A 1-bit Time-Modulated Reflectarray for Reconfigurable-Intelligent-Surface Applications

Design of Intelligent Reflect Surface Using Liquid Crystals

“…Hiroyasu Sato (1) , Toru Fujisawa (1) , Yosei Shibata (1) , Takahiro Ishinabe (1) , Hideo Fujikake (1) , Qiang Chen (1) (1) Graduate School of Engineering, Tohoku University; e-mail: hiroyasu.sato.b1@tohoku.ac.jp Intelligent Reflect Surface (IRS) technology which electrically controls the direction of reflected beam has attracted recent years. A representative phase control technology for implementing IRS is a reflect array using diodes, however, low efficiency is one of the problem due to losses of diode in the millimeter wave band, binary phase changes and harmonics.…”

Liquid crystal based reflectarray for reconfigurable intelligent surface applications

“…With the demand of massive data and rapid communication speed, the sixthgeneration (6G) wireless networks come to the public gradually, due to the tight spectrum resources, commercial companies and academic scholars divert attention to mm wave band and try to apply millimeter wave antenna in wireless communication system [1], but the physical properties of Wave-particle duality of electromagnetic waves and diffraction of electromagnetic waves at high frequency build barriers in the wireless channel to users and lower the signal noise ratio in communication. [2] For the weakness of millimeter wave penetration into the wall, reconfigurable intelligent surface is being widely studied [2,3,4] as a possible solution to the end users at high-frequency wireless communications owing to their reconfigurabilities such as controlled-direction beam, multibeam and beam forming, such a steering property of beam can be used in programmable transmitters or receivers to further strengthen the signal to the users in need and guide the electromagnetic wave transmitting to the desired districts.…”

A New Unit-Cell Design for a 2-Bit Reflective Metasurface for RIS Applications

“…RIS improves the coverage and quality of signal by intelligently controlling the propagation environment. RIS uses low-cost reflecting metasurface (MTS) integrated with switching components like PIN diodes [6][7][8][9][10][11][12][13][14][15][16][17], varactor diodes [18,19], and a smart controllers. MTS exhibits special properties due to its ability to modify the incident electromagnetic (EM) waves on its surface.…”

“…The number of diodes in the structure is determined by the number of bits and, usually, one PIN diode is required for 1-bit operation and two PIN diodes provide 2-bit operation. Currently, plenty of research is going on to design new unit cells, a 1-bit digital metasurface unit-cell is designed by connecting a PIN diode between two similarly slotted rectangular sub-patches [6], and a microstrip patch also works as a tunable resonator and provides 1-bit operation using the phase delay lines integrated with a pin diode [8]. The higher number of bits requires more PIN diodes, which increases the design complexity.…”