Journal
IEEE COMMUNICATIONS LETTERS
Volume 24, Issue 9, Pages 2060-2064Publisher
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC
DOI: 10.1109/LCOMM.2020.2993961
Keywords
Phase shifters; Integrated circuit modeling; Wireless communication; Equivalent circuits; Surface waves; Varactors; Impedance; Reconfigurable intelligent surface; phase shifter model; angle-dependent; angle-reciprocity
Categories
Funding
- National Key Research and Development Program [2018YFA0701602]
- National Science Foundation of China (NSFC) [61625106]
- NSFC [61941104]
Ask authors/readers for more resources
The existing phase shifter models adopted for reconfigurable intelligent surfaces (RISs) have ignored the electromagnetic (EM) waves propagation behavior, thus cannot reveal practical effects of RIS on wireless communication systems. Based on the equivalent circuit, this letter introduces an angle-dependent phase shifter model for varactor-based RISs. To the best of our knowledge, this is the first phase shifter model which reveals that the incident angle of EM waves has influence on the reflection coefficient of RIS. In addition, the angle-reciprocity on RIS is investigated and further proved to be tenable when the reflection phase difference of adjacent RIS unit cells is invariant for an impinging EM wave and its reverse incident one. The angle-dependent characteristic of RIS is verified through full-wave simulation. According to our analysis and the simulation results, we find that the angle-reciprocity of varactor-based RIS only holds under small incident angles of both forward and reverse incident EM waves, thus limits the channel reciprocity in RIS-assisted TDD systems.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available