Large-Spacing Periodic Beam Scanning Arrays With Dynamic Coupling Elements for Grating Lobe Suppression

This communication presents a method for large-spacing arrays with grating-lobe-free scanning capabilities. This method achieves grating lobe (GL) suppression by transforming the large-spacing arrays into a new array with an average spacing of less than half a wavelength. Dynamic coupling elements (DCEs) terminated with a reactive load are inserted between active ones, and a coupling structure is also added to tune their coupling coefficient. Simulations and prototype measurements of a $1\times 8$ large-spacing array with and without the DCEs are analyzed to verify the effectiveness of the method. The results show that the GL level is suppressed by 10.8 dB at 50°, and the main beam gain is increased by 2.2 dB compared to the array without DCEs. The proposed method provides a general solution for GL suppression of large-spacing periodic scanning arrays without introducing aperiodicity and excitation weighting.