Annular slot patch excited array

The target seeker system includes two radio frequency antennas consisting of two sets of radio frequency selective annular slot patch excited radiator receiver elements, one set for K-band energy, the other for X-band energy, sharing a common ground plane. The radio frequency antennas have a single multi-band image plate consisting of resonant dichroic surfaces which will selectively reflect X- and K-band energy. An image plate is formed with conductive patterns on each side of a low dielectric material. The reflective pattern acts as a quarter wavelength thick plate at the operating frequency. The top of the image plate which has X-band reflectors is spaced at one-half of the desired X-band wavelength above the ground plane and the K-band reflector on the bottom of the image plate is spaced at one-half of the desired K-band wavelength. The thickness of the image plate is adjusted to provide the appropriate relative spacing between the X-band reflecting surface on the top and the K-band reflecting surface on the bottom.