CN111755780A

CN111755780A - Basic unit and space phase shifter for analog signal processing constructed based on basic unit

Info

Publication number: CN111755780A
Application number: CN202010553479.7A
Authority: CN
Inventors: 程强; 陈明正; 夏芬; 戴俊彦; 张琤; 张青峰; 崔铁军
Original assignee: Southeast University
Current assignee: Southeast University
Priority date: 2020-06-17
Filing date: 2020-06-17
Publication date: 2020-10-09
Anticipated expiration: 2040-06-17
Also published as: CN111755780B

Abstract

The invention discloses a basic unit and a space phase shifter for analog signal processing constructed based on the basic unit, comprising: n is the n basic unit by n, n is the periodic arrangement of n basic unit by n, and every unit contains five layers of metal structure and four layers of dielectric structures, through well-designed structure, makes the electromagnetic signal of different frequencies produce different group delay, and then realizes analog signal processing. The spatial phase shifter with the step-type group delay response has the function of pulse position modulation, and the spatial phase shifter with the linear group delay response has the function of pulse broadening. The invention has simple principle, low manufacturing cost and wide application prospect.

Description

Basic unit and space phase shifter for analog signal processing constructed based on basic unit

Technical Field

The invention relates to the technical field of analog signal processing and novel artificial electromagnetic materials, in particular to a basic unit and a space phase shifter for analog signal processing constructed based on the basic unit.

Background

The analog signal processing device can directly process the ultra-wideband signal in real time at a very high frequency band. In contrast, the digital signal processing device requires an ultra-high sampling rate when processing the broadband signal, which results in a very high hardware complexity and a very high cost. At the heart of the analog signal processing device is a dispersive delay structure or so-called phase shifter that can provide the desired group delay response. At present, the algorithm of the phase shifter for synthesizing the required group delay response on the transmission line level is relatively mature, and the phase shifter with different group delay responses such as step type, linear and trapezoidal can be obtained, so that analog signal processing algorithms such as pulse position modulation, broadband frequency spectrum sniffing, pulse broadening, real-time Fourier transform and the like are realized.

The novel artificial electromagnetic surface, also called as a super surface, can control parameters such as amplitude phase, polarization, wave front, deflection and the like of electromagnetic waves by designing units and spatial arrangement modes of the units, and realizes functions such as holographic imaging, beam regulation and control and the like. Therefore, the singular characteristics of the super surface can be utilized to design a space phase shifter, and the group delay modulation is directly carried out on the space electromagnetic waves, so that the analog signal processing is realized.

Disclosure of Invention

In order to solve the above technical problems, the present invention provides a base unit and a spatial phase shifter for analog signal processing constructed based on the base unit.

In order to solve the above technical problem, the present invention provides a basic unit, which includes a first medium substrate layer, a second medium substrate layer, a third medium substrate layer, and a fourth medium substrate layer, which are stacked and cascaded in sequence, wherein one of the connection surfaces between the layers is provided with an annular metal patch structure, and the non-connection surface of the fourth medium substrate is provided with a metal patch.

For example, one of the connection surfaces between the first dielectric substrate layer and the second dielectric substrate layer is provided with a ring-shaped metal patch structure, and the other layers are arranged as described above.

Furthermore, the annular metal patch structure comprises a rectangular metal ring and a rectangular metal patch, wherein the rectangular metal patch is positioned in the rectangular metal ring, and the rectangular metal patch is not in contact with the rectangular metal ring.

Further, the thickness and/or dielectric constant of the dielectric substrate are the same or different.

Further, the length and the width of the dielectric substrate on each layer are consistent, and the length and the width of the rectangular metal patches on the dielectric substrate are the same or different.

Further, the rectangular metal rings on each layer of dielectric substrate are the same in width.

In addition, the invention also provides a space phase shifter for analog signal processing constructed according to the basic unit, which carries out periodic continuation on a single basic unit along the X direction and the Y direction to form a front surface connected by n × n units.

When a broadband electromagnetic wave is incident to the metamaterial with the group delay response changing along with the frequency step type, the electromagnetic waves with different frequencies have different delays. Therefore, the metamaterial can realize analog signal processing algorithms such as pulse separation, pulse overlapping and real-time spectrum sniffing on broadband electromagnetic pulse signals in space.

