A type of aerial, widely used with television and VHF radio receivers, consisting of two parallel dipoles connected together at their outer ends and fed at the center of one of them. The length is usually half the operating wavelength.
A type of aerial, widely used with television and VHF radio receivers, consisting of two parallel dipoles connected together at their outer ends and fed at the center of one of them. The length is usually half the operating wavelength.
A horn antenna or microwave horn is an antenna that consists of a flaring metal waveguide shaped like a horn to direct radio waves in a beam. Horns are widely used as antennas at UHF and microwave frequencies, above 300 MHz.
LEDs are of interest for fibre optics because of five inherent characteristics..
How it works?
Spectrum of an LED
Modulation of LED
LED Vs. Laser diode
disadvantages of LED
The attached narrated power point presentation explains the working principle of Thulium Doped Fiber Amplifiers based on their energy level diagrams. The material also attempts to explain the different types, advantages, disadvantages and applications of Thulium Doped Fiber Amplifiers, apart from comparison between different optical amplifier types. The material will be of interest to KTU final year B Tech students who prepare for the subject EC 405, Optical Communications.
In this chapter we examine the capacity of a single-user wireless channel where transmitter and/or receiver have a single antenna. We will discuss capacity for channels that are both time invariant and time varying. We first look at the well-known formula for capacity of a time-invariant additive white Gaussian noise (AWGN) channel and then consider capacity of time-varying flat fading channels. We will first consider flat fading channel capacity where only the fading distribution is known at the transmitter and receiver. We will also treat capacity of frequency-selective fading channels. For time -invariant frequency-selective channels the capacity is known and is achieved with an optimal power allocation that water-fills over frequency instead of time. We will consider only discrete-time systems in this chapter.
A horn antenna or microwave horn is an antenna that consists of a flaring metal waveguide shaped like a horn to direct radio waves in a beam. Horns are widely used as antennas at UHF and microwave frequencies, above 300 MHz.
LEDs are of interest for fibre optics because of five inherent characteristics..
How it works?
Spectrum of an LED
Modulation of LED
LED Vs. Laser diode
disadvantages of LED
The attached narrated power point presentation explains the working principle of Thulium Doped Fiber Amplifiers based on their energy level diagrams. The material also attempts to explain the different types, advantages, disadvantages and applications of Thulium Doped Fiber Amplifiers, apart from comparison between different optical amplifier types. The material will be of interest to KTU final year B Tech students who prepare for the subject EC 405, Optical Communications.
In this chapter we examine the capacity of a single-user wireless channel where transmitter and/or receiver have a single antenna. We will discuss capacity for channels that are both time invariant and time varying. We first look at the well-known formula for capacity of a time-invariant additive white Gaussian noise (AWGN) channel and then consider capacity of time-varying flat fading channels. We will first consider flat fading channel capacity where only the fading distribution is known at the transmitter and receiver. We will also treat capacity of frequency-selective fading channels. For time -invariant frequency-selective channels the capacity is known and is achieved with an optimal power allocation that water-fills over frequency instead of time. We will consider only discrete-time systems in this chapter.
Its a good presentation on Antenna topic because every one is know that in electrical engineering antenna is a complete subject & its too much difficult subject of electrical engineering....I hope this ppt slides helpful in your future...Thanks A lot guys.......
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A loop antenna has simple structure but its analysis is not easy to perform. Since a loop antenna is a dual pair of a dipole antenna, we can adopt the analysis of a dipole for a loop based on the duality theorem. By stacking a number of loops, we can increase the antenna gain and radiation resistance very easily.
Design and Simulation of Low Noise Amplifiers at 180nm and 90nm TechnologiesIJERA Editor
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Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
(C) 2024 Robbie E. Sayers
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Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
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In order to develop an e-commerce website, a number of Technologies must be studied and understood. These include multi-tiered architecture, server and client-side scripting techniques, implementation technologies, programming language (such as PHP, HTML, CSS, JavaScript) and MySQL relational databases. This is a project with the objective to develop a basic website where a consumer is provided with a shopping cart website and also to know about the technologies used to develop such a website.
This document will discuss each of the underlying technologies to create and implement an e- commerce website.
6th International Conference on Machine Learning & Applications (CMLA 2024)ClaraZara1
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Hybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdffxintegritypublishin
Advancements in technology unveil a myriad of electrical and electronic breakthroughs geared towards efficiently harnessing limited resources to meet human energy demands. The optimization of hybrid solar PV panels and pumped hydro energy supply systems plays a pivotal role in utilizing natural resources effectively. This initiative not only benefits humanity but also fosters environmental sustainability. The study investigated the design optimization of these hybrid systems, focusing on understanding solar radiation patterns, identifying geographical influences on solar radiation, formulating a mathematical model for system optimization, and determining the optimal configuration of PV panels and pumped hydro storage. Through a comparative analysis approach and eight weeks of data collection, the study addressed key research questions related to solar radiation patterns and optimal system design. The findings highlighted regions with heightened solar radiation levels, showcasing substantial potential for power generation and emphasizing the system's efficiency. Optimizing system design significantly boosted power generation, promoted renewable energy utilization, and enhanced energy storage capacity. The study underscored the benefits of optimizing hybrid solar PV panels and pumped hydro energy supply systems for sustainable energy usage. Optimizing the design of solar PV panels and pumped hydro energy supply systems as examined across diverse climatic conditions in a developing country, not only enhances power generation but also improves the integration of renewable energy sources and boosts energy storage capacities, particularly beneficial for less economically prosperous regions. Additionally, the study provides valuable insights for advancing energy research in economically viable areas. Recommendations included conducting site-specific assessments, utilizing advanced modeling tools, implementing regular maintenance protocols, and enhancing communication among system components.
