Dual-Band, Dual-Linearly Polarized Transmitarrays for SATCOM Applications at Ka-Band

We propose here a
$40\times 40$
-element shared-aperture dual-band dual linearly-polarized transmitarray with 1-bit phase resolution and fixed beam at Ka-band. The design is based on a stacked approach where the unit-cell size is compact and is equal to only
$0.48\times\lambda_{0}$
and
$0.32\times\lambda_{0}$
at 29 GHz and 19 GHz, respectively. The beam-scanning performances of this array are compared to those of an array with the same number of elements and same illumination but comprising unit-cells based on the interleaving approach (lattice size of
$0.72\times\lambda_{0}$
and
$0.47\times\lambda_{0}$
, respectively). The shared-aperture unit-cells include four printed U-slotted patch antennas and a connecting metallized via; the desired
$180^{\circ}$
phase shift is obtained by rotating one of the patches around its corresponding via. Our simulation results demonstrate that the transmitarray based on the stacked approach exhibits excellent beam scanning performance up to
$\pm 70^{\circ}$
on the two bands. A prototype pointing at broadside has been optimized and fabricated to validate the numerical simulations.