A Wideband Transmitarray Using Double-Petal Loop Elements

Abstract

Abstract-In this letter, a four-layer transmitarray operating at 9.5 GHz is designed using a doublepetal loop element as the unit cell. A configuration of the double-petal loop elements is used to increase transmission phase variation while maintaining a wide transmission magnitude bandwidth of the unit cell, and a full transmission phase range of 360 • is achieved for a transmission magnitude equals to or better than −2.4 dB. Furthermore, the oblique performance of the unit cell is also good. Then, a primefocus 676-element microstrip transmitarray with the proposed element is fabricated and measured. The highest measured gain is about 22.15 dBi at 9.8 GHz, resulting in a 31% aperture efficiency. The antenna bandwidth of 10.2% (from 9.3 to 10.3 GHz) for 1-dB gain is achieved in this design.

Holographic transmitarray antenna with linear polarization in X band

“…Table 1 compares the proposed hologram with some existing works that are designed based on the only-phase technique. In terms of the 1-dB gain bandwidth, the proposed antenna performs better than [12][13][14][15][16][17]. This is mainly due to considering the effects of almost all incident angles on the transmission admittance calculations and using subwavelength unit cells, which becomes possible due to using the holographic technique.…”

“…In terms of the aperture efficiency, the performance of the hologram is better than 12 . However, it has worse performance than [13][14][15][16][17]. The reduction in the aperture efficiency is because of the low illumination and spillover efficiencies of the feed horn.…”