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Study Of Ultra-Wideband Tightly Coupled Phased Arrays

Posted on:2016-02-01Degree:MasterType:Thesis
Country:ChinaCandidate:D W MiFull Text:PDF
GTID:2348330488473906Subject:Electromagnetic field and microwave technology
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With the rapid development of modern radar technology, the ultra wideband phased array has aroused wide attention all over the world recently. The ultra wideband tightly coupled phased array is implemented by utilizing the coupling characteristics of the adjacent elements to achieve the extended bandwidth. It is different from the traditional method to focus on the element characteristics.Tightly Coupled Phased Arrays not only has the advantages of ultra wideband and wide angle scanning, but also has the advantages of small cross section, and low profile.In this thesis, the design of the ultra wideband tight coupled phased array is studied, and author’s contribution is as follow:1. The analysis method of the infinite periodic array antenna is studied. Based on the basic concept of Floquet series, the Floquet mode function of infinite periodic array in Floquet periodic current source is studied. The basic conditions for realizing main mode of Floquet mode are derived and the equivalent circuit model of the array element is obtained. Then the circuit model can provide the initial design data for the actual element.2. The effect of the coupling on the performance of array antenna is analyzed, and the equivalent circuit is modeled by using ADS software. The full wave simulation of HFSS software verifies the correctness of the equivalent circuit model based on ADS. The initial size of the array element is solved by optimization. Since the array elements must be balanced feed, the two ultra wideband balanced converter is designed, which can obtain the impedance bandwidth of 5:1. Finally, the array elements are optimized in order to reduce the complexity of the feed network.3.Semi infinite array simulation is obtained, and effect of termination of array is studied.Then the VSWR of element can be improved by loading the parasitic structure of the edge element.Then, the full wave simulation is carried out for the finite array of 2×8, and the impedance bandwidth of 5:1 is obtained. Finally, the 2×8 finite array is processed with 4 elements loaded as a parasitic structure and the other elements are fed by a broadband power divider of 16/1. The final array prototype is tested in the frequency 0.7~3.8GHz and VSWR is no more than 2.5. The performance of array is excellent.
Keywords/Search Tags:tightly coupled phased arrays, floquet mode, ultra wideband, effect of termination, equivalent circuit
PDF Full Text Request
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