On-chip topological state modulator based on Schottky diode

Abstract

The invention discloses an on-chip topological state modulator based on a Schottky diode, which comprises an electromagnetic wave input area, a metal film topological structure transmission area, a control signal feed-in area and an electromagnetic wave output area, and is characterized in that the metal film topological structure transmission area is formed by arranging a plurality of two different primitive cells according to a hexagonal lattice array; a Schottky diode is installed at the junction of the domain walls of the primitive cells, the distribution period of the Schottky diode is the same as the lattice constant of the primitive cells, and the on-off state of the Schottky diode is controlled by the voltage of the control signal feed-in area. According to the invention, the metal film is utilized to construct a honeycomb lattice topological structure, structural perturbation is utilized to break space inversion symmetry in the topological structure so as to open a topological band gap, and a Schottky diode is installed at the junction of domain walls, so that topological boundary state single-mode transmission regulation and control with a high switch ratio can be realized by regulating and controlling band gap dispersion mode distribution.

Description

Technical Field

[0001] The invention belongs to the field of electromagnetic functional devices, and in particular relates to an on-chip topological state modulator based on a Schottky diode. Background Art

[0002] With the continuous development of communication technology, the frequency of mobile communication is getting higher and higher, and the on-chip integrated millimeter wave-sub-terahertz control technology has become one of the key technologies to meet the needs of the next generation of wireless communications. The existing control method is mainly based on the combination of on-chip transmission lines and artificial electromagnetic active resonant unit structures, and the transmission characteristics such as frequency, amplitude, phase, and polarization are controlled by the change and layout of the resonance mode of the on-chip artificial microstructure. For example, patents CN116360127A and CN105652475A use waveguide packaging modulation chips to prepare transmission lines and artificial microstructures on the substrate, and use high electron mobility transistors or diodes to switch the resonance mode of the artificial microstructure to achieve on-off control of the electromagnetic waves transmitted in the waveguide. Due to the good electromagnetic shielding characteristics of the metal cavity, higher modulation efficiency and modulation rate can be achieved.

[0003] Although the above method realizes on-chip transmission control of millimeter-wave-sub-terahertz signals, due to the limitation of modulation principle, it is impossible to achieve a high switching ratio due to the introduction of parasitic modes during mode switching, which limits the further improvement of modulation rate and communication rate. Therefore, it is urgent to break through the physical principles and develop on-chip modulators with more robust performance.

[0004] Topological photonic crystals are emerging photonic structures based on solid-state physics theory and topological physics. They have received extensive attention in recent years due to their robustness to local defects and immunity to corner transmission losses. For example, patent CN116247405B, based on metal film units with C3 symmetry, forms a topological transmission mode in the band gap by splicing photonic crystal regions with different Chern numbers, providing an efficient electromagnetic waveguide based on topological valley boundary states. Although on-chip transmission waveguides based on topological structures have made great progress, there is still a gap in the research of topological state electrically controlled modulators.

[0005] In summary, the problems and defects of the existing millimeter wave-sub-terahertz wave on-chip control technology are as follows:

[0006] (1) Difficulty in designing the control unit: Millimeter-wave to sub-terahertz wavelengths are short and high in frequency, requiring careful design of the composite active control structure. At the same time, the parasitic parameters introduced by artificial microstructures and transistors are difficult to control, making it difficult to achieve single-mode transmission control, thus affecting the control efficiency;

[0007] (2) Difficulty in feeding and wiring: Although the boundary states of the topological structure can realize single-mode transmission of millimeter waves to sub-terahertz waves, due to the periodicity of the topological structure, the large number of units, and the difficulty of feeding and wiring, the existing topological modulators are generally implemented using optical control, which makes it difficult to achieve electrically controlled on-chip topological transmission regulation, and thus difficult to achieve on-chip integration. Summary of the invention

[0008] The object of the present invention is to overcome the above-mentioned defects of the prior art and provide an on-chip topological modulator based on Schottky diodes.

[0009] The objective of the present invention is achieved through the following technical solutions:

[0010] A Schottky diode-based on-chip topological state modulator comprises an electromagnetic wave input region, a metal film topological structure transmission region, a control signal feeding region and an electromagnetic wave output region, wherein the electromagnetic wave input / output region is composed of a microstrip line, one end of which is connected to the metal film topological structure transmission region, and the other end is connected to a feeding source / receiving end through a probe; the metal film topological structure transmission region is composed of a plurality of A and B primitive cells arranged in a hexagonal lattice array, the A and B primitive cells are 180° central rotationally symmetrical, the A primitive cell region is connected to the B primitive cell region in a vertical direction, and a Schottky diode is installed at the junction of the A and B primitive cell domain walls for regulating the electromagnetic transmission characteristics of the topological boundary state, the distribution period of the Schottky diode is the same as the primitive cell lattice constant, and the on-off state of the Schottky diode is controlled by the voltage of the control signal feeding region.

