A dual polarised four-beam antenna array for the 1850-1990MHz frequency ban
d is presented. The polarisations are +/- 45 degrees to vertical. The: ante
nna has eight inputs corresponding to two orthogonal polarisations and four
beams. The return loss and cross-polar isolation for a single Butler beam
exceeds 15 and 22dB, respectively. The radiation pattern is similar to an i
deal Butler pattern and the cross-polarisation level is <-21dB in the beams
.