Rectangular cavity type through-type radio frequency voltage and current probe
By designing a rectangular cavity through-type RF voltage and current probe, the problems of insufficient design freedom and stability of traditional probes are solved, realizing low-cost, high-precision transmission line monitoring, especially in high-power scenarios.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-20
- Publication Date
- 2026-04-07
AI Technical Summary
Traditional RF voltage and current probes have limited design freedom, weak structural stability, complex manufacturing processes, and high losses in high-power scenarios, which affect accuracy.
The design employs a rectangular cavity through-type RF voltage and current probe, which includes a rectangular coaxial cavity, a voltage-coupled probe, and a current-coupled probe. Combined with a misalignment matching design, insertion loss is reduced, and a rectangular coaxial structure is used instead of a circular coaxial structure.
The structure stability and processing convenience of the probe have been improved, losses have been reduced, accurate monitoring in high-power scenarios has been achieved, and costs have been reduced.
Smart Images
Figure CN121805656A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the field of radio frequency transmission line measurement, and particularly relates to a rectangular cavity type through radio frequency voltage current probe. BACKGROUND
[0002] The radio frequency voltage current probe is a radio frequency transmission line detection device, which is composed of a transmission line cavity, a voltage coupling probe and a current coupling probe. The radio frequency voltage current probe is widely used in radio frequency plasma etching system monitoring and radio frequency system monitoring due to its non-invasiveness and detection accuracy. However, the traditional radio frequency voltage current probe generally adopts a circular cavity shape, has low design freedom, poor structural stability and complex processing. In order to meet the needs of radio frequency transmission line detection for low-cost and high-precision monitoring solutions, it is necessary to design a low-cost and easy-to-process through radio frequency voltage current probe. In addition, as the power of the device application scene increases, the power loss and heating of the device also increase accordingly, which urgently requires reducing the probe loss and improving the power capacity of the probe to reduce the risk and accuracy decline in the high-power scene. SUMMARY
[0003] In order to improve the traditional circular cavity type through radio frequency transmission line voltage current probe, the present application provides a rectangular cavity type through radio frequency transmission line voltage current probe design. The probe has higher structural stability, design freedom and processing convenience, and also has low loss in high-power scenes.
[0004] The first aspect of the present application provides a rectangular cavity type through radio frequency voltage current probe, which comprises a transmission line cavity (1), a voltage coupling probe (2), a current coupling probe (3) and a shielding structure (4). The transmission line cavity (1) comprises an inner conductor first connecting section (1-1), an inner conductor section (1-2), an inner conductor second connecting section (1-3), an N-type male head-outer conductor connecting section (1-4), an N-type female head-outer conductor connecting section (1-8), an outer conductor first connecting section (1-5), an outer conductor section (1-6) and an outer conductor second connecting section (1-7). The voltage coupling probe (2) comprises a voltage coupling plate (2-1), a voltage coupling plate signal line (2-2) and a voltage coupling plate parallel ground capacitor (2-3). The current coupling probe (3) comprises a current coupling coil (3-1), a current coupling coil first signal line (3-2) and a current coupling coil second signal line (3-3). The inner conductor first connecting section (1-1), the inner conductor section (1-2), the inner conductor second connecting section (1-3), the voltage coupling probe (2), the current coupling probe (3) and the shielding structure (4) are located on the middle layer PCB board. The N-type male connector-outer conductor connection section (1-4), the N-type female connector-outer conductor connection section (1-8), the first outer conductor connection section (1-5), the outer conductor section (1-6), and the second outer conductor connection section (1-7) are located on the metal upper and lower covers; The length of the inner conductor segment (1-2) is less than one-hundredth of the wavelength; The N-type male connector-outer conductor connection section (1-4), the first outer conductor connection section (1-5), the outer conductor section (1-6), the second outer conductor connection section (1-7), and the N-type female connector-outer conductor connection section (1-8) on the lower cover are connected to the corresponding parts of the PCB board and the upper cover to form a sealed outer conductor cavity; The N-type coaxial male connector and N-type coaxial female connector are respectively installed on the N-type male connector-outer conductor connection section (1-4) and the N-type female connector-outer conductor connection section (1-8) to connect to the standard radio frequency system and realize through-type measurement of the transmission line.
[0005] Optionally, in one embodiment of the present invention, the inner conductor first connecting segment (1-1), the inner conductor segment (1-2), the inner conductor second connecting segment (1-3), and the outer conductor segment (1-6) are all designed with rectangular cross sections to simulate a rectangular coaxial transmission line.
