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
WiFi to Switch on IoT Appliances
Electrolux says it is one of several white good makers...
eetimes.com
A CTO's View of Comms 2015
Ethernet has a growing role in automotive and industrial networks...
eetimes.com
Become a Measurement Master
Becoming a measurement master, like anything else, takes time and...
eetimes.com
Ten Flash Drives That Will Turn Heads (and Store Your Data!)
Today's flash drives have come a long way with iconic...
eetimes.com
10 Tech Gifts to Buy Your Engineer for Christmas
Here is a list of last minute ideas for making...
eetimes.com
Holiday Movies to Geek Out About
EE Times wants to ensure domestic bliss with a handy...
eetimes.com
Road to Auto Market Paved With Fault-Tolerant SoCs
Data protection and redundancy features implemented across entire SoC designs...
eetimes.com
Boston-Area Engineers to Share Expertise at ESC Boston 2015
In an exciting new session format at ESC Boston 2015,...
eetimes.com
Memory Design Trends in 2014
Memory transitions, increased-density drive design trends: Customers are looking for...
eetimes.com
True 3-D Chips Harness Nanotubes
Stanford University has learned how to stack any number of...
eetimes.com
Top 15 Analog, MEMS & Sensors News From 2014
From faulty MEMS mics to NXP's labor disputes, here are...
eetimes.com
Space Weather Satellite Set for Launch
NOAA's Deep Space Climate Observatory will serve as an early...
eetimes.com
Hackers Go Off-Grid for Power
Hackathon produces designs that could be assembled by villagers with...
eetimes.com
Ten Hot & Cool NASA Innovations
Partnering with industry, NASA has developed new technologies that are...
eetimes.com
The Circle – The Future's Imperfect in the Present Tense
Dystopian novel satirizes mega-Google companies and the modern techie ethos....
eetimes.com
Friday Quiz: S-Parameters
S-Parameters are no longer just for microwave engineers. High-speed digital...
eetimes.com
EEVblog #694 – Mailbag
Mailbag that’s not on a Monday, because Dave has been...
eevblog.com
So Much To Do, So Little Time
2015 will likely be the year of widespread awareness and...
eetimes.com
What Does It Take to Truly Leapfrog With Technology?
In January 2015, Lindsay Craig will be teaching technology workshops...
eetimes.com
Recommended Reads From the Engineer's Bookshelf
Are you wondering what to buy your family and friends...
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 +