DOCSLIB.ORG

Yagi – Uda Antenna

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Yagi – Uda Antenna Yagi-Uda (Beam) Antenna Gary A. Thiele KD8ZWS (Ex W8RBW) Co-author of Antenna Theory & Design John Wiley & Sons, 1981, 1998, 2013 Yagi-Uda (Beam) Antennas Outline • Preliminary Remarks • Part I Brief history of the Yagi-Uda (Beam) • Part II Brief personal notes • Part III A few antenna basics • Part IV A technical discussion Note: No equations! Book Facts • 3rd edition currently in print, 3rd printing pending • 3rd edition to be published in Korean, Portuguese and maybe Chinese • Over 1500 equations (but none in this talk!) • 822 pages, 16 chapters • 3rd edition pirated on the internet Part I A Brief History • Objective: to present some historical facts and early uses of the Yagi-Uda antenna. Part I A Brief History • The Yagi-Uda antenna was invented in 1926 in Sendai, Japan by Asst. Prof. Shintaro Uda in colaboration with his mentor Prof. Yagi. Shintaro Uda History – cont. • Uda initially was tasked to design an oscillator to radiate at 4.4m wavelenth ( ~68 Mhz.) • For the antenna he used a resonant loop. Then he placed a parasitic loop nearby and observed more directive radiation. History – cont. • Subsequently he replaced the loops with metal rods observing that more rods (now know as directors) increased the field intensity in the desired direction. • He then undertook a systematic investigation to determine the effect on antenna directivity of changes in length, spacing and geometric arrangement of the parasitic elements. • The 8 director 68 MHz Yagi-Uda on the next slide is a result of his investigation. History – cont. • Uda and Yagi jointly published the results of their investigation in 1926 in Japan. There followed a series of papers in the Journal of the IEE Japan (in Japanese). • U.S. engineers learned of the new antenna at a Tokyo conference in Nov. 1926. This was followed by a classic IEEE journal publication in the U.S. in May 1927 by Yagi and Uda. • Prof. Yagi visited the U.S. in 1928 giving a number of talks about the antenna further publicizing it. History – cont. • The Yagi-Uda antenna was widely used in WWII radar sets, both by Japan and the Allies. • Recall, kilowatts of power then could not be generated at centimeter wavelengths. Hence, the use of the Yagi-Uda at meter wavelengths. • When Japan captured Singapore and the British radar sets, they were at first interested in the Yagi-Uda antennas, not realizing they were invented in Japan in 1926! History – cont. • What was needed in WWII was a sufficient power source at centimeter wavelengths to enable the development of airborne radar. • In 1941 the British developed a cavity magnetron, capable of many kilowatts of power at centimeter wavelengths, and shared it in great secrecy with the U.S. • Centimeter wavelength radar was a major contributor to the defeat of the U-boat threat. History – cont. • After the war, the Yagi-Uda (Beam antenna) became a Ham favorite and various perturbations were developed for TV reception. Part II Some Personal Notes Objective: To provide some insights into the Japanese culture, and to show the pride the Japanese take in the fact that the Yagi-Uda was invented in their country. Japan 1978 • A senior colleague and I are in Japan for an antenna conference in Sendai. • We had a number of Japanese friends who had spent one or two years at the Antenna Laboratory at The Ohio State University when I was a graduate student 1963-1967. • Our friends are treating us to an overnight at the Hitachi Corp. Guest House. Mountains near Tokyo 1978 Hitachi Corp. Guest House Pre Dinner Table Dinner Table Saying Goodbye Shintaro Uda Historical Recognition • The Yagi-Uda antenna was named an IEEE Milestone in 1995. Part III A Few Antenna Basics Objective: To define a few basic terms used in Part IV. • Wavelength • Electromagnetic Field • Radiation Patterns • E-Plane and H-Plane • Gain Wavelength 180o 360o 0o 90o 270o The Electromagnetic Field Received by an Antenna The electric and magnetic fields are at right angles to each other and at right angles to the direction of