[0006] Optionally, in one embodiment of the present invention, the coupling ratio of the voltage coupling probe to the transmission line voltage and the lower sideband of the operating frequency are adjusted by adjusting the size and position of the voltage coupling plate (2-1) and the capacitance value of the voltage coupling plate connected in parallel to the ground capacitor (2-3). The coupling ratio of the current-coupled transmission line current to the lower sideband of the operating frequency is adjusted by adjusting the size, number of turns, and position of the current-coupled coil (3-1) in the current-coupled probe.
[0007] Optionally, in one embodiment of the present invention, the matching and transmission performance of the probe system can be adjusted by adjusting the dimensions of the inner conductor first connecting segment (1-1), inner conductor second connecting segment (1-3), inner conductor segment (1-2), outer conductor first connecting segment (1-5), outer conductor second connecting segment (1-7), and outer conductor segment (1-8).
[0008] Optionally, in one embodiment of the present invention, a voltage coupling plate parallel ground capacitor (2-3) is connected between the voltage coupling plate signal line (2-2) and ground to increase the equivalent ground capacitance of the voltage coupling plate (2-1).
[0009] Optionally, in one embodiment of the present invention, the voltage coupling plate (2-1) is equivalent to a parallel via array; The shielding structure (4) adopts a grounded parallel via array equivalent metal.
[0010] The rectangular cavity through-type RF voltage and current probe of this invention uses a rectangular coaxial cavity instead of the traditional circular coaxial cavity design, which reduces the difficulty of probe manufacturing, improves structural stability, and uses a misalignment matching design to reduce probe insertion loss. Combined with a calibration algorithm, it can achieve accurate non-invasive reflection monitoring.
[0011] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description
[0012] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 This is a schematic diagram of a rectangular cavity through-type radio frequency voltage and current probe sandwich structure according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the middle layer PCB board structure of the rectangular cavity through-type radio frequency transmission line voltage and current probe according to an embodiment of the present invention. Detailed Implementation
[0013] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.
[0014] Figure 1 This is a schematic diagram of a rectangular cavity through-type radio frequency voltage and current probe structure provided according to an embodiment of the present invention.
[0015] like Figure 1 As shown, the rectangular cavity through-type radio frequency voltage and current probe includes: 1. Transmission line cavity; 2. Voltage coupling probe; 3. Current coupling probe; 4. Shielding structure. The transmission line cavity 1 includes an inner conductor first connection segment 1-1, an inner conductor segment 1-2, an inner conductor second connection segment 1-3, an N-type male connector-outer conductor connection segment 1-4, an N-type female connector-outer conductor connection segment 1-8, an outer conductor first connection segment 1-5, an outer conductor segment 1-6, and an outer conductor second connection segment 1-7. The voltage coupling probe 2 includes a voltage coupling plate 2-1, a voltage coupling plate signal line 2-2, and a voltage coupling plate parallel grounding capacitor 2-3; The current coupling probe 3 includes a current coupling coil 3-1, a first signal line of the current coupling coil 3-2, and a second signal line of the current coupling coil 3-3; The inner conductor first connection segment 1-1, inner conductor segment 1-2, inner conductor second connection segment 1-3, voltage coupling probe 2, current coupling probe 3, and shielding structure 4 are located on the middle layer PCB board. N-type male connector-outer conductor connection section 1-4, N-type female connector-outer conductor connection section 1-8, outer conductor first connection section 1-5, outer conductor section 1-6, and outer conductor second connection section 1-7 are located on the upper and lower metal covers; fix the PCB board between the upper and lower metal shells, and install standard coaxial interfaces on the N-type male connector-outer conductor connection sections and N-type female connector-outer conductor connection sections on both sides, so that it can be connected to a standard RF system; The length of inner conductor segment 1-2 is less than one-hundredth of the wavelength; The N-type male connector-outer conductor connection section 1-4, the first outer conductor connection section 1-5, the outer conductor section 1-6, the second outer conductor connection section 1-7, and the N-type female connector-outer conductor connection section 1-8 on the lower cover are connected to the corresponding parts of the PCB board and the upper cover to form a sealed outer conductor cavity; The N-type coaxial male connector and N-type coaxial female connector are respectively installed on the N-type male connector-outer conductor connection section 1-4 and the N-type female connector-outer conductor connection section 1-8 to connect to the standard radio frequency system and realize through-type measurement of the transmission line.
[0016] The shielding structure 4 is a grounded metal wall placed between the current coupling coil 3-2 and the voltage coupling probe 2; the voltage coupling plate 2-1 is a parallel array of vias placed in the air medium; the current coupling coil 3-2 is a rectangular coil placed perpendicular to the magnetic field direction.
