Abstract: Methods and systems for thinning the output of an array antenna are disclosed. The thinning can be applied in response to determining that the performance of a multiple element antenna array with respect to a desired signal has been compromised by the presence of one or more interfering signals. The application of a thinning pattern has the effect of turning off selected antenna elements within the array. The effect of applying a particular thinning pattern on the realized performance of the antenna system can be determined. An alternate thinning pattern can be applied if the previous thinning pattern did not result in an improvement, or a sufficient improvement, in the performance of the antenna system.

Abstract: A method for economically producing low sidelobe levels in the far field pattern of an array antenna is disclosed. The current fed to the subarrays is identically tapered to the elements of each subarray. Both the subarray current taper and the element current tapers are optimized to yield the lowest possible sidelobe levels.

Abstract: Tapering the surface current density near the edges of a parabolic reflector antenna lowers the sidelobe level of the reflector. The current density is tapered by placing tapered resistive edge loads on the reflector for gradually decreasing the conductivity from the center of the reflector to the edge.

Abstract: A system for reducing sidelobes of phased array antenna systems is performed by tapering the current amplitide of edge elements in the array while maintaining a full uniform current to the center elements in the array. Tapering may be adjusted with variable impedance devices until optimum sidelobe reduction is achieved.

Abstract: Subarray amplitude tapering is a simple, lower cost method of generating low sidelobes in an antenna's far field pattern. Unfortunately, this simple technique also generates unwanted grating lobes. Placing the exact amplitude taper at the element outputs produces the desired far field pattern, but the architecture is complicated and expensive. An alternative to these two techniques is a design process that entails placing amplitude tapering at subarray outputs and element amplitude tapers that are identical between corresponding elements in groups of identical subarrays. In this way, the amplitude taper approximates the desired taper much better than subarray tapering alone, yet groups of subarrays are identical so that the design remains very simple.

Abstract: A monopulse radar having a single set of phase shifters shared by both sum and difference channels. The radar utilizes an algorithm that effects simultaneous nulling in the sum and difference patterns of its phased array antenna. An algorithm is developed for phase-only nulling which does not require knowledge of the location of interference sources.

Abstract: A space fed microwave lens antenna for deployment in outer space or other remote, hazardous or unattended location. Electronic means are provided for compensating for errors in the mechanical displacement of the phased array feed elements from the phased array lens elements.

Abstract: An electrostatically figured directional antenna array for deployment in outer space having means for suppressing sidelobe responses. A portion of the reflector surface symmetric about its center is vibrated by electrostatic controls to change the amplitude and phase of the sidelobe signals whereby the latter can be eliminated by passive filters or time averaging circuitry.

Abstract: A monopulse radar having a single set of adaptive weights shared by both sum and difference channels. The radar utilizes algorithm that effect simultaneous nulling in the sum and difference patterns of its phased array antenna. Algorithms are developed for both amplitude and phase nulling and for phase only nulling.