Miniaturized spoof SPPs filter based on multiple resonators or 5G applications

Behnam Mazdouri,Mohammad Mahdi Honari,Rashid Mirzavand

doi:10.1038/s41598-021-01944-6

Abstract

This paper presents a novel and compact band-pass filter based on spoof surface plasmon polaritons (SSPPs) concept for 5G applications. In the first place, an SSPPs unit cell including L-shaped grooves and its equivalent circuit model are introduced. The obtained results from dispersion analysis shows that cut-off frequency of the cell can be considerably decreased thanks to its geometrical configuration. In the second place, a miniaturized SSPP transmission line (TL) consisting of the proposed unit cell with cut-off frequency of 29.5 GHz is designed. Two mode convertors have been employed for efficient connection between coplanar waveguides and SSPP TL. Moreover, a new method based on loading one unit cell of SSPP TL by stub resonators is proposed in order to block a specific frequency band. An equivalent circuit model for the cell with the resonators is proposed to predict rejected frequency range. Thereafter, as an example of our method, a SSPPs filter operating at 26.5–29.5 GHZ is designed by means of connecting stub resonators with different lengths to provide close resonance frequencies. The circuit model, full wave simulation, and measurement results are in a good agreement. The results of proposed groundless SSPP TL and filter structures are promising to make groundless 5G applications possible.

Highlights

Over the years, the clients’ demands for wireless data services are increasing exponentially which are beyond what the current fourth mobile generation resources can afford[1]
5G brings an opportunity for such applications as massive MIMO3, Device-to-Device (D2D) or Machine-to-Machine (M2M) communications, and Internet of Things (IoT)4. 5G is considered as a millimetre wave technology with incredible data bandwidth, so that users will simultaneously send and receive nearly unfathomable amounts of data
Characteristics of the Spoof Surface Plasmon Polaritons (SSPPs) unit cell are controlled by its geometrical parameters, which are the gap between grooves g, the width of cell w, L-shaped dimensions including width of lx and length of ly, width of central conductor d, and period of p

Summary

Introduction

The clients’ demands for wireless data services are increasing exponentially which are beyond what the current fourth mobile generation resources can afford[1]. To overcome the drawback at lower frequencies, the concept of spoof SPP (SSPP) metamaterials has been proposed to simulate propagation of plasmonic waves by corrugating a metal’s surface as a unit-cell and repeating it periodically c ite[8,9]. As a matter of fact, intrinsic slow-wave characteristic of SSPPs makes it very good candidate in designing of various microwave filters with different performances such as ultra-wideband[30], band-stop[31,32,33] or multiband filters[34]. In previous researches in the field of designing filters with SSPPs, single-side and double-side SSP filters with several band-rejection performance have been proposed by etching complementary Split-ring resonators or SRRs32. To miniaturize SSPPs filters a multilayer SSPP band-pass filter based on the meanderline technology has been proposed[41]

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Results

Conclusion