Tightly Coupled Phased Antenna Array And RCS Reduction Techniques

With the rapid development of modern military technology, the demand for broadband and wide scan phased array with stealth capability is increasing. The traditional broadband phased arrays’ transverse or longitudinal dimension is large, antenna can not conform and has poor stealth performance. There is a strong coupling between the array unit, the antenna bandwidth is difficult to further expansion. Recently tightly coupled array antenna uses a strong mutual coupling between the elements to expansion bandwidth, it also has a flat structure, small size, low RCS. In this paper, tightly coupled array is designed to meet the requirements and we also put forward the corresponding strategies of reducing RCS. The main work is divided into four parts:Firstly, the related background, current research, and the research significance about phased array antenna and RCS reduction are introduced.Secondly, for avoiding the shortcomings of traditional broadband phased array, basing on a detailed analysis of mutual coupling theory, I design one tightly coupled array with periodic structure in HFSS software. The simulation results show that with the addition of the actual feed structure, the active standing wave ratio(VSWR≤2) bandwidth can reach five octave. When the antenna achieves ?45? scans, its active standing wave ratio(VSWR) is less than or equal to 3. Then, the unit is used to make up for a 6 × 6 array. And when the antenna achieves ?45? scans, the active S11 and gain pattern are presented.Thirdly, in order to improve the antenna stealth performance, analyzing the scattering mechanism of the antenna,I build 6 × 6 mode in CST software. In the case of matching load, the ground is the main source of structural model items. In order to reduce RCS, the ground miniaturization technology and conformal antenna is used. The simulation results show that the proposed strategies can play a good effect to reduce RCS without deterioration in its radiation properties. we examine the tightly coupled array plays good performance at bistatic RCS for that there is no scattering grating lobes when the incident wave is large angle.Finally, in order to verify the correctness of these conclusions, the tightly coupled antenna is processed and assembled, then in a large anechoic chamber, the antenna radiation performance is tested and the results are compared with the simulation results.