We develop novel antenna arrays in the entire sub-THz frequency regime, including ultra-wideband antenna arrays, high-gain antenna arrays, met surfaces, etc.
An Ultra-Wideband Fully-Planar Inverted-L Element (FILE) Array
A novel element for ultra-wideband tightly coupled arrays is introduced called the fully-planar inverted-L element (FILE). Our FILE element is inspired by a traditional monopole antenna, thereby reducing its complexity in both design and fabrication. It offers a unique solution to realize ultra-wideband tightly coupled dipole arrays in the V- and W- millimeter-wave (mmWave) bands. The unit cell of the FILE array consists of an inverted-L shaped radiator that is capacitively coupled to two grounded vias. This innovative design effectively shifts the common-mode resonance and loop-mode resonance outside the desired frequency range. Infinite array simulations of our array demonstrate an operational bandwidth of 3:1 (33 to 101 GHz) with VSWR<3 for a maximum scan-angle of ± 45◦ for all principal E-, H- and D-planes. The measured results align closely with these simulations, validating the performance of our FILM array.
M.Hamza, C. Exadaktylos, C. L. Zekios and S. V. Georgakopoulos, “An Ultra-Wideband Fully-Planar Inverted-L Element (FILE) Array,” in IEEE Transactions on Antennas and Propagation, doi: 10.1109/TAP.2024.3502900
A Low Profile Planar Dual-Polarized Tightly Coupled Dipole Reflectarray With 5:1 Bandwidth
This work introduces an extremely low profile ( 0.4λhigh ) planar ultra-wideband dual-polarized reflectarray. The unit-cell structure of the array is modular in nature, and without any electrical connection between adjacent unit-cells. The array uses tightly coupled dipoles arranged in an egg-crate fashion connected with true-time-delay lines. This array provides the required phase in the highest ever reported bandwidth of 5:1 (3 to 15 GHz) with VSWR< 2.5 for a planar reflectarray. The implementation of the delay-lines is done using a sandwich configuration between two conductive planes, which significantly improves the cross-polarization purity of our reflectarray. To validate our design concept, an 18×18 element ( 135×135 mm) reflectarray is designed, fabricated, and measured. The measurements exhibit excellent agreement with the simulations.
M. Hamza, C. L. Zekios and S. V. Georgakopoulos, “A Low Profile Planar Dual-Polarized Tightly Coupled Dipole Reflectarray With 5:1 Bandwidth,” in IEEE Open Journal of Antennas and Propagation, vol. 3, pp. 958-969, 2022, doi: 10.1109/OJAP.2022.3198468.