propagation along the z-axis to the right. E x Figure: The spatial behavior of the electric (solid) and magnetic (dashed) fields of a linearly z (vertical) polarized wave for a fixed instant of time. E and H in Time domian time phase H picture y S T U T Z M A N & T H I E L E Radiation Patterns A radiation pattern (antenna pattern) is a graphical representation of the radiation (far-field) properties of an antenna. The radiation fields from a transmitting antenna vary inversely with distance, e.g., 1/r. The variation with observation angles (θ, ), however, depends on the antenna only. The transmit and receive patterns of an antenna are identical by reciprocity. Reciprocity allows the calculation or measurement of an antenna pattern in either the transmit or receive case, whichever is more convenient. S T U T Z M A N & T H I E L E Pattern Characteristicsz Main lobe Major lobe (unidirectional) First null beamwidth (FNBW) Half-power beamwidth (HPBW) 0.5 Minor lobes Side lobe y Minor Back lobe (in this example) lobes Minor lobes x 3-D Picture S T U T Z M A N & T H I E L E Polar Radiation Patterns – cont. (c) Decibel pattern (b) Relative field pattern S T U T Z M A N & T H I E L E Gain The concept of (maximum) gain: “how much does an antenna concentrate radiation in one direction at the expense of other directions (if antenna ohmic losses are included).” Note: 1. Gain here does not include losses arising from impedance and polarization mismatches. 2. Manufacturers usually include the impedance mismatch loss in the gain. For a well-matched antenna, this inclusion results in the published gain being slightly reduced. S T U T Z M A N & T H I E L E Part IV A Technical Discussion • Objective: To show the influence of the reflector and director elements, and their effect on the wave velocity. Also, to explain how the Yagi-Uda radiates. 2 Ways to understand the Yagi-Uda • Element Phasing • Wave approach Yagi-Uda (Beam) Antennas Spatial Phase Delay (Ordinary Endfire, v=c ) o o o → Forward o o o 90 0 -90 ⋮ λ/4 ⋮ λ/4 ⋮ The Wave Approach Wave Launcher Guided Wave Surface Wave Launcher: Reflector and Driven Element Guided Wave Surface: Director Elements How does a Yagi-Uda radiate? When an electromagntic wave encounters a discontinuity, something will happen. In the case of the Yagi-Uda two things happen at the “end” of the guided wave surface: radiation and reflection. Radiation does not occur along the directors, only at the end where there is a discontinuity. That is, The Yagi-Uda is not a leaky wave antenna. 27 element currents Why is there usually only one reflector element? Yagi-Uda Antenna - effect of reflector element Optimum reflector spacing SR (for maximum directivity) is between 0.15 and 0.25 wavelengths as Fig. 5-35 shows. Note that the gain above an isolated dipole is more than 2.5 dBd, whereas if a flat plate were used, instead of a simple wire-like element, the gain would be 3 dBd. Thus, a single wire-like reflector element is almost as effective as a flat plate in enhancing the gain of a dipole! 3 Figure 5-35 Measured 2 gain [21] in dBd of a dipole and reflector element for different SR 1 spacings SR. Reflector Driver 0.05 0.10 0.15 0.20 0.25 0.30 0.35 Spacing SR () of reflector behind driven element S T U T Z M A N & T H I E L E Why was a folded dipole used for the driven element in the previous slide? Answer: The mutual coupling of the driven element with the nearby parasitic elements reduces the feed point impedance, sometimes dramatically. The self impedance of a folded dipole is 4 times the self impedance of straight wire half-wave dipole, which helps to overcome the effects of mutual coupling. Yagi-Uda Antennas - design 0.50 0.42λ Long Yagi 1 Dir, 1 Refl. SD 0.2λ 0.49 Reflector 2.2λ Long Yagi 10 Dir, 1 Refl. SD 0.2λ 0.48 0.47 Directors 0.8λ Long Yagi 3 Dir, 1 Refl, SD 0.2λ 0.46 1.2λ Long Yagi 4 Dir, 1 Refl, SD 0.25λ 3.2λ Long Yagi 0.45 15 Dir, 1 Refl, SD 0.2λ 4.2λ Long Yagi 13 Dir, 1 Refl, S 0.308λ 0.44 D 0.43 Length L Spacing SD 0.42 0.41 Diam d D1 D2 D3 . 0.40 . D4 0.39 0.38 0.001 0.002 0.003 0.004 0.006 0.008 0.01 0.02 0.03 Figure 5-37 Design curves for Yagi’s in Table 5-2. S T U T Z M A N & T H I E L E Yagi-Uda Antennas - correction for support boom 0.030 0.025 0.020 0.015 Figure 5-38 Graph showing effect of 0.010 supporting un-insulated metal boom on the length 0.005 of Yagi parasitic elements. 0.002 0.006 0.01 0.02 0.03 0.04 S T U T Z M A N & T H I E L E Question Why can we electrically connect the metallic parasitic elements to a metallic boom? Half wavelength V (+) Current Voltage (-) TV Channel 12 Yagi Antenna Design A 12-element Yagi for TV channel 12 at 205.25 Mhz is to be designed using 1-cm-diameter elements insulated from a metallic boom [23].
