The Role of Mutual Coupling in A 5:1 Bandwidth Stripline Notch Array

The bandwidth broadening effects of time-domain mutual coupling from adjacent elements in a linear array of stripline notch elements was briefly described in previous papers1, 2, 3. The array was designed at the Naval Research Laboratory (NRL) to demonstrate the feasibility of 5:1 bandwidth wide-scan angle arrays with one-half wavelength spacing at the highest operational frequency. This paper presents an expanded examination of the role of mutual coupling in pulse-excited linear and planar single polarization arrays as well as in a planar dual polarization array. When viewed in the time domain, inspection of mutual coupling leads to a physical understanding of the cause of the ultrawideband (UWB) behavior of the NRL arrays. The finite-difference time-domain (FDTD) method4,5 is employed to perform the studies, and measurements verify some of the calculations.