SSPP unit structure with multiband negative group delay

Abstract

The invention discloses an SSPP unit structure with multiband negative group delay, and belongs to the technical field of microwaves. According to the method, the multi-band negative group delay is innovatively generated on the basis of the artificial surface plasmon polaritons (SSPP), and the multi-band negative group delay is generated on the basis of the 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 two sides of the straight conductor strip to form an SSPP unit structure. The system has the characteristics of multiband, negative group delay and high integration. The multiband negative group delay SSPP unit has a wide application prospect and a huge market value in the fields of 5G communication, imaging systems, vehicle-mounted radar communication, satellite navigation and the like.

Description

Technical Field

[0001] The invention belongs to the field of microwave technology, and in particular relates to an SSPP unit structure with multi-band negative group delay. Background Art

[0002] Surface plasmon polaritons (SPP) are a physical phenomenon in the field of optics: when light from free space shines on the metal surface, the free electrons of the metal will oscillate with it, and the electromagnetic field will be bounded at the boundary between free space and the metal surface, and the electromagnetic field decays exponentially in the direction perpendicular to the interface. Artificial surface plasmons (SSPP) are electromagnetic metamaterials with negative dielectric constants or negative magnetic permeability in the microwave and millimeter wave bands, which make it possible to realize surface plasmons in low-frequency bands. This new plasma metamaterial has similar dispersion characteristics and field localization capabilities as optical SPPs, and exhibits low-pass characteristics as a whole, with near-field enhancement, surface confinement, and deep subwavelength characteristics near the cutoff frequency. The electromagnetic properties of artificial surface plasmons 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 indicates the change in the time required for different frequency components of a signal to propagate through a system. Group delay can be regarded 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 a composite signal (such as a modulated signal or a signal 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] The function of negative group delay (NGD) is to produce a phase advance effect, causing a "negative" delay phenomenon when the signal passes through the circuit. This characteristic of negative group delay is often used to compensate for phase delay in the system, especially in RF and microwave communication systems. The negative group delay circuit can be used to reduce the delay introduced by other circuits, so that the overall system has better timing characteristics. In addition, negative group delay can realize functions such as signal synchronization, signal phase adjustment, and group delay control, and has potential applications in ultra-wideband systems, radar, satellite communications, and other fields. Summary of the invention

[0005] The purpose of the present invention is to solve the technical problems mentioned in the above background technology and provide an SSPP unit structure with multi-band negative group delay. Combining the characteristics of SSPP and negative group delay, an SSPP unit structure with multi-band negative group delay is proposed. The 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] In order to achieve the above technical objectives, the technical solution of the present invention is:

[0007] A SSPP unit structure with multi-band negative group delay is provided, which is provided with a high-frequency dielectric substrate, which serves as a support for the structure and a medium for electromagnetic field propagation; a metal pattern is etched on one side of the high-frequency dielectric substrate, the metal pattern comprises a straight conductor strip and a spiral ring assembly on both sides of the straight conductor strip; the straight conductor strip is used to realize the forward efficient transmission of the 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 a spiral ring basic 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 spiral ring assembly is used to realize the negative group delay effect of the SSPP.

[0008] Furthermore, the high-frequency dielectric substrate may be a FR-4 high-frequency dielectric substrate having a relative dielectric constant 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 spiral ring assembly structure 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 are at least 2 iterations.

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

[0014] Furthermore, the specific structure of the spiral ring basic unit includes 14 rectangular metal strips connected at 90 degrees 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 4 segments of spiral ring basic units to form a symmetrical folded spiral ring assembly; by adjusting the number of iterations and combination methods of the spiral ring basic units, the frequency band range of the negative group delay is further expanded.

[0016] Furthermore, the SSPP unit structure has a negative group delay characteristic within a specific frequency band, including but not limited to 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 the prior art, this unit structure has the following advantages:

[0018] The negative group delay of SSPP is realized by the spiral ring assembly. Compared with the previous design method, it can realize multi-band negative group delay and meet the needs of multi-band communication systems. Compared with the prior art, the design process is significantly simplified. It has a negative delay effect and can be applied to microwave circuits. The SSPP unit structure can be used to realize multi-band negative group delay. Based on negative group delay compensation, the overall delay after equalization can be reduced in multiple bands, which is of great significance for communication systems such as 5G that require extremely low delay. The SSPP unit structure can be used in electromagnetic wave control, wireless communication, radar systems or other application scenarios that require the use 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 strip, the length and width of the rectangular metal strip in the spiral ring basic unit, etc.), the electromagnetic characteristics of the SSPP unit structure can be further optimized to meet the needs of different application scenarios. Based on the SSPP negative group delay, it is also helpful to realize highly integrated circuits and provide technical support for high-speed, low-latency communication systems such as 5G. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0020] Figure 2 Schematic diagram of the size structure of the SSPP structural unit according to an embodiment of the present invention.

[0021] Figure 3 Schematic diagram of the size structure of a single folded spiral ring according to an embodiment of the present invention.

