Miniature annular dual-ridged corrugated integrated chamber

Abstract

The application discloses a micro annular double-ridged wave integrated chamber, which comprises an annular double-ridged wave microwave cavity, a MEMS atomic gas chamber, magnetic excitation, a dielectric matching layer and a tuning structure; the annular double-ridged wave microwave cavity is combined by an inner annular structure and an outer cavity through a connecting rod; the inner annular structure is used for forming equivalent inductance and equivalent capacitance of a resonant frequency; the outer cavity is used for forming an electromagnetic loop and an electromagnetic shield for the inner annular structure; periodic ridged wave structures are arranged on the inner walls of the inner annular structure and the outer cavity; the MEMS atomic gas chamber is integrated in the inner annular double-ridged wave microwave cavity; the magnetic excitation is used for exciting a microwave magnetic field to the annular double-ridged wave microwave cavity; and the dielectric matching layer is used for improving the edge axial magnetic field distribution of the micro chamber. The size of the pure metal annular cavity can be greatly reduced to millimeter level (<1 cm³), which is the same order of magnitude as the existing printed annular cavity technology.

Description

Technical Field

[0001] This invention belongs to the field of atomic frequency measurement and time-frequency microwave technology, and relates to a micro-annular gap dual-ridge wave integrated cavity. Background Technology

[0002] Dual-resonance atomic clocks have gained widespread attention and application in timing, navigation, satellite positioning, and real-time synchronization due to their simple system architecture and high frequency stability. Because this type of atomic clock needs to simultaneously achieve resonance in both optical and microwave bands to satisfy the transitions between fine atomic energy levels, its physical system requires a resonant cavity capable of providing a precise microwave resonant frequency. However, the size of the microwave cavity is typically limited to the centimeter level due to the operating frequency. Breakthroughs in microwave cavity miniaturization and micro-miniaturization technology remain key to achieving chip-based and lightweight dual-resonance atomic clocks.

[0003] In the current field of miniaturization technology for microwave cavities dedicated to atomic clocks, micro-annular cavity technology shows great promise. However, printed micro-annular cavity technology based on general PCB fabrication processes suffers from low processing tolerance within a diameter range of less than 15mm, resulting in low yield and high manufacturing costs, which hinders the further development of miniaturized integrated cavities for dual-resonance atomic clocks. Addressing the bottlenecks in the development of PCB-printed micro-annular cavities, researching new process technologies for micro-microwave cavities, combined with novel designs and architectures, has become the core direction for breaking through the miniaturization of dual-resonance atomic clocks, in order to meet the demand for high-performance integrated cavities and achieve single-slot deployment capabilities for high-density equipment. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a micro-annular gap dual-ribbed wave integrated cavity to address the shortcomings of the existing technology.

[0005] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows:

[0006] A miniature annular gap dual-ridged microwave integrated cavity includes an annular gap dual-ridged microwave cavity, a MEMS atomic gas chamber, and a magnetic excitation structure. The annular gap dual-ridged microwave cavity is formed by connecting an inner annular gap structure and an outer cavity via a connecting rod. The inner annular gap structure is used to form the equivalent inductance and equivalent capacitance at the resonant frequency, while the outer cavity is used to form an electromagnetic circuit and electromagnetic shielding for the inner annular gap structure. Periodic ridged structures are provided on the inner walls of both the inner annular gap structure and the outer cavity. The MEMS atomic gas chamber is integrated inside the annular gap dual-ridged microwave cavity. The magnetic excitation structure is used to excite a microwave magnetic field into the annular gap dual-ridged microwave cavity.

[0007] The aforementioned inner ring gap structure has one or more longitudinal gaps for adjusting the equivalent capacitance of the resonant frequency.

[0008] The aforementioned ridged wave structure is a periodic unit structure with subwavelength dimensions such as rectangle, wedge, triangle, or wave.

