hybrid . 29 2.5.2 Low Cost Partially Balanced Coaxial Cable Feed . 31 2.5.3 Impedance Matching . 33 2.6 Summary . 35 ix 3. Broadband Phased Array Antenna Miniaturization . 37 3.1 Introduction . 37 3.2 Antenna Miniaturization Concept . 38 3.3 Inductive Loading via Volumetric Meandering . 39 3.4 Ferrite Substrate Loading . 41 3.5 Capacitive Loading using a Non-Symmetric Element . 45 3.6 Dielectric Superstrate Loading . 53 3.7 Summary . 60 4. Realization of Non-Symmetric Tightly Coupled Dipole Arrays . 61 4.1 Introduction . 61 4.2 Wideband Balun . 62 4.3 Integration of Aperture and Feed . 63 4.4 Single Feed Demonstration . 65 4.5 64 Element Array Demonstration . 71 4.5.1 Scan Element Pattern . 71 4.5.2 Mutual Coupling and Scan Impedance . 75 4.5.3 Fully Excited Radiation Performance . 83 4.6 Summary . 91 5. Conclusion and Future Work . 93 Bibliography . 97 x LIST OF TABLES Table Page 3.1 Miniaturized element performance comparison summary . 41 3.2 Ferrite resonant frequency comparison . 44 3.3 Dielectric constant for superstrate matching using Rogers TMM series array PCB . 56 xi LIST OF FIGURES Figure Page 2.1 (a) In¯nite current sheet over a ground plane, (b) tightly coupled dipole array implementation. 6 2.2 Planar phased array antenna elements under investigation inside unit cell; (a) wire or connected dipoles, (b) bowtie, (c) dipole, (d) slot. 8 2.3 Active resistance (solid) and reactance (dash) for various antenna ele- ± ments in free space scanned to θo = 0 . ................ 9 2.4 Active reflection coe±cient for di®erent system impedances (Zo) of ± each antenna element in free space scanned to θo = 0 ; (a) wire or connected dipoles, (b) bowtie, (c) dipole, (d) slot. 11 2.5 Active reflection coe±cient for various antenna elements in free space ± scanned to θo = 0 . ........................... 12 2.6 Active resistance (solid) and reactance (dash) for various antenna ele- ± ments when placed 8 mm over ground plane scanned to θo = 0 . 12 2.7 Active reflection coe±cient for various antenna elements when placed ± 8 mm over ground plane scanned to θo = 0 .
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]
  • Improving Wireless LAN Antenna Gain and Coverage
    APPLICATION NOTE Improving Wireless LAN Antenna Gain and Coverage antenna, which can help mitigate interference between floors. The only drawback is that the longer antenna may be somewhat less aesthetic. Mounting a dipole antenna on a conductive ground plane has a similar effect as using a longer antenna. The elevation pattern is flattened, creating higher gain around the perimeter of the doughnut. Additionally, the ground plane mounted antennas pattern is maximized downward slightly (if the antenna is mounted beneath a ceiling ground plane). This is an ideal elevation pattern for a ceiling mounted antenna in a multi-story building. The ground plane has the effect of minimizing gain below and especially above Most of the antennas provided with Wi-Fi the antenna. access points, or purchased separately, are simple dipole antennas with an omni- Wi-Fi antennas may be classified as ground directional pattern. Omni-directional means plane dependent and ground plane that the gain is the same in a 360º circle independent. The ground plane dependent around the axis of the antenna. antenna must be mounted on a conductive, flat ground plane which is several However, the elevation gain pattern is wavelengths long and wide in order to different. In cross section, the elevation provide the rated gain and impedance pattern is that of a doughnut, with the match. The ground plane independent antenna axis running through the center of antenna does not need to be mounted on a the doughnut. In the absence of a ground ground plane to provide the rated gain and plane, the gain of the dipole is a maximum impedance match.
    [Show full text]
  • Open Bradley Sherman Spring 2014.Pdf
    THE PENNSYLVANIA STATE UNIVERSITY SCHREYER HONORS COLLEGE DEPARTMENT OF ELECTRICAL ENGINEERING HIGH FREQUENCY ANTENNA COUPLING STUDY BRADLEY SHERMAN SPRING 2014 A thesis submitted in partial fulfillment of the requirements for a baccalaureate degree in Electrical Engineering with honors in Electrical Engineering Reviewed and approved* by the following: James K. Breakall Professor of Electrical Engineering Thesis Supervisor John D. Mitchell Professor of Electrical Engineering Honors Adviser Keith A. Lysiak Senior Research Associate Thesis Reader * Signatures are on file in the Schreyer Honors College. i ABSTRACT The objective of this project was to develop a methodology to accurately predict antenna coupling through the use of numerical electromagnetic modeling. A high-frequency (HF) ionospheric sounder is being developed for HF propagation studies. This sounder requires high power transmissions on one antenna while receiving on another antenna. In order to minimize the coupling of high power energy back into the receiver, the transmit and receive antenna coupling must be minimized. The results of this research effort have shown that the current antenna setup can be improved by choosing a co-polarization setup and changing the frequency to 6.78 MHz. Rotating the receive antenna so that it runs parallel to the receive antenna decreases the antenna coupling by 8 dB. Typically the cross-polarization created by putting two antennas perpendicular to each other would decrease the antenna coupling dramatically, but that does not work if the feeds are along the perpendicular access. Attaining the ideal perpendicular setup is not possible in this case due to space restrictions. ii TABLE OF CONTENTS List of Figures .........................................................................................................................