[0017] In an embodiment of the present invention, after the upper cover and the lower cover clamp the PCB board, a sealed space is formed inside as a rectangular coaxial cavity. The inner conductor first connecting segment 1-1, inner conductor segment 1-2, and inner conductor second connecting segment 1-3 serve as the inner conductors of the rectangular coaxial line. The current carrying capacity is increased by using a multi-layer conductor strip parallel via array on the PCB board. The N-type male connector-outer conductor connecting segment 1-4, N-type female connector-outer conductor connecting segment 1-8, outer conductor first connecting segment 1-5, outer conductor segment 1-6, and outer conductor second connecting segment 1-7 are connected to the corresponding parts of the PCB board and the upper cover to form an outer conductor cavity.
[0018] A voltage coupling plate 2-1 is connected in parallel with a grounding capacitor 2-3, which is connected between the voltage coupling plate signal line 2-2 and ground to increase the equivalent capacitance to ground of the voltage coupling plate 2-1. By adjusting the capacitance value, the coupling ratio can be easily adjusted.
[0019] The voltage coupling plate 2-1 adopts a parallel via array as an equivalent; the shielding structure 4 adopts a grounded parallel via array as an equivalent metal; the N-type coaxial male and female connectors are respectively installed on the N-type male connector-outer conductor connection section 1-4 and the N-type female connector-outer conductor connection section 1-8 to connect to the standard radio frequency system and realize through-type measurement of the transmission line.
[0020] In the embodiments of the present invention, the inner conductor first connecting segment 1-1, inner conductor segment 1-2, inner conductor second connecting segment 1-3, and outer conductor segment 1-6 all adopt a rectangular cross-section design to simulate a rectangular coaxial transmission line.
[0021] In an embodiment of the present invention, the coupling ratio of the voltage coupling probe to the transmission line voltage and the lower sideband of the operating frequency are adjusted by adjusting the size and position of the voltage coupling plate 2-1 and the capacitance value of the voltage coupling plate connected in parallel to the ground capacitor 2-3; the coupling ratio of the current coupling probe to the transmission line current and the lower sideband of the operating frequency are adjusted by adjusting the size, number of turns and position of the current coupling coil 3-1 in the current coupling probe.
[0022] In an embodiment of the present invention, by adjusting the dimensions of the inner conductor first connecting segment 1-1, the inner conductor second connecting segment 1-3, the inner conductor segment 1-2, the outer conductor first connecting segment 1-5, the outer conductor second connecting segment 1-7, and the outer conductor segment 1-8, the matching and transmission performance of the probe system is adjusted to ensure its non-invasive characteristics, thereby reducing the insertion loss of the through-type probe system.
[0023] The rectangular cavity through-type RF transmission line voltage and current probe employs a through-type detection method, with the inner and outer conductors connected to the inner and outer conductors of a standard coaxial connector, respectively. The probe is integrated into a standard RF system to monitor voltage and current amplitude and phase, load, and forward and reverse power. Electromagnetic waves are fed into the rectangular transmission line cavity through an external coaxial cable, creating a time-varying electric field perpendicular to the planes of the inner and outer conductors and a time-varying magnetic field parallel to these planes within the air-coaxial medium of the cavity. The voltage-coupled probe and current-coupled coil couple the electric and magnetic fields in the medium, respectively, and transmit the electrical signals to a post-processing circuit via the voltage-coupled plate signal line, the first signal line of the current coil, and the second signal line of the current coil. This allows for the calculation of the voltage and current amplitude and phase information of the cavity transmission line, and ultimately, the inference of the forward and reverse power and load information of the transmission line.
[0024] The inner conductor segment 1-2, voltage coupling plate 2-1, and grounding shield 4 are implemented by using a multi-layer conductive strip parallel via array, or by other methods such as current-carrying copper strips. Essentially, they are equivalent metal conductive strips or metal walls.
[0025] In terms of manufacturing, the N-type male connector-outer conductor connection section 1-4 and the N-type female connector-outer conductor connection section 1-8 are both designed to be compatible with N-type coaxial connectors. Other standard coaxial connectors such as BNC and SMA can also be used to adapt to different working scenarios, power and frequency bands. Only the size of the connection section needs to be modified for matching design.
[0026] Voltage-coupled probe 2 and current-coupled probe 3 are the detection coupling designs in the probe. The specific wiring, position and angle can be adjusted according to the actual design requirements.
