CN112018512A - A small planar medical directional microwave resonant antenna - Google Patents

Abstract

The invention relates to the field of radio frequency microwaves, in particular to a small plane medical directional microwave resonant antenna, comprising a dielectric substrate, a feeder made of metal foil, a feeder port, a platform mounting hole, a grounding radiation patch, an SMA connector and a connector mounting hole, a medium The bottom surface of the substrate is provided with a grounding radiation patch, the upper surface of the dielectric substrate is provided with a metal foil feeder and a feeder port, and the two feeder ports are located at both ends of the metal foil feeder; The SMA connector is installed in the connector mounting hole, and the SMA connector connects the feeding port and the grounding radiation patch. The platform mounting holes are set at the four corners of the dielectric substrate. The invention performs real-time simulation by changing the shape and size of the feeding antenna, and the structure of the antenna is simulated. , material and process optimization, confirm the reliability of the simulation results, increase the effective radiation resistance of the antenna, improve the radiation efficiency of the antenna, improve the overall effect of the antenna system, and meet the performance requirements of directional applications.

Description

A small planar medical directional microwave resonant antenna

technical field

The invention relates to the field of radio frequency microwaves, in particular to a small plane medical directional microwave resonance antenna, which is applied to the research in the field of microwave medicine.

Background technique

The basic properties of microwaves usually show three characteristics of penetration, reflection and absorption. They have great application potential in aerospace, military, civil, medical and other fields. Now they have been widely used in basic experimental research and clinical verification. With the improvement of the level of microwave technology, more and more microwave forms are used in medical research and clinical applications. At the same time, they have shown good results in treatment. Compared with the previous laser technology, the application of microwave treatment is more superior. .

With the help of different forms of microwave radiation antennas, microwave energy is guided to the part to be treated, and microwave energy is absorbed through dielectric loss to achieve heating and heating, anti-inflammatory sterilization, promote blood circulation and metabolism, and play a role in treatment and health care. With high radiation efficiency and small bandwidth, the selectivity and precision of microwave therapy are also higher.

Today's medical microwave antenna designs generally have complex structures, mini designs, multi-layer superimposed designs and three-dimensional complex designs, which are difficult to manufacture, and are limited by the application environment in terms of shape and volume.

SUMMARY OF THE INVENTION

In order to solve the above technical problems, the present invention provides a small plane medical directional microwave resonant antenna, which has the performances of high radiation efficiency and small bandwidth.

In order to achieve the above object, the present invention adopts the following technical solutions:

A small plane medical directional microwave resonant antenna includes a dielectric substrate, a feeder made of metal foil, a feeding port, a platform mounting hole, a grounding radiation patch, an SMA connector and a connector mounting hole, and the bottom surface of the dielectric substrate is provided with a grounding radiation patch The upper surface of the dielectric substrate is provided with a metal foil feeder and a feeder port, and the two feeder ports are located at both ends of the metal foil feeder; the feeder port is provided with a joint installation hole, and the joint installation hole is installed in the joint installation hole. SMA connector, the SMA connector connects the feeding port and the grounding radiation patch, and the four corners of the dielectric substrate are provided with platform mounting holes.

Further, the ground radiation patch 5 has the same size as the dielectric substrate 1 .

Further, the metal foil feeder adopts a symmetrical concave wiring method with a right-angle multi-fold line.

Further, the right angle of the broken line of the metal foil feeder is all 45°.

Further, the impedance of the feeding point is adjusted by changing the length of each side of the metal foil feeder, so that the actual input impedance of the antenna is matched with the characteristic impedance of 50Ω.

Further, six square through holes are arranged at one side port of the metal foil feeder as an SMA connection port.

Further, through the electromagnetic simulation software ANSYS HFSS, the antenna is simulated and optimized to obtain the antenna size that meets the needs of the experimental application. The dielectric substrate with low dielectric constant is used to determine the size of the substrate, and the size and shape of the feeder.

Working principle: The microwave antenna used is composed of metal foils of any shape loaded on the surface of the PCB. The antenna unit is etched onto the insulating dielectric substrate, and a continuous metal layer is pasted on the reverse side of the substrate to form a ground plane. The radio frequency current is input on the metal foil feeder with the ground through the adapter, and the high frequency current is converted into electromagnetic waves. In the design of the three-dimensional resonator, the shape is changeable; when it exists in the form of a plane microwave resonant antenna, it has a simple two-dimensional resonator antenna. Physical geometry, as well as the advantages of low loss and strong concentrated radiation capability; at the same time, the dielectric constant of the dielectric substrate has a wide selection range (usually in the range of 6~140), and the material of the dielectric substrate can be flexibly selected according to different application needs. Control size.

