A tm-mode dielectric resonator mechanism

Abstract

The application relates to a TM mode medium resonant mechanism, which comprises a resonant cavity, an upper cover plate, an elastic cover plate, a TEM metal resonant column, a TM medium resonator and a fastening screw. The resonant cavity is a square cavity structure, the bottom of the resonant cavity is provided with the TEM metal resonant column, the top of the TEM metal resonant column is provided with a limiting pit, the resonant cavity is provided with the TM medium resonator, the outer diameter of the TM medium resonator is the same as the diameter of the limiting pit, the TM medium resonator is located between the limiting pit of the TEM metal resonant column and the elastic cover plate, the upper cover plate is fixed on the top of the resonant cavity through the fastening screw, the resonant cavity forms an electromagnetic closed environment, and the bottom surface and the top end of the TM medium resonator are silver treated. In the case that the medium resonator and the height and the inner and outer diameter sizes remain unchanged, the working frequency of the resonator and the filter is changed by designing the outer diameter D1 of the metal step, so that the filter meets the design index performance.

Description

Technical Field

[0001] This invention belongs to the field of microwave passive technology, specifically relating to a TM mode dielectric resonator mechanism. Background Technology

[0002] With the rapid development of satellite technology, on the one hand, to improve communication transmission performance, the operating power of spaceborne microwave equipment is required to be increasingly higher; on the other hand, to improve integration, the size and weight of spaceborne microwave equipment are required to be increasingly smaller. These two factors lead to non-uniform and high-intensity electric fields in spaceborne microwave equipment, which can trigger discharge effects. Coaxial filters are commonly used domestically and internationally, and are widely applied in satellite relay, telemetry, tracking, and remote sensing systems. To obtain a higher power threshold, their size and weight inevitably increase. While waveguide filters in the L and S bands have a relatively high low-pressure power threshold, their large size and weight limit their application range.

[0003] In the tracking and control subsystem, the filter undergoes a process from atmospheric pressure to low pressure to vacuum from launch to orbit insertion. During the low-pressure phase, the filter's power threshold drops rapidly, rendering traditional coaxial filters inadequate. Therefore, the TM-mode dielectric filter design has become the preferred solution. The TM01-mode dielectric filter overcomes challenges in manufacturing and environmental testing, offering advantages such as small size, light weight, high Q value, and high low-pressure power threshold. TM-mode dielectric filters are widely used in satellite communication and navigation systems.

[0004] Because the resonant frequencies within each resonant cavity of a TM filter and multiplexer are different, each TM resonator has a different size. Combined with design and manufacturing errors, this necessitates the fabrication and backup of resonators with a wide variety of frequencies. Since using metal tuning screws causes a rapid drop in the low-pressure power threshold of the filter, polyimide tuning screws are often used to improve the low-pressure discharge threshold, but their tuning range is extremely limited. To obtain the resonant frequency of each resonator more accurately, the ceramic resonator needs to be sintered, and then the outer or inner diameter of the dielectric resonator needs to be ground to fine-tune its frequency. This process, followed by testing, classification, and numbering, significantly increases the complexity and difficulty of production, processing, and equipment debugging, as well as the overall cost. Summary of the Invention

[0005] The technical problem solved by this invention is to overcome the defects of the prior art and propose a novel TM-mode dielectric resonator mechanism. This TM-mode dielectric resonator has a simple structure, small size, and high Q value. It enables the production and processing of TM dielectric filters and multiplexers by using a TM dielectric resonator of a certain size, which greatly improves production efficiency and saves costs. It can meet the increasing application requirements of meteorological satellites, telemetry, tracking and control systems at present.

