azulykit - thanks for the input. from what i've seen so far, the broadbanded type mpa's appear to be more realizable for
a. single polarization
b. single elements or small arrays
i say single polarization because the bandwidth of the element is related to slots or assymetric patterns in the radiating element.
the requirement is dual linear, and not cp.
i'll look into the thick air gap approach, you have seen bandwidths of 20% and good broadside radiation patterns achievable?
also maybe you have read this paper:
'wideband apeture coupled stacked patch antenna using thick substrates' written by Taragonsi and Pozar.
are you familiar with this paper i could ask a question?