Use of mesh in antenna design

i am new to the antenna design, what is the use of mesh in the design. why this is required.

how we can design multiple dipole antenna in free space.

A mesh reflector is used for 2 main reasons

1) -- less material used so it doesnt weigh as much as a solid reflector

2) -- it has less wind resistance than a solid reflector ie. less windloading

cheers
Dave N
VK2TDN

Multiple dipole ... as in fed from the same transmitter ?
in another words a colinear array... look up any decent antenna design book for the answers :)