Abstract: Commutation switches for electronically scanning cylindrical arrays are disclosed. One embodiment reduces the number of transfer switches needed in a commutation switch by utilizing the commutation inversion property inherent to transfer switches having a binary number of input and output ports. A second embodiment having inversion capability provides a transfer switch with non-binary number of input and output ports. Commutation switches employing transfer switches of the second embodiment exhibit reduced complexity over the prior art and provide lower signal loss than that achievable with commutation switches of the prior art.

Abstract: A limited scan antenna wherein radiating element and phase requirements are reduced by positioning the radiating elements to radiate through a radial waveguide. The longer wavelength in the radial waveguide relative to the free space wavelength permits a wider actual separation, while maintaining grating lobe suppression. Wave refraction at the interface of the radial waveguide with free space is a function of the guide wavelength and determines the maximum scanning capability of the antenna.

Abstract: A system for adaptively positioning nulls in the pattern of an antenna utilizing an auxiliary antenna in conjunction with a correlation receiver to determine the gain in amplitude and phase of the antenna pattern at the location of the interfering source. This gain is then utilized with the known gain at the peak of the main lobe of the antenna to compute coefficients of sinusoidal perturbation functions applied to the phase function of the antenna to establish a null in the direction of the interfering source.

Abstract: A bootlace microwave lens antenna has orthogonal delay lines for reducing adratic phase errors to improve focusing capability. The collector and radiator elements consist of mutually orthogonal pairs of subelements with one of the subelements oriented radially and the other oriented tangentially on the respective collector and radiator surfaces. Individual delay lines interconnect corresponding radial and tangential subelements on each surface thus allowing for phase corrections in the axial planes parallel to and perpendicular to the plane of scan by the introduction of an appropriate phase delay in each delay line.

Abstract: An amplitude control circuit and variable phase shifter driver, employable in electronically steerable antennas, compares amplitude and phase command signals for the amplitude controller and phase shifter with command signals derived from the amplitude ratio and phase difference between a reference r.f. signal and an r.f. signal at a selected location. The difference signals resulting from this comparison are added to the amplitude and phase shift command signals and applied to the amplitude controller phase shifter drivers to adjust the amplitude controller and phase shifter.

Abstract: A scannable antenna having a radiating array of antenna elements correspondingly coupled, through equal line lengths, to a more closely spaced array of antenna elements positioned in a space coupling region. A feed array of antenna elements, with spacings substantially equal to the spacing in the radiating array and substantially of the same physical size as the more closely spaced array, is positioned in the space coupling region in close proximity, no more than a wave length away, to the more closely spaced array. The feed array is coupled to a distribution network which provides desired phase and amplitude aperture distributions.

Abstract: The novel multi-beam multi-lens antenna of the present invention provides multi-beam coverage over a hemisphere or greater three-dimensional spatial coverage region. In its simplest configuration, the antenna comprises two microwave lenses whose design is integrated to minimize path length errors and aberrations for beams over a 360.degree. azimuth coverage range. The antenna comprises a 3-D focal ring bootlace first microwave lens that is a figure of revolution and a non-planar dome second microwave lens which provides the refractive properties necessary to obtain the hemispheric coverage while providing additional degrees of freedom necessary to reduce errors and aberrations of the lens system to within acceptable levels. Both lenses are time delay lenses to effect broadband operation and are circularly symmetric. This symmetry results in antenna performance that is invariant with azimuth beam position.

Abstract: An apparatus and method for scanning a circular array through 360.degree. with tapered aperture illumination function to achieve radiated beams with desired sidelobe levels. A switching matrix selects a predetermined number of active elements from the total number of elements disposed about the circle to form a sub-array. To this sub-array a variable amplitude distribution network is coupled to establish excitations at each active element in accordance with a desired amplitude distribution function.

Abstract: An antenna and a method for obtaining predetermined far field antenna patterns is disclosed. Empirical adjustments of a focal region feed system provides for the compensation of tolerance or other imperfections of the antenna to achieve the desired far field pattern. An element of the feed system is adjusted when the antenna is angularly positioned, with respect to a receiving element in the far field, which corresponds to the location of the element in the feed array. A desired far field pattern may also be achieved by illuminating the antenna aperture, either simultaneously or sequentially, by several plane waves, the amplitude and incident angles of which are carefully controlled, measuring the phase and amplitude of the focal region distribution caused by this illumination, and designing the feed system to establish a focal region distribution that is the complex conjugate of that measured.

Abstract: A feed system for scanning focal plane antenna systems with which a variable focal spot illumination may be achieved within the focal region of a primary antenna over a limited scanning sector is disclosed. An array of collector elements positioned to receive radiation from a scannable feed antenna is coupled to an array of radiator elements positioned in the focal region of the primary antenna, the positioning of the radiator and collector elements are such that the focal spot illumination is caused to vary with the scan angle of the antenna.