An antenna includes a plurality of waveguide antenna elements arranged in a first array configured to operate with a first polarization. The antenna also includes a plurality of waveguide output ports arranged in a second array configured to operate with a second polarization. The second polarization is different from the first polarization. The antenna further includes a polarization-rotating layer with channels defined therein. The polarization-rotating layer is disposed between the waveguide antenna elements and the waveguide output ports. The channels are oriented at a first angle with respect to the waveguide antenna elements and at a second angle with respect to the waveguide output ports. The channels are configured to receive input electromagnetic waves having the first polarization and transmit output electromagnetic waves having a first intermediate polarization. The waveguide output ports are configured to receive input electromagnetic waves and radiate electromagnetic waves having the second polarization.