  The design of low-profile linear microstrip arrays with wide-band spatial
filtering capabilities is dealt with. An innovative architecture, leveraging
the angular selectivity of offset stacked patch (OSP) radiators, is proposed to
implement phased arrays (PAs) with inter-element spacing larger than
half-wavelength that feature remarkable grating lobes (GLs) suppression
properties and an enhanced gain within a non-negligible down-looking scanning
angular range. The PA layout is then obtained by optimizing the optimal
micro-scale geometrical descriptors of the radiating elements so that the
macro-scale electromagnetic (EM) features of the arising finite-size PA fulfill
the user-defined requirements. A set of numerical test cases, concerned with a
variation of the array size and its polarization, is presented to assess the
capabilities, the flexibility, and the potentialities of the proposed spatial
filtering technique (SFT) also in comparison with competitive state-of-the-art
alternatives. The performance of a printed circuit board (PCB)-manufactured
prototype are experimentally assessed, as well.
