The results of the theoretical estimations and experimental research of characteristics of some finite waveguide phased antenna arrays (PAA) consisting of waveguide elements having a cross–section of a complex shape has been considered; the estimated and experimental radiation patterns have been given; the mutual coupling coefficients, return loss and the level of lateral radiation for the finite PAA consisting of waveguides with a random cross-section working on both linear and circular polarization of the radiated field have been assessed.