    [Show full text]
  • Nested Loop Antennas This Low-Cost Five Band Loop Array Blends Into the Background
    Nested Loop Antennas This low-cost five band loop array blends into the background. G. Scott Davis, N3FJP This multi-band nested loop antenna array replaces my tribander Yagi, which is only up 20 feet. Inspired by suggestions from Bill Wisel, K3KEI, I first tried a full wave 20 meter band square loop antenna. On the air comparisons with my low Yagi confirmed instantly that this design was a hands-down winner for working both local and distant stations. I replaced that mono-band loop with a nested loop array for the 20, 17, 15, 12, and 10 meter bands. The antenna blends into the surroundings, so I needed the morning sun shining directly on it to snap the lead photo. This became a nice father-son project with my son Brad, KB3MNE. Here’s how we built the antenna. Construction We constructed the square loops shown in Figure 1 according to the dimensions in Table 1. The loops hang from a tree limb in the vertical plane. Because I feed them This stealthy nested loop is almost invisible among the trees. from the bottom corners, the loops radiate horizontal polarization. Calculate the perimeter size, P, of each holes through the pipe for the loop wire. screws into the PVC to hang the dipole loop by dividing the frequency in MHz After you run the wire through the holes, connectors seen in Figure 2. wrap a bit of electrical tape on each side of into 1005 feet. Table 1 shows the loop Matching and Feeding dimensions. Start with the 20 meter loop, the wire next to the pipe to keep the wire from sliding and to give the pipe additional Each loop antenna feed point impedance is the largest loop.
    [Show full text]
  • Application Note AN-00502
    Proper PCB Design for Embedded Antennas Application Note AN-00502 Introduction Embedded antennas are ideal for products that cannot use an external antenna. The reasons for this can range from ergonomic or aesthetic reasons or perhaps the product needs to be sealed because it is to be used in a rough environment. It could also simply be based on cost. Whatever the reason, embedded antennas are a popular solution. Embedded antennas are generally quarter wave monopole antennas. These are only half of the antenna structure with the other half being a ground plane on the product’s circuit board. The details of antenna operation are beyond the scope of this application note, but suffice it to say that the layout of the PCB becomes critical to the RF performance of the product. Common PCB Layout Guidelines While each antenna style has specific requirements, there are some requirements that are common to all of them. • Use a manufactured board for testing the antenna performance. RF is very picky and perf boards or other “hacked” boards will at best give Figure 1: Linx Embedded Antennas a poor indication of the antenna’s true performance and at worst will simply not work. Each antenna has a recommended layout that should be followed as closely as possible to get the performance indicated in the antenna’s data sheet. Most Linx antennas have an evaluation kit that includes a test board, so please contact us for details. • The antenna should, as much as reasonably possible, be isolated from other components on your PCB, especially high-frequency circuitry such as crystal oscillators, switching power supplies, and high-speed bus lines.
    [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]
  • Design Considerations for Mixed-Signal PCB Layout
    Design Considerations for Mixed-Signal PCB Layout Application Note 1. Introduction This application note aims at providing you with some recommendations to achieve better performance from the ADC. The initial assumptions are the following: • Proper grounding and routing of all signals is essential to ensure accurate signal conversion • Eliminate the loop area return by using both separate ground plane and power plane • Circuitry placement on mixed-signal PCBs is a crucial design point In many cases, engineers have preconceived notions about mixed-signal designs and how analog and digital placement, partitioning and associated design should be performed. When laying out components for a mixed-signal PCB, certain considerations are critical to achieve opti- mum performance. Mixed-signal PCB’s are particularly tricky to design since analog devices possess different characteristics compared to digital components: different power rating, current, voltage and heat dissipation requirements, to name a few. This study shows how to prevent digital logic ground currents from contaminating analog circuitry on a mixed-signal PCB and particularly ADC component. In our attempt to answer this question, let’s keep in mind two basic principles of electromagnetic compat- ibility. One is that currents should be returned to their source as locally and compactly as possible, through the smallest possible loop area. The second is that a system should have only one reference plane, if not we would create a dipole antenna. Visit our website: www.e2v.com for the latest version of the datasheet e2v semiconductors SAS 2010 0999B–BDC–08/10 Design Considerations for Mixed-Signal PCB Layout 2.