Load more

Recommended publications
  • FOX Hunting Basics FOX Hunting Basics
    FOX Hunting Basics FOX Hunting Basics Steps in a transmiter hunt •Signal acquisiton •Triangulaton –Plot bearings on map to get an estmated directon of the transmiter •Homing –“follow your nose” •Snifng –Up close and personal FOX Hunting Basics Following Clues •Finding the transmiter is a process of following clues to the source of the signal. Important clues include: –Directon –Signal Strength –Rate of change in directon –Rate of change in signal strength –Terrain shadowing –Non-radio clues: keep your eyes open! FOX Hunting Basics Tools for Determining Directon •Antenna with directonal patern •Some way to measure signal strength •Some way to reduce signal strength as you get close to avoid receiver overload –“Atenuator” Bearings Bearings Waldo ©DreamWorks Distribution Limited.All rights reserved. Imagery §>2018 Google, Msg data ©2Q1S Google United States Terms Send feel Bearings Equipment Used for DF’ing Equipment Used for DF’ing Equipment Used for DF’ing Radio Attenuator Directional Antenna Equipment Used for DF’ing The attenuator is used to reduce signals so the S meter is in the middle of the scale in the presence of a strong signal Attenuator Strong Signal Equipment Used for DF’ing The attenuator is used to reduce signals so the S meter is in the middle of the scale in the presence of a strong signal Attenuator Strong Signal Equipment Used for DF’ing Time Difference of Arrival TDOA Equipment Used for DF’ing Time Difference of Arrival TDOA How it works •Time Difference of Arrival RDF sets work by switching your receiver between two antennas at a rapid rate.
    [Show full text]
  • 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.
    [Show full text]
  • Communication Analysis of High Impedance Coils Both in Transmission and Reception Regimes
    1 Communication Analysis of High Impedance Coils both in Transmission and Reception Regimes M. S. M. Mollaei, C.C. van Leeuwen, A.J.E. Raaijmakers, and C. Simovski Abstract—Theory of a high impedance coil (HIC) – a cable loop point of the loop (which is opposite to the feeding point). antenna with a modified shield – is discussed comprehensively When this capacitance is sufficiently small, the current distri- for both in transmitting and receiving regimes. Understanding bution in the coil is not uniform – besides of a magnetic dipole a weakness of the previously reported HIC in transmitting regime, we suggest another HIC which is advantageous in both mode (uniform current) an electric dipole mode (in-phase with transmitting and receiving regimes compared to a conventional the magnetic current on the top of coil and opposite-phase loop antenna. In contrast with a claim of previous works, only on the bottom) are excited. Properly choosing the value of this HIC is a practical transceiver HIC. Using the perturbation this capacitance, magnetic coupling coefficient and electric approach and adding gaps to both shield and inner wire of coupling coefficient become balanced and opposite in phase. the cable, we tune the resonance frequency to be suitable for ultra-high field (UHF) magnetic resonance imaging (MRI). Our This grants the decoupling for two adjacent loops having theoretical model is verified by simulations. Designing the HIC nulls of their near-field pattern on the line connecting their theoretically, we have fabricated an array of three HICs operating centers. However, the coupling of non-neighboring antennas at 298 MHz.
