A microwave physiotherapy radiator based on multi-metallic column loading

Abstract

A microwave physiotherapy radiator based on multi-metal column loading, comprising a rectangular metal cavity, an excitation antenna is arranged in the interior of the rectangular metal cavity; the excitation antenna comprises a coaxial feeding port, a coaxial feeding needle and a top disc, the top disc is arranged in the interior space of the rectangular metal cavity, the coaxial feeding port is arranged on the outer surface of the rectangular metal cavity, and the coaxial feeding port is connected with the top disc through the coaxial feeding needle; a plurality of metal columns parallel to the coaxial feeding needle are further arranged in the interior space of the rectangular metal cavity, the plurality of metal columns are arranged around the excitation antenna and are fixed at one end to the same side inner wall of the rectangular metal cavity, and the inner wall is the opposite surface inner wall of the surface on which the coaxial feeding port is fixed; the end surface of the rectangular metal cavity is arranged as a radiation port surface, and the radiation port surface is an arc-shaped radiation surface designed according to the surface curvature of a human body. The microwave physiotherapy radiator can reduce the size, complexity and weight and improve the radiation efficiency.

Description

Technical Field

[0001] This invention relates to the field of microwave physiotherapy technology, specifically to a microwave physiotherapy radiator based on multi-metal column loading. Background Technology

[0002] In recent years, microwave thermotherapy has been widely used in clinical medicine. The direction of a microwave electromagnetic field changes twice as many times per second as its frequency. When microwaves of a certain power act on human tissue, they can cause high-frequency oscillations and friction of ions, water molecules, and dipoles in tissue cells, generating heat energy and raising the local temperature of the tissue. Therefore, it can improve local blood circulation, promote the absorption of edema, reduce inflammation and pain, and accelerate wound healing. When the radiator has a large aperture, high output power, and a large amount of radiated heat energy, especially when the operating frequency is low, it can heat tissues at a moderate depth, achieving good deep physiotherapy effects.

[0003] Microwave hyperthermia is divided into two types: internal hyperthermia and external hyperthermia. Internal hyperthermia involves implanting an antenna inside the body tissue, using the radiation field's thermal effect to ablate and treat diseased tissue. However, internal hyperthermia can cause significant damage to patients. External hyperthermia, on the other hand, concentrates microwave energy onto the patient's diseased tissue, heating it to above 42°C while keeping the temperature of surrounding healthy tissue below 44°C. Compared to internal hyperthermia, external hyperthermia significantly reduces damage to patients; therefore, the design and development of radiators in external microwave therapy devices is both challenging and necessary.

[0004] In the design of microwave therapy devices, technologies such as horn antennas, microstrip antennas, helical antennas, and waveguide radiators are currently being used. Compared to other methods, waveguide radiators allow microwaves to be transmitted in the main TE10 mode within a metal cavity filled with air. This results in a uniform heat distribution, high gain, and low power loss. Therefore, an increasing number of microwave therapy devices are now being manufactured using waveguide technology.

[0005] Commonly used frequencies for microwave therapy radiators are 433MHz, 915MHz, and 2450MHz, with different frequencies corresponding to different depths of penetration into human tissue. The penetration depth of 433MHz is approximately 7-15cm, 915MHz is approximately 4-7cm, and 2450MHz is approximately 1-3cm. Microwave therapy radiators with better penetration have a better therapeutic effect on human tissue; therefore, 433MHz microwave therapy radiators are widely used in clinical medicine.

[0006] However, for 433MHz microwave therapy radiators widely used in clinical medicine, the standard aperture size of the corresponding hollow rectangular waveguide is 454mm × 272mm, and the standard size of the corresponding hollow circular waveguide is 460mm. Regardless of whether it's a rectangular or circular waveguide, the structural size of microwave therapy radiators is too large, making them unsuitable for clinical applications. Currently, to reduce the structural size of microwave therapy radiators on the market, methods such as adding ridge capacitors or filling with ceramic dielectric materials are used. This complicates the structure of the microwave therapy radiator, increasing its weight, cost, and manufacturing difficulty.

