Antenna - Theory .com: The Antenna Site

Antenna Basics Antenna Types Smith Charts Antenna Measurements

antenna-theory.com :: View topic - SLL
antenna-theory.com Forum Index antenna-theory.com
Antenna Theory
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

SLL

 
Post new topic   Reply to topic    antenna-theory.com Forum Index -> Questions Related to Antenna Theory
View previous topic :: View next topic  
Author Message
balanita
Antenna-Theory.com Newbie


Joined: 17 Sep 2009
Posts: 2

PostPosted: Thu Sep 17, 2009 9:27 am    Post subject: SLL Reply with quote

sidelobe level: for instance, is better to have an SLL of -17dB or -27dB?
my professor said that it is better to have an SLL of -17dB and it is a bit confusing... please help!
Back to top
View user's profile Send private message
bigSteve
Antenna Wizard


Joined: 14 Mar 2009
Posts: 265

PostPosted: Thu Sep 17, 2009 4:00 pm    Post subject: Side Lobe Level Reply with quote

Typically, for a fixed array size (or fixed antenna size), if the sidelobe level is lower, the beamwidth will be higher (less directive). Hence, for very low sidelobes you might end up with a beamwidth larger than you would like.

You can't say -17 dB sidelobes is better than -27 dB sidelobes or vice versa. Engineering is all about tradeoffs, and it depends on the particular application.
Back to top
View user's profile Send private message
Mohammed
Antenna Theory Regular


Joined: 10 Nov 2009
Posts: 14
Location: malaysia

PostPosted: Tue Nov 10, 2009 5:04 am    Post subject: Reply with quote

talking about sidelobe level is a bit confusing and the more l read about it the more confusion i got ...

anyhow, what should be my expected sidelobe level for a smart broadband antenna and how will that reflect in my throughput ....

your hlep is highly appreciated


regards
Back to top
View user's profile Send private message Send e-mail Yahoo Messenger
bigSteve
Antenna Wizard


Joined: 14 Mar 2009
Posts: 265

PostPosted: Tue Nov 10, 2009 5:55 am    Post subject: Reply with quote

The sidelobe level depends on how many antennas (or elements) are in the array. If there is a single antenna, the sidelobe level depends on how large the antenna is (for instance, a horn antenna that is 5 wavelengths long will have higher sidelobes than a horn that is 10 wavelengths long).

There is no way to estimate the sidelobe level for a "smart broadband antenna".

Throughput cannot be estimated by just the antenna pattern alone. You need to know what modulation scheme you are using, what bandwidth, what range...etc
Back to top
View user's profile Send private message
SamuraiNeophyte
Antenna-Theory.com Newbie


Joined: 03 Dec 2009
Posts: 1
Location: Colorado - North

PostPosted: Tue Dec 08, 2009 11:09 pm    Post subject: Reply with quote

You can also change sidelobe levels in an array by changing the amplitude levels in the elements, phase, element positions, etc. There are many degrees of freedom to work with and the more elements the more degrees of freedom. Certain amplitudes will give you the most gain for a required SLL....

The desired SLL can be application dependent, location dependant, and gain dependent.
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    antenna-theory.com Forum Index -> Questions Related to Antenna Theory All times are GMT
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group