    [Show full text]
  • An Overview of the Underestimated Magnetic Loop HF Antenna
    An Overview of the Underestimated Magnetic Loop HF Antenna It seems one of the best kept secrets in the amateur radio community is how well a small diminutive magnetic loop antenna can really perform in practice compared with large traditional HF antennas. The objective of this article is to disseminate some practical information about successful homebrew loop construction and to enumerate the loop’s key distinguishing characteristics and unique features. A magnetic loop antenna (MLA) can very conveniently be accommodated on a table top, hidden in an attic / roof loft, an outdoor porch, patio balcony of a high-rise apartment, rooftop, or any other tight space constrained location. A small but efficacious HF antenna for restricted space sites is the highly sort after Holy Grail of many an amateur radio enthusiast. This quest and interest is particularly strong from amateurs having to face the prospect of giving up their much loved hobby as they move from suburban residential lots into smaller restricted space retirement villages and other shared residential communities that have strict rules against erecting antenna structures. In spite of these imposed restrictions amateurs do have a practical and viable alternative means to actively continue the hobby using a covert in-door or portable outdoor and sympathetically placed low visual profile small magnetic loop. This paper discusses how such diminutive antennas can provide an entirely workable compromise that enable keen amateurs to keep operating their HF station without any need for their previous tall towers and favourite beam antennas or unwieldy G5RV or long wire. The practical difference in station signal strength at worst will be only an S-point or so if good MLA design and construction is adopted.
    [Show full text]
  • MAGNETIC LOOP ANTENNA LA400 Instruction Manual
    MAGNETIC LOOP ANTENNA LA400 Instruction manual AOR Ltd. Authority On Radio Communications - 2 Table of contents 1. Introduction . 4 2. Included in this package . 5 3. Hardware setup . 6 4. Operating instructions . 7 5. Remote tuning system . 9 6. Directivity of a loop antenna . 10 7. Characteristics of a “shielded” loop antenna . 11 8. Options . 12 9. Specifications . 13 3 1. Introduction Thank you for purchasing the LA400 Magnetic loop antenna. To get the best possible results from your LA400, we recommend that you read this manual and familiarize yourself with the antenna. Since the invention of this revolutionary concept by KOLSTER in 1915, loop antennas, especially of the active type, have also been widely used by the military in the 70’s, before becoming very popular among hobby listeners. In recent years, the increase in man-made local noise (typical city noise) poses a problem for the reception of distant signals in the long wave, medium wave and shortwave bands. LA400 is our latest product based on the technology we developed since the original LA320 loop antenna. In addition to its exceptional directivity in order to minimize the effects of local noise, the revolutionary LA400 offers, with its REMOTE TUNING SYSTEM , the perfect solution to keep the antenna away from noise sources by setting it up in quiet areas! While the control (tuning) box stays at hand’s reach, the loop element can be set away by using simple LAN and BNC coaxial cables. 10kHz to 500MHz, 5 position band switch to peak only on the wanted signal. Small size 30.5cm diameter loop with exceptional 20dB gain Remote tuning – Unlike previous amplified indoor loop antennas, the band switching and fine tuning controls are not tied anymore to the loop element.