[0007] In clinical applications, changes in the patient's tissues or the distance between the tissues and the radiator can alter the resonant frequency and load of the microwave therapy radiator, causing it to malfunction. Furthermore, it can lead to uneven distribution of the radiator's thermal radiation field, severe microwave leakage, high losses, and low radiation efficiency. Summary of the Invention

[0008] The purpose of this invention is to address the problems in the prior art by providing a microwave therapy radiator based on multi-metal pillar loading. This radiator can reduce the overall structural size, structural complexity, and mass of the microwave therapy radiator. Furthermore, it can promote the rapid and efficient conversion of microwaves from the TEM mode to the main TE10 mode during microwave transmission in the waveguide radiator, resulting in a uniform distribution of the microwave radiation heat field and thus improving the radiation efficiency of the microwave therapy radiator.

[0009] To achieve the above objectives, the present invention provides the following technical solution:

[0010] A microwave therapy radiator based on multi-metal pillar loading includes a rectangular metal cavity, inside which an excitation antenna is disposed. The excitation antenna includes a coaxial feed port, a coaxial feed pin, and a top disk. The top disk is placed inside the rectangular metal cavity, and the coaxial feed port is placed on the outer surface of the rectangular metal cavity. The coaxial feed port and the top disk are connected by the coaxial feed pin. Multiple metal pillars parallel to the coaxial feed pin are also disposed inside the rectangular metal cavity. These metal pillars are arranged around the excitation antenna, with one end fixed to the same inner wall of the rectangular metal cavity. The inner wall is the inner wall of the surface opposite to the surface fixed by the coaxial feed port. The end face of the rectangular metal cavity is configured as a radiation port, which is an arc-shaped radiation surface designed according to the curvature of the human body surface.

[0011] As a preferred embodiment, the cross-sectional length 'a' of the rectangular metal cavity ranges from 260mm to 350mm, the cross-sectional width 'b' ranges from 100mm to 140mm, and the cross-sectional height 'h' ranges from 80mm to 200mm.

[0012] As a preferred embodiment, the length m of the coaxial feed needle is in the range of 88mm-105mm.

[0013] As a preferred embodiment, the length n of the top disc ranges from 7mm to 12mm, and the radius R2 ranges from 8.5mm to 11.5mm.

[0014] As a preferred embodiment, the center of the arc-shaped radiating surface is located on the central axis of the rectangular metal cavity, the central axis of the excitation antenna is orthogonal to the central axis of the rectangular metal cavity, and the distance d between the center of the arc-shaped radiating surface and the end face of the rectangular metal cavity ranges from 10mm to 60mm.

[0015] As a preferred embodiment, the length l of the metal column ranges from 70mm to 110mm, and the radius R1 ranges from 5mm to 8mm.

[0016] As a preferred embodiment, four metal pillars are provided, with two metal pillars distributed on each side of the top disc; the distance L1 between the two metal pillars in the transverse direction of the rectangular metal cavity ranges from 110mm to 170mm, and the distance L2 between the two metal pillars in the longitudinal direction of the rectangular metal cavity ranges from 30mm to 55mm.

[0017] As a preferred embodiment, the rectangular metal cavity, coaxial feed needle, top disk, and metal pillar are made of any one of gold, silver, copper, and aluminum.

[0018] As a preferred embodiment, the coaxial feed needle and the metal column are any one of the following shapes: cylindrical, rectangular, square, prismatic, and tubular.

[0019] Compared with the prior art, the present invention has at least the following beneficial effects:

[0020] A top disk is added to the end of the coaxial feed needle. By adjusting the size of the top disk, impedance matching can be adjusted to ensure good matching at the resonant frequency of 433MHz, reducing VSWR and return loss, and preventing microwave leakage. Multiple metal pillars are wrapped around the inner wall of the rectangular metal cavity to change the microwave transmission path, allowing the microwave to be converted from the TEM mode to the dominant TE10 mode in the waveguide radiator more quickly and efficiently, and making the microwave radiation heat field distribution more uniform, thus improving radiation efficiency. The technique of loading the coaxial feed needle, top disk, and metal pillars inside the rectangular metal cavity effectively reduces the waveguide cutoff frequency. For the same microwave frequency, the required waveguide radiator area is smaller, achieving radiator miniaturization. The radiating surface of the rectangular metal cavity in this invention adopts an arc-shaped radiating surface, which fits and is closer to human tissue, resulting in better treatment effects. At the same time, this invention has a simple structure, is easy to debug and process, is suitable for mass production, and can be widely used in clinical medicine. Attached Figure Description

