阅读说明：本技术 基于人工表面等离激元的模分复用电路 (Mode division multiplexing circuit based on artificial surface plasmon ) 是由 崔铁军 闫瑞婷 张浩驰 于 2019-09-25 设计创作，主要内容包括：本发明公开了一种基于人工表面等离激元的模分复用电路,包括两块介质基板,以中间层金属地为间隔,上层介质基板介电常数和厚度均大于下层介质基板,中间层金属地两端刻蚀有圆形通孔与槽线；上层介质基板的顶层金属条带纵向两侧对称地连接有金属短截线,构成顶层人工表面等离激元结构,顶层金属条带两端设有微带线到人工表面等离激元结构的过渡结构,作为偶模激励端口；下层介质基板的底层设有金属条带,其末端与圆形金属片相接位于两侧,作为奇模激励端口。本发明基于人工表面等离激元实现的模分复用技术,传输效率高,信道串扰小,可以有效地在微波频段提高系统的传输容量和频谱利用率,在微波通信领域有着广阔的应用前景。(The invention discloses a mode division multiplexing circuit based on artificial surface plasmons, which comprises two dielectric substrates, wherein the two dielectric substrates are spaced by taking a middle layer metal ground as an interval, the dielectric constant and the thickness of the upper layer dielectric substrate are both larger than those of the lower layer dielectric substrate, circular through holes and slot lines are etched at two ends of the middle layer metal ground, metal stub lines are symmetrically connected to two longitudinal sides of a top layer metal strip of the upper layer dielectric substrate to form a top layer artificial surface plasmon structure, transition structures from microstrip lines to the artificial surface plasmon structures are arranged at two ends of the top layer metal strip to serve as even mode excitation ports, a metal strip is arranged at the bottom layer of the lower layer dielectric substrate, and the tail end of the metal strip is connected with circular metal sheets at two sides to serve as odd mode excitation ports.)

The model division multiplexing circuit based on the artificial surface plasmons is characterized by comprising an upper dielectric substrate (1), a lower dielectric substrate (10) and an intermediate metal ground (7);

an th metal strip (2) is arranged in the middle of the top layer surface of the upper-layer dielectric substrate (1), the th metal strip (2) is symmetrically connected with series of th metal stub lines (6) with equal length along the two longitudinal sides, and the two ends of the th metal strip (2) are sequentially connected with a transition structure (3) and a microstrip line;

second metal strips (11) are symmetrically arranged at two ends of the bottom layer surface of the lower layer medium substrate (10), and the ends of the second metal strips (11) are connected with the round metal sheets (12);

the mode division multiplexing board comprises four electric connection ports, a microstrip line port of the upper-layer dielectric substrate (1) is an even mode input/output port of the artificial surface plasmon, and a second metal strip microstrip line port of the lower-layer dielectric substrate (10) is an odd mode input/output port of the artificial surface plasmon.

2. The artificial surface plasmon based mode division multiplexing circuit according to claim 1, wherein the dielectric constant of the upper dielectric substrate (1) is greater than that of the lower dielectric substrate (10), and the thickness of the upper dielectric substrate (1) is greater than that of the lower dielectric substrate (10).

3. The artificial surface plasmon based mode division multiplexing circuit according to claim 1, wherein the transition structure (3) comprises a third metal strip (4) of graded width and a second metal stub (5) of graded length.

4. The artificial surface plasmon based mode division multiplexing circuit of claim 3, wherein the width of the third metal strip (4) is tapered from the microstrip line width to the th metal strip (2) width, and the length of the second metal stub (5) is tapered from 0 to the length of the th metal stub (6).

5. The artificial surface plasmon based mode division multiplexing circuit according to claim 1, wherein circular through holes (8) and slot lines (9) are etched on the intermediate metal ground (7), and the circular through holes (8) and the slot lines (9) are connected with the connection points thereof being right opposite to the connection points of the bottom second metal strip (11) and the circular metal sheet (12).

Technical Field

The invention relates to artificial electromagnetic and microwave communication technologies, in particular to artificial surface plasmon-based mode division multiplexing circuits.

Background

In the visible light frequency band, the metal has negative dielectric constant, the free electrons in the metal are in plasma state, and the dielectric constant of air is positive value, so that the surface plasmon in natural state exists on the interface between the metal and the air.

The technical means of applying the artificial electromagnetic material can excite the artificial surface plasmon in the microwave millimeter wave frequency band, and researches prove that the specific sawtooth structure can support surface plasmon transmission similar to the natural state in the microwave and terahertz wave bands and is called as the artificial surface plasmon.

However, under the condition that the error rate is , the channel capacity is limited to , the shannon theorem shows that the maximum transmission capacity of the traditional single-mode transmission mode gradually approaches the shannon limit of the traditional single-mode transmission mode while the signal transmission quality is ensured, the contradiction between the huge bandwidth requirement and the limited transmission capacity is increasingly intensified, the available spectrum resources in the microwave communication field are deficient, and therefore, the search of a new parameter dimension becomes a research hotspot.

In the field of optical fiber communication, the expansion of transmission capacity can be realized by multiplexing of spatial dimensions, wherein, the mode division multiplexing technology is effective solutions.

Disclosure of Invention

The invention aims to solve the problems, and provides artificial surface plasmon-based mode division multiplexing circuits for solving the problem of crowded bandwidth of microwave frequency band spectrum.

