Contents I. Introduction
With the rapid development of modern electronic technology, the active phased array antenna has been widely used in radar, ECM, communication system, etc. The application platforms have been expanded from land-based to airborne, missile-borne, space-borne and other platforms; The performances of active phased array antenna are evolving towards miniaturization, light weight, low cost, and high integration [1]–[3]. In order to satisfy the application requirements of missile-borne and space-borne platforms, which have great limitations on antenna profile and weight, horizontally integrated and longitudinally assembled multilayer tile antenna has become one of the important development trends of active phased array antenna. Under the condition that the horizontal dimension of the antenna array is strictly limited, the multi-layer tile antenna compresses and arranges the functional circuits perpendicular to the direction of the array to form a standardized, low-profile, and horizontally scalable RF subarray. The design can effectively reduce the antenna size and profile, optimize the connection between the layers and modules, and also can reduce the interconnection loss [4]. As described above, when the horizontal space of antenna array is relatively shortage, the interconnections between each module have become particularly important and complex. How to realize the interconnections among modules of array with high efficiency, low loss and high integration has become the key problem of tile active array.
