Abstract: The operational status of individual phase control modules within a phased array antenna can be determined using a radio frequency oscillator, a directional coupler, a spiral antenna, an attenuator, a harmonic frequency converter, a network analyzer, and a phase magnitude display. The radio frequency oscillator generates a test radio frequency signal which is conducted into the sum port of the array by the directional coupler. The phase control modules normally phase shift radio frequency signals they receive from the sum port by amounts indicated in a command signal from the radar control system. When using this test system, the radar control system should be directed to send a test command signal which direct the phase control modules to repeatedly phase shift received radio frequency signals between a first and second phase state. The spiral antenna, when placed in proximity of each individual phase control module, receives and conducts phase shifted radio frequency signals to the harmonic analyzer.

Abstract: A loosely coupled microstrip microwave coupler with high directivity is disclosed. The coupler comprises a ground plane substrate, a dielectric layer disposed over the substrate, and a section of each of the main and coupled transmission lines disposed on the exposed surface of the dielectric layer adjacently aligned with a predetermined gap therebetween to form a coupling region. The length of the coupling region is substantially less than 1/4 wavelength of the operating microwave signal. A capacitive coupling element is disposed within the coupling region across the main and coupled transmission line sections for supplementing the dielectric capacitive coupling of the gap therebetween to increase the directivity of the microwave signal coupling.

Abstract: A feed which is stationary relative to a parabolic reflector is located in close proximity to a prime focus of the reflector along its central axis. A moving element which is opaque to r.f. energy is moved along a path of revolution about the reflector axis, the path of revolution being located between the reflector and the stationary feed. The shape of the opaque element and the path of revolution are such that different portions of the aperture of the feed are masked as the element travels along the path of revolution. This imparts predictable scanning motion to the beam pattern which is coupled into the stationary feed. One highly useful embodiment of this invention is a construction in which the stationary feed is a secondary feed installed in a nutating feed antenna, and the nutating feed itself constitutes the opaque moving element.