Ka-band 1-bit reconfigurable metasurface unit

Abstract

The utility model discloses a Ka-band 1-bit reconfigurable metasurface unit, which sequentially comprises a first metal layer, a first dielectric layer, a second metal layer, a second dielectric layer and a third metal layer from top to bottom, and is characterized in that the first metal layer is connected with the third metal layer through a metalized via hole; the metalized via hole penetrates through the first dielectric layer, the second metal layer and the second dielectric layer, the first metal layer is provided with a PIN diode, the Ka-band 1-bit reconfigurable metasurface unit aims to overcome the defect that the amplitude phase of a traditional reflection unit cannot be changed, the reflection amplitude phase can be flexibly changed, and the performance of the Ka-band 1-bit reconfigurable metasurface unit is improved. And real-time control of electromagnetic waves is realized.

Description

Technical Field

[0001] The utility model belongs to the technical field of electromagnetic communication, and relates to a Ka-band 1-bit reconfigurable metasurface unit. Background Art

[0002] Electromagnetic metamaterials have been attracting much attention because they can control electromagnetic waves. As a two-dimensional form of electromagnetic metamaterials, electromagnetic metasurfaces have the advantages of low profile, low loss, small volume, light weight, simple design, convenient processing and easy integration. Traditional metasurfaces have a fixed topological geometry structure and can only achieve a single control function after being fabricated. To eliminate the shortcoming that the electromagnetic characteristics of metasurfaces are difficult to change, a reconfigurable metasurface came into being.

[0003] By loading control devices such as PIN diodes, varactor diodes or MEMS switches in the metasurface, a fixed-form metasurface can exhibit dynamic adjustable or reconfigurable functional characteristics, realizing flexible control of amplitude, phase, polarization, etc., and having great application potential in new-generation mobile communication, imaging systems and stealth. At the same time, since the metasurface does not require complex devices to work and only changing the state of the device can achieve the control of electromagnetic waves, compared with antenna base stations that require complex circuit designs, the reconfigurable passive metasurface has lower cost and loss. A 1-bit reconfigurable metasurface reflection unit loaded with a PIN diode has two control states. The diode "OFF" and "ON" respectively simulate the digital "0" and "1", and the phase difference between the two states is 180°. Compared with the unit form of the traditional reflection unit with unchangeable amplitude and phase, the reconfigurable passive metasurface can achieve flexible variation of amplitude and phase, realize real-time control of electromagnetic waves, and thus can achieve a wider range of applications. However, the metasurface structure in the prior art can only achieve a single control function after being fabricated and cannot control the reflection amplitude and phase. Therefore, it is necessary to propose a Ka-band 1-bit reconfigurable metasurface unit to solve the above problems. Summary of the Utility Model

[0004] In view of the above problems, to overcome the defects of the prior art, the utility model proposes a Ka-band 1-bit reconfigurable metasurface unit. The purpose of the utility model is to overcome the defect that the amplitude and phase of the traditional reflection unit are unchangeable, and propose a Ka-band 1-bit reconfigurable metasurface unit, which can achieve flexible variation of reflection amplitude and phase and realize real-time control of electromagnetic waves.

[0005] To achieve the above object, the technical solution adopted by the present utility model is as follows: The metasurface unit of the present utility model sequentially includes from top to bottom: a first metal layer, a first dielectric layer, a second metal layer, a second dielectric layer, and a third metal layer. The first metal layer and the third metal layer are connected by a metallized via, and the metallized via penetrates through the first dielectric layer, the second metal layer, and the second dielectric layer. A PIN diode is installed on the first metal layer.

[0006] Preferably, the metasurface unit is of a square structure, and the unit period T is:

[0007]

[0008] In the formula: c is the speed of light in vacuum, and f0 is the center frequency point frequency.

[0009] Preferably, the first metal layer includes two metal main patches that are centrosymmetric and have a gap, and two metal sub-patches that are not connected to the metal main patches and play a coupling role. A PIN diode is lapped between the two metal main patches. The two metal sub-patches and the two metal main patches are both adhered to the first dielectric layer.

[0010] Preferably, the metal main patch includes a rectangular metal patch and a plurality of metal branches, and the plurality of metal branches are fixed on the rectangular metal patch.

[0011] Preferably, the length of the gap between the two metal main patches is less than the length of the PIN diode.

[0012] Preferably, the metal sub-patch is a rectangular metal patch, and a groove for cooperating with the metal branches is formed on the metal sub-patch.

[0013] Preferably, a round hole is formed on the second metal layer, the diameter of the round hole is larger than the diameter of the metallized via, the metallized via passes through the round hole, and the metallized via does not contact the round hole.