[0006] The technical solution of this invention is:

[0007] A TM-mode dielectric resonator mechanism includes: a resonant cavity, an upper cover plate, an elastic cover plate, a TEM metal resonant column, a TM dielectric resonator, and fastening screws;

[0008] The resonant cavity has a square cavity structure, with a TEM metal resonant pillar at the bottom. The top of the TEM metal resonant pillar has a limiting pit, and a TM dielectric resonator is installed inside the resonant cavity. The outer diameter of the TM dielectric resonator is the same as the diameter of the limiting pit. The TM dielectric resonator is located between the limiting pit of the TEM metal resonant pillar and the elastic cover plate. The upper cover plate is fixed to the top of the resonant cavity by fastening screws, so that the resonant cavity forms an electromagnetically sealed environment. The bottom and top surfaces of the TM dielectric resonator are silver-treated.

[0009] Furthermore, a pressure ring or pressure platform is provided in the middle of the upper cover plate to apply pressure to the elastic cover plate, ensuring good contact between the elastic cover plate and the top metallized surface of the TM dielectric resonator under different temperature and mechanical environments.

[0010] Furthermore, the height of the metal cavity is H, the diameter of the TEM metal resonator is D1, and the height is h1; the diameter of the limiting pit and the outer diameter of the TM dielectric resonator are both D, and the depth of the limiting pit is h2; the inner diameter of the TM dielectric resonator is d, and the height is h.

[0011] Furthermore, with the height and inner and outer diameters of the TM dielectric resonator remaining unchanged, the operating frequency of the entire TM dielectric resonator can be changed by adjusting the outer diameter D1 of the TEM metal resonator pillar.

[0012] Furthermore, the larger the diameter D1 of the TEM metal resonator, the higher the resonant frequency of the TM mode dielectric resonator; the smaller the diameter D1 of the TEM metal resonator, the lower the resonant frequency of the TM mode dielectric resonator.

[0013] Furthermore, the relationship between the metal cavity height H, the TM dielectric resonator height h, the TEM metal resonator height h1, and the TEM metal resonator limiting pit depth h2 must satisfy the following:

[0014] H = h + h1 - h2.

[0015] Furthermore, the metal cavity is made of Invar steel or aluminum, and the surface of the metal cavity is silver-plated; the elastic cover is made of beryllium copper.

[0016] Furthermore, the TM dielectric resonator is a hollow ring-shaped columnar structure made of ceramic.

[0017] Furthermore, it also includes a tuning screw, which is mounted on the TEM metal resonator on the bottom metal surface of the cavity or on the top cover plate. The tuning screw can enter the hole inside the TM dielectric resonator to tune the resonant frequency of the TM dielectric resonator.

[0018] Furthermore, the frequency tuning screw is made of a dielectric material.

[0019] The advantages of this invention compared to the prior art are:

[0020] (1) The TEM metal resonator-TM mode dielectric resonator of the present invention can adjust the resonant frequency by designing the diameter of the TEM metal resonator. Only one size of TM dielectric resonator needs to be designed and processed to obtain resonators of all frequencies required by filters and multiplexers. There is no need to prepare multiple molds with corresponding inner diameter sizes, which greatly reduces the types of dielectric resonators and reduces the procurement cost of TM resonators.

[0021] (2) The TM mode dielectric resonator of the present invention has a simple structure and a high Q value. While ensuring a high low-pressure discharge threshold, it greatly improves the efficiency of production, processing and debugging.

[0022] (3) The present invention adopts a TEM metal resonator-TM dielectric resonator mechanism, and the operating frequency of the resonator and filter is determined by the metal resonator pillar, the TM dielectric resonator and the cavity size.

