K.S. Rao

Bio: K.S. Rao is an academic researcher. The author has contributed to research in topics: Antenna aperture & Periscope antenna. The author has an hindex of 1, co-authored 1 publications receiving 4 citations.

A template for shaped-beam satellite antenna patterns

Abstract: A modified template is proposed for shaped-beam satellite antenna patterns for use in orbit-planning studies of a fixed satellite service. Based on a previously discussed simple model, the template now includes the effects of beam scanning, aperture blockage, and surface errors. It is found to agree well with the measured data on current satellites and is a reasonable upper bound specification for future satellite antennas. >

Design and analysis of multiple-beam reflector antennas

Abstract: Simplified design and analysis equations are presented for multiple-beam reflector antennas based on the Gaussian-beam analysis of the primary and secondary patterns. The derived equations are useful for the quick design and performance analysis in terms of the coverage-area directivity and the inter-beam isolation of multiple-beam antenna systems. Results of the analysis given in this paper agree well with rigorous computations based on physical-optics analysis of the reflector-antenna radiation patterns. Extension of the analysis to multiple-beam lens antennas, and to shaped/contoured-beam antennas, is also presented.

Development of a 45 GHz multiple-beam antenna for military satellite communications

Abstract: Design and experimental results of a wide-angle coverage 45 GHz multiple-beam antenna for military satellite communications are presented in this paper. The high-gain spot beams with low sidelobe levels and efficient adjacent beam overlap are generated by employing an offset parabolic reflector with overlapping feed clusters. The beam shape can be adapted to cancel either single- or multiple-jammers by varying excitations within the feed cluster corresponding to the beam. Development of antenna components including Potter horn, polarizer, phase-amplitude controller, and beamforming network is discussed. Measured results of the demonstration antenna have shown that sidelobe and crosspolar levels of better than -25 dB are achieved for beams scanned over an eight-degree diameter circular coverage region. The adapted patterns of the antenna agree well with the computations, and null depths of better than 30 dB have been realized over a 4.5% bandwidth. >

Efficient optimization and realization of a shaped-beam planar array for very large array application

Abstract: The optimization and simulated realization of planar 2-D antenna array with a flat-top shaped-beam pattern are proposed in this paper. The shaped-beam planar array can be used as an element of Very Large Array for the Deep Space Detection. A conventional genetic algorithm is chosen for the optimization. However, the synthesis of flat-top shaped-beam using a planar 2-D array is difficult because of the inherently large number of degrees of freedom involved in the algorithm (in generally, the amplitude and phase of each element must be determined). Therefore, a sub-array rotation method, which lies on the flat-top pattern synthesis itself, is proposed in this study to resolve the design problem. Besides, the proposed synthesis has taken the actual element patterns but identical and isotropic ones into account, which can reduce the error between computation and realization. A 8 × 8 (64)-element rectangular array is exampled, and the results of the optimized flat-top patterns are shown to illustrate the validity and high efficiency of the technique.

Efficient optimization of flat-top patterns using genetic algorithm for the deep space detection application

Abstract: The optimization of a flat-top pattern of planar 2-D array antenna is proposed in this paper The shaped-beam planar array is employed to be an element of very large array for the deep space detection A conventional genetic algorithm is chosen for the optimization However, the synthesis of a flat-top shaped beam using a planar 2-D array is difficult because of the inherently large number of degrees of freedom involved in the algorithm (in generally, the amplitude and phase of each element must be determined) Therefore, a sub-array rotation method, which lies on the flat-top pattern synthesis itself, is proposed in this study to resolve the design problem A 10times10 (100) element array is employed, and the results of the optimized flat-top pattern are shown to illustrate the validity and high efficiency of the technique