数字编码超材料相频响应扩展及验证

doi:10.19665/j.issn1001-2400.2022.05.011

摘要/Abstract

摘要：

数字编码超材料具有优异的电磁调控能力,通过开关形式控制相位以达到调制空间辐射场的能力,可用于实现低成本的数字阵列。然而,数字编码超材料在实际应用中存在色散效应,使得数字量化相位调制一致性带宽过窄。以1 bit编码超材料单元为例,提出了表征相位调制一致性的δ-相位带宽定义,并根据数字编码超材料的结构特点结合传输线理论,给出了一种用于数字编码超材料单元的传输线结构。通过引入非均匀传输线、增加多支节传输线的方法,不仅扩展了数字编码超材料单元的相频响应、幅频响应的调谐范围,同时能根据不同相位调制一致性下的带宽要求提出设计标准。使用电磁仿真软件CST对非均匀传输线与多支节传输线相应的结构参数进行优化,仿真结果表明:在不同单元相位差δ的情况下,δ-相位带宽均得到展宽。最后,在阵列波束合成与随机辐射场生成两种典型应用背景下,分别对数字编码超材料的波束指向性与方向图相关性两项指标进行测试,证明了所提方法在宽带应用中的有效性。

关键词: 数字编码超材料, δ-相位带宽, 非均匀传输线, 多支节传输线

Abstract:

Digital coded metamaterials have an excellent electromagnetic control ability,and can be used to realize low-cost digital arrays by controlling the phase in the form of switches to modulate the spatial radiation field.However,the dispersion effect of digital coded metamaterials in practical applications makes the coherent bandwidth of digital quantization phase modulation too narrow.Taking 1 bit coded metamaterial unit as an example,the phase bandwidth is proposed to characterize the phase modulation consistency.According to the structural characteristics of digital coded metamaterials and the transmission line theory,a transmission line structure for a digital coded metamaterial unit is given.By introducing a non-uniform transmission line and adding a multi-branch transmission line,the tuning range of phase-frequency response and amplitude-frequency response of a digital coded metamaterial unit is extended,and the design standard can be proposed according to the bandwidth requirements under different phase modulation consistencies.The electromagnetic simulation software CST is used to optimize the structure parameters of the non-uniform transmission line and the multi-branch transmission line.Simulation results show that the -phase bandwidth is broadened under different unit -phase differences.Finally,under the two typical application backgrounds of array beamforming and random radiation field generation,the effectiveness of the proposed method in broadband applications is proved by the two indicators of beam directivity and pattern correlation of digital coded metamaterials.

Key words: digital coded metamaterials, δ-phase bandwidth, nonuniform transmission line, multi-branch transmission lines

中图分类号:

TN82

王国强,马晖,高思哲. 数字编码超材料相频响应扩展及验证[J]. 西安电子科技大学学报, 2022, 49(5): 92-99.

WANG Guoqiang,MA Hui,GAO Sizhe. Phase-frequency response expansion and verification of digital coded metamaterials[J]. Journal of Xidian University, 2022, 49(5): 92-99.

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参数	数值
采样率/GHz	2
脉冲次数	100
信号带宽/GHz	1
超材料阵元数	100
阵元间隔/m	0.015
网格数	400
网格划分范围/m	-90~90 -90~90
网格大小/(m×m)	9×9
信噪比	30