[0023] (4) While keeping the dielectric resonator and its height and inner and outer diameter dimensions unchanged, the operating frequency of the resonator and filter can be changed by designing the outer diameter D1 of the metal step so that the filter meets the design performance specifications. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of a TM-mode dielectric resonator in the prior art;

[0025] Figure 2 This is a schematic diagram of the dimensions of the TM-mode dielectric resonator according to the present invention;

[0026] Figure 3 This is a schematic cross-sectional view of the TM-mode dielectric resonator according to the present invention;

[0027] Figure 4 This is a schematic diagram of the structure of a TM-mode dielectric resonator according to an embodiment of the present invention;

[0028] Figure 5 This is a diagram showing the resonant frequency curve of a TM-mode dielectric resonator according to an embodiment of the present invention;

[0029] Figure 6This is a schematic diagram of a filter composed of TM-mode dielectric resonators according to an embodiment of the present invention;

[0030] Figure 7 This is a transmission characteristic curve of a TM-mode dielectric filter according to an embodiment of the present invention. Detailed Implementation

[0031] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0032] This invention designs a novel TM dielectric resonator, employing a mechanism combining a TM-mode dielectric resonator and a TEM metal resonant pillar. Without altering the dimensions of the TM ceramic resonator, the resonant frequency of the entire resonator is changed by adjusting the diameter of the metal step at the bottom of the cavity. This makes it possible to use only one size of TM resonator for TM dielectric filters and multiplexers, significantly reducing the types of resonators, the complexity of assembly and debugging, and the procurement cost of TM resonators.

[0033] like Figure 1 , 2 As shown in Figures 3 and 4, the TM mode dielectric resonator proposed in this invention includes: a resonant cavity 1, an upper cover plate 2, an elastic cover plate 3, a TEM metal resonant column 4, a TM dielectric resonator 5, and a fastening screw 7.

[0034] The resonant cavity 1 has a square cavity structure, and a TEM metal resonant pillar 4 is located at the bottom of the resonant cavity 1. A limiting pit is provided at the top of the TEM metal resonant pillar 4. A TM dielectric resonator 5 is provided inside the resonant cavity 1. The outer diameter of the TM dielectric resonator 5 is the same as the diameter of the limiting pit. The TM dielectric resonator 5 is located between the limiting pit of the TEM metal resonant pillar 4 and the elastic cover plate 3. The upper cover plate 2 is fixed to the top of the resonant cavity 1 by fastening screws 7, so that the resonant cavity forms an electromagnetically sealed environment. The bottom and top surfaces of the TM dielectric resonator 5 are silver-treated.

[0035] The upper cover plate 2 has a pressure ring or pressure platform in the middle to apply pressure to the elastic cover plate 3, ensuring good contact between the elastic cover plate 3 and the top metallized surface of the TM dielectric resonator 5 under different temperature and mechanical environments.

[0036] like Figure 2 As shown, the height of the metal cavity 1 is H, the diameter of the TEM metal resonator 4 is D1, and the height is h1; the diameter of the limiting pit and the outer diameter of the TM dielectric resonator 5 are both D, and the depth of the limiting pit is h2; the inner diameter of the TM dielectric resonator 5 is d, and the height is h.

[0037] With the height and inner and outer diameters of the TM dielectric resonator 5 remaining constant, the operating frequency of the entire TM mode dielectric resonator mechanism can be changed by adjusting the outer diameter D1 of the TEM metal resonator 4. The larger the diameter D1 of the TEM metal resonator 4, the higher the resonant frequency of the TM mode dielectric resonator mechanism; the smaller the diameter D1 of the TEM metal resonator 4, the lower the resonant frequency of the TM mode dielectric resonator mechanism.

[0038] The relationship between the height H of the metal cavity 1, the height h of the TM dielectric resonator 5, the height h1 of the TEM metal resonator 4, and the depth h2 of the limiting pit of the TEM metal resonator 4 must satisfy the following:

[0039] H = h + h1 - h2.

[0040] Preferably, the metal cavity 1 is made of Invar steel or aluminum, and the surface of the metal cavity is silver-plated.

[0041] Preferably, the upper cover plate is made of aluminum alloy and is connected to the metal cavity by fastening screws to form an electromagnetically sealed environment for the resonant cavity; a pressure ring or pressure platform is required in the middle of the upper cover plate to apply pressure to the elastic cover plate and ensure good contact between the elastic cover plate and the top metallized surface of the dielectric resonator under different temperature and mechanical environments.

