5. Antenna Types
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Chapter 22 Fundamentalfundamental Propertiesproperties Ofof Antennasantennas
ChapterChapter 22 FundamentalFundamental PropertiesProperties ofof AntennasAntennas ECE 5318/6352 Antenna Engineering Dr. Stuart Long 1 .. IEEEIEEE StandardsStandards . Definition of Terms for Antennas . IEEE Standard 145-1983 . IEEE Transactions on Antennas and Propagation Vol. AP-31, No. 6, Part II, Nov. 1983 2 ..RadiationRadiation PatternPattern (or(or AntennaAntenna Pattern)Pattern) “The spatial distribution of a quantity which characterizes the electromagnetic field generated by an antenna.” 3 ..DistributionDistribution cancan bebe aa . Mathematical function . Graphical representation . Collection of experimental data points 4 ..QuantityQuantity plottedplotted cancan bebe aa . Power flux density W [W/m²] . Radiation intensity U [W/sr] . Field strength E [V/m] . Directivity D 5 . GraphGraph cancan bebe . Polar or rectangular 6 . GraphGraph cancan bebe . Amplitude field |E| or power |E|² patterns (in linear scale) (in dB) 7 ..GraphGraph cancan bebe . 2-dimensional or 3-D most usually several 2-D “cuts” in principle planes 8 .. RadiationRadiation patternpattern cancan bebe . Isotropic Equal radiation in all directions (not physically realizable, but valuable for comparison purposes) . Directional Radiates (or receives) more effectively in some directions than in others . Omni-directional nondirectional in azimuth, directional in elevation 9 ..PrinciplePrinciple patternspatterns . E-plane . H-plane Plane defined by H-field and Plane defined by E-field and direction of maximum direction of maximum radiation radiation (usually coincide with principle planes of the coordinate system) 10 Coordinate System Fig. 2.1 Coordinate system for antenna analysis. 11 ..RadiationRadiation patternpattern lobeslobes . Major lobe (main beam) in direction of maximum radiation (may be more than one) . Minor lobe - any lobe but a major one . Side lobe - lobe adjacent to major one . -
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. -
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. -
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. -
25. Antennas II
25. Antennas II Radiation patterns Beyond the Hertzian dipole - superposition Directivity and antenna gain More complicated antennas Impedance matching Reminder: Hertzian dipole The Hertzian dipole is a linear d << antenna which is much shorter than the free-space wavelength: V(t) Far field: jk0 r j t 00Id e ˆ Er,, t j sin 4 r Radiation resistance: 2 d 2 RZ rad 3 0 2 where Z 000 377 is the impedance of free space. R Radiation efficiency: rad (typically is small because d << ) RRrad Ohmic Radiation patterns Antennas do not radiate power equally in all directions. For a linear dipole, no power is radiated along the antenna’s axis ( = 0). 222 2 I 00Idsin 0 ˆ 330 30 Sr, 22 32 cr 0 300 60 We’ve seen this picture before… 270 90 Such polar plots of far-field power vs. angle 240 120 210 150 are known as ‘radiation patterns’. 180 Note that this picture is only a 2D slice of a 3D pattern. E-plane pattern: the 2D slice displaying the plane which contains the electric field vectors. H-plane pattern: the 2D slice displaying the plane which contains the magnetic field vectors. Radiation patterns – Hertzian dipole z y E-plane radiation pattern y x 3D cutaway view H-plane radiation pattern Beyond the Hertzian dipole: longer antennas All of the results we’ve derived so far apply only in the situation where the antenna is short, i.e., d << . That assumption allowed us to say that the current in the antenna was independent of position along the antenna, depending only on time: I(t) = I0 cos(t) no z dependence! For longer antennas, this is no longer true. -
W5GI MYSTERY ANTENNA (Pdf)
W5GI Mystery Antenna A multi-band wire antenna that performs exceptionally well even though it confounds antenna modeling software Article by W5GI ( SK ) The design of the Mystery antenna was inspired by an article written by James E. Taylor, W2OZH, in which he described a low profile collinear coaxial array. This antenna covers 80 to 6 meters with low feed point impedance and will work with most radios, with or without an antenna tuner. It is approximately 100 feet long, can handle the legal limit, and is easy and inexpensive to build. It’s similar to a G5RV but a much better performer especially on 20 meters. The W5GI Mystery antenna, erected at various heights and configurations, is currently being used by thousands of amateurs throughout the world. Feedback from users indicates that the antenna has met or exceeded all performance criteria. The “mystery”! part of the antenna comes from the fact that it is difficult, if not impossible, to model and explain why the antenna works as well as it does. The antenna is especially well suited to hams who are unable to erect towers and rotating arrays. All that’s needed is two vertical supports (trees work well) about 130 feet apart to permit installation of wire antennas at about 25 feet above ground. The W5GI Multi-band Mystery Antenna is a fundamentally a collinear antenna comprising three half waves in-phase on 20 meters with a half-wave 20 meter line transformer. It may sound and look like a G5RV but it is a substantially different antenna on 20 meters. -
