A terahertz tripling structure based on open-ring resonant array near-field modulation, a tripler and electronic equipment

Abstract

The present application relates to the technical field of terahertz solid-state source and terahertz frequency multiplier, and particularly relates to a terahertz tripler structure based on open loop resonant array near-field regulation, a terahertz tripler and electronic equipment.The terahertz tripler structure comprises a metal cavity, and a suspended dielectric substrate is arranged in the metal cavity; the suspended dielectric substrate has a first surface, and an input matching network, an output matching network, an open loop resonant array and a Schottky diode assembly are arranged on the first surface; the Schottky diode assembly is assembled in an inverted manner above the suspended dielectric substrate, and the open loop resonant array is located in the near-field region below the Schottky diode assembly.By constructing a subwavelength scale artificial electromagnetic regulation environment in the near-field region of the inverted diode, the present application can reduce the transverse diffusion of high-frequency surface current in the diode metal pad and substrate region, improve the local electric field distribution of the diode junction region, and is conducive to improving the impedance matching and output flatness of the wideband tripler.

Description

Technical Field

[0001] This invention relates to the field of terahertz solid-state sources and terahertz frequency multipliers, and particularly to a terahertz third frequency multiplier structure, third frequency multiplier, and electronic device based on near-field modulation of an open-loop resonant array. Background Technology

[0002] The terahertz band has significant applications in broadband communications, high-resolution radar, imaging detection, and astronomical observation. Solid-state frequency multipliers based on Schottky barrier diodes can generate stable high-frequency coherent signals at room temperature and are important components in terahertz source links. For third frequency multipliers in the 90 GHz to 510 GHz band, a suspended microstrip, waveguide probe, and anti-parallel Schottky diode chip are typically used to achieve fundamental input, nonlinear frequency multiplication, and third harmonic output.

[0003] As operating frequencies enter the submillimeter-wave and terahertz bands, near-field electromagnetic coupling between flip-chip diodes, interconnect solder joints, metal pads, dielectric substrates, and metal cavities significantly increases. Traditional designs often approximate diodes as lumped-parameter nonlinear elements, relying primarily on external input / output matching networks to improve performance. However, this approach lacks sufficient control over the local electromagnetic environment beneath and around the diode chip, easily leading to problems such as surface current divergence near metal pads and dielectric substrates, difficulty in concentrating local electric fields, and limited broadband matching flatness.

[0004] Therefore, there is an urgent need to develop a terahertz triplet structure that can construct an artificial electromagnetic boundary in the near-field region of a flip-chip Schottky diode and coordinate with a broadband matching network to enhance the effective excitation of the diode junction region in a high-frequency packaging environment and improve the broadband output stability of the frequency multiplier. Summary of the Invention

[0005] The purpose of this invention is to provide a terahertz tripler structure, tripler, and electronic device based on near-field modulation of an open-loop resonant array, in order to solve the problems of lack of effective electromagnetic boundary modulation, surface current divergence, and insufficient broadband matching flatness in the near-field region of traditional flip-chip Schottky diode triplers.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A terahertz third harmonic structure based on near-field modulation of an open-loop resonant array includes a metal cavity, in which a suspended dielectric substrate is disposed; the suspended dielectric substrate has a first surface, on which an input matching network, an output matching network, an open-loop resonant array, and a Schottky diode assembly are disposed;

[0008] The Schottky diode assembly is suspended and mounted on the side of the first surface facing away from the bottom wall of the metal cavity via a flip-chip interconnect at its bottom. The flip-chip interconnect is located between the Schottky diode assembly and the first surface, and the flip-chip interconnect is electrically connected to the signal line ends of the input matching network and the output matching network on the first surface, respectively.

[0009] The open-loop resonant array is positioned between the input matching network and the output matching network along the signal transmission direction, and is located within the projection area of ​​the Schottky diode assembly on the first surface; the open-loop resonant array and the Schottky diode assembly are positioned opposite each other and spaced apart in a direction perpendicular to the first surface to form a near-field coupling structure;

[0010] The unit period and geometry of the open-loop resonant array are configured to regulate the current and electric field distribution within the Schottky diode component region in the fundamental and third harmonic frequency bands.

