A single‐layer Ka‐band broadband reflectarray antenna using log‐periodic elements

Abstract

This letter presents a novel log‐periodic reflectarray element based on a single‐layer substrate. To achieve a full 360° phase coverage with a gentle slope, the corresponding parameters are optimized. For the sake of minimizing the effects of the feed blockage, the proposed element is used to construct a Ka‐band offset‐fed reflectarray antenna whose aperture size is 81 mm × 81 mm. Moreover, a corresponding prototype is also fabricated to test the actual radiation performance. The measured maximum gain is 26.65 dB at the center frequency of 33 GHz with the aperture efficiency of 46.34%. Moreover, the measured peak sidelobe for E‐plane is lower than −17.87 dB and 10.69% of 1‐dB gain bandwidth is also achieved, which demonstrates that the proposed antenna features the characteristic of broadband. The simulated and measured results show that the proposed antenna features good radiation performance, which has the potential for 5G communication systems.

A novel broadband reflectarray for 5G satellite communications

“…4. Compared with the values reported in References [5,7,9,11], this work reports a better 3 dB pencil beamwidth of 5.7 at the center frequency of 26.5 GHz.…”

“…The proposed concentric square split rings offer an increased phase variation of 420 over 24-32 GHz which is more compared to References [6-11] 2. The proposed RA offers a better 1-dB gain-bandwidth of 28.6% over a frequency range of 24.5-32 GHz than the RAs reported in References [5][6][7][8][9][10][11].…”

“…References [5,6,9,11], the designed RA offers an increased value of 27.1 dBi using only 413 elements. 4.…”

“…Multiple structures in a single unit cell provides phase range above 550 , and the RA offers an increased 1 dB gain bandwidth of 10.6% with a sidelobe level of À13.1 dB. Another single-layer Ka-band RA reported in Reference [9] is constructed using log-periodic elements which provide a phase variation of 360 by varying the dipole length at 33 GHz. By designing smaller phase sensitivity structure of 13.36 per rotation, a better linearity slope is achieved.…”

“…Based on the study made through the literature, side tilting technique, 5 varying dielectric resonator height, 7 varying log periodic elements, 9 subwavelength elements, 10 perforated dielectric substrate, 15 and complex unit cell designs offers narrower bandwidth that needs to be addressed. So simple unit cell with concentric coupled half-square rings having two delay lines attached to the outer ring is proposed to provide a phase range of 420 .…”