[0021] Figure 1 A three-dimensional schematic diagram of the overall structure of a microwave therapy radiator based on multi-metal pillar loading according to an embodiment of the present invention;

[0022] Figure 2 The present invention is based on a front view of the overall structure of a microwave physiotherapy radiator loaded with multi-metal pillars in an embodiment of the invention;

[0023] Figure 3 A top view of the overall structure of a microwave therapy radiator based on multi-metal pillar loading in this embodiment of the invention;

[0024] Figure 4 Simulation results of S-parameters of the microwave therapy radiator of this invention under optimal size and structure;

[0025] Figure 5 A simulation result of the standing wave ratio of the distance d1 between the arc-shaped radiating surface of the microwave physiotherapy radiator and the human tissue model in an embodiment of the present invention;

[0026] Figure 6 Volume loss density diagram of human tissue under optimal size and structure of microwave physiotherapy radiator in this embodiment of the invention;

[0027] In the attached diagram: 1-rectangular metal cavity; 2-arc radiating surface; 3-coaxial feed port; 4-coaxial feed needle; 5-top disk; 6-metal column. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] In the following description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0030] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can also refer to the internal connection of two components; and they can refer to a wireless connection or a wired connection. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0031] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0032] Example 1

[0033] In Example 1, the microwave physiotherapy radiator based on multi-metal column loading of the present invention uses 4 metal columns for loading. If the number of metal columns is reduced or increased, the same effect of the microwave physiotherapy radiator can be achieved.

[0034] See Figures 1 to 3This invention relates to a microwave therapy radiator based on a multi-metal pillar loading structure, comprising a rectangular metal cavity 1, an arc-shaped radiating surface 2, a coaxial feed port 3, a coaxial feed needle 4, a top disk 5, and metal pillars 6. The arc-shaped radiating surface 2 is the radiating port of the rectangular metal cavity 1. The coaxial feed port 3 is connected to the coaxial feed needle 4 and the top disk 5, serving as an excitation antenna. Four identical metal pillars 6 are fixed to the inner wall of the rectangular metal cavity 1 and surround the excitation antenna. In this embodiment, the coaxial feed port 3 is first connected to the coaxial feed needle 4, and then to the top disk 5. Microwaves fed in along the coaxial line are transmitted through the coaxial feed needle 4 and the top disk 5, exciting microwave energy within the rectangular metal cavity 1. This microwave energy is transmitted within the rectangular metal cavity 1, and after passing through the four evenly distributed metal pillars 6, it finally passes through the arc-shaped radiating surface 2 and acts on the human tissue, achieving the purpose of microwave therapy.

[0035] In one possible implementation, the cross-sectional length of the rectangular metal cavity 1 is denoted as 'a', the cross-sectional width as 'b', and the height as 'h', where the value of 'a' ranges from 260mm to 350mm, the value of 'b' ranges from 100mm to 140mm, and the value of 'h' ranges from 80mm to 200mm. Furthermore, the optimal value for the cross-sectional length 'a' of the rectangular metal cavity 1 is 300mm, the optimal value for the width 'b' is 120mm, and the optimal value for the height 'h' is 180mm.

[0036] In one possible implementation, the length of the coaxial feed needle 4 is denoted as m, the length of the top disk 5 is denoted as n, and the radius is denoted as R2, where m ranges from 88mm to 105mm, n ranges from 7mm to 12mm, and R2 ranges from 8.5mm to 11.5mm. Furthermore, the optimal value for the length m of the coaxial feed needle 4 is 92mm, the optimal value for the length n of the top disk 5 is 10mm, and the optimal value for the radius R2 is 10mm.

