A SSPP cell structure with multi-band negative group delay

Abstract

The application discloses a SSPP unit structure with multi-band negative group delay, and belongs to the microwave technical field. The multi-band negative group delay is innovatively generated based on a spoof surface plasmon polariton (SSPP). The structure is provided with a dielectric substrate, a straight conductor strip is etched on the dielectric substrate, and metal sideband folding spiral rings are arranged on both sides of the straight conductor strip, so that the SSPP unit structure is formed. The SSPP unit structure has the characteristics of multi-band, negative group delay and high integration. The multi-band negative group delay SSPP unit has wide application prospects and great market value in the fields of 5G communication, imaging systems, vehicle-mounted radar communication and satellite navigation.

Description

Technical Field

[0001] This invention belongs to the field of microwave technology, specifically relating to an SSPP unit structure with multi-band negative group delay. Background Technology

[0002] Surface plasmon polaritons (SPPs) are a physical phenomenon in optics: when free-space light shines on a metal surface, the free electrons in the metal oscillate, and the electromagnetic field is confined at the boundary between free space and the metal surface, decaying exponentially in the direction perpendicular to the interface. Artificial surface plasmon polaritons (SSPPs) are electromagnetic metamaterials with negative permittivity or negative permeability in the microwave and millimeter-wave bands, offering the possibility of realizing surface plasmon polaritons at low frequencies. This new plasmonic metamaterial shares similar dispersion characteristics and field localization capabilities with optical SPPs, exhibiting low-pass characteristics and near-field enhancement, surface confinement, and deep subwavelength characteristics near the cutoff frequency. The electromagnetic properties of artificial surface plasmon polaritons can be easily controlled by changing their geometry.

[0003] Group delay is an important parameter in signal processing that describes the relationship between phase change and frequency. It represents the variation in the time required for different frequency components of a signal to propagate through a system. Group delay can be viewed as the time required for the envelope of a signal to propagate through the system. Therefore, it is usually used to describe the propagation time of the envelope in composite signals (such as modulated signals or signals with a wide bandwidth), rather than the propagation speed of a single sinusoidal signal. In many fields such as communications, radar, and optics, group delay is an important indicator for analyzing signal propagation and system performance.

[0004] Negative Group Delay (NGD) works by creating a phase advance effect, causing a negative time delay when the signal passes through the circuit. This characteristic is commonly used to compensate for phase delays in systems, especially in radio frequency and microwave communication systems. NGD circuits can reduce delays introduced by other circuits, resulting in better overall system timing characteristics. Furthermore, NGD can be used for signal synchronization, signal phase adjustment, and group delay control, and has potential applications in ultra-wideband systems, radar, and satellite communications. Summary of the Invention

[0005] The purpose of this invention is to solve the technical problems mentioned in the background section and provide an SSPP cell structure with multi-band negative group delay. Combining the characteristics of SSPP and negative group delay, an SSPP cell structure with multi-band negative group delay is proposed. This structure has multi-band characteristics and can achieve negative group delay in multiple frequency bands, providing technical support for high-speed, low-latency communication systems.

[0006] To achieve the above-mentioned technical objectives, the technical solution of the present invention is as follows:

[0007] A multi-band negative group delay (SSPP) cell structure is provided, comprising a high-frequency dielectric substrate, which serves as the structural support and the medium for electromagnetic field propagation. A metal pattern is etched on one side of the high-frequency dielectric substrate, the metal pattern comprising a straight conductor strip and a spiral ring assembly on both sides of the straight conductor strip. The straight conductor strip is used to achieve efficient forward transmission of SSPP, and the length and width of the straight conductor strip are optimized according to design requirements. The spiral ring assembly is formed by iterating and symmetrically forming multiple basic spiral ring units, with the bottom of the spiral ring assembly connected to the straight conductor strip and occupying a certain position on the surface of the dielectric substrate. The spiral ring assembly is used to achieve the negative group delay effect of SSPP.

[0008] Furthermore, the high-frequency dielectric substrate may be an FR-4 high-frequency dielectric substrate with a relative permittivity εr = 4.3.

[0009] Furthermore, the metal pattern is made of a metal material with good electrical conductivity, such as copper, silver, or gold.

[0010] Furthermore, the SSPP unit structure uses a bottom straight conductor strip structure and a combination structure of spiral rings on both sides.

[0011] Furthermore, the length of the straight conductor strip is equal to the width of the dielectric substrate.

[0012] Furthermore, the multiple iterations refer to at least two iterations.

[0013] Furthermore, the basic unit of the spiral ring is formed by bending several rectangular metal strips, each rectangular metal strip having the same width and different lengths.