The technical scheme includes that artificial surface plasmon-based mode division multiplexing circuits comprise an upper-layer dielectric substrate, a lower-layer dielectric substrate and an intermediate-layer metal ground, wherein a metal strip is arranged in the middle of the top layer surface of the upper-layer dielectric substrate, series of metal stub lines with equal length are symmetrically connected to metal strips along the longitudinal two sides, two ends of the metal strip are sequentially connected with a transition structure and a microstrip line, second metal strips are symmetrically arranged at two ends of the bottom layer surface of the lower-layer dielectric substrate, an end of each second metal strip is connected with a circular metal sheet, each mode division multiplexing circuit comprises four power connection ports, microstrip line ports of the upper-layer dielectric substrate are even mode input and output ports of artificial surface plasmons, and microstrip line ports of the lower-layer dielectric substrate are odd mode input and output ports of the artificial surface plasmons.

, the dielectric constant of the upper dielectric substrate is larger than that of the lower dielectric substrate, and the thickness of the upper dielectric substrate is larger than that of the lower dielectric substrate.

, the transition structure includes a third metal strip with a gradual width change and a second metal stub with a gradual length change.

, the width of the third metal strip is gradually changed from the width of the microstrip line to the width of the metal strip, and the length of the second metal stub is gradually changed from 0 to the length of the metal stub.

And , etching a circular through hole and a slot line on the middle metal ground, wherein the circular through hole is connected with the slot line, and the connection point of the circular through hole is right opposite to the connection point of the bottom layer second metal strip and the circular metal sheet.

The mode division multiplexing circuit based on the artificial surface plasmons can realize mode division multiplexing in a microwave frequency band, and has the advantages that compared with the prior art, the mode division multiplexing circuit based on the artificial surface plasmons has the advantages that (1) common-frequency and efficient excitation of odd and even modes is realized on artificial surface plasmon transmission lines, (2) the isolation degree of the odd mode and the even mode of the artificial surface plasmon transmission lines is high, (3) the channel capacity can be improved by times compared with single-mode transmission in a working frequency band, (4) the mode division multiplexing of multiple frequency bands can be realized by utilizing the advantage that the structure characteristic of the artificial surface plasmons is highly controllable, and (5) the sub-wavelength effect of the artificial surface plasmons is utilized, so that the miniaturization of a system is facilitated.

Drawings

FIG. 1 is a schematic structural diagram of an artificial surface plasmon-based mode division multiplexing circuit according to the present invention;

FIG. 2 is a schematic structural diagram of an upper dielectric substrate according to the present invention;

FIG. 3 is a schematic structural view of the interlayer metal of the present invention;

FIG. 4 is a schematic view of the structure of the lower dielectric substrate of the present invention.

Detailed Description

The technical solution of the present invention is further illustrated in step with reference to the accompanying drawings and examples.

As shown in fig. 1, the mode division multiplexing circuit based on artificial surface plasmons according to the present invention includes an upper dielectric substrate 1 and a lower dielectric substrate 10, and an intermediate metal ground 7 is used as a space between the upper dielectric substrates.

As shown in fig. 2, an th metal strip 2 is disposed at the middle of the top surface of the upper dielectric substrate 1, series of th metal stubs 6 with equal length are symmetrically connected along the two longitudinal sides to form a top artificial surface plasmon structure, and both ends of the th metal strip 2 are connected to the microstrip line transition structure 3 and the microstrip line.

The transition structure 3 from the microstrip line to the artificial surface plasmon fourth metal strip 2 comprises a third metal strip 4 with gradually changing width and a second metal stub 5 with gradually changing length, wherein the width of the third metal strip 4 with gradually changing width is gradually changed from 50 ohm microstrip line width to the width of the artificial surface plasmon fourth metal strip 2, and the length of the second metal stub 5 is gradually changed from 0 to the length of the artificial surface plasmon fourth metal stub 6.

As shown in fig. 3, a circular through hole 8 and a slot line 9 are etched on the middle metal ground 7, and the circular through hole 8 is connected with the slot line 9 at a connection point opposite to a connection point of the bottom layer second metal strip 11 and the circular metal sheet 12.

As shown in fig. 4, the bottom surface of the lower dielectric substrate 10 is provided with second metal strips 11, the second metal strips 11 are symmetrically arranged at two ends of the lower dielectric substrate 10, and the ends of the second bottom metal strips 11 are connected with the circular metal sheet 12.

The upper dielectric substrate 1 is different from the lower dielectric substrate 10, and the dielectric constant and the thickness of the upper dielectric substrate 1 are both larger than the parameters of the lower dielectric substrate 10, and correspond to different excitation modes of odd and even modes.

The invention relates to an artificial surface plasmon mode division multiplexing circuit, which is based on four-port structures, wherein the interface circuits are all microstrip circuits, the port of a microstrip line on the top layer is an even mode input/output port of an artificial surface plasmon, and the port of a microstrip line on a second metal strip on the bottom layer is an odd mode input/output port of an artificial surface plasmon.

In terms of process, the artificial surface plasmon-based mode division multiplexing circuit according to the embodiment of the present invention can be implemented by a common Printed Circuit Board (PCB) process, and can also be conveniently transplanted into a CMOS process.