Shortwave Antennas
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ANTENNAS for LOW POWER APPLICATIONS Basic Full
ANTENNAS FOR LOW POWER APPLICATIONS By Kent Smith Introduction: There seems to be little information on compact antenna design for the low power wireless field. Good antenna design is required to realize good range performance. A good antenna requires it to be the right type for the application. It also must be matched and tuned to the transmitter and receiver. To get the best results, a designer should have an idea about how the antenna works, and what the important design considerations are. This paper should help to achieve effective antenna design. Some Terms: Wavelength; Important for determination of antenna length, this is the distance that the radio wave travels during one complete cycle of the wave. This length is inversely proportional to the frequency and may be calculated by: wavelength (cm)=30000 / frequency (Mhz). Groundplane; A solid conductive area that is an important part of RF design techniques. These are usually used in transmitter and receiver circuits. An example is where most of the traces will be routed on the topside of the board, and the bottom will be a mostly solid copper area. The groundplane helps to reduce stray reactances and radiation. Of course, the antenna line needs to run away from the groundplane. dB, or decibel; A logarithmic scale used to show power gain or loss in an rf circuit. +3 dB is twice the power, while -3 dB is one half. It takes 6 dB to double or halve the radiating distance, due to the inverse square law. The Basic Antenna, and how it works. An antenna can be defined as any wire, or conductor, that carries a pulsing or alternating current. -
High Frequency Communications – an Introductory Overview
High Frequency Communications – An Introductory Overview - Who, What, and Why? 13 August, 2012 Abstract: Over the past 60+ years the use and interest in the High Frequency (HF -> covers 1.8 – 30 MHz) band as a means to provide reliable global communications has come and gone based on the wide availability of the Internet, SATCOM communications, as well as various physical factors that impact HF propagation. As such, many people have forgotten that the HF band can be used to support point to point or even networked connectivity over 10’s to 1000’s of miles using a minimal set of infrastructure. This presentation provides a brief overview of HF, HF Communications, introduces its primary capabilities and potential applications, discusses tools which can be used to predict HF system performance, discusses key challenges when implementing HF systems, introduces Automatic Link Establishment (ALE) as a means of automating many HF systems, and lastly, where HF standards and capabilities are headed. Course Level: Entry Level with some medium complexity topics Agenda • HF Communications – Quick Summary • How does HF Propagation work? • HF - Who uses it? • HF Comms Standards – ALE and Others • HF Equipment - Who Makes it? • HF Comms System Design Considerations – General HF Radio System Block Diagram – HF Noise and Link Budgets – HF Propagation Prediction Tools – HF Antennas • Communications and Other Problems with HF Solutions • Summary and Conclusion • I‟d like to learn more = “Critical Point” 15-Aug-12 I Love HF, just about On the other hand… anybody can operate it! ? ? ? ? 15-Aug-12 HF Communications – Quick pretest • How does HF Communications work? a. -
An Electrically Small Multi-Port Loop Antenna for Direction of Arrival Estimation
c 2014 Robert A. Scott AN ELECTRICALLY SMALL MULTI-PORT LOOP ANTENNA FOR DIRECTION OF ARRIVAL ESTIMATION BY ROBERT A. SCOTT THESIS Submitted in partial fulfillment of the requirements for the degree of Master of Science in Electrical and Computer Engineering in the Graduate College of the University of Illinois at Urbana-Champaign, 2014 Urbana, Illinois Adviser: Professor Jennifer T. Bernhard ABSTRACT Direction of arrival (DoA) estimation or direction finding (DF) requires mul- tiple sensors to determine the direction from which an incoming signal orig- inates. These antennas are often loops or dipoles oriented in a manner such as to obtain as much information about the incoming signal as possible. For direction finding at frequencies with larger wavelengths, the size of the array can become quite large. In order to reduce the size of the array, electri- cally small elements may be used. Furthermore, a reduction in the number of necessary elements can help to accomplish the goal of miniaturization. The proposed antenna uses both of these methods, a reduction in size and a reduction in the necessary number of elements. A multi-port loop antenna is capable of operating in two distinct, orthogo- nal modes { a loop mode and a dipole mode. The mode in which the antenna operates depends on the phase of the signal at each port. Because each el- ement effectively serves as two distinct sensors, the number of elements in an DoA array is reduced by a factor of two. This thesis demonstrates that an array of these antennas accomplishes azimuthal DoA estimation with 18 degree maximum error and an average error of 4.3 degrees. -
Investigating Energy Harvesting Technology to Wirelessly Charge Batteries of Mobile Devices