When a broadband electromagnetic wave is incident to a metamaterial with group delay response changing linearly with frequency, the electromagnetic waves with different frequencies have different delays. Therefore, the metamaterial can realize the broadening of the time domain pulse signal to the broadband electromagnetic pulse signal in the space.

Has the advantages that: compared with the prior art, the technical scheme of the invention has the following remarkable progress:

(1) the invention designs a spatial phase shifter based on a super surface, which has simple structure and low processing and manufacturing cost;

(2) the step type group delay response space phase shifter designed by the invention can realize real-time pulse position modulation of broadband analog electromagnetic waves, thereby realizing analog signal processing algorithms such as time domain pulse separation, time domain pulse superposition, real-time frequency spectrum sniffing and the like;

(3) the linear group delay response space phase shifter designed by the invention can realize real-time pulse broadening of broadband analog electromagnetic waves;

(4) compared with a transmission line type phase shifter, the space phase shifter designed by the invention can directly modulate space electromagnetic waves, expands the application range of the phase shifter, can be used for constructing a new system analog signal processing system different from a digital signal processing technology, can reduce the hardware cost and improve the frequency and bandwidth of processed signals.

Drawings

FIG. 1(a) is a schematic diagram of a wavefront of a spatial phase shifter based on a super-surface in accordance with the present invention;

FIG. 1(b) is a schematic diagram of a unit of a spatial phase shifter based on a super-surface in the present invention;

FIG. 1(c) is a schematic structural view of a ring-shaped metal patch according to the present invention;

FIG. 1(d) is a side view of a spatial phase shifter according to the present invention;

FIG. 2 is a plot of the group delay response of a designed, simulated and tested spatial phase shifter of the present invention;

FIG. 3 is a phase response curve of a designed, simulated and tested spatial phase shifter of the present invention;

FIG. 4 is an amplitude response curve of a simulated and tested spatial phase shifter of the present invention;

FIG. 5 is a schematic diagram of a trapezoidal group delay response spatial phase shifter according to the present invention for separating electromagnetic wave pulses overlapped in the time domain;

FIG. 6 is a diagram of a linear group delay response spatial phase shifter according to the present invention for broadening electromagnetic wave pulse in time domain;

FIG. 7 is a graph showing the amplitude of the envelope of the time domain reflected waveforms of air, metal plate and sample in accordance with the present invention.

Detailed Description

The spatial phase shifter for analog signal processing based on the super surface is formed by periodically arranging a basic unit. As shown in fig. 1(a) to 1(b), the basic unit of the spatial phase shifter is composed of four layers of medium substrates cascaded by an annular metal patch structure and a last layer of complete metal patch, and the spatial phase shifter structure with the required group delay response can be obtained by designing the size of the metal patch structure, the thickness and the relative dielectric constant of the medium substrate.

Fig. 1(c) shows a schematic diagram of the structure of the annular metal patch of the present invention. The parameters determining the size are: the length Px and width Py of the basic cell, the rectangular metal loop width w, and the length Lx and width Ly of the middle rectangular metal patch.

Fig. 1(d) shows a side view of the spatial phase shifter of the present invention, from which the cascading relationship of the metal structure layer and the dielectric substrate layer can be clearly seen.

Fig. 2-4 show predicted, simulated and measured group delay, phase and amplitude response curves for a particular design example, further demonstrating the effectiveness of the spatial phase shifter design theory. First, it is assumed that one spatial phase shifter is designed to have a group delay response linearly increasing from 8GHz to 9GHz and a group delay response linearly decreasing from 9GHz to 10GHz, as shown by a solid line in fig. 2.

Through full-wave simulation and analysis, the parameters of the spatial phase shifter shown in tables 1-2 were obtained. Wherein the thicknesses of the dielectric substrates of the first layer to the fourth layer are respectively 5.5mm, 2.3mm, 5.5mm and 3.5 mm; their relative dielectric constants were 2.25, 13 and 2.25, respectively.

