An Ultralow Profile Large Spaced Phased Array With Grating Lobe Suppression Capability by Exciting Leaky Wave Waveguide

In this communication, a design method for an ultralow profile, periodically large spacing phased array antenna capable of suppressing grating lobe is presented. We first propose and demonstrate a theoretical model for calculating the relationship between flat-topped element pattern and dispersion constants of bidirectional in-phase leaky wave. Then, our novel method of exciting metasurface leaky wave waveguide, not only proving the effectiveness of the aforementioned model but also offering the advantage of an ultralow profile compared with previous flat-topped pattern works. During the implementation process, a magnetic current source was used to excite bidirectional in-phase leaky wave, resulting in a quasi-circular aperture field distribution. Simultaneously, an approximate circuit model was established to explain the underlying radiation mechanism. Finally, through measurement and comparison, under the premise of an ultralow profile, our designed large spacing phased array with a period of $0.9\mathbf {\lambda _{0}}$ and a scanning sector of ±20° demonstrates comparable grating lobe suppression performance across the operating band.