Investigating energy harvesting technology to wirelessly charge batteries of mobile devices By Neetu Ramsaroop (19751797) Submitted in fulfilment of the requirements of the Master of Information and Communications Technology degree In the Department of Information Technology in the Faculty of Accounting and Informatics Durban University of Technology Durban, South Africa July, 2017 DECLARATION I, Neetu Ramsaroop, declare that this dissertation represents my own work and has not been previously submitted in any form for another degree at any university or institution of higher learning. All information cited from published and unpublished works have been acknowledged. ________________________ ____________________________ Student Date Approved for final submission Supervisor: ___________________________ ____________________________ Prof. O. O. Olugbara Date Co-supervisors: ___________________________ ____________________________ Esther D. Joubert Date i DEDICATION To My family and my supportive friends ii ACKNOWLEDGMENTS I am grateful to God for embracing me with the strength and inspiration all through this research journey. My sincere gratitude is accorded to my Supervisor, Professor O.O. Olugbara, for his dedication, academic knowledge, expertise, guidance, patience, direction, feedback, comments and meticulous checking of this study. Not to mention his “reminder” phone calls to keep me in check. I would also like to express my deepest appreciation to my Co-Supervisor, Mrs Esther Joubert, for her dedication, constant encouragement, guidance, motivation, outstanding academic writing, patience with my messages at odd hours, dealing with my panic moments and the pleasant manner in which she provided direction in this study. I am thankful to all my friends, DUT colleagues and work colleagues for their support, motivation and advice during this work. -
The 3-D Folded Loop Antenna
The 33---DD Folded Loop Antenna Dave Cuthbert WX7G Introduction This article will introduce you to an antenna I call the 3-Dimensional Folded Loop. This antenna is the result of my continuing efforts to compact full-size antennas by folding and bending the elements. I will first describe the basic 3-DFL and then provide construction details for the 2-meter and 10-meter 3-DFL antennas. Here are some features of the 3-DFL: • Reduced height and footprint • Full-sized antenna performance • Wide bandwidth • Ground independent • Can be built using standard hardware store parts Description The 3-D Folded Loop, or simply the 3-DFL, is a one-wavelength loop that is reduced in height and width by being folded into three dimensions. A 28-MHz loop that is normally 9 feet on a side becomes a box-shaped antenna that is 3 by 3 by 5 feet. It exhibits performance that is competitive with a ground plane yet requires only 15 square feet of ground area versus 50 for the ground plane. So, compared to a ground plane it is only 60% as tall and has a footprint only 30% as large. And the 2-meter 3-DFL is so compact it can be placed on a table and connected to your HT for added range and reduced RF at the operating position. 1 3-DFL Theory of Operation The familiar one-wavelength square loop is shown in Fig. 1 and is fed in the center of one vertical wire. Note that the current in the vertical wires is high while the current in the horizontal wires and is low. -
A Flexible 2.45 Ghz Rectenna Using Electrically Small Loop Antenna
A Flexible 2.45 GHz Rectenna Using Electrically Small Loop Antenna Khaled Aljaloud1,2, Kin-Fai Tong1 1Electronic and Electrical Engineering Department, University College London, London, UK, [email protected] 2Electrical Engineering Department, King Saud University, Riyadh, Saudi Arabia Abstract—We present the concept and design of a compact schlocky diode connected in series to one of the two feed flexible electromagnetic energy-harvesting system using electri- terminals of the antenna and to the coplanar transmission line, cally small loop antenna. In order to make the integration of the a capacitor to minimize the ripple level. The reported system system with other devices simpler, it is designed as an integrated system in such a way that the collector element and the rectifier in this letter is sufficiently capable of reusing low microwave circuit are mounted on the same side of the substrate. The energy for both flat and curved configurations. rectenna is designed and fabricated on flexible substrate, and its performance is verified through measurement for both flat and curved configurations. The DC output power and the efficiency II. DESIGN AND RESULT are investigated with respect to power density and frequency. It is observed through measurements that the proposed system The two main parts of rectenna system are largely designed can achieve 72% conversion efficiency for low input power level, individually and unified through the matching network. In this -11 dBm (corresponding power density 0.2 W=m2), while at the work, the proposed rectenna is built as an integral system, and same time occupying a smaller footprint area compared to the thus the rectifier circuit is matched to the collector to maximize existing work. -
The Classic Rain-Gutter Loop Antenna – Is It Any Good?