The length Px and the width Py of all the four layers of rectangular metal rings are respectively 9.6mm and 7.1 mm; the widths w of the rectangular metal rings are unified to be 0.4 mm; the lengths Lx of the middle rectangular metal patch are respectively 8.3mm, 2mm and 8.3 mm; the widths Ly of the middle rectangular metal patches are 5.7mm, 1mm and 5.7mm, respectively.

The group delay, phase and amplitude response of the simulated spatial phase shifter are shown as dashed lines in fig. 2-4, consistent with the theoretical values of the design. Likewise, fig. 2-4 show that the response of the actual processed sample is also consistent with the results of the simulation and design. Although the loss of the spatial phase shifter in actual test is larger due to processing and experimental errors, the related result can still verify the effectiveness of the design method.

The space phase shifter is used as a core component of a real-time analog signal processing system, and can modulate the time domain waveform of a high-frequency electromagnetic signal in real time. Although the spatial phase shifters with different group delay responses have different signal modulation effects, the two most important effects are the pulse position modulation effect based on the ladder type group delay response phase shifter and the pulse broadening effect based on the linear group delay response phase shifter, as shown in fig. 5-6. In the pulse position modulation process, gaussian pulses loaded onto different carrier frequencies are superimposed together and incident on a spatial phase shifter with a stepped group delay response. The modulated composite pulses are separated in time due to the phase shifters applying different time delays to the signals of different frequency components. The pulse position modulation effect has wide application prospect in the aspects of signal spectrum sniffing, electronic detection resistance and the like.

Unlike pulse position modulation, the spatial phase shifter needs to have a linear group delay response in a specified frequency band in broadening the pulse width. In this case, the incident signal, which contains abundant spectral components, is temporally broadened after being modulated, and the peak value of its pulse is correspondingly reduced. Further, combining the two effects, we can implement more complex analog signal processing algorithms such as real-time fourier transforms.

To verify that the designed and fabricated spatial phase shifter has the effects of time delay and pulse spreading, we tested the time domain reflection responses of air, metal plate and sample as shown in fig. 7. Wherein, the sample and the metal flat plate are positioned at the same position during the test. The frequency range tested was 9-10 GHz. On one hand, compared with a metal flat plate, the signal peak reflected by the sample is delayed by about 1ns, and the sample is proved to have the effect of modulating the time delay of the incident signal; on the other hand, as the sample is designed to have linear group delay response in the frequency range of 9-10GHz, the reflected signal of the sample is obviously broadened in time compared with that of a metal flat plate.

TABLE 1 dielectric substrate parameters in spatial phase shifters

TABLE 2 basic unit metal structure parameters in spatial phase shifters

In summary, the present invention provides a spatial phase shifter structure with a specific group delay response. The space phase shifter designed by the invention has the capability of real-time analog signal processing. The invention has the advantages of simple principle, low cost, easy realization and the like, and has great application prospect in future real-time analog signal processing systems.

Claims

1. A basic unit is characterized by comprising a first medium substrate layer, a second medium substrate layer, a third medium substrate layer and a fourth medium substrate layer which are sequentially overlapped and cascaded, wherein an annular metal patch structure is arranged on one surface of a layer-to-layer connection surface, and a metal patch is arranged on a non-connection surface of the fourth medium substrate layer.

2. The base unit of claim 1, wherein the annular metal patch structure comprises a rectangular metal ring and a rectangular metal patch, the rectangular metal patch is located in the rectangular metal ring, and the rectangular metal patch is not in contact with the rectangular metal ring.

3. A base unit according to claim 1 or 2, wherein the thickness and/or dielectric constant of each dielectric substrate is the same or different.

4. A base unit according to claim 1 or 2, wherein the length and width of each dielectric substrate are the same, and the metal patches provided on the non-connecting surface of the fourth dielectric substrate are the same as the length and width of the dielectric substrate.

5. A base unit according to claim 1 or 2, wherein the rectangular metal rings on each dielectric substrate are of the same width.

6. A base unit according to claim 1 or 2, wherein the rectangular metal patches on each dielectric substrate are of the same or different length and width.

7. A spatial phase shifter for analog signal processing constructed according to any one of claims 1 to 6 wherein individual elementary units are periodically extended in the X and Y directions to form a wavefront of n X n elementary units connected.