In this paper the response of a dual-layer, ultra wideband (UWB) frequency selective surface (FSS) reflector to obliquely incident electromagnetic waves is investigated. The results show a stable transmission response over an ultra-wide bandwidth for both transverse magnetic (TM) and transverse electric (TE) polarizations. Performance of the FSS is evaluated for incidence angles up to 50 with respect to the normal to the surface. The unit cell consists of a two-layer structure and possesses symmetry in two orthogonal planes. For 0 incidence, the designed FSS shows a linear phase response with a stop bandwidth greater than 100%. These printed FSS reflectors are highly suitable for use with planar UWB antennas, giving flexibility of mounting antennas close to conducting surfaces. They provide good isolation between the antennas and external conductors and minimize near field effects such as impedance mismatch.