[0011] Furthermore, the primitive cell region A is connected to the primitive cell region B in the vertical direction, and the number of primitive cell cycles in the vertical direction is ≥ 4.

[0012] Furthermore, the cathode of the Schottky diode is mounted on the topological structure at the junction of the original cell domain wall, connected to the back metal plate through a metal through hole and grounded, and the anode of the Schottky diode is mounted on the pad, connected to the signal feed-in area through a first metal blind hole connected to the pad, a middle metal layer and a second metal blind hole, and the number of Schottky diodes is M in total, M ≥ 4.

[0013] Furthermore, each primitive cell is composed of three thin metal Y-shaped branches and three thick metal Y-shaped branches interlaced with each other.

[0014] Furthermore, the metal film material of the metal film topological structure transmission region is Au, Ag, Cu or Al.

[0015] The present invention inputs electromagnetic waves through a probe, constructs a honeycomb lattice topological structure using a metal film, breaks the spatial inversion symmetry in the topological structure using structural perturbations to open a topological band gap, and inverts a Schottky diode at the junction of the domain walls to control the distribution of the band gap dispersion mode to achieve control of the electromagnetic transmission characteristics of the topological boundary state, and finally transmits the modulated electromagnetic wave through the probe structure.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] (1) Single-mode transmission control: The present invention uses a metal thin film periodic structure to construct a topological chip. By regulating the distribution of band gap dispersion modes in the band structure, the introduction of higher-order parasitic modes is avoided, and on-chip electromagnetic wave single-mode transmission control with a high switching ratio can be achieved.

[0018] (2) Strong field locality: The present invention utilizes the topological boundary state generated by the metal structure for transmission, which has good electric field locality and avoids energy leakage.

[0019] (3) High integration: The present invention uses a Schottky diode that has a fast response capability to millimeter-wave to sub-terahertz waves to control the on-off of the topological state, which can effectively improve the modulation rate; at the same time, it adopts an electronic control method for regulation, without the need for a bulky laser source excitation, and has a higher integration level.

[0020] (4) Easy to manufacture: The present invention can be manufactured using a multi-layer printed circuit board process and an additive manufacturing process, which has mature technology and low manufacturing cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic diagram of the structure of a topological state modulator according to an embodiment of the present invention;

[0022] Figure 2 A schematic side view of a topological state modulator according to an embodiment of the present invention;

[0023] Figure 3 The energy band structure diagram of the topological state modulator according to the embodiment of the present invention when a voltage is applied to the Schottky diode and when no voltage is applied;

[0024] Figure 4 It is a transmission curve diagram of the topological state modulator according to the embodiment of the present invention when a voltage is applied to the Schottky diode and when no voltage is applied;

[0025] Figure 5 The electric field distribution diagram of the topological state modulator according to the embodiment of the present invention when a voltage is applied to the Schottky diode and when no voltage is applied;

[0026] Markings in the figure: 1. Electromagnetic wave input area; 2. Metal film topological structure transmission area; 3. Control signal feeding area; 4. Electromagnetic wave output area; 5. Schottky diode; 6. Metal through hole; 7. Second metal blind hole; 8. First metal blind hole; 9. Middle metal layer. DETAILED DESCRIPTION

[0027] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments, but the protection scope of the present invention is not limited thereto.

[0028] like Figure 1 As shown, the on-chip topological modulator based on Schottky diode provided in this embodiment includes an electromagnetic wave input area 1, a metal thin film topological structure transmission area 2, a control signal feeding area 3, an electromagnetic wave output area 4 and a Schottky diode 5, wherein the electromagnetic wave input area 1 and the electromagnetic wave output area 2 are composed of microstrip lines, one end of the microstrip line is connected to the metal thin film topological structure transmission area 2, and the other end is connected to the feeding source / receiving end through a probe; the metal thin film topological structure transmission area is composed of a plurality of A and B primitive cells arranged in a hexagonal lattice array, and a Schottky diode 5 is installed at the junction of the domain walls of the A and B primitive cells, the distribution period of the Schottky diode 5 is the same as the primitive cell lattice constant a, and the on-off state of the Schottky diode 5 is controlled by the voltage of the control signal feeding area 3.

[0029] The structure of the metal film topological structure transmission region 2 is grown by Au, and the substrate is RO3003 with a dielectric constant of 3; the two primitive cells A and B are arranged in a hexagonal lattice array, and the two primitive cells A and B are 180° central rotation symmetric; the primitive cell regions A and B are connected in the vertical direction, and the number of periods of the two primitive cells in the vertical direction is 5. Each primitive cell is composed of three thin metal Y-shaped branches and three thick metal Y-shaped branches interlaced, and the width w2 of the thick metal Y-shaped branches is greater than the width w1 of the thin metal Y-shaped branches.

