阅读说明：本技术 一种磁激励915MHz圆形波导辐射器 (Magnetic excitation 915MHz circular waveguide radiator ) 是由 马淑允 李冶 于 2020-07-03 设计创作，主要内容包括：本发明涉及一种磁激励915MHz圆形波导辐射器,属于微波物理治疗技术领域。包括壳体、激励天线和调节杆,激励天线设置在辐射器后部的导体封闭端采用偏置电流环进行磁激励。两对调节杆所在平面与激励天线所在平面成45°角,对称布置,对辐射器进行加载,并在辐射器口面处形成准圆极化波。本发明的有益效果是：能起到良好的加载作用,有效降低波导腔的截止频率；获得准圆极化波,使口面处的热场分布较为均匀。能有效减少辐射器长度(高度)尺寸,径向外周空间无结构件,壳体端部中心便于安装连接杆。(The invention relates to a magnetic excitation 915MHz circular waveguide radiator, belonging to the technical field of microwave physical therapy. The electromagnetic excitation device comprises a shell, an excitation antenna and an adjusting rod, wherein the excitation antenna is arranged at the closed end of a conductor at the rear part of a radiator and is magnetically excited by adopting a bias current loop. The planes of the two pairs of adjusting rods and the plane of the exciting antenna form an angle of 45 degrees, the two pairs of adjusting rods are symmetrically arranged, the radiator is loaded, and quasi-circular polarized waves are formed at the mouth surface of the radiator. The invention has the beneficial effects that: the loading function can be well achieved, and the cut-off frequency of the waveguide cavity is effectively reduced; the quasi-circular polarized wave is obtained, so that the distribution of the thermal field at the mouth surface is more uniform. The length (height) of the radiator can be effectively reduced, the radial peripheral space has no structural part, and the connecting rod is convenient to mount in the center of the end part of the shell.)

1. A magnetically excited 915MHz circular waveguide radiator, comprising: the electromagnetic excitation device comprises a shell (1), an excitation antenna (2) and an adjusting rod (3), wherein the excitation antenna (2) is arranged at the closed end of a conductor at the rear part of a radiator and is magnetically excited by adopting a bias current loop.

2. A magnetically excited 915MHz circular waveguide radiator as claimed in claim 1 wherein: the inner diameter of the shell (1) is 160mm, and the length of the inner cavity is 140 mm.

3. A magnetically excited 915MHz circular waveguide radiator as claimed in claim 1 wherein: the adjusting rod (3) and the plane where the exciting antenna (2) is located form an angle of 45 degrees, and the adjusting rod and the plane are symmetrically arranged on the transmission section to load the radiator.

4. A magnetically excited 915MHz circular waveguide radiator as claimed in claim 1 wherein: the radiator adopts current loop magnetic excitation, microwave energy fed in by a coaxial cable is converted by an excitation antenna (2) and then excites an electromagnetic field in a waveguide, human tissues are radiated outwards from a radiation opening after passing through a transmission section, and an adjusting rod (3) of the transmission section is used for loading the radiator, reducing cut-off frequency, adjusting phase and carrying out impedance matching.

Technical Field

The invention relates to a magnetic excitation 915MHz circular waveguide radiator, belonging to the technical field of microwave physical therapy.

Background

At present, in the technical field of microwave physical therapy, a 915MHz circular radiator for human tissue thermotherapy has a hollow waveguide with the size of about phi 220mm, and for some local applications, the caliber is larger and the required pushing power is higher. The dipole radiator can be made smaller in overall dimension, but the distribution of a thermal field is uneven, hot spots exist, the proportion of the electric field of a vertical component is larger, and the phenomenon of fat overheating is easy to occur.

