Wideband 1-bit Reconfigurable Circularly Polarized Transmitarrays in Ka-Band
Year: 2025
Type: article
Abstract: This study details the design of an active Transmitarray (TA) operating in the Ka-band made of a reconfigurable linear-to-circular-polarization (LP-CP) unit-cell. The unit-cells incorporate a true-time-delay (TTD) polarization conversion mechanism and a stacked patch configuration to achieve wide transmission and axial ratio bandwidths. Each cell integrates a pair of PIN diodes for electronically controllable 180° phase shifts. This is the first demonstration of a wide-band reconfigurable and circularly polarized unit-cell in millimeter wave bands, without the use of an external polarizer. A 20 × 20 cells Ka-band circularly polarized TA was designed and fabricated. A random symmetric distribution of rotations applied to the inner patch antenna enhances CP purity and increases the scan range. Measurement results demonstrate a broadside gain of 20.55 dB, with both -3 dB gain bandwidth and 3 dB axial ratio bandwidth exceeding 22%, which surpasses all previous millimeter-wave reconfigurable design. In the case of the 20 × 20 cell array manufactured the scan range extends to ±60° in both E and H planes, with a maximum scan loss of 4.2 dB and axial ratio values under 2 dB for elevation angles up to ±50°. Additional full wave simulations of a larger 60 × 60 cell array demonstrate a better maximum scan loss of 2.4 dB for elevation angles reaching ±50°, 3.8 dB for an elevation angle of ±60° and 6 dB for an elevation angle of ±70° with axial ratio values consistently under 3 dB.
Source: IEEE Access
Institutions: Office National d'Études et de Recherches Aérospatiales, Institut National Polytechnique de Toulouse, Laboratoire Plasma et Conversion d'Energie, École Nationale Supérieure d'Électrotechnique, d'Électronique, d'Informatique, d'Hydraulique et des Télécommunications, Université de Toulouse
Language: English
Subfield: Aerospace Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,075
OpenAlex ID: W4414603471