Quantcast End-Fire Arrays

Share on Google+Share on FacebookShare on LinkedInShare on TwitterShare on DiggShare on Stumble Upon
Custom Search
 
  
 
4-33 elements that may be used. The construction problem increases with the number of elements, especially when they are polarized horizontally. Q32.   What is the primary cause of broadside arrays losing efficiency when not operating at their designed frequency? Q33.   When more than two elements are used in a broadside array, how are the elements arranged? Q34.   As the spacing between elements in a broadside array increases, what is the effect on the major lobes? End-Fire Arrays An end-fire array looks similar to a broadside array. The ladder-like appearance is characteristic of both (fig. 4-28, view A). The currents in the elements of the end-fire array, however, are usually 180 degrees out of phase with each other as indicated by the arrows. The construction of the end-fire array is like that of a ladder lying on its side (elements horizontal). The dipoles in an end-fire array are closer together (1/8-wavelength to 1/4 -wavelength spacing) than they are for a broadside array. Figure 4-28.—Typical end-fire array. Closer spacing between elements permits compactness of construction. For this reason an end-fire array is preferred to other arrays when high gain or sharp directivity is desired in a confined space. However, the close coupling creates certain disadvantages. Radiation resistance is extremely low, sometimes as low as 10 ohms, making antenna losses greater. The end-fire array is confined to a single frequency. With changes in climatic or atmospheric conditions, the danger of detuning exists. RADIATION PATTERN.—The radiation pattern for a pair of parallel half-wave elements fed 180 degrees out of phase is shown in figure 4-29, view A. The elements shown are spaced 1/2 wavelength apart. In practice, smaller spacings are used. Radiation from elements L and M traveling toward point P begins 180 degrees out of phase. Moving the same distance over approximately parallel paths, the respective wavefronts from these elements remain 180 degrees out of phase. In other words, maximum cancellation takes place in the direction of P. The same condition is true for the opposite direction (toward P1). The P to P1 axis is the line of least radiation for the end-fire array.


Electrical News
Vision Explosion Requires Mobile Architecture Rethink
CEVA's Eran Briman examines the explosion in vision processing and...
eetimes.com
ECC Brings Reliability and Power Efficiency to Mobile Devices
Error correcting code increases memory density and bandwidth while maintaining...
eetimes.com
Friday Quiz: Spectrum and Network Measurements
Wireless is everywhere, but not without spectral measurements....
eetimes.com
LTE-U for Small Cells Improves Wi-Fi Environment
In LTE-U, LTE technology over an unlicensed band is paired...
eetimes.com
Web Giants Dictate Road Maps
Big data centers such as Amazon, Google and Facebook are...
eetimes.com
IoT Terrain Still Shifting
The Internet of Things continues to fragment with competing networks...
eetimes.com
Maker Faire Sydney – Trends in Hardware Innovation Fireside Chat
2014 Sydney Maker Faire Power House Museum 17/8/2014 Trends in...
eevblog.com
Tessera Buys Smart Sensors for Iris Recognition
FotoNation Limited, a wholly owned subsidiary of chip packaging company...
eetimes.com
Hi-Speed Transistors from Liquid Processing
A University of Chicago lab has invented a new kind...
eetimes.com
An Appetizing Archive of Propitious & Pragmatic Resources
EE Times blogger Adam Taylor has created a website containing...
eetimes.com
ESC Boston 2015 Sneak Peek -- Open Source Electromagnetic Trackers
Here's a sneak peek at one of the presentations to...
eetimes.com
Radars Can't Spot Mysterious Drones over Paris
Unidentified drones were spotted in the skies above Paris two...
eetimes.com
18 Views of ISSCC
Engineers showed advances in lower power, higher performance and media-rich...
eetimes.com
IoT Starter Kit Connects Developer to Cloud in Moments
Seeking to simplify the prospect of creating an IoT prototype...
eetimes.com
Benchmark Stresses Big Chips
The EEMBC consortium rolled out CoreMark-Pro, a benchmark suite for...
eetimes.com
iOS, Android Crushing Rival Platforms, IDC Finds
Apple's iOS and Google Android own a combined 96.3% of...
eetimes.com
Are We Ready for Autonomous Vehicles?
Driving a smartphone gives rise other issues - safety, security,...
eetimes.com
Android For Work Brings Google To The Office
Google aims to make Android better suited to the demands...
eetimes.com
7 Linux Facts That Will Surprise You
Here are seven things we bet you didn't know about...
eetimes.com
What Will it Take for Apple's Next Big Thing to be a Car?
Despite much breathless news about how Apple will transform the...
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 +