[0014] Preferably, the third metal layer includes two sector branches respectively centered on the center of the metallized via and two feed lines respectively connected to the metallized via. The metallized via is connected between the sector branches and the feed lines. The radius of the sector branch:

[0015]

[0016] In the formula: c is the speed of light in vacuum, f0 is the center frequency point frequency, and E r is the dielectric constant of the plate.

[0017] Compared with the prior art, the present utility model has the following beneficial effects:

[0018] 1. The structure of the present utility model belongs to a two-dimensional planar structure, which has the characteristic of low profile compared with three-dimensional metamaterials and is easy to integrate in a circuit.

[0019] 2. The working principle of the present utility model is simple. By only changing the working state of the diode, the amplitude and phase can be regulated, greatly reducing the circuit complexity. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the overall structure of the present utility model.

[0021] Figure 2 It is a schematic diagram of the structure of the first metal layer of the present utility model (the shaded part in the figure is the copper-clad layer).

[0022] Figure 3 It is a schematic diagram of the structure of the second metal layer of the present utility model (the shaded part in the figure is the copper-clad layer).

[0023] Figure 4 It is a schematic diagram of the structure of the third metal layer of the present utility model (the shaded part in the figure is the copper-clad layer).

[0024] Figure 5 It is a result diagram of the reflection amplitude of the metasurface unit in the present utility model.

[0025] Figure 6 It is a post-processing result diagram of the reflection phase of the metasurface unit in the present utility model.

[0026] Reference numerals: 1. First metal layer; 2. First dielectric layer; 3. Second metal layer; 4. Second dielectric layer; 5. Third metal layer; 6. Metallized via; 7. PIN diode; 8. Metal main patch; 9. Metal sub-patch; 10. Round hole; 13. Fan-shaped branch; 14. Feeder line. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0028] Next, a more detailed description will be given of the specific implementation manners of the present utility model in conjunction with the attached Figure 1-6 drawings.

[0029] Figure 1 It is a schematic diagram of the overall structure of the metasurface unit, as shown in Figure 1As shown, the unit structure includes a first metal layer 1, a first dielectric layer 2, a second metal layer 3, a second dielectric layer 4, and a third metal layer 5. A metallized via 6 connects the first metal layer 1 and the third metal layer 5. The first metal layer 1 contains a PIN diode 7.

[0030] The metasurface unit structure is a square structure, and the unit period T is:

[0031]

[0032] Where: c is the speed of light in vacuum, f0 is the center frequency,

[0033] After simulation optimization, the optimal unit cycle is determined to be

[0034] Figure 2 Schematic diagram of the first metal layer 1 of the metasurface unit, which is the patch layer of the metasurface unit; the first metal layer 1 includes two centrally symmetrical metal main patches 8 with a gap and two metal sub-patches 9 that are not connected to the metal main patches 8 and have a coupling effect, and a PIN diode 7 is connected between the two metal main patches 8;

[0035] The first metal layer 1 of the metasurface unit has two centrally symmetrical metal main patches 8 with gaps. The metal main patches 8 are composed of rectangular metal patches and a plurality of connected metal branches. There is a gap between the two metal main patches 8, and the gap distance is sufficient to meet the minimum welding pad distance of the PIN diode 7; the two metal sub-patches 9 are rectangular metal patches, and there are corresponding depressions in the protruding parts of the branches of the metal main patches 8. There are gaps of a certain distance between the metal sub-patches 9 and the adjacent metal main patches 8. By adjusting the length of the metal branches of the metal main patches 8 and the metal main patches 8, the gaps are adjusted. The gap between the main metal patch 8 and the metal sub-patch 9 is used to determine the coupling degree between the patches; after simulation optimization, the dimensions are determined as follows: L1 = 2.1mm, W1 = 4.4mm, gap = 0.35mm, gap1 = 0.127mm, L2 = 1.4mm, W2 = 0.4mm, where gap is the soldering distance of the PIN diode pins, gap1 is the distance between the main metal patch 8 and the metal sub-patch 9, 0.16T≤L1≤0.21T, 0.36T≤W1≤0.47T, 0.6L1≤L2≤0.85L1;

[0036] Figure 3 Schematic diagram of the second metal layer 3 of the metasurface unit, which is the metal layer of the metasurface unit and works together with the first metal layer 1 to realize a reflective metasurface; the entire surface of the metal layer is covered with copper, and only a circular hole 10 with a radius slightly larger than the radius of the metallized via 6 is etched at the position of the metallized via 6 to avoid the metallized via 6 and prevent the metallized via 6 from short-circuiting with the metal layer;

