A Wideband Thin Transmitarray Antenna by Using L-probe Patch Antenna With True-Time Delay

• Published in: IEEE antennas and wireless propagation letters 2023-10, Vol.22 (10), p.1-5
• Main Authors: Zhai, Zhen Jun, Lin, Feng, Zhao, Guo Qiang, Sun, Hou Jun
• Format: Article
• Language: English
• Subjects: Antennas; Apertures; Bandwidths; Broadband; Broadband antennas; Cross polarization; Frequency ranges; Gain; Linear phase; Metals; Patch antenna; Patch antennas; Phase shift; Phase shifters; Receiving; Receiving antennas; Substrates; thin; Time lag; Transmission; Transmission loss; transmitarray; Transmitting antennas; true-time delay; Wideband
• ISSN: 1536-1225; 1548-5757
• DOI: 10.1109/LAWP.2023.3292250

This paper presents a wideband thin transmitarray (TA) antenna by using low-profile L-probe patch antennas, which act as the receiving and transmitting antennas of the TA element. The receiving and transmitting antennas are connected by a microstrip-line phase shifter with true-time delay, so the TA element maintains low transmission loss and linear phase-shift characteristic within a wide frequency range. The continuous 360° phase shift is obtained by rotating the receiving antenna and changing the length of microstrip-line phase shifter, which is integrated with the L-probe of receiving antenna in the same substrate. Thus, the TA antenna achieves a high aperture efficiency, wide gain bandwidth with a reduced profile. For verification, a prototype of 132-element TA antenna operating at 14 GHz is fabricated and measured. The size of the element is 0.42 λ 0 × 0.42 λ 0 , and the thickness of TA antenna is 0.13 λ 0 (λ 0 is the wavelength in free space at the lowest working frequency). The measured peak gain is 22.2 dBi and the maximum aperture efficiency is 50.7%. The measured 1-dB gain bandwidth is from 12.6 to 15.2 GHz (18.7%). The measured results also show a good radiation pattern with low cross polarization of 30 dB.