Research On The Performance Of Wide-Angle Scanning Phased Array Based On Pattern Reconfigurable Technology

The wide-angle scanning phased array can find targets in a large airspace, whichcould provide timely information for electronic guidance, detection, search, recognition,acquisition and tracking. Millimeter-wave phased arrays have some particularadvantages, such as excellent characteristic in penetration propagation, good capabilitiesin anti-jamming and anti-stealth, small size, and light weight, so they have been widelyutilized in airborne, shipborne, and spaceborne platforms. Therefore, it is of greatimprotance to research on the millimeter-wave phased array with wide-angle scanning.This dissertation takes investigation on the analysis and design methods ofwide-angle scanning millimeter phased array and is organized as follows:In Chapter1, the research background and recent developments about phased array,wide-angle phased array, and pattern reconfigurable antenna technology are reviewed.Some critical problems in the development process of phased array are discussed andspecial focus is cast on one of them, the wide-angle scanning. Several ways to realizewide-angle scanning are summarized. And then the features of pattern reconfigurabletechnology and its implementation methods are analyzed.In Chapter2, some parameters impacted on the scanning beam angle, gain,beam-wdith, and greating lobes of phased array are analyzed at first. Then patternreconfigurable technology and design of phased array are combined, and a new idea forwide-angle scanning is presented. This new idea includes a wide-angle scanningapproach, an experimental verification scheme, and a model of experimental antenna.Detailed implementation steps for wide-angle scanning are introduced in the new wideangle scanning approach. Experimental verification steps and corresponding indexdecomposition for a1×4active phased array are explained in the new experimentalverification scheme. Finally, an experimental antenna model is proposed, which consistsof pattern reconfigurable elements,1×4active phased array, Transmitter andReceiver(T/R) unit, and feeding networks.In Chapter3, a novel millimeter-wave pattern reconfigurable antenna withreconfigurable feeding networks is proposed. The proposed reconfigurable antenna canobtain its different radiating patterns by reconifgurabling its feeding networks. Firstly,the reconfigurable principle is investigated and a detailed analytical expression for reconfigurable mode estimation is provided. Secondly, according to the calculationresults of the analytiacal expression, three types of reconfigurable feeding networks aredesigned. Finally, a quantitative design method for this kind of pattern reconfigurableantenna is proposed. Futhermore, the analytical estimation expression is amended andimproved, which takes the mutual coupling effect between the pattern reconfigurableantenna’s basic radiation elements and the insert loss of the embeded PIN diodeswitches into account. The test results show that the pattern reconfigurable antnena hasthree different reconfigurable modes and its jointed3dB beam-width can cover about128°in the elevation plane, and the radiating gain reaches9dB with a gain fluctuationless than1dB.In Chapter4, firstly, a1×4phased array with pattern reconfigurable elements isproposed. The specific structure and its feeding networks are provided. According to thenew wide-angle scanning approach, the scanning space is divided into three sub-spaces,phased scanning is implemented in each sub-space, and then wide-angle scanning isrealized in the jointed sub-spaces. Secondly, the proposed phased array and its scanningbeams are analyzed. When the array factor of the phased array is analyzed, it is foundthat the phased array with pattern reconfigurable elements has a two-dimensionalfreedom of scanning. When the structure of the feeding networks are analyzed, aanalytical method is proposed to avoid the grating lobes in each sub-space bycontrolling the space between each radiating unit in the pattern reconfigurable element,the space between each reconfigurable element in the phased array, and thereconfigurable modes. And a specific description with diagrams and analytical formulasare given. Finally, for the problems of high levels of side lobes, inaccurate beampointing angles, and mutable beam width, a genetic algorithm is used to get optimizedscanning beams. The test results show that the phased array can scan its main lobe from-75°to+75°and its jointed3dB beam width can cover±80°in the elevation planewith a gain fluctuation less than3dB.In Chapter5, a summary of the whole dissertation is given and topics for futureresearch are suggested.