[0014] Furthermore, the specific structure of the basic unit of the spiral ring includes 14 rectangular metal strips connected at 90° to form a specific spiral shape; by changing the size and bending angle of the rectangular metal strips, the resonant frequency and negative group delay characteristics of the spiral ring can be adjusted.

[0015] Furthermore, the spiral ring assembly is composed of four basic spiral ring units, forming a symmetrical folded spiral ring assembly; by adjusting the iteration number and combination method of the basic spiral ring units, the frequency range of the negative group delay is further expanded.

[0016] Furthermore, the SSPP unit structure has negative group delay characteristics in specific frequency bands, including but not limited to the frequency bands of 1.298 GHz to 1.505 GHz, 2.032 GHz to 2.115 GHz, 2.564 GHz to 2.661 GHz, 2.859 GHz to 3.015 GHz, and 4.03 GHz to 5 GHz.

[0017] Compared with existing technologies, this unit structure has the following advantages:

[0018] Achieving negative group delay in SSPP (Short-Side Component Proportioning) using a spiral ring assembly, compared to previous design methods, enables multi-band negative group delay, meeting the requirements of multi-band communication systems. The design process is significantly simplified compared to existing technologies. Its negative delay effect can be applied to microwave circuits. This SSPP unit structure can be used to achieve multi-band negative group delay. Based on negative group delay compensation, the overall delay after equalization can be reduced across multiple frequency bands, which is of great significance for communication systems requiring extremely low latency, such as 5G. The SSPP unit structure can be used in electromagnetic wave modulation, wireless communication, radar systems, or other application scenarios requiring the utilization of negative group delay characteristics. By adjusting the size of the dielectric substrate and the structural parameters of the metal pattern (such as the width of the straight conductor strips, the length and width of the rectangular metal strips in the spiral ring basic unit, etc.), the electromagnetic characteristics of this SSPP unit structure can be further optimized to meet the needs of different application scenarios. Based on the negative group delay of SSPP, it also helps to realize highly integrated circuits, providing technical support for high-speed, low-latency communication systems such as 5G. Attached Figure Description

[0019] Figure 1 This is a three-dimensional schematic diagram of the structural composition of an embodiment of the present invention.

[0020] Figure 2 This is a schematic diagram of the dimensions of the SSPP structural unit according to an embodiment of the present invention.

[0021] Figure 3 This is a schematic diagram of the dimensions and structure of a single folded spiral ring according to an embodiment of the present invention.

[0022] Figure 4 The simulation results of the dispersion curves for the two SSPP modes in this embodiment of the invention are shown.

[0023] Figure 5 The simulation results show the normalized group velocity of the two modes of the unit structure in this embodiment of the invention.

[0024] Figure 6 The simulation results show the transmission coefficient and reflection coefficient of the unit structure in this embodiment of the invention.

[0025] Figure 7 The simulation results are for the phase of the unit structure S21 in this embodiment of the invention.

[0026] Figure 8 The simulation results are for the transmission group delay parameters of the unit structure in an embodiment of the present invention. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0028] See Figure 1 The SSPP unit structure with multi-band negative group delay described in this embodiment of the invention includes a dielectric substrate 1, and a metal pattern etched on one side of the dielectric substrate: a straight metal conductor strip 2 and a folded spiral ring assembly 3 on both sides thereof. The spiral ring assembly is formed by iterating the basic spiral ring unit structure twice and symmetrically.

[0029] See Figure 2 The dielectric substrate 1 uses FR-4 high-frequency dielectric with a relative permittivity of 4.3. The length of the dielectric substrate 1 is L=40mm, the width of the dielectric substrate 1 is p=8mm, and the thickness of the dielectric substrate 1 is H=0.8mm. The length of the metal straight conductor strip 2 is equal to the width of the dielectric substrate 1, and the width of the metal straight conductor strip 2 is W1=1.5mm. The bottom of the spiral ring assembly 3 is connected to the metal straight conductor strip 2, and the right side of the spiral ring assembly 3 is D=6.75mm from the edge of the dielectric substrate. The basic units of the straight conductor strip and the spiral ring are both composed of a metal layer with a thickness of H1=0.035mm.

[0030] See Figure 3 The basic unit of the spiral ring is composed of 14 rectangular metal strips joined at 90° intervals. The width of each rectangular metal strip is W2 = 0.5 mm, and the lengths of the rectangular metal strips are L1 = 6 mm, L2 = 5.5 mm, L3 = 4.5 mm, L4 = 3.5 mm, L5 = 2.5 mm, L6 = 1.5 mm, L7 = 1 mm, L8 = 1.5 mm, L9 = 2.5 mm, L10 = 3.5 mm, L11 = 4.5 mm, L12 = 5.5 mm, L13 = 6.5 mm, and L14 = 6.5 mm, respectively. This design gives the spiral ring specific electromagnetic response characteristics.

