A Single-Layer Broadband Reflectarray Antenna by Using Quasi-spiral Phase Delay Line

Abstract

A novel broadband unit-cell is proposed in this paper. This new cell element consists of three coupled circular rings where four quasi-spiral delay lines are connected to the outer ring to provide the required phase shift. The spiral shape of the delay lines exhibits more than 1000 o of phase swing. The cross polarization level of the presented element is considerably improved compared to previous designs with a similar phasing mechanism. The capability of operating in linearly or circularly polarized incident wave is an important advantage of the proposed cell. In other words, depending on polarization of the feed antenna, the present reflectarray can operate in vertical, horizontal or circular polarization. Finally a moderate size reflectarray, 27×27 cm 2 , is designed and fabricated based on the mentioned element. The measured results showed about 16.5% of 1 dB gain bandwidth. The antenna gain at 8.5 GHz is 26.4 dB which is equivalent to 59.2% efficiency. Also, the measured sidelobe level and cross polarization of this antenna are about -20 dB and -25 dB, respectively.Index Terms-Quasi-spiral phase delay line, phase shift mechanism, reflectarray antenna, delay line.

Dual-band X/Ku Reflectarray Antenna Using a Novel FSS-Backed Unit-Cell with Quasi-Spiral Phase Delay Line

“…12. This wideband element has been previously introduced by the authors [14], and to avoid redundancy is not repeated here. Based on [9] the larger spacing between two arrays results in smaller coupling.…”

“…However, because of some restrictions on facilities this space was chosen to be 1 cm. Utilizing the cell element in [14], As it was shown in Fig. 7(c) the performance of FSS-backed RA has low sensitivity to the X-band horn and its angle of illumination.…”

A Low Cross-Polarization Reflectarray Antenna Based on SIW Slot Antenna

“…In addition, an element with quasi-spiral phase delay line was also proposed to realize a reduction of cross-polarization [9].…”

“…The SIW longitudinal slot antenna-based reflectarray element can provide over 360° linear phase shift with low sensitivity. Benefit from this SIW structure, lower cross-polarization level is easily achieved, compared with conventional microstrip and relevant improvement works [7]- [9]. Based on the proposed element, a The proposed SIW slot antenna element is shown in Fig.…”

Analytical Method for Designing FSS-Backed Reflectarray Antenna Using Transmission Line Approach

“…To overcome this disadvantage several multiband and broadband antennas have been used to increase the band width [1][2][3][4][5][6][7][8][9]. Multi band antennas can be implemented in single layer or multilayer configuration [1][2][3][4][5][6][7][8][9].…”