A 4 × 4 Beamforming Network for Spatial Diversity and Multiplexing Reconfiguration

Li Sun,Gao-Ang Li,Shi-Gang Zhou,Yuan Gao,Guan-Xi Zhang,Mourad Nedil

doi:10.1155/2022/7983456

Abstract

A simple 4 × 4 beamforming network with spatial diversity and multiplexing reconfiguration is proposed in this paper. By analyzing and decomposing the simplified transmission matrix of the network, it is found that the 4 × 4 butler matrix can achieve spatial diversity and multiplexing reconfiguration by switching the operating modes of the four-port devices. Therefore, by designing a reconfigurable device with three modes among hybrid coupler, crossover, and transmission line, a simple 4 × 4 reconfigurable beamforming network is achieved. The proposed network can achieve orthogonal spatial diversity responses with equal amplitude and progressive phase distribution responses at the four output ports (State 1) and hybrid spatial diversity and multiplexing responses (State 2) with equal amplitude and progressive phase distribution responses at the two adjacent output ports. For the experimental validation, a particular version of the reconfigurable device and network which work at 4.9 GHz, have been designed, fabricated, and tested. Good results indicate the proposed network can be widely used in wireless communication networks for MIMO applications.

Highlights

Nowadays, with the rapid development of wireless communication, the multiple-input multiple-output (MIMO) technique is adopted as a representative multiplexing radiation pattern forming technique in modern communication systems [1, 2]
Spatial multiplexing can increase the data transmission rate by transmitting independent information streams in parallel through the spatial channels, which is important in the high-SNR regime where the system is degree-offreedom limited [5, 6]. erefore, a MIMO system usually provides two types of gains: spatial diversity gain and spatial multiplexing gain
The actual radiation patterns should agree with the simulations due to the good S-parameters. All these results suggest that with the reconfigurable radiation patterns, the proposed reconfigurable multibeam antenna array network system can be well operated in dynamic environments

Summary

Introduction

With the rapid development of wireless communication, the multiple-input multiple-output (MIMO) technique is adopted as a representative multiplexing radiation pattern forming technique in modern communication systems [1, 2]. Spatial diversity and multiplexing are two important applications in MIMO systems. Transmit or receive diversity is a means to combat channel fading, providing higher directional gains and higher spectrum efficiency [3, 4]. Erefore, a MIMO system usually provides two types of gains: spatial diversity gain and spatial multiplexing gain. Erefore, reconfigurable beam-forming networks have aroused extensive concern by scholars [8–11]. In [10], by controlling the RF signal path through the developed microstrip feedline network using PIN diodes, a pattern-

Methods

Results

Conclusion