[0009] To optimize the above technical solution, the specific measures also include:

[0010] The manufacturing process of the aforementioned annular gap double-ridged microwave cavity is as follows: a microwave cavity integrated structure is formed by 3D printing of lightweight non-metallic materials, and then a conductive cavity wall is formed by metallization coating on the integrated microwave cavity structure.

[0011] The aforementioned MEMS atomic gas chamber is filled with alkali metal atomic gas and inert gas. The cross-section of the MEMS atomic gas chamber is circular or polygonal. The MEMS atomic gas chamber is formed in the longitudinal direction by a three-layer bonding method of "glass layer-silicon layer-glass layer" or a five-layer bonding method of "glass layer-silicon layer-glass layer-silicon layer-glass layer".

[0012] The aforementioned magnetic excitation structure is disposed above the inner annular gap structure. The magnetic excitation structure includes a dielectric substrate, a printed microstrip line disposed on the dielectric substrate, and a microwave coaxial line connected to the printed microstrip line.

[0013] A micro-annular gap dual-ridged wave integrated cavity also includes several dielectric matching layers with different dielectric constants and thicknesses; wherein, at least: a first dielectric matching layer that contacts the top of the outer ring cavity, a second dielectric matching layer that contacts the bottom of the outer ring cavity, and a third dielectric matching layer that is close to the top and bottom of the MEMS atomic gas chamber, and the material of each dielectric matching layer has a low temperature coefficient or temperature compensation characteristics.

[0014] The aforementioned annular gap dual-ribbed microwave cavity has axial light-transmitting holes on its top, bottom, magnetic excitation structure, and each dielectric matching layer.

[0015] A miniature annular gap dual-ribbed wave integrated cavity also includes a frequency fine-tuning structure, wherein the frequency fine-tuning structure is a frequency adjustment probe disposed at the longitudinal gap of the inner annular gap structure.

[0016] A miniature annular gap dual-ridge microwave integrated cavity also includes an integrated heating structure, which is a heating metal wire embedded in a groove on the outer surface of the annular gap dual-ridge microwave cavity.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] 1. This invention utilizes a "double-ridged annular cavity" structural design to effectively increase the equivalent wavelength of microwaves by adding ridged waves. This allows for a significant reduction in the size of the pure metal annular cavity to the millimeter level (<1 cm³) while maintaining the same resonant frequency (such as 6.835 GHz required for a rubidium atomic clock). This is comparable to existing printed annular cavity technology and lays the physical foundation for realizing an ultra-miniature dual-resonance atomic clock.

[0019] 2. The annular gap dual-ridged microwave cavity of this invention utilizes 3D printing technology to integrally form the inner annular gap structure, outer cavity, connecting rod, heating wire groove, and frequency fine-tuning through-hole, achieving a high degree of integrated construction. This not only eliminates errors caused by assembling multiple parts but also avoids the difficulties of machining large aspect ratio and high-precision through-holes in printed annular gap cavities, providing a feasible process path for the miniaturization and lightweighting of complex three-dimensional structures.

[0020] 3. The integrated microwave cavity structure of this invention has a high quality factor. Combined with the independently optimized inner and outer ring ridge wave structure, it can generate a microwave magnetic field with a high degree of uniformity and distribution in the region where the MEMS atomic gas cell is located, so that the cavity can obtain high magnetic field uniformity and high field rotation factor (FOF).

[0021] 4. This invention utilizes 3D printing technology to easily realize complex internal three-dimensional structures (such as ridges, deep grooves, and through holes) that are difficult to achieve with traditional machining or PCB processes. It overcomes the bottlenecks of low tolerance and low yield in printed annular cavity processing, which helps to reduce production costs and promote large-scale mass production.

