Single-SICL-Fed Dual-Band Dual-Circularly Polarized Antenna Array Using Pixel Structures

In this letter, a dual-band dual-circularly polarized (CP) antenna array based on the design and optimization of a parasitic pixel structure is presented. The proposed array can achieve simultaneous radiation of right-hand CP around 20 GHz and left-hand CP around 30 GHz with a single substrate integrated coaxial line (SICL) feeding structure. The array element comprises a linearly polarized (LP) magnetoelectric dipole as the driven source and a parasitic pixel layer providing the dual CP radiation. Assisted by nondominated sorting genetic algorithm II and the internal multiport method, the pixel layer is optimized to transform the LP radiation of the source into dual CP ones within dual desired frequency bands. Finally, a prototype of an SICL-based low-loss four-way feeding network integrated with the proposed 2 × 2 array is designed, fabricated, and experimentally verified. Measured results demonstrate that the impedance and AR bandwidths are 18.4 GHz to 21.6 GHz and 19.5 GHz to 20.7 GHz at <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">K</i> band, 28.6 GHz to 31 GHz and 29.5 GHz to 31.2 GHz at <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Ka</i> band, respectively. Besides, the realized peak gains within the two operation bands are 10.7 dBic and 12.8 dBic, offering a more efficient and compact solution compared to existing designs.