Antenna Array With Superdirectivity Properties and Possible UWB Application

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Antenna Array With Superdirectivity Properties and Possible UWB Application

Journal Title: Цифрові технології - Year 2018, Vol 1, Issue 23

Abstract

The algorithm for full rejection of the side lobes of a pattern antenna array at the given azimuth angle points outside the main lobe area are considered.Ultra wideband (UWB) radars are use not only ultrashort pulses, but also a very low level of radiated power for compressed signals with long enough duration. High range resolution and accuracy of mesuaring the distance to the target is provided by UWB radars. High spatial resolution also provides the ability to isolate the target from background noise [11]. The modern UWB radars aren’t free from lot of drawbacks, including high enough side lobes level of radar antenna array diagram. It leads to impossibility of separation reflected signals from the big targets (which have big effective reflecting surface (ERS)) and from the small targets, which has small ERS, and which are situated on the same distance and have azimuth angle’s with close value. The solution of this problem can be obtained by means radar antenna pattern formation on the base of antenna array with controlled elementsThe algorithm for full rejection of the side lobes of a pattern antenna array at the given azimuth angle points outside the main lobe area are considered. The antenna pattern side lobes required suppression level are realized with the simple methods by using the arrays with limited number of tunable weight coefficients of spatial filter (antenna array elements), for example, with only two of such tunable weight coefficients. In this case all weights coefficients of the receiving antenna array, except two (first and last: , ), are fixed (selected under the condition of providing the required average antenna pattern side lobes level - ).Those (no tuning) elements of the array are chosen to obtain given average side lobe level suppression with given value of the antenna directivity. Also,different algorithms for calculation fixed weights coefficients for providing the required average antenna pattern side lobes level are presented: on the base mean-square criteria [5,6] and more simple ones on the base of weighting functions sin(x) and [7,8], which give the possibility of changing depth of modulation of weighting function in wide interval (from equal values maximum and minimum weight coefficients till the biggest possible difference between them) and correspondingly different levels of the average side lobes suppression and losses in antenna’s directivity. Numerical examples were considered for demonstration the efficiency of different weighing functions suggested for fix coefficients. The partial diagrams were calculated for this purpose. The special interaction of these no tuning elements for realizing the superdirectivity properties is used. The full reception diagram of 10 elements antenna (2 tuned elements and 8 fix elements) provided side lobes suppression in given points with equal and unequal elements weighting functions are investigated. The efficiency of suggested design has been investigated. The structural diagram of the array is presented.

Authors and Affiliations

V. M. Koshevyy, A. A. Shevchenko

Keywords

EP ID EP674184
DOI -
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