[0027] In terms of manufacturing, the current method is to use a sandwich structure of "metal shell-PCB board-metal shell". Alternatively, a sealed rectangular cavity can be achieved by inserting the shell into the PCB board or embedding the shell into the PCB board.
[0028] The rectangular cavity through-type RF voltage and current probe proposed in this embodiment of the invention connects to a standard coaxial interface and is integrated into a standard RF system. It monitors the voltage and current amplitude and phase information on the transmission line via coupling, thereby monitoring the forward and reverse power and load conditions of the transmission line. By using a rectangular coaxial structure instead of the traditional circular coaxial structure, the manufacturing difficulty and cost are reduced. This invention achieves low cost and high structural stability in a through-type RF transmission line voltage and current probe, and also allows for control of the probe's insertion loss.
[0029] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.
[0030] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "N" means at least two, such as two, three, etc., unless otherwise explicitly specified.
Claims
1. A rectangular cavity type through-type radio frequency voltage and current probe, characterized in that, include: Transmission line cavity (1), voltage coupling probe (2), current coupling probe (3), shielding structure (4); The transmission line cavity (1) includes an inner conductor first connection section (1-1), an inner conductor section (1-2), an inner conductor second connection section (1-3), an N-type male connector-outer conductor connection section (1-4), an N-type female connector-outer conductor connection section (1-8), an outer conductor first connection section (1-5), an outer conductor section (1-6), and an outer conductor second connection section (1-7). The voltage coupling probe (2) includes a voltage coupling plate (2-1), a voltage coupling plate signal line (2-2), and a voltage coupling plate parallel grounding capacitor (2-3). The current coupling probe (3) includes a current coupling coil (3-1), a first signal line of the current coupling coil (3-2), and a second signal line of the current coupling coil (3-3). The inner conductor first connection segment (1-1), inner conductor segment (1-2), inner conductor second connection segment (1-3), voltage coupling probe (2), current coupling probe (3), and shielding structure (4) are located on the middle layer PCB board; The N-type male connector-outer conductor connection section (1-4), the N-type female connector-outer conductor connection section (1-8), the first outer conductor connection section (1-5), the outer conductor section (1-6), and the second outer conductor connection section (1-7) are located on the metal upper and lower covers; The length of the inner conductor segment (1-2) is less than one-hundredth of the wavelength; The N-type male connector-outer conductor connection section (1-4), the first outer conductor connection section (1-5), the outer conductor section (1-6), the second outer conductor connection section (1-7), and the N-type female connector-outer conductor connection section (1-8) on the lower cover are connected to the corresponding parts of the PCB board and the upper cover to form a sealed outer conductor cavity; The N-type coaxial male connector and N-type coaxial female connector are respectively installed on the N-type male connector-outer conductor connection section (1-4) and the N-type female connector-outer conductor connection section (1-8) to connect to the standard radio frequency system and realize through-type measurement of the transmission line.
2. The rectangular cavity type through-type radio frequency voltage and current probe according to claim 1, characterized in that, The inner conductor first connecting section (1-1), inner conductor section (1-2), inner conductor second connecting section (1-3), and outer conductor section (1-6) all adopt a rectangular cross-section design to simulate a rectangular coaxial transmission line.
3. The rectangular cavity through-type radio frequency voltage and current probe according to claim 1, characterized in that, The coupling ratio of the voltage coupling probe to the lower sideband of the operating frequency is adjusted by adjusting the size and position of the voltage coupling plate (2-1) and the capacitance value of the voltage coupling plate connected in parallel to the ground capacitor (2-3). The coupling ratio of the current-coupled transmission line current to the lower sideband of the operating frequency is adjusted by adjusting the size, number of turns, and position of the current-coupled coil (3-1) in the current-coupled probe.
4. The rectangular cavity through-type radio frequency voltage and current probe according to claim 1, characterized in that, The matching and transmission performance of the probe system can be adjusted by adjusting the dimensions of the first connecting section (1-1), the second connecting section (1-3), the inner conductor section (1-2), the first connecting section (1-5), the second connecting section (1-7), and the outer conductor section (1-8).
5. The rectangular cavity type through-type radio frequency voltage and current probe according to claim 1, characterized in that, The voltage coupling plate is connected in parallel to ground capacitor (2-3) between the voltage coupling plate signal line (2-2) and ground to increase the equivalent capacitance to ground of the voltage coupling plate (2-1).
6. The rectangular cavity type through-type radio frequency voltage and current probe according to claim 1, characterized in that, The voltage-coupled electrode (2-1) is equivalent to a parallel via array; The shielding structure (4) adopts a grounded parallel via array equivalent metal.