Compared with the prior art, the present invention has the beneficial effects that real-time simulation is performed by changing the shape and size of the feeding antenna, the structure, material and process of the antenna are optimized, the reliability of the simulation results is confirmed, and the effectiveness of the antenna is increased. Radiation resistance, reducing the generation of high-order modes, improving the radiation efficiency of the antenna, and improving the overall effect of the antenna system, achieving high radiation efficiency and small bandwidth requirements on the same substrate and plane, improving selectivity and accuracy, and achieving directional function application needs.

Description of drawings

Fig. 1 is the explosion schematic diagram of small plane medical directional microwave resonant antenna;

2 is a three-dimensional overall schematic diagram of a small planar medical directional microwave resonant antenna;

Fig. 3 is the S11 parameter simulation diagram of the small planar medical directional microwave resonant antenna;

Fig. 4 is a simulation diagram of the standing wave ratio parameters of a small planar medical directional microwave resonant antenna;

Fig. 5 is a field distribution diagram of a small planar medical directional microwave resonant antenna;

Fig. 6 is the gain diagram of small plane medical directional microwave resonant antenna;

1. Dielectric substrate; 2. Feeder made of metal foil; 3. Feeding port; 4. Platform mounting hole; 5. Ground radiation patch; 6. SMA connector; 7. Connector mounting hole.

Detailed ways

The present invention will be described in detail below with reference to the accompanying drawings and embodiments.

Taking the microwave 2.87GHz control experiment as an example, the heat penetration depth of the antenna operating in the 2.87GHz frequency band is not deep, and different application requirements can be achieved by increasing the microwave power or changing the antenna feeder parameters.

As shown in Figure 1, a small planar medical directional microwave resonant antenna includes a dielectric substrate 1, a grounding radiation patch 5, a feed port 3 and a metal foil feeder 2, and a grounding radiation patch 5 is provided on the bottom surface of the dielectric substrate 1. The upper surface of the dielectric substrate 1 is provided with a metal foil feeder 2 and a feeder port 3, and the two feeder ports 3 are located at both ends of the metal foil feeder 2; Install the SMA connector 6. The SMA connector 6 connects the feeder port 3 and the grounding radiation patch 5, and the inner core is directly welded on the feeder port 3 with the SMA connector. The four corners of the dielectric substrate 1 are provided with platform mounting holes 4, which are connected through the platform mounting holes. The experimental platform is easy to move and fix; by setting six square through holes corresponding to the SMA connector at both ends of the feeder, the connection between the connector and the antenna is convenient, the error caused by the simulation in this process is reduced, and the inconsistency caused by the connection of the SMA adapter is reduced. Continuity; using SMA connector, small size, wide frequency band, and good mechanical properties;

The ground radiation patch 5 is the same size as the dielectric substrate 1 .

Feeder 2 is in the form of a microstrip feeder with a characteristic impedance of 50Ω. The three-dimensional structure of the antenna is shown in Figure 2. The feeder adopts a right-angle multi-fold line symmetrical concave wiring method. The length of the multi-frequency antenna reduces the space occupied by the antenna and the dielectric loss.

The right angle of the broken line of the feeder is all 45° to improve the radiation efficiency and reduce the return loss.

The dielectric substrate of high dielectric constant material will limit most of the energy inside the feeder, increase the structural Q value, and reduce the efficiency of radiation to the surrounding area. On the premise of ensuring the radiation efficiency and power capacity of the antenna, the dielectric constant is The dielectric substrate of 4.4, the plane area of the dielectric substrate is 30mm×83mm.

Using a small planar medical directional microwave resonant antenna on a single-layer substrate structure, by changing the shape of the feeder, it is designed in a right-angle polyline shape, with a reasonable layout, to achieve high radiation efficiency on a small dielectric substrate, meeting the bandwidth within 100M, covering 2.87GHz In the frequency band (about 2.2GHz to 3.43GHz), in order to adapt to different experimental platforms, the design of the antenna is based on practicality and miniaturization, with small size and simple structure.