[0022] In addition to the applications and advantages described above, this invention is also applicable to other quantum instruments and devices that require the use of MEMS atomic gas chambers and microwave cavities. Attached Figure Description

[0023] Figure 1 This is a cross-sectional structural diagram of an embodiment of the present invention;

[0024] Figure 2 This is a schematic diagram of the structure of the double-ridged microwave cavity with the annular gap removed from the top and bottom layers in an embodiment of the present invention;

[0025] Figure 3 This is a schematic cross-sectional view of the annular gap double-ridged microwave cavity in an embodiment of the present invention.

[0026] Figure 4 This is a schematic diagram of the pattern matching excitation structure in an embodiment of the present invention;

[0027] Figure 5 This is a schematic diagram of the MEMS atomic gas chamber structure in an embodiment of the present invention;

[0028] Figure 6 This is a schematic diagram of the structure of each medium matching layer in an embodiment of the present invention;

[0029] The reference numerals in the attached figures are as follows: MEMS atomic gas cell 1, glass layer 2, silicon layer 3, annular gap double-ridged microwave cavity 4, inner annular gap structure 5, outer cavity 6, connecting rod 7, longitudinal gap 8, ridged structure 9, heating wire 10, double-sided through hole 11, first dielectric matching layer 12, second dielectric matching layer 13, third dielectric matching layer 14, frequency adjustment probe 15, light transmission hole 16, magnetic excitation structure 17, printed microstrip line 18, microwave coaxial line 19. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this application clearer, the application is described and illustrated 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 scope of this application. All other embodiments obtained by those skilled in the art based on the embodiments provided in this application without inventive effort are within the scope of protection of this application.

[0031] Obviously, the accompanying drawings described below are merely some examples or embodiments of this application. Those skilled in the art can apply this application to other similar scenarios based on these drawings without any inventive effort. Furthermore, it is understood that although the efforts made in this development process may be complex and lengthy, for those skilled in the art related to the content disclosed in this application, any changes to design, manufacturing, or production based on the technical content disclosed in this application are merely conventional technical means and should not be construed as insufficient disclosure of the content of this application.

[0032] refer to Figures 1 to 6 The present invention provides a micro-annular gap dual-ridged wave integrated cavity, which consists of the following six parts: annular gap dual-ridged wave microwave cavity 4, MEMS atomic gas cell 1 that can be integrated inside the microwave cavity, several dielectric matching layers, mode matching magnetic excitation structure 17, micro-tuning structure, and integrated cavity heating structure.

[0033] The MEMS atomic gas chamber 1 is the core of the system, filled with alkali metal atomic gases (such as rubidium or cesium) and buffer gases. Its function is to provide a sealed environment for the interaction of atoms with light and microwaves. This gas chamber can be constructed using a glass layer 2 and a silicon layer 3, through a three-layer bonding structure such as "glass-silicon-glass" or a more complex five-layer bonding method, with a highly axisymmetric circular or polygonal cross-section. This MEMS-based gas chamber not only enables chip-level mass production, but the high dielectric constant silicon material, when loaded into the microwave cavity, can further perturb the electromagnetic field, helping to reduce the overall volume of the chamber.

[0034] The annular gap dual-ribbed microwave cavity 4 is the key structure for miniaturization and high performance in this invention. It is integrally formed by the inner annular gap structure 5 and the outer cavity 6 through several connecting rods 7.

[0035] The inner ring gap structure 5: Its core function is to form the equivalent inductance and equivalent capacitance at the resonant frequency. The equivalent inductance is provided by the ring metal path itself, while the equivalent capacitance is generated by one or more longitudinal gaps 8 formed in this structure.

[0036] The outer cavity 6 has two core functions: first, to provide a closed path for the magnetic field lines generated by the inner annular gap structure 5, forming a complete electromagnetic circuit, thereby constraining and optimizing the magnetic field distribution; second, to act as an electromagnetic shield to prevent internal microwave energy from radiating outward, while blocking external electromagnetic interference from entering, ensuring that atoms interact with a pure microwave field.

