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A Weather Vane Antenna for 2 Meters VHF Incognito! Here’S a 2 Meter Antenna Figure 1—The Completed Weather Vane Your Neighbors Won’T Recognize
John Portune, W6NBC, and Fred Adams, WD6ACJ A Weather Vane Antenna for 2 Meters VHF incognito! Here’s a 2 meter antenna Figure 1—The completed weather vane your neighbors won’t recognize. antenna. Can you find the loop? eeping a homeowners’ association happy isn’t easy. criminate than a dipole or J-pole. [While horizontal loops do bet- Many hams burdened with CC&Rs often live with ter in noisy situations because that local noise tends to be mainly Kbadly compromised antennas. Why not combine a com- E-field oriented, the perceived SNR improvement of a narrow- pact magnetic loop with a functional weather vane and put band antenna is principally due to the reduction in out-of-band high-performance right out in full view? A neighbor even asked signals that cause IMD, rather than any reduction of the receiver me where I got mine, so she could get one, too. noise floor.—Ed.] They also tend to work better close to the ground Compact loops, often called magnetic loops, have been or near other objects. around for years. They’re tiny open-ended ring radiators, al- 1 ways less than roughly /10th wavelength in diameter. Recently Construction we’ve seen them mostly on HF where their small size is of All materials (Figures 3A and 3B) are common hardware store great appeal. But they work very well on other bands too; here items. I recommend a tubing cutter for cutting the pipe, copper on 2 meters. Remarkably, this VHF ver- and PVC. Also, a different brand of copper sion achieves an efficiency of 93%, yet fittings may require slight adjustments to radiates as if it were a full-sized dipole the cutting dimensions shown. -
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. -
Performance Analysis of Helical Antenna for Different Physical Structure
International Journal of Innovative Research in Electronics and Communications (IJIREC) Volume 5, Issue 4, 2018, PP 21-25 ISSN 2349-4050 (Online) & ISSN 2349-4042 (Print) DOI: http://dx.doi.org/10.20431/2349-4050.0504004 www.arcjournals.org Performance Analysis of Helical Antenna for Different Physical Structure Rahul koshti1, Simran Yadav2, Shikha Sharma3 MPSTME, NMIMS, Shirpur *Corresponding Author: Rahul koshti, MPSTME, NMIMS, Shirpur Abstract: Wireless technology is such of the potent areas of scan in the presence of communication systems today and a design of communication systems is incomplete without a perspective of the activity and fabricatio n of antennas. Helical antenna is used as easily done and shrewd radiators completely the get by few decades, this antenna can be utilized as an encourage for an explanatory dish for higher additions.. So in this we have varied various parameters of helical antenna. Manipulations for this helical antenna antenna have been done with the assist of Matlab softwar Keywords: helical antennas, Antenna gain, Directivity. 1. INTRODUCTION In 1946 Kraus invented the helix form of antenna that is helical antenna. For longer period of time this helical antenna gets famous. [1] Helical antennas are further called as unfiled helix. By the all of diameter D in large helical antenna is revitalizing by a coaxial line along the little ground plane. In communication system helical antenna have a very large approach, so there is a foist of broadband circular polarized antennas [2].This antenna is most significantly used nowadays in point communications, telephone, and television and Information communication. The normal mode helical antenna is particularly attractive for mobile communication and adaptable equipment [3].The shape of helix antenna is a cross breed of two straightforward emanating essentials, the dipole and circle reception apparatuses. -
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. -
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. -
Antenna Articles Collection of Short Articles Relating to All Manners of Antennas
Antenna Tips page 1 of 31 Source : http://www.funet.fi/pub/dx/text/antennas/antinfo.txt Antenna Articles Collection of short articles relating to all manners of antennas. These articles are the hard work of Wayne Sarosi KB4YLY (995 Alabama Street, Titusville, FL 32796) SUBJECT: Circular Polarized Antenna There has been a request for a series on 'CP' antennas. The term 'CP' eluded me at first as I was not familar with the abriviated designator for circular polarization. At work, we just use the entire words. I'm going to begin this ten part series with the basics. After researching CP designs with a few engineers and fellow hams, I found that they knew very little about the subject. I also found I didn't know quite as much as I thought I did about circular polarization. So starting at the begining will help all out. First, let's discuss the circular polarized wave. There seems to be conflicting standards used by the world of physics and the IEEE. I found this to be true in four reference manuals including the ARRL Antenna Handbook. At least it's stated right up front but biased according to which text you read. We will follow the IEEE/ARRL standard in the following series for obvious reasons. There are two types of circular polarization; right and left. All of us agree up to this point. According to the ARRL Antenna Handbook, the following statement: 'Polarization Sense is a critical factor, especially in EME work or if the satellite uses a circular polarized 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. -
Helical Feed Manipulation for Parabolic Reflector Antenna Gain Control