[0022] Figure 4 1 is a simulation result of dispersion curves of two modes of SSPP according to an embodiment of the present invention.

[0023] Figure 5 The following are simulation results of normalized group velocities of two modes of the unit structure according to an embodiment of the present invention.

[0024] Figure 6 1 is a simulation result of the transmission coefficient and reflection coefficient of the unit structure of the embodiment of the present invention.

[0025] Figure 7 1 is a simulation result of the phase of the unit structure S21 according to an embodiment of the present invention.

[0026] Figure 8 The figure is a simulation result of the transmission group delay parameter of the unit structure according to the embodiment of the present invention. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

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

[0029] See also Figure 2 The dielectric substrate 1 adopts FR-4 high-frequency dielectric with a relative dielectric constant 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 away from the edge of the dielectric substrate; the straight conductor strip and the spiral ring basic unit are both composed of a metal layer with a thickness of H1=0.035mm.

[0030] See also Figure 3 The basic unit of the spiral ring is composed of 14 rectangular metal strips connected at 90°; 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; this design enables the spiral ring to have specific electromagnetic response characteristics.

[0031] See also Figure 4 , the dispersion curves of the two modes of the SSPP unit structure of this embodiment are simulated and analyzed, where k is the phase constant and p is the period of the SSPP structure unit. The dispersion curves of the two modes show a downward trend, which is an abnormal dispersion phenomenon.

[0032] See also Figure 5 The normalized group velocities of the two modes of the unit structure of this embodiment are simulated and analyzed. The negative group velocity bands of the two modes coincide with the anomalous dispersion bands in the dispersion curve, verifying the anomalous dispersion characteristics of the structure.

[0033] See also Figure 6 , the transmission coefficient and reflection coefficient of the unit structure of 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 also Figure 7 The embodiment is simulated and analyzed based on the unit structure transmission phase of the waveguide transmission method. In the negative group delay frequency band, the advanced phase offsets the phase lag effect under normal dispersion, thereby reducing the overall lag effect.

[0035] See also Figure 8 The transmission group delay simulation analysis of the SSPP unit structure of this embodiment is performed. The structure exhibits negative group delay in 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, and has multi-band characteristics.

[0036] The present invention innovatively generates multi-band negative group delay based on artificial surface plasmon polaritons (SSPP). The structure is provided with a dielectric substrate, on which a straight conductor strip is etched, and metal sideband folded spiral rings are provided on both sides of the straight conductor strip to form an SSPP unit structure. It has the characteristics of multi-band, negative group delay, and high integration. The multi-band negative group delay SSPP unit has broad application prospects and huge market value in the fields of 5G communication, imaging system, vehicle-mounted radar communication, satellite navigation, etc. The present invention has broad application prospects in the fields of electromagnetic wave control and wireless communication.

[0037] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principle of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention. The basic principles, main features and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements fall within the scope of the protection required.

Claims

1. A SSPP unit structure with multi-band negative group delay, characterized in that A high-frequency dielectric substrate is provided, which serves as a structural support and a medium for electromagnetic field propagation; a metal pattern is etched on one side of the high-frequency dielectric substrate, and 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 realize the forward efficient transmission of SSPP; and the spiral ring assembly is used to realize the negative group delay effect of SSPP.

2. A SSPP unit structure with multi-band negative group delay as claimed in claim 1, characterized in that The high-frequency dielectric substrate adopts a FR-4 high-frequency dielectric substrate with a relative dielectric constant εr=4.

3.

3. The SSPP unit structure with multi-band negative group delay as claimed in claim 1, characterized in that The length of the straight conductor strip is equal to the width of the dielectric substrate.

4. The SSPP unit structure with multi-band negative group delay as claimed in claim 1, characterized in that The spiral ring assembly is formed by iterating spiral ring basic units 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.

5. A SSPP unit structure with multi-band negative group delay as claimed in claim 4, characterized in that The multiple iterations are at least 2 iterations.

6. A SSPP unit structure with multi-band negative group delay as claimed in claim 4, characterized in that The spiral ring basic unit is formed by bending a plurality of rectangular metal strips, and each rectangular metal strip has the same width and different lengths.

7. A SSPP unit structure with multi-band negative group delay as claimed in claim 6, characterized in that The basic unit of the spiral ring includes 14 rectangular metal strips connected at 90 degrees to form a specific spiral shape; the resonant frequency and negative group delay characteristics of the spiral ring are adjusted by changing the size and bending angle of the rectangular metal strips.

8. The SSPP unit structure with multi-band negative group delay as claimed in claim 1, characterized in that The spiral ring assembly is composed of four spiral ring basic units to form a symmetrical folded spiral ring assembly; the frequency band range of negative group delay is expanded by adjusting the number of iterations and combination methods of the spiral ring basic units.

9. The SSPP unit structure with multi-band negative group delay as claimed in claim 1, characterized in that The SSPP unit structure has a negative group delay characteristic within a specific frequency band, 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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