    [Show full text]
  • 3D Multi-Beam and Null Synthesis by Phase-Only Control for 5G Antenna Arrays
    electronics Article 3D Multi-Beam and Null Synthesis by Phase-Only Control for 5G Antenna Arrays Massimiliano Comisso * , Gabriele Palese , Fulvio Babich and Francesca Vatta and Giulia Buttazzoni Department of Engineering and Architecture, University of Trieste, Via A. Valerio 10, 34127 Trieste, Italy; [email protected] (G.P.); [email protected] (F.B.); [email protected] (F.V.); [email protected] (G.B.) * Correspondence: [email protected] Received: 5 May 2019; Accepted: 8 June 2019; Published: 11 June 2019 Abstract: This paper presents an iterative algorithm for the synthesis of the three-dimensional (3D) radiation pattern generated by an antenna array of arbitrary geometry. The algorithm is conceived to operate in fifth-generation (5G) millimeter-wave scenarios, thus enabling the support of multi-user mobile streaming and massive peer-to-peer communications, which require the possibility to synthesize 3D patterns with wide null regions and multiple main beams. Moreover, the proposed solution adopts a phase-only control approach to reduce the complexity of the feeding network and is characterized by a low computational cost, thanks to the closed-form expressions derived to estimate the phase of each element at the generic iteration. These expressions are obtained from the minimization of a weighted cost function that includes all the necessary constraints. To finally check its versatility in a 5G environment, the developed method is validated by numerical examples involving planar and conformal arrays, considering desired patterns with different numbers of main beams and nulls. Keywords: 3D synthesis; conformal antenna arrays; phase-only control; multi-beam pattern; null constraints 1.
    [Show full text]
  • Phased Array of 619-Element Yagi-Uda Antenna for Wind Profiler
    URSI AP-RASC 2019, New Delhi, India; 09 - 15 March 2019 Phased array of 619-element Yagi-Uda antenna for Wind Profiler Radar at Cochin University of Science and Technology Titu K Samson(1), Binoy Babu(1), V. K. Anandan(2), Rakesh V(1),Rejoy Rebello(1),K Mohanakumar(1), and P Mohanan(1) (1) Advanced Aenter for Atmospheric Radar Research, Cochin University of Science and Technology,Cochin-22,Kerala India, http://acarr.cusat.ac.in (2) Indian Space Research Organization (ISTRAC), Bangalore, India Abstract wind through out the troposphere in all weather conditions. Colorado WPR network has given confidence to the me- During the last 3 to 4 decades radar technology has grown teorologist to use WPR as a tool for operational forecast. into an indispensable technology for weather phenomenon Department of Science and Technology, Govt. of India has detection , prediction and tracking. There are mainly two sanctioned a project to Cochin University of Science and types of atmospheric radar, Doppler weather radar to de- Technology to establish a Stratosphere Troposphere wind tect clouds, thunder storms, cyclone etc and Wind Profiler profiler radar operating at 205MHz for wind profiling ap- Radars (WPR) used to detect the speed and direction of plication from 500m to 20Km above earth [1, 2, 3]. wind above the radar. In this paper we are discussing the design of 619 element Yagi-Uda antenna array for Strato- 2 Yagi-Uda antenna Theory and operation sphere Troposphere Wind profiler radar(ST Radar) operat- ing at 205MHz. Frequency was selected considering the Yagi-Uda antennas are suitable for these kind of applica- objective of height coverage of 500m to 20Km above earth.