International Journal of Engineering and Advanced Technology (IJEAT) ISSN: 2249 – 8958, Volume-4 Issue-2, December 2014 Helical Feed Manipulation for Parabolic Reflector Antenna Gain Control Zohair Mohammed Elhassan Hussein, Abdelrasoul jabar kizar alzubaidi Abstract Helical antennas have long been popular in A sketch of a typical helical antenna is shown in Figure (1). applications from VHF to microwaves requiring circular The radiating element is a helix of wire, driven at one end polarization, since they have the unique property of naturally and radiating along the axis of the helix. A ground plane at providing circularly polarized radiation. One area that takes the driven end makes the radiation unidirectional from the advantage of this property is satellite communications. Where far (open) end. There are also configurations that radiate more gain is required than can be provided by a helical antenna alone, a helical antenna can also be used as a feed for perpendicular to the axis, with an unidirectional pattern. a parabolic dish for higher gains. The helical antenna can be W e shall only consider the axial-mode configuration. an excellent feed for a dish, with the advantage of circular Typical helix dimensions for an axial-mode helical antenna polarization. One limitation is that the usefulness of the have a helix circumference of one wavelength at the center circular polarization is limited since it cannot be easily frequency, with a helix pitch of 12 to 14 degrees. Kraus reversed to the other sense, left- handed to right-handed or defines the pitch angle α as: vice-versa. This paper deals with applying an electronic technique to control the helical feed of the parabolic reflector = ………………..(1) feed. -
Various Types of Antenna with Respect to Their Applications: a Review
INTERNATIONAL JOURNAL OF MULTIDISCIPLINARY SCIENCES AND ENGINEERING, VOL. 7, NO. 3, MARCH 2016 Various Types of Antenna with Respect to their Applications: A Review Abdul Qadir Khan1, Muhammad Riaz2 and Anas Bilal3 1,2,3School of Information Technology, The University of Lahore, Islamabad Campus [email protected], [email protected], [email protected] Abstract– Antenna is the most important part in wireless point to point communication where increase gain and communication systems. Antenna transforms electrical signals lessened wave impedance are required [45]. into radio waves and vice versa. The antennas are of various As the knowledge about antennas along with its application kinds and having different characteristics according to the need is particularly less thus this review is essential for determining of signal transmission and reception. In this paper, we present various antennas and their applications in different systems. comparative analysis of various types of antennas that can be differentiated with respect to their shapes, material used, signal In this paper a detailed review of various types of antenna bandwidth, transmission range etc. Our main focus is to classify which developed to perform useful task of communication in these antennas according to their applications. As in the modern different field of communication network is presented. era antennas are the basic prerequisites for wireless communications that is required for fast and efficient II. WIRE ANTENNA communications. This paper will help the design architect to choose proper antenna for the desired application. A. Biconical Dipole Antenna Keywords– Antenna, Communications, Applications and Signal There is no restriction to the data transfer capacity of an Transmission infinite constant-impedance transmission line however any pragmatic execution of the biconical dipole has appendages of constrained extend forming an open-circuit stub in the same I. -
Reflector Spacings of Helical Beam Antennas by Donald O Marriage A
Reflector spacings of helical beam antennas by Donald O Marriage A THESIS Submitted to the Graduate Committee in partial fulfillment of the requirements for the degree of Master of Science in Electrical Engineering Montana State University © Copyright by Donald O Marriage (1954) Abstract: Antennas possessing circular polarization characteristics have become increasingly important in recent years. Such an antenna finds an important use in aircraft to airfield and missile to control station communications as a means of stabilising random polarization changes of the received signal. The dimensional ,requirements for a helix to radiate in the axial or beam mode are discussed and a test helix is designed using an average of each dimension A radiation pattern is calculated for the test antenna, and radiation patterns are plotted for various reflector to first turn spacings, The reflector spacing for maximum gain is indicated# and pattern beam width is discussed. A method of obtaining, linear polarisation with a possible gain increase is suggested. :: REELECTOR SPACIMGS OE HELICAL BEAM ANTENNAS by DONALD O.. MARRIAGE 't A BESIS Submitted to the Graduate Committee’ ,, ■ , • ■ .... : , in - V " ‘ , ■ : : partial fulfillment of the requirement's ■' .:n: ■ ' ■ ■ ' ■' for the degree of %' Master of Scienbe in Electrieal Engineering i, -'V ,- at - > ■ Montana State College . • Approved? -V . ■ ) ■ ■ /:. ".V Siaizraan6 ExAmihg Copaittee iSanfl Graduate ^!vision ■ Bosemans Montana Junes 1954 ' '! lVuV- I,.'; 1 ' I I. ,• p!\ 3 A cIr -2 C - ■ 2— I TABLE OF CONTENTS ACKNOWLEDGMENT......................................... 3 ABSTRACT.............................................. 4 INTRODUCTION........................................... 5 THE HELICAL ANTENNA IN GENERAL.......................... 7 THE AXIAL MODE OF RADIATION.............................. 11 CONSTRUCTION OF THE TEST ANTENNA..........................15 SUMMARY OF RESULTS...................................... 22 CONCLUSIONS............................................