Abstract: An antenna subsystem having advantageous characteristics for single channel monopulse tracking applications is described. The antenna subsystem may include an array of wave guides such as a square array of four wave guides operating in a monopulse tracking operating frequency band. A single aperture horn may be connected with the array such that one or more wave guide geometry transitions deliberately generates higher order modes. The single aperture horn may be configured such that the dominant mode and the higher order modes combine to generate a corresponding radiation pattern having an enhanced symmetry and/or uniformity. A wave guide circuit may be coupled with the array and configured to generate one or more signals usable to track a moving target such as an elevation error tracking signal and an azimuth error tracking signal.

Abstract: A dual-frequency antenna (100) includes a ground plane (105) that is substantially planar and a radiator (110) that is substantially planar and formed of a conductive material. A slot (115) having first and second ends is formed in the radiator (110), and first and second apertures (120, 125) are formed at the first and second ends, respectively, of the slot (115). The radiator (110) also includes transmission connections (140) for coupling to external transmission circuitry and receiving connections (130) for coupling to external reception circuitry. The transmission connections (140) and the receiving connections (130) are located along the slot and separated by a distance of approximately one-quarter wavelength. Preferably, the height of the antenna (100), i.e., the distance between the radiator (110) and the ground plane (105) is equal to or less than about 1.9 centimeters for low-profile mounting on truck-drawn trailers.