Greedy-algorithm-empowered design of wideband achromatic beam deflector based on spoof surface plasmon polariton mode
Shaanxi Key Laboratory of Artificially-Structured Functional Materials and Devices, Air Force Engineering University, 710051, Xi’an, Shaanxi, China
Accepted: 25 April 2022
Published online: 9 May 2022
Similar to chromatic aberration in optics, electromagnetic waves with different frequencies will accumulate different phases when they propagate the same path, which causes the performances of devices to vary with frequencies. To guarantee the stable performance, these devices have to work in narrow band or at a single frequency, which inevitably hinders their wide applications. Thus, it is extremely urgent to eliminate or reduce chromatic aberration. Fortunately, metamaterials supporting spoof surface plasmon polariton (SSPP) modes can be tailored to achieve phase compensation in a specified space. Herein, we propose a method of designing achromatic SSPP beam deflector using greedy algorithm. Impedance matching and phase control are realized by designing SSPP with exponential spline. A large number of phase curves are obtained by parameter scanning, and a searching graph is constructed on this basis. Empowered by the greedy algorithm, some units of phase compensation with small error are found to assemble a transmissive beam deflector. Simulated and measured results show that the deflected angle of transmitted waves can be made constant within the entire X band (8.0–12.0 GHz). This method can be readily extended to designing other functional devices-based SSPP modes and may find potential applications in wireless communication, imaging and so on.
© The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2022