The Classic Rain-Gutter Loop Antenna – Is it any Good? A simple technical look at an HF horizontal loop of wire strung around your house at rain-gutter height, plus. some novel loop disguise techniques. By John Portune W6NBC Compromise disguise antennas are no strangers to hams, especially on HF. But which ones are worth the effort? We often just put them up and hope for the best. But when I moved to a CC&R restrictive mobile home park recently, I wanted better answers, particularly for the classic rain-gutter loop, Figure 1. I couldn’t put up more of an HF antenna without the neighbors noticing. But was it any good, or only little more than a dummy load? Figure 1: Classic rain-gutter-height loop, elevated on standoffs (stylized for emphasis) To find out, I challenged the rain-gutter loop with EZNEC antenna modeling software. This required best-case and worst-caswe models to encompass most house variables: (1) two loop heights, (2) two house types and (3) several bands. These would place most houses somewhere within these limits. Loop heights were: 10 ft. (rain-gutter height) and 25 ft. (a more conventional loop height). House types were: all wood (best case) and stucco/chicken wire (worst case). Bands were: 40M, 20M and 10M. Why didn’t I include 80M and 160M? Well, I did at first, but right up front, EZNEC revealed something very important about horizontal loops – Rule of Thumb 1. RULE OF THUMB 1 To be efficient, a closed loop must have a perimeter greater than one wavelength (1λ) on the lowest band in use. -
3.1Loop Antennas All Antennas Used Radiating Elements That Were Linear Conductors
SECX1029 ANTENNAS AND WAVE PROPAGATION UNIT III SPECIAL PURPOSE ANTENNAS PREPARED BY: MS.L.MAGTHELIN THERASE 3.1Loop Antennas All antennas used radiating elements that were linear conductors. It is also possible to make antennas from conductors formed into closed loops. Thereare two broad categories of loop antennas: 1. Small loops which contain no morethan 0.086λ wavelength,s of wire 2. Large loops, which contain approximately 1 wavelength of wire. Loop antennas have the same desirable characteristics as dipoles and monopoles in that they areinexpensive and simple to construct. Loop antennas come in a variety of shapes (circular,rectangular, elliptical, etc.) but the fundamental characteristics of the loop antenna radiationpattern (far field) are largely independent of the loop shape.Just as the electrical length of the dipoles and monopoles effect the efficiency of these antennas,the electrical size of the loop (circumference) determines the efficiency of the loop antenna.Loop antennas are usually classified as either electrically small or electrically large based on thecircumference of the loop. electrically small loop = circumference λ/10 electrically large loop - circumference λ The electrically small loop antenna is the dual antenna to the electrically short dipole antenna. That is, the far-field electric field of a small loop antenna isidentical to the far-field magnetic Page 1 of 17 SECX1029 ANTENNAS AND WAVE PROPAGATION UNIT III SPECIAL PURPOSE ANTENNAS PREPARED BY: MS.L.MAGTHELIN THERASE field of the short dipole antenna and the far-field magneticfield of a small loop antenna is identical to the far-field electric field of the short dipole antenna. -
Broadband Antenna 1
Broadband Antenna Broadband Antenna Chapter 4 1 Broadband Antenna Learning Outcome • At the end of this chapter student should able to: – To design and evaluate various antenna to meet application requirements for • Loops antenna • Helix antenna • Yagi Uda antenna 2 Broadband Antenna What is broadband antenna? • The advent of broadband system in wireless communication area has demanded the design of antennas that must operate effectively over a wide range of frequencies. • An antenna with wide bandwidth is referred to as a broadband antenna. • But the question is, wide bandwidth mean how much bandwidth? The term "broadband" is a relative measure of bandwidth and varies with the circumstances. 3 Broadband Antenna Bandwidth Bandwidth is computed in two ways: • (1) (4.1) where fu and fl are the upper and lower frequencies of operation for which satisfactory performance is obtained. fc is the center frequency. • (2) (4.2) Note: The bandwidth of narrow band antenna is usually expressed as a percentage using equation (4.1), whereas wideband antenna are quoted as a ratio using equation (4.2). 4 Broadband Antenna Broadband Antenna • The definition of a broadband antenna is somewhat arbitrary and depends on the particular antenna. • If the impendence and pattern of an antenna do not change significantly over about an octave ( fu / fl =2) or more, it will classified as a broadband antenna". • In this chapter we will focus on – Loops antenna – Helix antenna – Yagi uda antenna – Log periodic antenna* 5 Broadband Antenna LOOP ANTENNA 6 Broadband Antenna Loops Antenna • Another simple, inexpensive, and very versatile antenna type is the loop antenna. -
Evaluation of an Electronically Switched Directional Antenna for Real-World Low-Power Wireless Networks
