Miniaturized low-pass filter based on artificial surface plasmons

Abstract

The invention discloses an artificial surface plasmon-based miniaturized low-pass filter. The artificial surface plasmon-based miniaturized low-pass filter is characterized by mainly comprising a coplanar waveguide, wherein two ground strips of the coplanar waveguide are provided with groove unit arrays which are periodically distributed along the length direction of the coplanar waveguide; the two groove unit arrays are longitudinally symmetric about a center conductor strip; the depths of groove units are uniformly and progressively increased from two sides to the middle part in the length direction of the coplanar waveguide; and the depth of the groove unit in the middle part is fixed. On the basis of the coplanar waveguide, an artificial surface plasma structure is constructed by etching the periodic groove units on the ground strips by the coplanar waveguide to achieve the filtering function. T-shaped grooves are introduced; and equivalent depths of the grooves in the width direction are increased, so that the device miniaturization is achieved. The artificial surface plasmon-based miniaturized low-pass filter has a series of advantages of being simple in structure, compact in size, good in filter performance, easy to process, suitable for being matched with a traditional microwave transmission line and the device for use and the like.

Description

technical field [0001] The invention relates to a filter, in particular to a miniaturized low-pass filter based on artificial surface plasmons. Background technique [0002] Surface Plasmon Polaritons (SPPs for short) are special electromagnetic waves transmitted at the interface between metal and medium (usually air) at a light frequency. SPPs are a kind of surface wave with two distinctive features: first, along the perpendicular to the interface, it is an evanescent wave, and the intensity of the wave decreases exponentially, so the wave is bound near the interface; second, the SPPs The transmission wavelength is shorter, so it can break the diffraction limit. The research on SPPs was once limited to the optical band or higher frequencies. The plasma frequency of metals is generally in the ultraviolet band, and the dielectric constant of metals in the low frequency band is very large, so that the skin depth of electromagnetic waves is very small. Therefore, in the low f...

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Problems solved by technology

However, the mismatch of the wave vector leads to the failure of the transmission conversion efficiency to meet the ideal requirements.

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