[0030] The cathode of the Schottky diode 5 at the junction of the domain walls of the A and B primitive cells is assembled on the topological structure, using a PCB multi-layer punching process, such as Figure 2 As shown, the cathode of the Schottky diode 5 is connected to the back metal plate through a metal through-hole 6 and grounded, and the anode of the Schottky diode 5 is mounted on the pad and connected to the signal feeding area 3 through a first metal blind hole 8, a middle metal layer 9 and a second metal blind hole 7 connected to the pad. The Schottky diode 5 is made of GaAs material. In this embodiment, the number of Schottky diodes 5 is 8 in total, and the 8 Schottky diodes 5 are connected to the signal feeding area 3 through the first metal blind hole 8, the middle metal layer 9 and the second metal blind hole 7 respectively.

[0031] In this embodiment, the unit cell lattice constants a=1.3 mm, w1=0.2, w2=0.5 mm.

[0032] The working principle of this embodiment is: input electromagnetic waves through the probe, use metal film to build a honeycomb lattice topological structure, use structural perturbation in the topological structure, that is, w1 is not equal to w2, break the spatial inversion symmetry and open the topological band gap. By flipping the Schottky diode 5 at the junction of the domain wall, the electromagnetic transmission characteristics of the topological boundary state can be regulated by regulating the distribution of the band gap dispersion mode. Figure 3 The topological modulator described in this embodiment is shown in the energy band structure dispersion diagram when the Schottky diode 5 is turned on and off. In the figure, when the Schottky diode 5 is turned off, it supports a single topological mode in the range of 67GHz-73GHz; when the Schottky diode 5 is turned on, the band gap range becomes narrower, and almost only supports single-frequency transmission. Since there are no high-order and parasitic modes in this band gap range, it is possible to achieve high modulation depth topological electromagnetic transmission characteristic regulation. Figure 4 As shown, the topological state modulator of this embodiment can achieve a maximum of 50dB high switching ratio single-mode modulation in the 67GHZ-73GHZ range, and an insertion loss of -7dB. In addition, the topological state modulator also exhibits excellent topological boundary state electric field localization, such as Figure 5 As shown, electromagnetic waves are only transmitted at the domain wall boundaries when no voltage is applied, thus avoiding energy leakage.

[0033] The above description is only a preferred implementation manner of the present invention, but the protection scope of the present invention is not limited thereto, and any modification and replacement based on the technical solution and inventive concept provided by the present invention should be included in the protection scope of the present invention.

Claims

1. An on-chip topological modulator based on a Schottky diode, characterized in that: It includes an electromagnetic wave input area, a metal film topological structure transmission area, a control signal feeding area and an electromagnetic wave output area. The electromagnetic wave input / output area is composed of a microstrip line, one end of the microstrip line is connected to the metal film topological structure transmission area, and the other end is connected to the feeding source / receiving end through a probe; the metal film topological structure transmission area is composed of a plurality of A and B primitive cells arranged in a hexagonal lattice array, the A and B primitive cells are 180° central rotationally symmetrical, the A primitive cell area is connected to the B primitive cell area in a vertical direction, and a Schottky diode is installed at the junction of the A and B primitive cell domain walls to regulate the electromagnetic transmission characteristics of the topological boundary state, the distribution period of the Schottky diode is the same as the primitive cell lattice constant, and the on-off state of the Schottky diode is controlled by the voltage in the control signal feeding area.

2. The on-chip topological modulator based on Schottky diode according to claim 1, characterized in that: The A primitive cell region is connected to the B primitive cell region in the vertical direction, and the number of primitive cell cycles in the vertical direction is ≥4.

3. The on-chip topological modulator based on Schottky diode according to claim 1, characterized in that: The cathode of the Schottky diode is mounted on the topological structure at the junction of the original cell domain wall, and is connected to the back metal plate through a metal through-hole to be grounded. The anode of the Schottky diode is mounted on the pad, and is connected to the control signal feeding area through a first metal blind hole connected to the pad, a middle metal layer and a second metal blind hole. The number of Schottky diodes is M in total, and M≥4.

4. The on-chip topological modulator based on Schottky diode according to claim 1, characterized in that: Each primitive cell is composed of three thin metal Y-shaped branches interlaced with three thick metal Y-shaped branches.

5. The on-chip topological modulator based on Schottky diode according to claim 1, characterized in that: The metal film material of the metal film topological structure transmission area is Au, Ag, Cu or Al.

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