S.L. Chernyshev - Dr.Sci. (Eng.), Professor, Scientific Researcher Institute of Radio-Electronic Engineering, Bauman MSTU
A.R. Vilenskiy - Scientific Researcher Institute of Radio-Electronic Engineering, Bauman MSTU

Travelling wave slot antennas (TSA) is a well-known type of ultra-wideband (UWB) radiators, widely discussed earlier. Typically achieved for such antennas UWB matching, stable angle-temporal characteristics and close to constant group delay stipulate their active implementation in wideband and UWB impulse systems. In this paper we propose a novel modified TSA to adopt it performance in wideband X-band antenna arrays by reduction of array elements mutual coupling. The idea of modification is an additional dielectric inclusion in the end-fire area of a radiator. We start from synthesis of the singular balanced TSA using the minimization of internal reflections criterion. Then, a dielectric element is included into the design. Its parameters are optimized during full-wave simulations. After achieving the required performance for (8,5 - 9,8) GHz band we succeed to three-element linear array investigation. Such model helps to reveal mutual coupling levels between nearest neighbour elements. And we found the considerable reduction of coupling in (7 - 16) GHz band for array with the proposed TSA. Then the proposed TSA was investigated in planar oblique array by its simulation in a finite segment. The results predict wideband array element matching for wide-angle scanning in H-plane. On the other hand, frequency characteristics stability is lower for E-plane scanning due to stronger element coupling in E-plane. Summarizing we can conclude that proposed modified TSA design is very suitable for wideband antenna arrays.