Beamwidth of array antennas?

[ping-pong]

Hi,

I am working on the design of array antennas. I have studied using arrays will increase the directivity if they are properly placed . but what is the effect on the beam-width. whether it incraeses or decreases or remains the same. I havent find any reference about it. Kindly provide some useful information as well as some link about it. waiting an early reply.

 

[flatulent]

The beam width is the product of the individual antenna pattern and the "array factor" shape. You can calculate the array factor shape by having point sources at the locations of the individual antennas and doing the simple algebra. One thing to keep in mind is that each antenna has a "capture area" and putting them close enough for these areas to overlap will reduce the total gain from the maximum possible and also widen the beam width. Gain and beam width are related.

 

[ping-pong]

how to calculate the array factor for each individual antenna. and also if the antennas are placed in such a way that there is no decrase in gain than what will be the effect on beam-width. Kindly provide me some link on it so that I can study in a bit detail

 

[flatulent]

Here is a lecture handout on array factor www.ee.ucla.edu/~ywang/EE262/Notes/Class5.ppt