Using recycled concrete aggregates (RCA) for pavements is crucial to achieving sustainability. Implementing RCA for new pavement can minimize carbon footprint, conserve natural resources, reduce harmful emissions, and lower life cycle costs. Compared to natural aggregate (NA), RCA pavement has fewer comprehensive studies and sustainability assessments.
Saudi Arabia stands as a titan in the global energy landscape, renowned for its abundant oil and gas resources. It's the largest exporter of petroleum and holds some of the world's most significant reserves. Let's delve into the top 10 oil and gas projects shaping Saudi Arabia's energy future in 2024.
Sachpazis:Terzaghi Bearing Capacity Estimation in simple terms with Calculati...Dr.Costas Sachpazis
Terzaghi's soil bearing capacity theory, developed by Karl Terzaghi, is a fundamental principle in geotechnical engineering used to determine the bearing capacity of shallow foundations. This theory provides a method to calculate the ultimate bearing capacity of soil, which is the maximum load per unit area that the soil can support without undergoing shear failure. The Calculation HTML Code included.
2. Introduction
• A multi element, directional, antenna designed to
operate over a wide band of frequencies
• A broadband, multi-element, unidirectional,
narrow-beam antenna.
• That has impedance and radiation characteristics
that are regularly repetitive .
• logarithmic function of the excitation frequency.
4. LPDA Array
Log-periodic Dipole Array (LPDA)
with
(a) coaxial feed (this is typically 50 Ω
or 75 Ω)
(b) criss-crossed open-wire line for
twin-lead feed (this is typically 300 Ω).
5. • Why? Need existed for broadband antennas
• Where? University of Illinois
• When? 1955-1961
• Who? V. H. Rumsey
G. A. Deschamps
J. D. Dyson
P.E.Mayes
R. H. DuHamelD.E.Isbell
F.R.Ore
D. G. Berry
R. L. Carrel
History or Origin of LPDAs
7. Log-periodic Dipole Array (LPDA) with various
connections
a) Crisscross connection
b) Coaxial connection
8. Log-periodic Dipole Array (LPDA) with (a)
coaxial feed (this is typically 50 Ω or 75 Ω)
and (b) criss-crossed open-wire line for twin-lead
feed (this is typically 300 Ω)
9. 7 dBi LPDA with 11 dipoles showing an
active central region and inactive regions
10. 1) The lengths ln, locations Rn from apex, diameters dn, and
gap spacings sn of the dipole elements increase
logarithmically as 1/τ, where τ is a LPDA design parameter
called the scale factor
Notes
11. 2) Another LPDA design parameter is the spacing factor σ
Cont…
3) By drawing straight lines through the ends of the dipole
elements of the LPDA, we see that they intersect at a point
called the apex and enclose an angle 2α.
Typically, 10° ≤ α ≤ 45° with 0.95 ≤ τ ≤ 0.7 where α and τ
are inversely related
12. 4) The LPDA is a backfire array. i.e., the maximum
radiation occurs at the feed side (small end) of the antenna.
Cont…
5) For a compact LPDA, larger values of α (smaller τ) are used.
This leads to fewer dipole elements. A trade-off is larger
variations in the input impedance and lower directivity (gain).
6) Smaller values of α (larger τ) LPDA designs have more
elements that are spaced more closely. This yields a larger
LPDA. A benefit is that more elements fall in the active
region with the result being smaller variations in the input
impedance and higher directivity (gain).
13. 1,Determine the bandwidth of the active region Bar
Bar = 1.1 + 7.7(1 – τ)2
cot α ….................(1)
2. Determine the structure (array) bandwidth Bs
Bs = B X Bar ………………….(2)
Where, Bs=designed bandwidth
B=desired bandwidth
Bar=active region bandwidth
3. Determine the boom length L, number of elements N, and
longest element length l1
L = λ max/4 {1– 1/Bs } cot α ...........(3)
Ν= 1+{ln Bs/ln (1/τ} ………………(4)
Zav = average characteristic impedance of a dipole
Za=120[ln(ln/dn)-2.25] ………..(5)
Design Equations.
14. A log periodic antenna is used in a number of applications
where a wide bandwidth is required along with directivity and a
modest level of gain..
Applications.
1) UHF Terrestrial TV: The television spectrum extends over a
wide bandwidth - more than normal Yagi antennas
2) HF communications: Log periodic antenna arrays are often
used in applications where HF communications for diplomatic
traffic
3) EMC measurements: EMC measurements require scans
over a wide bands of frequencies. Log periodic antennas can
be used in this application,
4) Other applications: where log periodic antennas can be
used. Any applications where directivity and a wide
bandwidth are needed
15. Log-periodic antennas are designed to work across a wide
range of frequencies(UHF),
Advantage.
On lower frequencies (HF, VHF) a disadvantage of the Log-
Periodic Dipole Antenna (LPDA) is the number of elements
needed, and therefore weight and wind load when installed
outside.
Disadvantage.