[0011] Furthermore, the Schottky diode assembly includes an anti-parallel Schottky diode chip, the junction region of which is arranged facing the open-ring resonant array.

[0012] Furthermore, the open-loop resonant array includes multiple open-loop resonant units, which are periodically arranged on the first surface.

[0013] Furthermore, the plurality of open-loop resonant units are arranged in a two-dimensional array on the first surface, and the plurality of open-loop resonant units are arranged in groups along the signal transmission direction between the input matching network and the output matching network.

[0014] Furthermore, each of the said open-ring resonant units includes a metal ring arm and a capacitor opening formed on the metal ring arm, the capacitor opening being oriented toward the center of the projection area of ​​the Schottky diode assembly on the first surface.

[0015] Furthermore, the metal cavity forms an upper shielding cavity and a lower shielding cavity on opposite sides of the suspended dielectric substrate in the thickness direction.

[0016] A terahertz third harmonic generator includes a terahertz third harmonic structure, an input waveguide cavity, and an output waveguide cavity. The terahertz third harmonic structure is the aforementioned terahertz third harmonic structure based on near-field modulation of an open-loop resonant array. Its input matching network is coupled to the input waveguide cavity, and its output matching network is coupled to the output waveguide cavity.

[0017] An electronic device comprising the aforementioned terahertz tripler.

[0018] Compared with the prior art, the present invention has at least the following beneficial effects:

[0019] 1. The present invention sets an open-loop resonant array in the near-field region corresponding to the flip-chip Schottky diode assembly. The electromagnetic boundary conditions under the diode chip are changed by the equivalent high impedance surface response formed by the open-loop resonant unit, thereby reducing the degree of lateral diffusion of high-frequency surface current along the dielectric substrate and improving the local electromagnetic distribution in the diode region.

[0020] 2. The number and arrangement of the open-ring resonant units of the present invention can be adjusted according to the flip chip size and diode assembly area, so that the near-field control area matches the effective working area of ​​the diode, which is beneficial to improving the electric field distribution in the diode area;

[0021] 3. The open-loop resonant array of the present invention works in conjunction with the input and output matching networks and the shielding cavity, which is beneficial to improving the impedance matching, output power flatness and conversion efficiency stability of the tripler in a wide frequency band.

[0022] 4. The terahertz triplet structure of the present invention is mainly composed of planar metal patterns and suspended dielectric substrates, which are suitable for photolithography and flip-chip assembly. Attached Figure Description

[0023] Figure 1 This is a top view schematic diagram of the terahertz third harmonic structure according to an embodiment of the present invention;

[0024] Figure 2 This is a schematic diagram showing the relative positions of the flip-chip Schottky diode assembly and the open-ring resonant array according to an embodiment of the present invention;

[0025] Figure 3 This is a schematic diagram of the open-loop resonant array structure according to an embodiment of the present invention;

[0026] Figure 4 This is a cross-sectional schematic diagram of the suspended dielectric substrate, the open-ring resonant array, and the shielding cavity according to an embodiment of the present invention;

[0027] Figure label:

[0028] 100. Terahertz third harmonic structure; 110. Metal cavity; 111. Input waveguide cavity; 112. Output waveguide cavity; 113. Upper shielding cavity; 114. Lower shielding cavity; 120. Suspended dielectric substrate; 122. First surface; 130. Input matching network; 140. Output matching network; 150. Schottky diode assembly; 151. Anti-parallel Schottky diode chip; 154. Flip-chip interconnect; 160. Open-loop resonant array; 161. Open-loop resonant unit; 164. Capacitor opening; 165. Metal ring arm; 166. Unit gap. Detailed Implementation

[0029] The present invention will now be described in conjunction with the accompanying drawings and embodiments. It should be understood that the described embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the invention. Unless otherwise specified, the following embodiments and features described herein can be combined with each other.

[0030] like Figure 1 As shown, this embodiment provides a terahertz third harmonic structure 100 based on near-field modulation of an open-loop resonant array, including a metal cavity 110. A suspended dielectric substrate 120 is disposed within the metal cavity 110.