[0037] The distance between the center of the arc-shaped radiating surface 2 and the end face of the rectangular metal cavity 1 is denoted as d, where the value of d ranges from 10mm to 60mm. Furthermore, the optimal value of the distance d between the center of the arc-shaped radiating surface 2 and the end face of the rectangular metal cavity 1 is 30mm.

[0038] The length of the metal column 6 is denoted as l, and its radius as R1. The distance between two metal columns 6 in the horizontal direction of the rectangular metal cavity 1 is denoted as L1, and the distance between two metal columns in the vertical direction is denoted as L2. The values ​​of l, R1, and L2 range from 70mm to 110mm, R1 from 5mm to 8mm, L1 from 110mm to 170mm, and L2 from 30mm to 55mm. Furthermore, the optimal values ​​for the length l of the metal column 6 are 90mm, the optimal value for the radius R1 is 6mm, the optimal value for the horizontal distance L1 between two metal columns 6 is 140mm, and the optimal value for the vertical distance L2 between two metal columns 6 is 40mm.

[0039] Example 2

[0040] In Example 2, the microwave physiotherapy radiator based on multi-metal column loading of the present invention uses 4 metal columns for loading. If the number of metal columns is reduced or increased, the same effect of the microwave physiotherapy radiator can be achieved.

[0041] Example 2 has the same overall structure as Example 1, with only minor adjustments to the following parameters.

[0042] In this embodiment, the cross-sectional length a of the rectangular metal cavity 1 is 300mm, the width b is 120mm, and the height h is 100mm.

[0043] The length m of the coaxial feed needle 4 is 95mm, the length n of the top disk 5 is 10mm, and the radius R2 is 10mm.

[0044] The distance d between the center of the arc-shaped radiating surface 2 and the end face of the rectangular metal cavity 1 is 29 mm.

[0045] The length l of the metal column 6 is 100mm, the radius R1 is 5mm, the horizontal distance L1 between the two metal columns 6 is 160mm, and the vertical distance L2 between the two metal columns 6 is 45mm.

[0046] The following simulations verify the effectiveness of the microwave therapy radiator based on multi-metal pillar loading of the present invention.

[0047] 1. Simulation conditions

[0048] A human tissue model is placed above the arc-shaped radiating surface of the microwave physiotherapy radiator. It is assumed that the dielectric constant of the human tissue model is 55 and the conductivity is 0.92 S / m. The distance between the human tissue model and the arc-shaped radiating surface is denoted as d1, where d1 takes three values: 10 mm, 20 mm, and 30 mm.

[0049] 2. Simulation Content

[0050] Electromagnetic simulations were performed on the above simulation model using the commercial simulation software HFSS_19.0. The results of the S-parameters, standing wave ratio, and human tissue loss density are as follows: Figure 4 , 5 As shown in Figure 6.

[0051] 3. Simulation Results

[0052] Figure 4 This is the simulation curve of the optimal size structure for the reflection coefficient of the transmitting antenna of this invention. Figure 4 The horizontal axis represents the frequency set during the simulation, in MHz, ranging from 300MHz to 600MHz. Figure 4 The vertical axis represents the return loss set during the simulation, i.e., the magnitude of the reflection coefficient (S11) in decibels, in dB, ranging from 0dB to -25dB.

[0053] from Figure 4 As can be seen, the resonant point of the transmitting antenna curve of the microwave physiotherapy radiator based on multi-metal pillar loading in this invention is around 433MHz. At a frequency of 433MHz, the corresponding return loss is -24.08dB. The results indicate that the return loss (S11) of the microwave physiotherapy radiator under this structure can achieve the optimal value, and the impedance bandwidth is the maximum.

[0054] Figure 5 This is a simulation curve showing the VSWR of the transmitting antenna of the present invention under optimal size and structure, with the distance d1 between the arc-shaped radiating surface and the human tissue model being 10mm, 20mm, and 30mm. Figure 5 The horizontal axis represents the frequency set during the simulation, in MHz, ranging from 300MHz to 600MHz. Figure 5 The vertical axis represents the standing wave ratio set during the simulation, ranging from 0 to 50. The variable is the distance d1 between the arc-shaped radiation surface and the human tissue model, which is 10 mm, 20 mm, and 30 mm respectively.

