A Frequency Independent Framework for Synthesis of Programmable Non-reciprocal Networks

• Published in: Scientific reports Vol. 8; no. 1; pp. 14655 - 7
• Main Authors: Lu, Ruochen, Krol, Jack, Gao, Liuqing, Gong, Songbin
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 02.10.2018; Nature Publishing Group; Nature Portfolio
• Subjects: 639/166/987; 639/766/930/1032; Bandwidths; Communication; Communications systems; Delay Line Module; Humanities and Social Sciences; Input Multiple Output (MIMO); multidisciplinary; Nonreciprocal Networks; Science; Science (multidisciplinary); Single Pole Single Throw (SPST); Switching Board; Input Multiple Output (MIMO); Delay Line Module; Switching Board; Nonreciprocal Networks; Single Pole Single Throw (SPST)
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-018-32898-x

Passive and linear nonreciprocal networks at microwave frequencies hold great promises in enabling new front-end architectures for wireless communication systems. Their non-reciprocity has been achieved by disrupting the time-reversal symmetry using various forms of biasing schemes, but only over a limited frequency range. Here we demonstrate a framework for synthesizing theoretically frequency-independent multi-port nonreciprocal networks. The framework is highly expandable and can have an arbitrary number of ports while simultaneously sustaining balanced performance and providing unprecedented programmability of non-reciprocity. A 4-port circulator based on such a framework is implemented and tested to produce a broadband nonreciprocal performance from 10 MHz to 900 MHz with a temporal switching effort at 23.8 MHz. With the combination of broad bandwidth, low temporal effort, and high programmability, the framework could inspire new ways of implementing multiple input multiple output (MIMO) communication systems for 5G.