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Swedish Institute of Computer Science Publications Database Evaluation of an Electronically Switched Directional Antenna for Real-world Low-power Wireless Networks Erik Ostr¨ om,¨ Luca Mottola, Thiemo Voigt Swedish Institute of Computer Science (SICS), Kista, Sweden Abstract. We present the real-world evaluation of SPIDA, an electronically swit- ched directional antenna. Compared to most existing work in the field, SPIDA is practical as well as inexpensive. We interface SPIDA with an off-the-shelf sensor node which provides us with a fully working real-world prototype. We assess the performance of our prototype by comparing the behavior of SPIDA against tradi- tional omni-directional antennas. Our results demonstrate that the SPIDA proto- type concentrates the radiated power only in given directions, thus enabling in- creased communication range at no additional energy cost. In addition, compared to the other antennas we consider, we observe more stable link performance and better correspondence between the link performance and common link quality estimators. 1 Introduction The use of external antennas is a common design choice in many deployments of low- power wireless networks [13]. Indeed, an external antenna often features higher gains compared to the antennas found aboard mainstream devices, enabling increased relia- bility in communication at no additional energy cost. To implement such design, re- searchers and domain-experts have hitherto borrowed the required technology from WiFi networks [10, 22]. This holds both w.r.t. scenarios requiring omni-directional communication [22], and where the application at hand allows directional communica- tion [10]. -
AB Antenna Family.Qxp
WIRELESS PRODUCTS Airborne™ Antenna Product Family ACH2-AT-DP000 series ACH0-CD-DP000 series (other accessories) Airborne™ Antennas are designed for connection to 802.11 wireless devices operating in the 2.4GHz ISM band. These antennas fully support the entire line of Airborne™ wireless 802.11 products. This assortment of antennas is intended to provide OEMs with solutions that meet the demanding and diverse requirements for transportation, medical, warehouse logistics, POS, industrial, military and scientific applications. Applications The Airborne™ Antenna family offers antennas for embedded applications, fixed stations, mobile operation and client side devices, and for indoor and outdoor applications. The antennas feature RP-SMA, N-type and U.FL connectors that provide the designer with flexible ways to connect to Airborne wireless products. A wide range of antenna types and gain options enable an OEM to select the antenna that best matches their application requirements. The Recommended for AirborneTM 802.11 lower gain and smaller antennas, such as the “rubber duck” antennas, would fit applications embedded and system bridge products where the range is not required to exceed 200- 400m while the higher gain directional antennas Made for Embedded or External mounting, would be suitable for extended range that require greater than 800m reach. Embedded antennas Mobile or Fixed station, and Indoor and/or provide ranges from 50m up to 300m. Outdoor operation Specialty Antenna Embedded antenna options are intended for Select from Omni Directional, Highly applications where it is not desirable to use an Directional, or Corner Reflector external antenna, or where the enclosure or application does not allow for an external antenna. -
Antenna Catalog. Volume 3. Ship Antennas
UNCLASSIFIED AD NUMBER AD323191 CLASSIFICATION CHANGES TO: unclassified FROM: confidential LIMITATION CHANGES TO: Approved for public release, distribution unlimited FROM: Distribution authorized to U.S. Gov't. agencies and their contractors; Administrative/Operational use; Oct 1960. Other requests shall be referred to Ari Force Cambridge Research Labs, Hansom AFB MA. AUTHORITY AFCRL Ltr, 13 Nov 1961.; AFCRL Ltr, 30 Oct 1974. THIS PAGE IS UNCLASSIFIED AD~ ~~~~~~O WIR1L_•_._,m,_, ANTENNA CATALOG Volume m UNCLASSIFIED SHIP ANTENN October 1960 Electronics Research Directorate AIR FORCE CAMBRIDGE RESEARCH LABORATORIES Can+rftc AT I9(6N4,4 101 by GEORGIA INSTITUTE OF TECHNOLOGY Engineering Experiment Station •o•log NOTIC 11ý4 Sadoqh amd P4is4,ej ww~aI~.. 1! d' ths, . 'to0 t,UL .. -+~~~~~-L#..-•...T... -w 0 I tdin #" "•: ..."- C UNCLASSIFIED AFCRC-TR-60-134(111) ANTENNA CATALOG Volume III SHIP ANTENNAS (Title UOwlnIied) October 1960 Appeoved: Mmurice W. Long, Electronics Division Submitteds A oed: Technical Information Section k Jeme,. L d, Directot Esis..ielng Expe•immnt Station Prepared by GEORGIA INSTITUTE OF TECHNOLOGY Engineering Experiment Station DOWNGRADED A-r 3 YEAR INTERVAIS. DECL~IFED AFTER 12 YEA&RS. DOD DIR 5200.10 UNC-LASSIFIED. , ~K-11. 574-1 ." TABLE OF CONTENTS Page INTRODUCTION . 1 EQUIPMENT FUNCTION ................ .................. ... 3 ANTENNA TYPE . 7 ANTENNA DATA AB Antennas ......... ................. .............. ...................... ... 15 AN Antennas ............................ ......................................