In order to reduce the caliber of the waveguide radiator, a dielectric loading method can be adopted, but the radiator is heavy and is inconvenient for clinical use. If the ridge capacitance method is adopted for loading, the electric field energy is concentrated in the ridge area, and the effective heating area of the microwave can be reduced. Circular waveguide radiators usually use radial probe excitation, i.e. an electrical excitation method, to form a transverse electric mode, and therefore, a certain space for connectors and coaxial cables needs to be reserved radially on the periphery of the waveguide. For impedance matching adjustments, the electrically excited probe needs to be spaced from the closed end of the conductor at the rear of the waveguide. Together with the dimensions of the waveguide transmission section, there is a minimum dimensional requirement for the internal length (height) of the overall radiator. For some applications, the radial peripheral space of the radiator does not allow the presence of structural elements, while the length (height) of the radiator is limited. And therefore requires redesign.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention provides a magnetic excitation 915MHz circular waveguide radiator, which adopts a magnetic excitation method, wherein an excitation antenna is a bias current loop, and an excitation loop is positioned at the closed end of a conductor at the rear part of the radiator.

The invention is realized by the following technical scheme: a magnetically excited 915MHz circular waveguide radiator, comprising: the electromagnetic excitation device comprises a shell, an excitation antenna and an adjusting rod, wherein the excitation antenna is arranged at the closed end of a conductor at the rear part of a radiator and is magnetically excited by adopting a bias current loop.

The inner diameter of the shell is 160mm, and the length of the inner cavity is 140 mm.

The adjusting rod and the plane where the exciting antenna is located form an angle of 45 degrees, and the adjusting rod and the plane are symmetrically arranged on the transmission section to load the radiator.

The radiator adopts current loop magnetic excitation, microwave energy fed in by a coaxial cable is converted by an excitation antenna to excite an electromagnetic field in a waveguide, human tissues are radiated outwards from a radiation opening after passing through a transmission section, and an adjusting rod of the transmission section is used for loading the radiator, reducing cut-off frequency, adjusting phase and performing impedance matching.

The invention has the beneficial effects that: the loading function can be well achieved, and the cut-off frequency of the waveguide cavity is effectively reduced; the quasi-circular polarized wave is obtained, so that the distribution of the thermal field at the mouth surface is more uniform. The length (height) of the radiator can be effectively reduced, the radial peripheral space has no structural part, and the connecting rod is convenient to mount in the center of the end part of the shell.

Drawings

The invention is further illustrated below with reference to the figures and examples.

FIG. 1 is a schematic structural view of the present invention;

fig. 2 is a side view of the present invention.

Detailed Description

A magnetically excited 915MHz circular waveguide radiator as shown in fig. 1, characterized by: the antenna comprises a shell 1, an exciting antenna 2 and an adjusting rod 3, wherein the exciting antenna 2 is arranged at the closed end of a conductor at the rear part of a radiator and is magnetically excited by adopting a bias current loop.

The inner caliber of the shell 1 is 160mm, and the length of the inner cavity is 140 mm.

The adjusting rod 3 and the plane where the exciting antenna 2 is located form an angle of 45 degrees, and the adjusting rod and the plane are symmetrically arranged on a transmission section to load the radiator. The radiators are placed with two pairs of adjusting rods 3 diametrically and at an angle of 45 ° to the plane of the excitation current loop, so that the electric field is resolved into two components of equal amplitude, horizontal and vertical. The length of the rods 3 and the distance between the two pairs of rods are adjusted so that the horizontal and vertical components are 90 out of phase, thereby forming a circularly polarized wave at the output. Due to the existence of the adjusting rod 3, when the height of the rod is larger, a good loading effect can be achieved, and the cut-off frequency of the waveguide cavity is effectively reduced. Therefore, by increasing the height of the rods and adjusting the positions of the rods, the distance between the two pairs of rods is adjusted, and under the condition of ensuring lower standing wave at the working frequency, quasi-circular polarized waves can be obtained, so that the distribution of the thermal field at the mouth surface is more uniform.

The radiator adopts current loop magnetic excitation, microwave energy fed in by a coaxial cable is converted by an excitation antenna 2 to excite an electromagnetic field in a waveguide, human tissues are radiated outwards from a radiation opening after passing through a transmission section, and an adjusting rod 3 of the transmission section is used for loading the radiator, reducing cut-off frequency, adjusting phase and performing impedance matching.