Quantcast Broadside Arrays

Share on Google+Share on FacebookShare on LinkedInShare on TwitterShare on DiggShare on Stumble Upon
Custom Search
 
  
 
4-31 an important factor to be considered when any two elements are parallel and are spaced so that considerable coupling is between them. There is very little mutual impedance between collinear sections. Where impedance does exist, it is caused by the coupling between the ends of adjacent elements. Placing the ends of elements close together is frequently necessary because of construction problems, especially where long lengths of wire are involved. The effects of spacing and the advantages of proper spacing can be demonstrated by some practical examples. A collinear array consisting of two half-wave elements with 1/4-wavelength spacing between centers has a gain of 1.8 dB. If the ends of these same dipoles are separated so that the distance from center to center is 3/4 wavelengths and they are driven from the same source, the gain increases to approximately 2.9 dB. A three-dipole array with negligible spacing between elements gives a gain of 3.3 dB. In other words, when two elements are used with wider spacing, the gain obtained is approximately equal to the gain obtainable from three elements with close spacing. The spacing of this array permits simpler construction, since only two dipoles are used. It also allows the antenna to occupy less space. Construction problems usually dictate small-array spacing. Broadside Arrays A broadside array is shown in figure 4-26, view A. Physically, it looks somewhat like a ladder. When the array and the elements in it are polarized horizontally, it looks like an upright ladder. When the array is polarized vertically, it looks like a ladder lying on one side (view B). View C is an illustration of the radiation pattern of a broadside array. Horizontally polarized arrays using more than two elements are not common. This is because the requirement that the bottom of the array be a significant distance above the earth presents construction problems. Compared with collinear arrays, broadside arrays tune sharply, but lose efficiency rapidly when not operated on the frequencies for which they are designed. Figure 4-26.—Typical broadside array. RADIATION PATTERN.—Figure 4-27 shows an end view of two parallel half-wave antennas (A and B) operating in the same phase and located 1/2 wavelength apart. At a point (P) far removed from the antennas, the antennas appear as a single point. Energy radiating toward P from antenna A starts out in phase with the energy radiating from antenna B in the same direction. Propagation from each antenna travels over the same distance to point P, arriving there in phase. The antennas reinforce each other in this direction, making a strong signal available at P. Field strength measured at P is greater than it would be if the total power supplied to both antennas had been fed to a single dipole. Radiation toward point P1 is built up in the same manner.


Electrical News
Super-Sensitive Magnetic Sensor Exploits Diamond Defect
The quest to measure tiny and enormous values of common...
eetimes.com
Dave Is The Human In The Machine
The Google Brain project with 1000 servers (16,000 cores) simulating...
eevblog.com
ESC Boston 2015 Sneak Peek! Embedded Systems That Glow in the Dark
At ESC Boston 2015, Max Maxfield will be giving a...
eetimes.com
Know Your Open Source License
If you think open source means unrestricted use, you need...
eetimes.com
Delphi Selected to Build Audi's Autopilot Computer
Automated driving is ante portas - but how will the...
eetimes.com
10 Greatest Hoaxes in the History of Engineering
From faux innovations, to fake artificial intelligence, to an Internet-ready...
eetimes.com
Analog EDA Finally Automated
Reutlingen University has created automated techniques for designing analog circuits,...
eetimes.com
IoT Snags $25M in Europe
EuropeCPS aims to spend $25 million over three years helping...
eetimes.com
Festival Redesigns San Francisco
The Market Street Prototyping Festival will transform downtown San Francisco's...
eetimes.com
Mixed-Signal Oscilloscopes to Invade ESC Boston
Designers of embedded systems need to test and troubleshoot designs...
eetimes.com
Net-Zero Homes: Powered By Dreams?
A home that generates more power than it uses sounds...
eetimes.com
KIT, Schaeffler Optimize Power Steering for Electric Cars
A joint research project from mechatronics company Schaeffler AG and...
eetimes.com
Medical Chip Market on 12% CAGR
Moves to smaller and portable medical equipment for use away...
eetimes.com
Philips Offloads LED Lighting Components Unit for $2.8 Billion
Philips has agreed to sell an 80.1 percent stake in...
eetimes.com
Toshiba Ups Ante in 3D NAND Fray
Toshiba's 48-layer BiCS technology will be a stepping stone for...
eetimes.com
3D Qualcomm SoCs by 2016
Qualcomm is doing extensive research into how to build 3D...
eetimes.com
Juggling Data Connectivity Protocols for Industrial IoT
With much legacy equipment existing with older protocols and requiring...
eetimes.com
IoT Sensor Networks Seek Routes
Sensor networks for the Internet of Things present some unique...
eetimes.com
eevBLAB #8 – New Tektronix AGO3000 Oscilloscope
Dave talks about Tektronix’s new unreleased AGO3000 Gravity Compensated Oscilloscope...
eevblog.com
Graphene's First Commercial Success: Energy-Saving Light Bulbs?
The first commercially viable consumer product to use graphene will...
eetimes.com
 


Privacy Statement - Copyright Information. - Contact Us

comments powered by Disqus

Integrated Publishing, Inc.
9438 US Hwy 19N #311 Port Richey, FL 34668

Phone For Parts Inquiries: (727) 755-3260
Google +