    [Show full text]
  • Long Wire and Traveling Wave Antennas
    Chapter 13 Long Wire and Traveling Wave Antennas he power gain and directive characteristics of the harmonic wires (which are “long” in terms of wavelength) described in Chapter 2 make them useful for long-distance transmission and recep- Ttion on the higher frequencies. In addition, long wires can be combined to form antennas of various shapes that will increase the gain and directivity over a single wire. The term “long wire,” as used in this chapter, means any such configuration, not just a straight-wire antenna. Long Wires Versus Multielement Arrays In general, the gain obtained with long-wire antennas is not as great, when the space available for the antenna is limited, as can be obtained from the multielement arrays in Chapter 8. However, the long-wire antenna has advantages of its own that tends to compensate for this deficiency. The construction of long-wire antennas is simple both electrically and mechanically, and there are no espe- cially critical dimensions or adjustments.The long-wire antenna will work well and give satisfactory gain and directivity over a 2-to-1 frequency range; in addition, it will accept power and radiate well on any frequency for which its overall length is not less than about a half wavelength. Since a wire is not “long,” even at 28 MHz, unless its length is equal to at least a half wavelength on 3.5 MHz, any long- wire can be used on all amateur bands that are useful for long-distance communication. Between two directive antennas having the same theoretical gain, one a multielement array and the other a long-wire antenna, many amateurs have found that the long-wire antenna seems more effective in reception.
    [Show full text]
  • 71-22,477 University Microfilms, a XEROX Company, Ann Arbor
    71-22,477 FREELAND, John, 1941- YAGI-UDA ARRAYS OF V DIPOLES. The Ohio State University, Ph.D., 1971 Engineering, electrical University Microfilms, A XEROX Company, Ann Arbor, Michigan © Copyright by John Freeland 1971 YAGI-Um ARRAYS OF V DIPOLES DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University By John Freeland, B.E.E., M.Sc. * * * * * The Ohio State University 1971 Approved by Department of Electrical Engineering PLEASE NOTE: Some pages have indistinct print. Filmed as received. UNIVERSITY MICROFILMS. ACKNOWLEDGMENTS I wish to express my gratitude to Professor Richmond for his patience during the ten or eleven drafts through which this dissertation went, and to Professors Roger C. Rudduck and Daniel B. Hodge of the reading committee for their objective appraisel of my efforts. I am also grateful to my parents, Mr. and Mrs. Albert Freeland, for their steadfast confidence in my ability to finish the academic program which I began eleven years ago. 11 VITA December 29, 19^1 • • Born - Linton, Indiana 196k • ••••••• B.E.E., The Ohio State University, Columbus, Ohio 1968 •••••••• M.Sc., The Ohio State University, Columbus, Ohio PUBLICATIONS "An Evaluation of Several Approximate Methods for Analyzing the Scattering from Strips (Plates)," URSI-FGAP Digest, 196 6 Fall Meeting, p. 90, December, 1 9 6 6. "Strip Current Approximation by Fresnel Integrals," PGAP Digest and Technical Program, 1 9 6 7 International Antenna and Propagation Symposium, pp.23^-237, October 1967. "Ifedified Single Diffraction," URSI-PGAP Digest, 1 9 6 8 Fall Meeting, p.
    [Show full text]
  • Practical Null Steering in Millimeter Wave Networks Sohrab Madani and Suraj Jog, University of Illinois Urbana Champaign; Jesus O
    Practical Null Steering in Millimeter Wave Networks Sohrab Madani and Suraj Jog, University of Illinois Urbana Champaign; Jesus O. Lacruz and Joerg Widmer, IMDEA Networks; Haitham Hassanieh, University of Illinois Urbana Champaign https://www.usenix.org/conference/nsdi21/presentation/madani This paper is included in the Proceedings of the 18th USENIX Symposium on Networked Systems Design and Implementation. April 12–14, 2021 978-1-939133-21-2 Open access to the Proceedings of the 18th USENIX Symposium on Networked Systems Design and Implementation is sponsored by Practical Null Steering in Millimeter Wave Networks Sohrab Madani∗, Suraj Jog∗, Jesus O. Lacruz†, Joerg Widmer†, Haitham Hassanieh∗ ∗University of Illinois at Urbana Champaign, †IMDEA Networks Abstract – Millimeter wave (mmWave) is playing a central TX TX TX role in pushing the performance and scalability of wireless Interferer Interferer Interferer networks by offering huge bandwidth and extremely high data rates. Millimeter wave radios use phased array technology Main to modify the antenna beam pattern and focus their power lobe towards the transmitter or receiver. In this paper, we explore Side the practicality of modifying the beam pattern to suppress RX lobes RX RX interference by creating nulls, i.e. directions in the beam pat- (a) No Nulling (b) Single Null (c) Wide Null tern where almost no power is received. Creating nulls in Figure 1: Directional beams in mmWave networks practice, however, is challenging due to the fact that practical mmWave phased arrays offer very limited control in setting the data rate and in dense networks reduce the total network the parameters of the beam pattern and suffer from hardware throughput to half (by up to 18 Gbps) [14, 27, 44, 55, 61].
