Beam steering through phased arrays is a well-established technique, used extensively inultrasonic imaging for medical, NDE and SHM applications. Phased arrays typically needindividual control of their elements, which involves hardware and software complexity. Thispaper presents the characterization of a novel frequency-steerable array for structuralhealth monitoring. In the considered configuration, beam steering is achievedby exploiting interference phenomena generated by the spatial lay-out of thearray elements, and their simultaneous activation at specific frequencies. Suchfrequencies correspond to wavenumbers which are associated with radiation indetermined spatial directions. In essence, the array acts as a spatial filter, whichpreferentially radiates at wavenumbers defined by the spatial arrangement of theelements. As such, the array is also effective at tuning its radiation to specific wavemodes. In this paper, a simple quadrilateral periodic topology illustrates thedirectional properties of the array and shows its tuning capabilities. The investigationsare supported by a preliminary numerical analysis, which is used to design anexperimental prototype. Tests successfully validate the numerical predictions anddemonstrate the directional and tuning capabilities of the proposed array design.