[0031] See Figure 4 The dispersion curves of the SSPP unit structure in this embodiment were simulated and analyzed for two modes, where k is the phase constant and p is the period of the SSPP unit. Both dispersion curves showed a decreasing trend, which is an anomalous dispersion phenomenon.

[0032] See Figure 5 The normalized group velocity of the unit structure in this embodiment was simulated and analyzed. The negative group velocity frequency band of the two modes coincides with the anomalous dispersion frequency band in the dispersion curve, thus verifying the anomalous dispersion characteristics of the structure.

[0033] See Figure 6 The transmission coefficient and reflection coefficient of the unit structure in this embodiment are simulated and analyzed based on the waveguide transmission method. In the negative group delay frequency band, the transmission coefficient decreases, the reflection coefficient increases, and the energy flow transmission is limited.

[0034] See Figure 7 A simulation analysis of the transmission phase of the unit structure based on the waveguide transmission method was performed on this embodiment. In the negative group delay frequency band, the leading phase cancels out the phase lag effect under normal dispersion, thereby reducing the overall lag effect.

[0035] See Figure 8 Transmission group delay simulation analysis was performed on the SSPP unit structure of this embodiment. The structure exhibits negative group delay in the frequency bands of 1.298 GHz ~ 1.505 GHz, 2.032 GHz ~ 2.115 GHz, 2.564 GHz ~ 2.661 GHz, 2.859 GHz ~ 3.015 GHz, and 4.03 GHz ~ 5 GHz, and also has multi-band characteristics.

[0036] This invention innovatively generates multi-band negative group delay based on spoof surface plasmon polaritons (SSPP). The structure includes a dielectric substrate on which a straight conductor strip is etched. Folded helical rings with metal side strips form the SSPP unit structure. It features multi-band operation, negative group delay, and high integration. The multi-band negative group delay SSPP unit has broad application prospects and significant market value in 5G communication, imaging systems, vehicle radar communication, and satellite navigation. This invention also has broad application prospects in electromagnetic wave manipulation and wireless communication.

[0037] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the described embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention should be considered equivalent substitutions and are included within the protection scope of the present invention. The basic principles, main features, and advantages of the present invention have been shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the present invention. Various changes and modifications can be made to the present invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims.

Claims

1. An SSPP unit structure with multi-band negative group delay, characterized in that... A high-frequency dielectric substrate is provided, which serves as the structural support and the medium for electromagnetic field propagation. A metal pattern is etched on one side of the high-frequency dielectric substrate. The metal pattern includes a straight conductor strip and a spiral ring assembly on both sides of the straight conductor strip. The straight conductor strip is used to achieve positive high-efficiency transmission of SSPP. The spiral ring assembly is used to achieve the negative group delay effect of SSPP. The high-frequency dielectric substrate is made of FR-4 high-frequency dielectric substrate with a relative permittivity εr = 4.3; The length of the straight conductor strip is equal to the width of the dielectric substrate; The spiral ring assembly is formed by iterating the basic spiral ring unit multiple times and symmetrically. The bottom of the spiral ring assembly is connected to the straight conductor strip and occupies a certain position on the surface of the dielectric substrate. The basic unit of the spiral ring is formed by bending several rectangular metal strips, each of which has the same width and different lengths. The spiral ring assembly is composed of four basic spiral ring units, forming a symmetrical folded spiral ring assembly. By adjusting the iteration number and combination method of the basic spiral ring units, the frequency range of the negative group delay is expanded.

2. The SSPP unit structure with multi-band negative group delay as described in claim 1, characterized in that... The multiple iterations refer to at least two iterations.

3. The SSPP unit structure with multi-band negative group delay as described in claim 1, characterized in that... The basic unit of the spiral ring consists of 14 rectangular metal strips connected at 90° to form a specific spiral shape; by changing the size and bending angle of the rectangular metal strips, the resonant frequency and negative group delay characteristics of the spiral ring can be adjusted.

4. The SSPP unit structure with multi-band negative group delay as described in claim 1, characterized in that... The SSPP unit structure has negative group delay characteristics in specific frequency bands, including but not limited to 1.298–1.505 GHz, 2.032–2.115 GHz, 2.564–2.661 GHz, 2.859–3.015 GHz, and 4.03–5 GHz.

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