    [Show full text]
  • Understanding the RF Path TABLE of CONTENTS
    Understanding the RF path TABLE OF CONTENTS Chapter 1 Introduction: Welcome to RF communications 3 Chapter 2 The solutions, practices and trends: Cell site development 8 Chapter 3 Getting the signal across: Base station antennas 19 Chapter 4 Working within the limits: Co-siting solutions 44 Chapter 5 Talking and listening at the same time: Transmission and receiving isolation systems 59 Chapter 6 Getting from the air to the network: Cables and connectivity 76 Chapter 7 Clearing the connections: Overcoming passive intermodulation (PIM) 97 Chapter 8 Getting the most from every cycle: Spectrum management 105 Chapter 9 The infrastructure behind the call: Backhaul 115 Chapter 10 The next RF architecture evolution: C-RAN 137 Chapter 11 The energy of communications: Powering wireless networks 147 Chapter 12 Successfully planning against failure: Reliability in wireless systems 172 Chapter 13 Extending the network indoors: DAS, C-RAN antenna systems, and small cell solutions 187 Chapter 14 Finding safer ground: Lightning protection 196 Biographies 210 | Appendix A 214 | Glossary 219 www.commscope.com 2 Introduction: Welcome to RF communications Chapter 1 www.commscope.com 3 Introduction: Chapter 1 Welcome to RF communications Microwave backhaul The use of microwave communications to networks. It encompasses indoor wireless solutions that For decades, CommScope has grown up aggregate and transmit allow a mobile user to find a clear connection from alongside the science of communication with cellular voice and data anywhere in a vast building complex, aboard an aloft practical solutions. We have been dedicated to and from the main airliner or from a bullet train zipping through a tunnel network.
    [Show full text]
  • Chapter 3: Antennas
    CHAPTER 3: ANTENNAS Antennas couple propagating electromagnetic waves to and from circuits and devices, typically using wires (treated in Section 3.2) or apertures (treated in Section 3.3). In practice complicated solutions of Maxwell’s equations for given boundary conditions are usually not required for system design and analysis because the antenna properties have already been specified by the manufacturer, and must only be understood. Section 3.1 characterizes these general transmitting and receiving properties of antennas, which are derived in subsequent sections. 3.1 BASIC ANTENNA PROPERTIES Most antennas reversibly link radiation fields to currents flowing in wires at frequencies ranging from sub-audio through the far-infrared region. Aperture antennas that link radiation fields to materials can operate in microwave, infrared, visible, ultraviolet, X-ray, gamma ray, and even higher energy regimes. The design of lens and mirror systems for coupling radiation directly to materials is generally called “optics”, and the use of these optical techniques for coupling radiation to wires or waveguides is often called “quasi-optics”. For the most part, all of these systems can be characterized by the definitions that follow. A transmitter with available power PT will radiate PTR , where the antenna radiation ' efficiency K PP1TR T d , and typically is close to unity for most antennas. Ideally, this power would be radiated exclusively in the intended direction, but in practice some fraction is radiated instead to the side into sidelobes, or to the rearward 2S steradians in the form of backlobes. The ability of an antenna to radiate energy in a desired direction is characterized by its antenna directivity, D(f,T,I), which is the ratio of power actually transmitted in a particular direction to that which would be transmitted had the power PTR been radiated isotropically; therefore, directivity is sometimes called “directivity over isotropic”.
    [Show full text]