[0031] The suspended dielectric substrate 120 has a first surface, on which an input matching network 130, an output matching network 140, an open-loop resonant array 160, and a Schottky diode assembly 150 are disposed; wherein:

[0032] like Figure 2 As shown, the Schottky diode assembly 150 is suspended and mounted on the side of the first surface 122 of the suspension dielectric substrate 120 facing away from the bottom wall of the metal cavity through the flip-chip interconnects at its bottom. The flip-chip interconnects 154 are located between the Schottky diode assembly and the first surface 122. Each flip-chip interconnect is electrically connected to the signal line end of the input matching network and the output matching network provided on the first surface 122. In this embodiment, the Schottky diode assembly 150 includes an anti-parallel Schottky diode chip 151, which is mounted on the suspended dielectric substrate 120 in a flip-chip configuration. The flip-chip interconnect 154 serves to fix the chip in the flip-chip configuration and also provides electrical interconnection for the device. The junction region of the anti-parallel Schottky diode chip 151 faces the open-ring resonant array 160 disposed on the first surface 122 of the suspended dielectric substrate 120, and the open-ring resonant array 160 is located entirely within the near-field region below the anti-parallel Schottky diode chip 151, forming a near-field coupling relationship between the two.

[0033] The open-loop resonant array 160 is composed of multiple open-loop resonant units 161, which are arranged in a periodic one-dimensional or two-dimensional array on the first surface 122 and grouped together along the signal transmission direction between the input matching network 130 and the output matching network 140. The overall number and arrangement can be adapted and adjusted according to the size of the anti-parallel Schottky diode chip 151, the flip-chip mounting area, and the position of the diode junction region to ensure that the near-field constraint region of the array covers or is adjacent to the diode junction region, effectively improving the junction electric field excitation effect. Each open-loop resonant unit 161 consists of a metal ring arm 165 and a capacitor opening 164 located on one side of the metal ring arm 165, thereby forming an equivalent inductor-capacitor resonant structure, and the capacitor opening 164 is uniformly oriented towards the center direction of the projection area of ​​the Schottky diode assembly 150 on the first surface 122.

[0034] like Figure 3 As shown, the structural parameters of each unit can be flexibly fine-tuned according to the target operating frequency band and the size of the Schottky diode chip, thereby adapting and controlling the equivalent inductance, equivalent capacitance and coupling strength between units. At the same time, the open-loop resonant array 160, the input matching network 130 and the output matching network 140 are jointly arranged on the first surface 122 of the suspended dielectric substrate 120. Together with the metal cavities 110 on both sides of the thickness direction of the suspended dielectric substrate 120, they form the upper shielding cavity 113 and the lower shielding cavity 114, respectively. Through the overall structural cooperation, the near-field electromagnetic distribution of the Schottky diode component area can be adjusted. In this embodiment of the terahertz third harmonic structure, the mechanism by which the open-ring resonant array 160 forms a high surface impedance near-field boundary is as follows: the metal ring arm 165 provides an equivalent inductance, and the capacitor opening 164 and the unit gap 166 between adjacent open-ring resonant units 161 provide an equivalent capacitance. When the equivalent resonant frequency or impedance peak of the open-ring resonant array 160 is near the target modulation frequency band, the array surface presents a large equivalent impedance to the high-frequency surface current that diffuses laterally along the suspended dielectric substrate 120, thereby reducing the lateral expansion of the surface current in the corresponding region of the anti-parallel Schottky diode chip 151, the flip-chip interconnect 154, and the metal pad region. At the same time, an enhanced local electric field can be formed near the capacitor opening 164, causing near-field energy to concentrate in the diode region, improving the local electric field distribution of the diode junction region, and increasing the effective RF excitation. By adjusting the external dimensions of the open-ring resonant unit 161, the linewidth of the metal ring arm 165, the width of the capacitor opening 164, and the unit gap 166, the near-field boundary can act on the fundamental frequency band, the third harmonic output frequency band, or the near-field coupling control frequency band between the fundamental frequency band and the third harmonic output frequency band, thereby working in conjunction with the input matching network 130 and the output matching network 140 to improve broadband impedance matching and output flatness.

[0035] The metal cavity 110 forms an upper shielding cavity 113 and a lower shielding cavity 114 on opposite sides of the suspended dielectric substrate 120 in the thickness direction.

