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

In this paper, a design method for an ultra-low 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 ultra-low profile compared to previous flat-topped pattern works. During the implementation process, a magnetic current source was utilized 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 ultra-low profile, our designed large spacing phased array with a period of 0.9λ<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> and a scanning sector of ±20° demonstrates comparable grating lobe suppression performance across the operating band.