论文部分内容阅读
随着高g、高速导弹的使用,占居整个电磁频谱的机载、舰载和陆用威胁雷达在不断地扩展,这就要求现代防御系统不仅能覆盖宽频带宽,而且能覆盖宽范围的视界角。战术飞机上现有的可容纳天线的位置数有限,这就鼓励发展适合于多种雷达功能以及电子对抗(ECM)和电子侦察(ESM)功能的、可编程的多功能(或共用孔径)天线系统。如ICNIA和PAVE PILLAR一类程序早已对战术飞机的共用孔径系统作过验证。只有相控阵才具有满足共用孔径系统要求同时也满足战术飞行器恶劣环境和空间限制要求所必要的扫描角覆盖范围、频带宽度和计算机控制的灵活性。本文将论述提供孔径(天线单元的阵列)的问题,该孔径与其工作带宽和栅瓣要求相一致,并且可组成收-发(T/R)模件相控阵。要求的频率覆盖范围已逐渐加宽到使目前典型的频带带宽超过几个倍频程。随着频率覆盖范围的增大,可以考虑的辐射元类型已逐渐减少。目前,随着频带宽度超过三个倍频程,只有像对数-周期阵列、指数切口或扩口缝隙那样的端射单元才可视作可行的辐射元。孔径性能的另一限制是孔径提供给阵列其余部分的有效扫描电压驻波比(VSWR)。需要研究和弄清的是在低频时发生的高有效扫描VSWR的现象。本文将讨论适合于多功能系统应用的有源线阵和宽带相控阵孔径的设计和性能。
With the use of high-g and high-speed missiles, the airborne, shipborne and land-based threat radars that occupy the entire electromagnetic spectrum are constantly expanding. This requires that modern defense systems not only cover broadband bandwidth but also cover a wide range of horizons angle. The limited number of positions available on tactical aircraft to house an antenna encourages the development of programmable multipurpose (or shared aperture) antennas suitable for a variety of radar functions as well as electronic countermeasure (ECM) and electronic reconnaissance (ESM) functions system. Programs such as ICNIA and PAVE PILLAR have long validated the common aperture system for tactical aircraft. Only phased arrays have the scanning angle coverage, bandwidth, and computer-controlled flexibility necessary to meet common aperture system requirements while also meeting the tactical aircraft harsh environment and space constraints requirements. This article addresses the issue of providing an aperture (array of antenna elements) that is consistent with its operating bandwidth and grating lobe requirements and that can form a T / R phased array. The required frequency coverage has gradually widened to more than a few octaves typical of current bandwidth. As the frequency coverage increases, the types of radiators that can be considered have been gradually decreasing. At present, only end-fired units such as logarithmic-periodic arrays, exponential notches or flared slots can be considered as viable radiating elements as the frequency bandwidth exceeds three octaves. Another limitation of aperture performance is the effective scan voltage standing wave ratio (VSWR) that the aperture provides to the rest of the array. What needs to be studied and clarified is the phenomenon of high effective scanning VSWR at low frequencies. This article will discuss the design and performance of active and broadband phased-array apertures suitable for multi-function system applications.