Reflective array antenna

About: Reflective array antenna is a research topic. Over the lifetime, 4366 publications have been published within this topic receiving 57884 citations.

A conformal conical phased array antenna for modern radars

Abstract: In this paper a new conformal array antenna of conical structure has been proposed. A conical phased array antenna can steer the radar beam electronically in both azimuth and elevation to cover a hemi-sphere mesh surrounding the radar antenna. Beam steering can be accomplished either continuously or discretely at definite directions. The proposed technique not only overcomes the limitations of mechanical steering systems and surveillance radar dead cone but also improves the radar tracking capability. Moreover, it is suitable to be used in MIMO radars and enemy deception systems. Element weights of the conical phased array antenna are optimized using a genetic algorithm (G.A). The optimization process improves the beam pattern peak side lobe level (PSLL) while maintaining a narrow beam width. A high resolution phase shifter and adaptive attenuator have been used for each element to acquire both the desired phase and optimum weight for conical array beam pattern. Beam pattern is simulated and tested using a Matlab Program. Improvement achieved in both antenna gain and PSLL are 18.8 and 8 dB respectively. There is a 6° tilting angle and 24° half power beam width.

A study of the antenna array configuration of an M-branch diversity combining mobile radio receiver

Abstract: The theoretical analysis in this paper is based on the assumption that the angles of signal arrival on the mobile receiver are uniformly distributed. From the analysis and experimental studies, we find that if the antenna spacing between two adjacent antennas in a space diversity array is greater than 0.5λ the array configuration does not affect the cumulative distribution curves nor the shapes of the level-crossing-rate (LCR) curves, and only slightly affects the signal level at which the maximum LCR occurs. Hence a three-element array with a triangular shape or a four-element array with a rectangular shape can be considered a good arrangement, provided each side (antenna spacing) is greater than 0.5λ. Two slightly better arrangements than those we just mentioned for improving the signal fading are also proposed for three-branch and four-branch diversity signals, respectively.

Leaky‐Wave Antennas

Abstract: The sections in this article are 1 Distinctive Features And Applications 2 Operation Principles 3 Design Techniques 4 Overview Of Specific Structures 5 Practical Considerations And Measurements

Smart antenna array

Abstract: The present invention relates to a beamforming method for smart antenna arrays. Smart antennas employ arrays of low gain antennas connected to a combining/beamforming network. Smart antennas can provide enhanced coverage through range extension, hole filling and improved building penetration. By improving transmission and reception at the base station, the tolerable path losses can be increased whereby the range of the base station can be improved. A first aspect of the invention addresses the feedback signalling technique presently being considered by standards bodies for four antennas in large arrays. The invention is suitable for CDMA wireless cellular systems, as presently determined for third generation cellular wireless networks, and other wireless systems such as TDMA systems and wireless LANs.

Design of a low-loss low-noise tapered slot phased array feed for reflector antennas

Abstract: Upgrading the Multi-Frequency-Front-Ends of the Westerbork Synthesis Radio Telescope (WSRT) by multiple-beam phased array feeds will improve its survey speed by a factor 20. The present paper describes two design steps of the dual-polarized tapered slot antenna (TSA) array required for this upgrade. Redesign of the TSA element, integration of the Low Noise Amplifier on the feed line substrate and a more rigid connection between the elements improved the low-noise performance, stability and reproducibility of the array. Although, the described array is aimed to be used as a phased array feed, the approach is also applicable in directly radiating beam-steering antenna arrays.