    [Show full text]
  • Class C Pool of Questions
    Class C Pool of Questions T2 1. What is the most common repeater frequency offset in the 2 meter band? T2 2. What is the national calling frequency for FM simplex operations in the 70 cm band? T2 3. What is a common repeater frequency offset in the 70 cm band? T2 4. What is an appropriate way to call another station on a repeater if you know the other station's call sign? T2 5. How should you respond to a station calling CQ? T2 6. What must an amateur operator do when making on-air transmissions to test equipment or antennas? T2 7. Which of the following is true when making a test transmission? T2 8. What is the meaning of the procedural signal “CQ”? T2 9. What brief statement is often transmitted in place of “CQ” to indicate that you are listening on a repeater? T2 10. What is a band plan, beyond the privileges established by the SMA? T2 11. Which of the following is an SMA rule regarding power levels used in the amateur bands, under normal, non-distress circumstances? T2 12. Which of the following is a guideline to use when choosing an operating frequency for calling CQ? T2B – VHF/UHF operating practices: SSB phone; FM repeater; simplex; splits and shifts; CTCSS; DTMF; tone squelch; carrier squelch; phonetics; operational problem resolution; Q signals T2 1. What is the term used to describe an amateur station that is transmitting and receiving on the same frequency? T2 2. What is the term used to describe the use of a sub-audible tone transmitted with normal voice audio to open the squelch of a receiver? T2 3.
    [Show full text]
  • Low-Profile Wideband Antennas Based on Tightly Coupled Dipole
    Low-Profile Wideband Antennas Based on Tightly Coupled Dipole and Patch Elements Dissertation Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University By Erdinc Irci, B.S., M.S. Graduate Program in Electrical and Computer Engineering The Ohio State University 2011 Dissertation Committee: John L. Volakis, Advisor Kubilay Sertel, Co-advisor Robert J. Burkholder Fernando L. Teixeira c Copyright by Erdinc Irci 2011 Abstract There is strong interest to combine many antenna functionalities within a single, wideband aperture. However, size restrictions and conformal installation requirements are major obstacles to this goal (in terms of gain and bandwidth). Of particular importance is bandwidth; which, as is well known, decreases when the antenna is placed closer to the ground plane. Hence, recent efforts on EBG and AMC ground planes were aimed at mitigating this deterioration for low-profile antennas. In this dissertation, we propose a new class of tightly coupled arrays (TCAs) which exhibit substantially broader bandwidth than a single patch antenna of the same size. The enhancement is due to the cancellation of the ground plane inductance by the capacitance of the TCA aperture. This concept of reactive impedance cancellation was motivated by the ultrawideband (UWB) current sheet array (CSA) introduced by Munk in 2003. We demonstrate that as broad as 7:1 UWB operation can be achieved for an aperture as thin as λ/17 at the lowest frequency. This is a 40% larger wideband performance and 35% thinner profile as compared to the CSA. Much of the dissertation’s focus is on adapting the conformal TCA concept to small and very low-profile finite arrays.
    [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]
  • Patch Antenna Array for RF Energy Harvesting Systems in 2.4 Ghz WLAN Frequency Band
    Published by : International Journal of Engineering Research & Technology (IJERT) http://www.ijert.org ISSN: 2278-0181 Vol. 9 Issue 05, May-2020 Patch Antenna Array for RF Energy Harvesting Systems in 2.4 GHz WLAN Frequency Band Akash Kumar Gupta V. Praveen, V. Swetha Sri, Department of ECE CH. Nagavinay Kumar, B. Kishore Raghu Institute of Technology UG-Student, Department of ECE Raghu Visakhapatnam, India Institute of Technology Visakhapatnam, India Abstract—In present days, technology have been emerging harvesting topologies that operates low power devices. It has with significant importance mainly in wireless local area network. three stages receiving antenna, energy conversion into DC In this Energy harvesting is playing a key role. The RF Energy output, utilization of output of output in low power applications. harvesting is the collection of small amounts of ambient energy to power wireless devices, Especially, radio frequency (RF) energy II. RADIO FREQUENCY ENERGY HARVESTING has interesting key attributes that make it very attractive for low- power consumer electronics and wireless sensor networks (WSNs). FOR MICROSTRIP ANTENNA Commercial RF transmitting stations like Wi-Fi, or radar signals Microstrip patch antenna is a metallic patch which is may provide ambient RF energy. Throughout this paper, a specific fabricated on a dielectric substrate. The microstrip patch emphasis is on RFEH, as a green technology that is suitable for antenna is layered structure of ground plane as bottom layer solving power supply to WLAN node-related problems throughout and dielectric substrate as medium layer and radiating patch difficult environments or locations that cannot be reached. For RF harvesting RF signals are extracted using antennas.in this work to as top layer.
    [Show full text]