Through the electromagnetic simulation software ANSYS HFSS, the antenna is simulated and optimized to obtain the antenna size that meets the needs of the experimental application. The dielectric substrate with low dielectric constant is used to determine the size of the substrate, and the size and shape of the feeder.

Because the microstrip antenna itself has the characteristics of high Q value, the bandwidth is large, the Q value is reduced, and the working effect of the antenna at the frequency point will be sacrificed; In the design process, according to the feedback results of the simulation software, the initial definition value is continuously changed to realize the overall change of the feeder, as well as the tuning between the required S parameters and impedance matching.

Through the SMA adapter connecting the microstrip feeder and the grounding radiation patch, the radio frequency current is input on the microstrip feeder, and then the high frequency current is converted into electromagnetic waves, so as to realize the regulation of the electromagnetic waves by the antenna.

Calculate the value of the reflection coefficient S11 from the port definition point of view, and show it in the sweep frequency range from 1GHz to 5GHZ through ANSYS HFSS simulation as shown in Figure 3. It is easy to observe the antenna bandwidth, working frequency and other related information to understand the frequency of the antenna characteristic.

Due to the fact that the incident wave energy cannot be completely radiated during the use of the antenna, the superposition of the reflected waves will cause the reduction of the radiation efficiency of the antenna, which is expressed as the standing wave ratio VSWR. After the simulation of the simulation software ANSYS HFSS, the frequency sweep from 1GHz to 5GHz can be obtained. The VSWR image in the range is shown in Figure 4.

The electromagnetic field calculation of the antenna is a huge project. With the simulation software ANYS HFSS based on the finite element method, the electromagnetic field distribution, magnetic flux and magnetic field strength of the antenna are simulated and calculated, and the spatial electromagnetic field distribution of the small planar medical directional microwave resonant antenna is obtained as shown in Figure 5 shown.

The input power concentration radiation degree of the small planar medical directional microwave resonant antenna is quantitatively described by the simulation software ANSYS HFSS, and an infinite ideal matching boundary is set. On the premise that the input power of the port is equal, the actual antenna and the ideal radiating element are at one point in space. The power density ratio of the generated signal at , as shown in the three-dimensional gain map of Figure 6.

The present invention proposes an innovative design idea for related antennas implemented in the context of microwave medicine. The above is a detailed description of the design and use of small planar medical directional microwave resonant antennas, but antennas are widely manufactured and used in the field of radio frequency microwaves. It is not limited to the scope of the present invention; obviously, the implemented cases are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, those of ordinary skill in the art have no creative work. On the premise, all other embodiments made should also belong to the protection scope of the present invention.

Claims (7)

1. A small planar medical directional microwave resonant antenna, characterized in that it comprises a dielectric substrate (1), the bottom surface of the dielectric substrate (1) is provided with a ground radiation patch (5), and the upper surface of the dielectric substrate (1) A metal foil feeder (2) and a feed port (3) are provided, and the two feed ports (3) are located at both ends of the metal foil feeder (2); the dielectric substrate (1) is located on the feed port A connector mounting hole (7) is opened at (3), and an SMA connector (6) is installed in the connector mounting hole (7), and the SMA connector (6) connects the feeding port (3) and the ground radiation patch (5). ) connection, and platform mounting holes (4) are formed at four corners of the dielectric substrate (1). 2 . The small planar medical directional microwave resonant antenna according to claim 1 , wherein six square through holes are provided at one side port of the metal foil feeder ( 2 ). 3 . 3 . The small planar medical directional microwave resonant antenna according to claim 1 , wherein the feeder ( 2 ) made of metal foil is in the shape of a right-angle polyline. 4 . 4 . The small-sized planar medical directional microwave resonant antenna according to claim 1 , wherein the right angles of the broken lines of the feeder made of metal foil are all 45°. 5 . 5 . The small planar medical directional microwave resonant antenna according to claim 3 , wherein the metal foil feeder ( 2 ) is in the form of a microstrip feeder with a characteristic impedance of 50Ω. 6 . 6 . The small planar medical directional microwave resonant antenna according to claim 1 , wherein the ground radiation patch ( 5 ) has the same size as the dielectric substrate ( 1 ). 7 . 7 . The small planar medical directional microwave resonant antenna according to claim 1 , wherein the antenna is simulated and optimized by electromagnetic simulation software ANSYS HFSS to obtain the antenna size that meets the needs of experimental applications. 8 .

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