[0037] Ridged wave structure 9: Periodic ridged wave structures 9 are engraved on the inner walls of both the inner annular gap structure 5 and the outer cavity 6. Their shapes can be wedge-shaped, rectangular, triangular, or wave-shaped. Their core function is to effectively increase the equivalent wavelength of microwaves by slowing down the phase velocity of electromagnetic waves, thereby significantly reducing the physical size of the cavity while maintaining the target resonant frequency, achieving miniaturization. Importantly, the ridged wave structures 9 of the inner and outer rings are different in shape, size, or period. This design increases multiple structural degrees of freedom, allowing for independent optimization of cavity volume, magnetic field uniformity, and suppression of stray modes.

[0038] Several dielectric matching layers with different dielectric constants and thicknesses are set at the top and bottom of MEMS atomic gas chamber 1.

[0039] The first dielectric matching layer 12 and the second dielectric matching layer 13 respectively contact the top and bottom of the outer ring cavity 6. Their main function is to construct the perfect magnetic conductor boundary conditions of the annular cavity, which can effectively improve the magnetic field uniformity at the cavity edge, i.e., the field rotation factor FOF.

[0040] The third dielectric matching layer 14 is attached to the top and bottom of the MEMS atomic gas cell 1. Its main function is to act as an impedance matching layer, serving as an electromagnetic field transition layer, which can further optimize mode matching and reduce the overall axial dimension of the microwave cavity.

[0041] In addition, all materials of the dielectric matching layer must have low temperature coefficients or temperature compensation characteristics to compensate for the slight frequency deviation caused by temperature drift in the integrated chamber and improve the thermal stability of the system.

[0042] The magnetic excitation structure 17 is positioned above the inner annular gap structure 5, and its function is to efficiently excite the microwave magnetic field required for the desired operating mode into the annular gap dual-ribbed microwave cavity 4. It mainly includes a dielectric substrate, a printed microstrip line 18 printed on the substrate, and a microwave coaxial line 19 connected to a standard SMA connector. This structure feeds microwave energy into the cavity through electromagnetic matching coupling between the printed microstrip line 18 and the microwave cavity.

[0043] A frequency adjustment probe 15 is positioned at the longitudinal slot 8 of the inner annular structure 5. The annular dual-ridge microwave cavity 4 has dual-sided through-holes 11 through which the frequency adjustment probe 15 passes. The function of the frequency adjustment probe 15 is to provide fine-tuning capability for the resonant frequency. By screwing it in or out, the equivalent capacitance of the longitudinal slot 8 region can be changed, thereby finely compensating for the resonant frequency of the integrated cavity to correct frequency deviations caused by manufacturing tolerances or environmental changes.

[0044] The heating wire 10 is embedded in a recessed groove on the outer surface of the annular double-ridged microwave cavity 4, forming an integrated design. Its function is to uniformly heat the entire integrated cavity, causing the alkali metal in the MEMS atomic gas chamber 1 to change from liquid or solid to gaseous atoms, achieving the atomic vapor density and specified operating temperature necessary for the normal operation of the atomic clock.

[0045] The annular gap dual-ribbed microwave cavity 4, each dielectric matching layer, and the magnetic excitation structure 17 are all provided with axially aligned light-passing holes 16. Their function is to allow the pump laser and probe laser to pass through the integrated cavity without damage along the axis of the cavity, interact with the atoms in the MEMS atomic gas cell 1, and realize the optical pumping of atoms and the detection of transition signals.

[0046] Besides employing high-precision metal machining and metal 3D printing technologies, the annular gap double-ridged microwave cavity 4 in this embodiment is preferably manufactured using non-metallic 3D printing technology. First, using a high-precision 3D printer, a complex structure comprising an inner annular gap structure 5, an outer cavity 6, a connecting rod 7, a ridged structure 9, heating wire grooves, and double-sided through-holes 11 is integrally printed using a lightweight non-metallic material such as photosensitive resin. Then, a metallization coating process, such as electroless copper plating or electroplating gold, is applied to this non-metallic structure to form a dense, highly conductive metal layer on its surface. This process avoids the difficulties encountered in traditional metal machining and PCB manufacturing, significantly reducing the processing difficulty, cycle time, and cost of complex three-dimensional structures, while also significantly reducing the cavity weight.

