| It is well known that low Slow Small Target(LSST)flying objects appearing in the ultra-low altitude region have become the difficulty of detection and prevention because of their small size,simple control,ultra-low flying altitude,and many shelters on the ground.As a result,the air force and conventional radar equipment are often unable to cover.Therefore,the research on the higher efficiency,higher gain,and circular-polarization performance of the antenna will become the pursuit and development direction of LSST detection radar.The Substrate Integrated Waveguide(SIW)slot antenna has the advantages of high gain,high efficiency,low profile and low processing cost.Consequently,a kind of dual-circularly-polarized SIW slot antenna array based on SIW structure design is investigated in this paper.The main research contents are as follows:Firstly,the current research on the circularly-polarized slot antenna and SIW structure is summarized.The operating principle and basic parameters of waveguide slot antenna are introduced.The design principles of linear array and planar array antenna are illustrated and compared in detail.Secondly,a kind of SIW dual-circularly-polarized slot antenna array with operating frequency at about 35 GHz is designed.The unit of array comes from the longitudinal oblique slots etched on the surface of the SIW metal layer.A pair of oblique slots at a certain angle is controlled to form a circular-polarized radiation unit.Using the pattern synthesis method of Taylor's distributed array,a 1×16 linear array is designed which opening direction is rotated to obtain the 2×16 linear array.By analogy,the dual-circular-polarized plane antenna array with 16×16 elements is obtained by rotating the opening direction in turn.The gain of the obtained planar array is 26.1 dB,the impedance bandwidth is 6%,the axis ratio bandwidth is 4.57%and cross polarization isolation is 28.1dB.Thirdly,a kind of convenient and efficient feed network based on SIW structure is proposed to realize the effective operation of the antenna array according to the previous designed 16×16 planar array.The feeder network which is designed based on SIW structure employs the cascaded mode and combines Y,T and L types together perfectly.The in-band bandwidth is up to 6.57%,which achieves high transmission efficiency in large bandwidth.In this paper,a kind of double-circularly-polarized SIW slot antenna array is proposed with novel SIW structure instead of traditional waveguide structure.The double-circularly-polarized radiation is realized by rotating the slots in turn in the opening direction.The obtained antenna structure not only has the advantages of high gain and high efficiency of conventional waveguide slot antenna,but also is easy to realize the design of circular polarization,and easy to expand to obtain large gain array.The obtained antenna array has good application prospects with the goodcharacteristics of compact structure,low profile and easy fabrication by PCB technology. |
PDF Full Text Request