[0055] from Figure 5 As can be seen, when the distance between the microwave physiotherapy radiator and the human tissue model is 10mm to 30mm, the standing wave ratio of the transmitting antenna is less than 3 around 433MHz, indicating that the structure is the optimal size structure with low standing wave and high radiation efficiency.

[0056] Figure 6 To simulate the volume loss density of human tissue under optimal structure, such as... Figure 6 As shown, electromagnetic waves can penetrate more than 7cm into the human tissue model, and the electromagnetic waves are evenly distributed in the human tissue model, which meets the heating effect of human tissue. This conforms to the uniform distribution of microwave radiation heat field and previous theoretical calculations, and both the therapeutic effect and safety are protected.

[0057] In summary, the microwave therapy radiator based on multi-metal pillar loading proposed in this invention, with its optimized size and structure, is smaller overall than existing microwave therapy radiators and has a simpler structure. Furthermore, it exhibits good impedance matching, a large impedance bandwidth, high radiation efficiency, and uniform heat field distribution near a pre-set 433MHz frequency. This microwave therapy radiator functions well within a range of 10mm to 30mm from the human tissue model.

[0058] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A multi-metallic post loaded microwave diathermy applicator characterized by: The utility model provides a kind of rectangular metal cavity (1), excitation antenna is arranged in the inside of rectangular metal cavity (1);The excitation antenna includes coaxial feed port (3), coaxial feed needle (4) and top disc (5), the top disc (5) is placed in the inside space of rectangular metal cavity (1), coaxial feed port (3) is placed on the outer surface of rectangular metal cavity (1), and coaxial feed port (3) is connected with top disc (5) by coaxial feed needle (4);The inside space of rectangular metal cavity (1) is also provided with multiple metal columns (6) parallel with coaxial feed needle (4), multiple metal columns (6) are arranged around excitation antenna and one end is fixed with the same side inner wall of rectangular metal cavity (1), and the inner wall is the opposite side surface inner wall of the surface fixed by coaxial feed port (3);End surface of the rectangular metal cavity (1) is set as radiation port face, and the radiation port face is arc radiation face (2) designed according to the curvature of human body surface; The center of the arc radiation face (2) is located on the central axis of the rectangular metal cavity (1), and the central axis of the excitation antenna is orthogonal to the central axis of the rectangular metal cavity (1); The length l of the metal column (6) is in the range of 70mm-110mm, and the radius R1 is in the range of 5mm-8mm; The metal column (6) is provided with four, and two metal columns (6) are distributed on both sides of the top disc (5); The distance L1 between the two metal columns (6) in the transverse direction of the rectangular metal cavity (1) is in the range of 110mm-170mm, and the distance L2 between the two metal columns (6) in the longitudinal direction of the rectangular metal cavity (1) is in the range of 30mm-55mm.

2. The microwave diathermy applicator based on multiple metallic column loading according to claim 1, characterized in that: The length a of the cross section of the rectangular metal cavity (1) is in the range of 260mm-350mm, the width b of the cross section is in the range of 100mm-140mm, and the height h of the cross section is in the range of 80mm-200mm.

3. The microwave diathermy applicator based on multi-metallic post loading of claim 1, wherein: The length m of the coaxial feed needle (4) is in the range of 88mm-105mm.

4. The microwave diathermy applicator based on multi-metallic post loading of claim 2, wherein: The length n of the top disc (5) is in the range of 7mm-12mm, and the radius R2 is in the range of 8.5mm-11.5mm.

5. The microwave diathermy applicator based on multi-metallic post loading of claim 1, wherein: The distance d between the center of the arc radiation face (2) and the end surface of the rectangular metal cavity (1) is in the range of 10mm-60mm.

6. The microwave diathermy applicator based on multi-metallic post loading of claim 1, wherein: The materials of the rectangular metal cavity (1), the coaxial feed needle (4), the top disc (5) and the metal column (6) are any one of gold, silver, copper and aluminum.

7. The microwave diathermy applicator based on multi-metallic post loading of claim 1, wherein: The shape of the coaxial feed needle (4) and the metal column (6) is any one of cylinder, rectangular column, square column, prism and pipe column.

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