[0042] Preferably, the elastic cover plate is made of beryllium copper or other metal materials with good ductility. Its main functions include two aspects: First, the elastic cover plate absorbs the stress generated by different materials in the mechanical and thermal environments of the entire resonant cavity through deformation, avoiding stress cracking and damage to the TM dielectric resonator, and improving the reliability and stability of the resonator under different environments; Second, the pressure applied by the upper cover plate to the elastic cover plate causes the elastic cover plate to generate deformation force, providing a stable clamping force to the dielectric resonator under different environments, ensuring good contact between the metallized bottom surface of the dielectric resonator and the limiting pit of the TEM metal resonator, and between the metallized top surface of the dielectric resonator and the elastic cover plate, so that the no-load Q value of the entire resonator remains unchanged.

[0043] The TEM metal resonator pillar is located on the bottom surface of the metal cavity and can be integrally designed and manufactured with the metal cavity. A limiting recess is located at the top of the metal resonator pillar. The center frequency of the entire resonator or filter is determined by designing the height of the metal pillar and the dielectric resonator. After determining the center frequency of the entire resonator or filter, a dielectric resonator of a specific size is used, and the operating frequency of each resonator is designed by adjusting the diameter of the metal resonator pillar to meet the electrical performance requirements of the filter or multiplexer.

[0044] Preferably, the TM dielectric resonator pillar is a hollow annular columnar structure, and the material of the dielectric resonator pillar is ceramic. Both the bottom and top surfaces of the TM dielectric resonator need to be silvered. This TM dielectric resonator pillar is located between the limiting pit at the top of the metal resonator pillar and the elastic cover plate.

[0045] Furthermore, the resonant mechanism of this invention also includes a tuning screw (6). The frequency tuning screw is installed on the TEM metal resonant pillar on the bottom metal surface of the cavity, or on the upper cover plate, and can enter the hole inside the TM dielectric resonator to tune the resonant frequency of the resonator. The material of the frequency tuning screw is a dielectric material. Low-pressure discharge is gas discharge, and the power threshold is mainly related to the electric field, voltage, and energy storage in the cavity. When the metal screw or limiting stage enters the hole of the TM01 mode dielectric resonator, the magnitude of the electric field in the air hole and the electric field inside the dielectric increases, strongly disturbing the electric field distribution and increasing the internal voltage, thus reducing the low-pressure power threshold of the filter.

[0046] Example 1:

[0047] The resonant cavity is made of aluminum alloy with a silver-plated surface. The internal dimensions are 30mm x 30mm, the cavity height is 25mm, and the chamfer around the cavity is 4mm. The dielectric resonator has a dielectric constant of 45, an outer diameter of 14mm, an inner diameter of 6mm, and a height of 20.5mm. The metal resonant pillar has a height of 6mm, a locating pit diameter of 14mm, and a locating pit depth of 1.5mm. While keeping the dielectric resonator dimensions unchanged, changing the diameter of the metal resonant pillar from 16mm to 26mm changes the resonant frequency of the entire resonator from 1.39GHz to 1.54GHz, as shown in the curve. Figure 5 As shown, the horizontal axis represents the radius (in mm), and the vertical axis represents the resonant frequency (in GHz).

[0048] Example 2:

[0049] A novel TM-mode dielectric resonator mechanism of this invention is used to construct a TM dielectric filter. The TM dielectric filter has a center frequency of 1.5 GHz, an operating bandwidth of 40 MHz, a return loss of less than -20 dB, and is a fourth-order filter. Its appearance is shown in [details omitted]. Figure 6 .

