{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

# 450fall09hw4 - ECE 450 Homework 4 Due Tue 5 PM 1 In class...

This preview shows page 1. Sign up to view the full content.

ECE 450 Homework 4 Due: Tue, Sept 22, 2009, 5 PM 1. In class notes it is given that the e ff ective length of a ˆ z -directed half-wave dipole antenna is ( θ ) = λ π cos( π 2 cos θ ) sin 2 θ . a) Use l’Hospital’s rule to determine (0) . b) Plot ( θ ) as a function of θ from 0 to 180 degrees. c) Plot ( θ ) sin θ as a function of θ from 0 to 180 degrees. 2. Suppose an antenna has a gain function G ( θ , φ ) = D for 0 < θ < π 2 , D sin 2 θ for π 2 < θ < π . Determine D such that the solid angle integral of G ( θ , φ ) equals 4 π . 3. Three identical ˆ z -directed short dipoles are located at ( x, y, z ) = ( - d, 0 , 0) , (0 , 0 , 0) , and ( d, 0 , 0) and have input current phasors of 1 0 A, 2 0 A, and 1 0 A, respectively. Show that the radiation field of the array of dipoles at an arbitrary location on xy -plane (i.e., θ = 90 plane) su ffi ciently far away from the origin (so that paraxial approximation can be used) is proportional
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

Ask a homework question - tutors are online