A planar and thin‐grooved Fresnel lens is a great candidate for gain enhancement in millimetre wave communication, imaging systems, and wireless power transfer applications. The authors report the design, fabrication, and measurement of a 3D‐printed Fresnel lens, using a single material. A low‐profile (1.2λthick) 4‐zone Fresnel lens with 16 annular rings is designed with a focal length of 40 mm (≃4λ) operating at 30 GHz. Authors’ design consists of four‐step heights with outer radius of 69 mm (6.9λ). Permittivity and loss tangent of polylactic acid are measured to be 2.79 and 0.0048 at 30 GHz, respectively. Focusing ability of the lens is studied using full‐wave simulation. The lens is fabricated using a table‐top commercial fused deposition modelling printer. The surface roughness, step heights, and radii of each zone are measured and verified using a 3D optical profilometer. Impact of the 3D‐printed limitation on performance of the device is discussed. The gain of the fabricated prototype is measured, in conjunction with a horn antenna, in an anechoic chamber. Pattern measurement results illustrate 6.6 dB gain enhancement at broadside at 30 GHz. Gain enhancing behaviour is studied at three different focal lengths and frequencies of 29–31 GHz.
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Computational Analysis of a 200 GHz Phased Array Using Lens-Coupled Annular-Slot Antennas
We report the design, simulation, and analysis of a THz phased array, using lens-coupled annular-slot antennas (ASAs) for potential beyond 5G or 6G wireless communications. For a prototype demonstration, the ASA employed was designed on a high resistivity Si substrate with a radius of 106 μm, and a gap width of 6 um for operation at 200 GHz. In order to achieve higher antenna gain and efficiency, an extended hemispherical silicon lens was also used. To investigate the effect of the silicon lens on the ASA phased array, a 1 × 3 array and 1 × 5 array (the element distance is 0.55λ) were implemented with a silicon lens using different extension lengths. The simulation shows that for a 1 × 3 array, a ±17° scanning angle with an about −10 dB sidelobe level and 11.82 dB gain improvement (compared to the array without lens) can be achieved using a lens radius of 5000 μm and an extension length of 1000 μm. A larger scanning angle of ±31° can also be realized by a 1 × 5 array (using a shorter extension length of 250 μm). The approach of designing a 200 GHz lens-coupled phased array reported here is informative and valuable for the future development of wireless communication technologies.
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- Award ID(s):
- 1711631
- PAR ID:
- 10382395
- Date Published:
- Journal Name:
- Applied Sciences
- Volume:
- 12
- Issue:
- 3
- ISSN:
- 2076-3417
- Page Range / eLocation ID:
- 1407
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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