[0050] The filter's resonant cavity has internal dimensions of 30mm x 30mm, a cavity height of 25mm, and a 4mm chamfer around its perimeter. The four dielectric resonators in the TM dielectric filter each have an outer diameter of 14mm, an inner diameter of 6mm, and a height of 20.5mm; the dielectric constant of the dielectric resonators is 45. The metal resonant pillars have a height of 6mm, a recess diameter of 14mm, and a recess depth of 1.5mm. While keeping the dimensions of the TM dielectric resonators constant, changing the diameter of the metal resonant pillars allows the filter's return loss to be less than -21dB, while the filter's electrical performance meets the design requirements. The diameters of the four metal resonant pillars in the TM dielectric filter are 19.06mm, 21.4mm, 21.5mm, and 19.1mm, respectively. Transmission characteristics are as follows... Figure 7As shown, the horizontal axis represents frequency, and the vertical axis represents the S-parameter transmission characteristics of the filter constructed using the novel TM-mode dielectric resonator of this invention. The center insertion loss of the filter does not exceed 0.3dB, and no low-pressure discharge phenomenon is emitted when the continuous wave power is increased to 40W.

[0051] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A TM-mode dielectric resonator mechanism, characterized in that... include: The resonant cavity (1), the upper cover plate (2), the elastic cover plate (3), the TEM metal resonant column (4), the TM dielectric resonator (5), and the fastening screw (7). The resonant cavity (1) is a square cavity structure, and the bottom of the resonant cavity (1) has a TEM metal resonant pillar (4); the top of the TEM metal resonant pillar (4) is provided with a limiting pit, and the resonant cavity (1) is provided with a TM dielectric resonator (5), the outer diameter of the TM dielectric resonator (5) is the same as the diameter of the limiting pit; the TM dielectric resonator (5) is located between the limiting pit of the TEM metal resonant pillar (4) and the elastic cover plate (3); the upper cover plate (2) is fixed to the top of the resonant cavity (1) by fastening screws (7), so that the resonant cavity forms an electromagnetically sealed environment; the bottom and top surfaces of the TM dielectric resonator (5) are silver-treated; The height of the metal cavity (1) is H, the diameter of the TEM metal resonator (4) is D1, and the height is h1; the diameter of the limiting pit and the outer diameter of the TM dielectric resonator (5) are both D, and the depth of the limiting pit is h2; the inner diameter of the TM dielectric resonator (5) is d, and the height is h. With the height and inner and outer diameters of the TM dielectric resonator (5) remaining unchanged, the operating frequency of the entire TM dielectric resonator mechanism is changed by adjusting the outer diameter D1 of the TEM metal resonator (4). The relationship between the height H of the metal cavity (1), the height h of the TM dielectric resonator (5), the height h1 of the TEM metal resonator (4), and the depth h2 of the limiting pit of the TEM metal resonator (4) must satisfy: H = h + h1 - h2; The larger the diameter D1 of the TEM metal resonator (4), the higher the resonant frequency of the TM mode dielectric resonator; the smaller the diameter D1 of the TEM metal resonator (4), the lower the resonant frequency of the TM mode dielectric resonator. The upper cover plate (2) has a pressure ring or pressure platform in the middle to apply pressure to the elastic cover plate (3). Under different temperature and mechanical environments, it ensures good contact between the top metallized surface of the elastic cover plate (3) and the TM dielectric resonator (5). The TM dielectric resonator (5) is a hollow annular columnar structure made of ceramic. The TM dielectric resonator mechanism also includes a tuning screw (6). The frequency tuning screw (6) is mounted on the TEM metal resonator on the bottom metal surface of the cavity or on the top cover plate. The frequency tuning screw (6) tunes the resonant frequency of the TM dielectric resonator through a hole that enters the interior of the TM dielectric resonator (5).

2. The TM-mode dielectric resonator mechanism according to claim 1, characterized in that: The metal cavity (1) is made of Invar steel or aluminum, and the surface of the metal cavity (1) is plated with silver; the elastic cover plate (3) is made of beryllium copper.

3. The TM-mode dielectric resonator mechanism according to claim 1, characterized in that: The frequency tuning screw (6) is made of dielectric material.

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