[0036] It should be noted that the suspended dielectric substrate 120 in this embodiment is a low-loss dielectric substrate, preferably a quartz substrate or a quartz glass substrate; the metal cavity 110 is a split-type shielded waveguide cavity, formed by processing conductive metal material, and its surface can be metallized to reduce conductor loss. The specific dimensions of the suspended dielectric substrate 120 and the shielded cavity can be determined according to the operating frequency band, assembly process, and matching network form.

[0037] Based on the above-described terahertz third harmonic structure, this embodiment also provides a terahertz third harmonic generator, which includes the terahertz third harmonic structure 100 described in any of the above embodiments, an input waveguide cavity 111, and an output waveguide cavity 112. The input waveguide cavity 111 is connected to an input matching network 130, and the output waveguide cavity 112 is connected to an output matching network 140. The input waveguide cavity 111 receives the fundamental frequency signal, which is then used by the input matching network 130 to excite the Schottky diode assembly 150 to generate the third harmonic component. The third harmonic signal is then output through the output matching network 140 and the output waveguide cavity 112.

[0038] The present invention also provides an electronic device comprising the aforementioned terahertz third harmonic. The electronic device may be a terahertz communication device, a terahertz radar, a terahertz imaging device, a terahertz testing instrument, an astronomical observation receiving front-end, or other device requiring a terahertz local oscillator or a terahertz solid-state source.

[0039] The specific values, frequency bands, waveguide types, and materials described in the above embodiments are merely examples to illustrate the technical solutions of the present invention. For those skilled in the art, adjustments can be made to the number of elements, opening direction, array spacing, metal linewidth, substrate material, cavity height, and matching network shape of the open-loop resonant array without departing from the concept of the present invention; all such adjustments should fall within the protection scope of the present invention.

Claims

1. A terahertz third harmonic structure based on near-field modulation of an open-ring resonant array, characterized in that, Includes a metal cavity, within which a suspended dielectric substrate is disposed; The suspended dielectric substrate has a first surface, on which an input matching network, an output matching network, an open-loop resonant array, and a Schottky diode assembly are disposed; The Schottky diode assembly is suspended and mounted on the side of the first surface facing away from the bottom wall of the metal cavity via a flip-chip interconnect at its bottom. The flip-chip interconnect is located between the Schottky diode assembly and the first surface, and the flip-chip interconnect is electrically connected to the signal line ends of the input matching network and the output matching network on the first surface, respectively. The open-loop resonant array is positioned between the input matching network and the output matching network along the signal transmission direction, and is located within the projection area of ​​the Schottky diode assembly on the first surface; the open-loop resonant array and the Schottky diode assembly are positioned opposite each other and spaced apart in a direction perpendicular to the first surface to form a near-field coupling structure; The unit period and geometry of the open-loop resonant array are configured to regulate the current and electric field distribution within the Schottky diode component region in the fundamental and third harmonic frequency bands.

2. The terahertz third harmonic structure according to claim 1, characterized in that, The Schottky diode assembly includes an anti-parallel Schottky diode chip, the junction region of which is arranged facing the open-ring resonant array.

3. The terahertz third harmonic structure according to claim 1, characterized in that, The open-loop resonant array includes multiple open-loop resonant units, which are periodically arranged on the first surface.

4. The terahertz third harmonic structure according to claim 3, characterized in that, The plurality of open-loop resonant units are arranged in a two-dimensional array on the first surface, and the plurality of open-loop resonant units are arranged in groups along the signal transmission direction between the input matching network and the output matching network.

5. The terahertz third harmonic structure according to claim 3, characterized in that, Each of the open-ring resonant units includes a metal ring arm and a capacitor opening formed on the metal ring arm, the capacitor opening being oriented toward the center of the projection area of ​​the Schottky diode assembly on the first surface.

6. The terahertz third harmonic structure according to claim 1, characterized in that, The metal cavity forms an upper shielding cavity and a lower shielding cavity on opposite sides of the suspended dielectric substrate in the thickness direction.

7. A terahertz third harmonic generator, comprising a terahertz third harmonic structure, an input waveguide cavity, and an output waveguide cavity, wherein the terahertz third harmonic structure is the terahertz third harmonic structure according to any one of claims 1 to 6, wherein its input matching network is coupled to the input waveguide cavity, and its output matching network is coupled to the output waveguide cavity.

8. An electronic device comprising a terahertz tripler as described in claim 7.

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