[0047] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the embodiments described above. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A micro-annular gap dual-ribbed wave integrated chamber, characterized in that, The system includes a double-ridged microwave cavity with annular gap (4), a MEMS atomic gas chamber (1), and a magnetic excitation structure (17). The double-ridged microwave cavity with annular gap (4) is formed by connecting an inner annular gap structure (5) and an outer cavity (6) through a connecting rod (7). The inner annular gap structure (5) is used to form the equivalent inductance and equivalent capacitance at the resonant frequency, and the outer cavity (6) is used to form an electromagnetic circuit and electromagnetic shielding for the inner annular gap structure (5). Periodic ridged structures (9) are provided on the inner walls of both the inner annular gap structure (5) and the outer cavity (6). The MEMS atomic gas chamber (1) is integrated into... The interior of the annular gap double-ridged microwave cavity (4); the magnetic excitation structure (17) is used to excite the microwave magnetic field to the annular gap double-ridged microwave cavity (4); the inner annular gap structure (5) is provided with one or more longitudinal gaps (8); the interior of the MEMS atomic gas chamber (1) is filled with alkali metal atomic gas and inert gas, the cross-section of the MEMS atomic gas chamber (1) is circular or polygonal, and the MEMS atomic gas chamber (1) is formed in the longitudinal direction by a three-layer bonding method of "glass layer-silicon layer-glass layer" or a five-layer bonding method of "glass layer-silicon layer-glass layer-silicon layer-glass layer".

2. The micro-annular gap dual-ridged wave integrated chamber according to claim 1, characterized in that, The ridged wave structure (9) is rectangular, wedge-shaped, triangular, or wave-shaped.

3. The micro-annular gap double-ridged wave integrated chamber according to claim 1, characterized in that, The manufacturing process of the annular gap double-ridged microwave cavity (4) is as follows: the microwave cavity integral structure is formed by 3D printing of lightweight non-metallic materials, and then the integral structure of the microwave cavity is metallized to form a conductive cavity wall.

4. The micro-annular gap dual-ridged wave integrated chamber according to claim 1, characterized in that, The magnetic excitation structure (17) is disposed above the inner ring gap structure (5). The magnetic excitation structure (17) includes a dielectric substrate, a printed microstrip line (18) disposed on the dielectric substrate, and a microwave coaxial line (19) connected to the printed microstrip line (18).

5. The micro-annular gap dual-ridged wave integrated chamber according to claim 1, characterized in that, It also includes several dielectric matching layers with different dielectric constants and different thicknesses; among them, at least: a first dielectric matching layer (12) that contacts the top of the outer ring cavity (6), a second dielectric matching layer (13) that contacts the bottom of the outer ring cavity (6), and a third dielectric matching layer (14) that is close to the top and bottom of the MEMS atomic gas chamber (1), and the material of each dielectric matching layer has a low temperature coefficient or temperature compensation characteristics.

6. The micro-annular gap dual-ridged wave integrated chamber according to claim 1, characterized in that, The top, bottom, magnetic excitation structure (17), and each dielectric matching layer of the aforementioned annular gap double-ribbed microwave cavity (4) are provided with axial light-transmitting holes (16).

7. The micro-annular gap dual-ridged wave integrated chamber according to claim 1, characterized in that, It also includes a frequency fine-tuning structure, which is a frequency adjustment probe (15) set at the longitudinal gap (8) of the inner ring gap structure (5).

8. The micro-annular gap dual-ridged wave integrated chamber according to claim 3, characterized in that, It also includes an integrated heating structure, which is a heating metal wire (10) embedded in a groove on the outer surface of the annular double-ridged microwave cavity (4).

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