# Antenna array weights and Power input

A big request for clearing this simple doubt. For an application, I am using antenna arrays(say dipoles and array length is 11 elements). Now, this antenna array will have the beamforming vectors based on the users distance and angle which I calculate using triangulation. I have a few questions on this.

1st question:

Now, that I know user's distance from the antenna, and I know I need to cast my beam onto the user who is at a distance d, I need to adjust my weights of the antenna. The steering angle I give the input from triangulation and get it and the beam rotates in angle. Now, I want to reduce the amplitude of the beam. Can the user distance in meters from the base station be considered directly for the amplitude of the beam ? If not, how can we convert the user distance to the amplitude required for the beam to just cover the user(user should always be in the tip of the beam)

2nd question:

I am also thinking on power saving. I assume that every antenna element will be fed with a current "I". I would like to know the equations(if they exist) for the changes in array weights for a specific user using beamforming, I should be able to get a relation with reduced current values. Because, If the user is close to the base station, I will have a lessen the gain and I will need lesser current for each element for supporting that gain. Is this theory right ?

3rd question:

suppose for a case, weight for one of the antenna array element is 1 and and for another element is 0.5 so is this relation true ? I (w=1) = 2 x I(w=0.5)

• I see. Are you using a book or online tutorial? I would need to see the derivation that uses the complex exponential form of the phases and angles. By the way, you can install Greasemonkey/MathJax in your browser and use LaTex in your questions and comments. Just put double dollar signs around your LaTeX. Something like this I think, which is easier for us old school types to read. $$ascan_{n} = a_{n} e^{\left( -j\left( n-\frac{\left( N-1 \right)}{2} \right)ps0 \right)},\; n\; =\; 0,1,...,N-1\; –$$ – C. Towne Springer Apr 2 '14 at 5:23