Reflectarray Antenna Using Notch-Loaded Elements on a Hyperuniform Aperiodic Distribution

Aperiodic element distributions can reduce reflectarray element count by 35%, but they introduce two problems absent in periodic designs: (i) the required phases form a continuum rather than the discrete set a regular lattice produces,
demanding wider S-curve coverage than a single-parameter element typically provides, and (ii) non-uniform inter-element spacing causes physical overlaps when variable-size patches are used. This paper addresses both problems through a proportionally notch-loaded rectangular patch element at 28GHz. The
element has a fixed width W_p = 2.5mm, variable length L_p, and two symmetric notches of depth d_n = 0.15 L_p on the non-radiating edges, yielding 336^◦ of phase range on 0.508mm Rogers RO4003C substrate, with a second, independent axis
supplying a further 211^◦ of fine tuning at 0.762mm. Combined with a stealthy hyperuniform distribution on a 120mm diameter circular aperture, the design achieves 19.7dBi realised gain at 27GHz with 287 elements, matching a 441-element periodic reference to within 0.2dB in gain and 0.3dB in sidelobe level
while using 35% fewer elements. At the 28GHz design frequency the two apertures separate to 15.8dBi and 18.1dBi, a difference traced to the dependence of the element resonance on its local lattice spacing. To the best of the authors’ knowledge, this is the first reflectarray to combine a proportional notch-loaded
element with a hyperuniform distribution at millimetre-wave frequencies.