[0037] Figure 4 Schematic diagram of the third metal layer 5 of the metasurface unit. This metal layer is the feeding circuit layer of the metasurface unit. The metal layer includes two sector-shaped branches 13 with the centers of the metallized vias 6 as their centers respectively, and two feeding lines 14 connected to the metallized vias 6 respectively. The purpose of loading the sector-shaped branches 13 is to prevent microwave energy from leaking into the DC feeding circuit and causing problems such as self-excitation. The radius of the sector-shaped branches 13:

[0038]

[0039] In the formula: c is the speed of light in vacuum, f0 is the center frequency point, and E r is the dielectric constant of the board. When there is microwave energy leakage in some design frequency bands, it will be short-circuited after passing through the sector-shaped branches 13, ensuring that the interference between the microwave signal and the feeding signal is small;

[0040] The metallized via 6 connects the metal main patch 8 of the first metal layer 1 and the feeding line 14 of the third metal layer 5. By applying different voltages to the two feeding lines 14, the conduction and cut-off of the PIN diode 7 are realized, thereby realizing different reflection amplitudes and phases of the metasurface unit;

[0041] Encoding PIN Diode State Reflection Phase "00” Turn Off 0° "11” Turn On 180°

[0042] The first dielectric layer 2 is a conventional PCB board, and its thickness H range is:

[0043]

[0044] c is the speed of light in vacuum, f0 is the center frequency point, and E r is the dielectric constant of the board,

[0045] After simulation optimization and a compromise selection with the thickness of the existing conventional PCB board, it is finally determined that The second dielectric layer 4 is a conventional PCB board. The influence of this layer of board on the performance is limited, and it is only necessary to ensure the normal routing of the feeding circuit;

[0046] Figure 5 is the reflection amplitude curve of the metasurface unit. In the operating frequency band of 26.5 GHz - 29.5 GHz, the losses in the "00" and "11" states are within 0.8 dB. Almost all the energy is reflected in this frequency band, indicating that the unit has a very high reflection efficiency. The efficiency of this metasurface unit is above 82%;

[0047] Figure 6It is the phase difference curve obtained by subtracting the reflection phase of the "00" state from the reflection phase of the metasurface unit "11". In the operating frequency band of 26.5 GHz - 29.5 GHz, the phase difference between the "00" and "11" states is within 180° ± 30°, demonstrating good 1-bit controllable characteristics within a relative bandwidth of 10.7%.

[0048] Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. A Ka-band 1-bit reconfigurable metasurface unit, characterized in that: The metasurface unit includes, from top to bottom, a first metal layer, a first dielectric layer, a second metal layer, a second dielectric layer, and a third metal layer. The first metal layer and the third metal layer are connected by metallized vias, and the metallized vias penetrate the first dielectric layer, the second metal layer, and the second dielectric layer. A PIN diode is installed on the first metal layer.

2. The Ka-band 1-bit reconfigurable metasurface unit according to claim 1, characterized in that: The metasurface unit is a square structure, and the unit period T is: Where: c is the speed of light in vacuum, f0 is the center frequency.

3. The Ka-band 1-bit reconfigurable metasurface unit according to claim 1, characterized in that: The first metal layer includes two centrally symmetrical metal main patches with a gap and two metal sub-patches which are not connected to the metal main patches and play a coupling role. A PIN diode is overlapped between the two metal main patches. The two metal sub-patches and the two metal main patches are all adhered to the first dielectric layer.

4. The Ka-band 1-bit reconfigurable metasurface unit according to claim 3, characterized in that: The metal main patch includes a rectangular metal patch and a plurality of metal branches, and the plurality of metal branches are fixed on the rectangular metal patch.

5. The Ka-band 1-bit reconfigurable metasurface unit according to claim 3, characterized in that: The length of the gap between the two metal main patches is smaller than the length of the PIN diode.

6. The Ka-band 1-bit reconfigurable metasurface unit according to claim 4, characterized in that: The metal sub-patch is a rectangular metal patch, and a groove matching the metal branch is formed on the metal sub-patch.

7. The Ka-band 1-bit reconfigurable metasurface unit according to claim 1, characterized in that: A circular hole is formed on the second metal layer. The diameter of the circular hole is larger than the diameter of the metallized via hole. The metallized via hole passes through the circular hole, and the metallized via hole does not contact the circular hole.

8. The Ka-band 1-bit reconfigurable metasurface unit according to claim 1, characterized in that: The third metal layer includes two fan-shaped branches with the axis of the metallized via as the center and two feeders connected to the metallized via respectively. The metallized via is connected between the fan-shaped branches and the feeders. The radius of the fan-shaped branches is: Where: c is the speed of light in vacuum, f0 is the center frequency, E r is the dielectric constant of the plate.

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