Synthesis Procedure for Thinned Leaky-Wave-Based Arrays With Reduced Number of Elements
Abstract
We proposed a synthesis method to design thinned leaky-wave-based arrays. The array elements are small waveguide apertures opened on a ground plane. A superstrate (impedance sheet, dielectric slab, etc.) is placed above the array. The array elements excite leaky-wave modes between the ground plane and the superstrate, enhancing the aperture efficiency of the final antenna. An iterative optimization procedure based on a convex l1 minimization is used to reduce the number of array elements, maintaining the radiated field within a predefined mask. All the embedded element patterns are evaluated for each source through a fast Green's function spectral approach, taking into account the effects of the mutual coupling during the optimization procedure. The use of a superstrate provides array structures with a reduced number of elements and enhanced aperture efficiency with respect to configurations without superstrate. The level of the grating lobes is also controlled during the optimization. A parametric study is performed to understand the capabilities of the leaky-wave-thinned array varying the reflectivity of the superstrate. As an example, an array of 18 elements working over a 7% fractional bandwidth is synthesized, providing a reduction by a factor of 4 in the number of elements when compared to a configuration with the same requirements, but without superstrate
Keywords
Antenna arrays
antenna radiation patterns
Apertures
array elements
convex minimization
embedded element patterns
fast Green function spectral approach
grating lobes
Gratings
ground plane
iterative methods
iterative optimization procedure
leaky wave antennas
Leaky-wave antennas
Leaky-wave antennas (LWAs)
leaky-wave modes
leaky-wave-thinned array
minimisation
Minimization
mutual coupling
Optimization
radiated field
reduced number of elements
thinned array antennas
thinned leaky-wave-based arrays
waveguide antenna arrays
waveguide apertures