California State University, Northridge
CALIFORNIA STATE UNIVERSITY, NORTHRIDGE Design of a 5.8 GHz Two-Stage Low Noise Amplifier A graduate project submitted in partial fulfillment of the requirements For the degree of Master of Science in Electrical Engineering By Yashika Parwath August 2020 The graduate project of Yashika Parwath is approved: Dr. John Valdovinos Date Dr. Jack Ou Date Dr. Brad Jackson, Chair Date California State University, Northridge ii Acknowledgement I would like to express my sincere gratitude to Dr. Brad Jackson for his unwavering support and mentorship that aided me to finish my master’s project. With his deep understanding of the subject and valuable inputs this design project has been quite a learning wheel expanding my knowledge horizons. I would also like to thank Dr. John Valdovinos and Dr. Jack Ou for being the esteemed members of the committee. iii Table of Contents Signature page ii Acknowledgement iii List of Figures v List of Tables vii Abstract viii Chapter 1: Introduction 1 1.1 Communication System 1 1.2 Low Noise Amplifier 2 1.3 Design Goals 2 Chapter 2: LNA Theory and Background 4 2.1 Introduction 4 2.2 Terminology 4 2.3 Design Procedure 10 Chapter 3: LNA Design Procedure 12 3.1 Transistor 12 3.2 S-Parameters 12 3.3 Stability 13 3.4 Noise and Noise Figure 16 3.5 Cascaded Noise Figure 16 3.6 Noise Circles 17 3.7 Unilateral Figure of Merit 18 3.8 Gain 20 Chapter 4: Source and Load Reflection Coefficient 23 4.1 Reflection Coefficient 23 4.2 Source Reflection Coefficient 24 4.3 Load Reflection Coefficient 26 Chapter 5: Impedance Matching -
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 ......................................................................................................................... -
3794 Series Granger Wideband Conical Monopole Antennas
3794 Series Granger Wideband Conical Monopole Antennas ● 2-30 MHz Bandwidth permits Frequency change without antenna tuning ● Up to 25 KW average power rating ● 50 Ohm input provides 2.0:1 nominal VSWR without impedance transformers ● Single tower ● Short, medium, long-range communications General Description The Model 3794 series antenna is a vertically polarized, omnidirectional broadband antenna for transmitting or receiving applications. It is designed for high power area coverage. The 3794 Wideband Conical Monopole Antenna is an inverted cone- like structure with it’s apex pointing downwards. The array is supported by a 17 inch (431 mm) face steel guyed tower and consists of a number of evenly spaced radiator wires. The radiators spread out from the tower top to an outer guyed catenary then converge back down at the tower base. The antenna is fed at the apex of the cone through a 50 ohm coaxial connector. A ground screen is laid over the area below the antenna and consists of a radial pattern of wire laid on the ground with it’s centre at the apex of the antenna. The radiating elements of the array are prefabricated to facilitate installation. All radiators are manufactured from aluminum clad steel wire for maximum conductivity and corrosion resistance. The mechanical arrangement provides high strength while keeping both manufacturing and installation costs to a minimum. Application The 3794 Wideband Conical Monopole Antenna Series provides a cost effective solution for the vertical omnidirectional antenna if the reduced ground area offered by the 1794 Monocone is not required. The broad frequency range permits use of the optimum frequency for any distance. -
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. -
Coordinate Transformations-Based Antenna Elements Embedded in a Metamaterial Shell with Scanning Capabilities
electronics Article Coordinate Transformations-Based Antenna Elements Embedded in a Metamaterial Shell with Scanning Capabilities Dipankar Mitra 1,*, Sukrith Dev 2, Monica S. Allen 2, Jeffery W. Allen 2 and Benjamin D. Braaten 1,* 1 Department of Electrical and Computer Engineering, North Dakota State University, Fargo, ND 58105, USA 2 Air Force Research Laboratory, Munitions Directorate, Eglin Air Force Base, FL 32542, USA; [email protected] (S.D.); [email protected] (M.S.A.); [email protected] (J.W.A.) * Correspondence: [email protected] (D.M.); [email protected] (B.D.B.) Abstract: In this work transformation electromagnetics/optics (TE/TO) were employed to realize a non-homogeneous, anisotropic material-embedded beam-steerer using both a single antenna element and an antenna array without phase control circuitry. Initially, through theory and validation with numerical simulations it is shown that beam-steering can be achieved in an arbitrary direction by enclosing a single antenna element within the transformation media. Then, this was followed by an array with fixed voltages and equal phases enclosed by transformation media. This enclosed array was scanned, and the proposed theory was validated through numerical simulations. Further- more, through full-wave simulations it was shown that a horizontal dipole antenna embedded in a metamaterial can be designed such that the horizontal dipole performs identically to a vertical Citation: Mitra, D.; Dev, S.; Allen, dipole in free-space. Similarly, it was also shown that a material-embedded horizontal dipole array M.S.; Allen, J.W.; Braaten, B.D. -
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.