Method and equipment for improving matching of measured pieces in attenuation measurement system

Abstract

The invention discloses a method and equipment for improving matching of a measured piece in an attenuation measurement system, belongs to the field of radio metering, and comprises the method for improving matching of the measured piece in the attenuation measurement system, and the core of the method is that a precise matching absorption load is added in a front-end transmission system of the measured piece; energy transmission is realized on a waveguide wide side of the precise matching absorption load through a coupling hole; a transmission waveguide is additionally arranged above the coupling hole, and energy is transmitted to a measured piece in the forward direction; and a precise matching absorption load is added in the reverse direction to absorb energy in the reverse direction, so that the measured piece matching improvement equipment in the attenuation measurement system is formed, and finally the measured piece matching of the attenuation measurement system is improved. According to the method and the equipment, the impedance matching of the measured piece is improved by using the precise matching load, the voltage standing-wave ratio of the load level is realized, and the attenuation measurement accuracy is improved. The tested piece matching improvement equipment developed by using the method is directly connected to two ends of the tested piece in an attenuation measurement system, so that the impedance matching of the tested piece is improved.

Description

Technical Field

[0001] This invention belongs to the field of radio metrology technology, and particularly relates to a method and device for improving the matching of the device under test in an attenuation measurement system. Background Technology

[0002] Attenuation is one of the fundamental parameters in radio metrology. It characterizes the degree to which the amplitude of a radio signal weakens during transmission and is a transmission characteristic of various transmission lines, electronic components, electronic devices, and systems.

[0003] Attenuation measurement is of great significance in military and defense metrology. Due to loss and reflection, signals are attenuated during transmission, with higher frequencies experiencing greater attenuation. If cable loss causes an attenuation of 3dB, it means the signal power is halved. To obtain the required power, the output power of the signal source or transmitter must be doubled, increasing costs and technical complexity. Therefore, minimizing attenuation is crucial in the design, development, and use of electronic equipment. In other cases, such as stealth and electromagnetic shielding technologies, the absorbing materials used must have the highest possible attenuation. Attenuation is also a critical technical indicator for various electronic components, parts, assemblies, and equipment.

[0004] For example, attenuators, isolators, couplers, filters, power dividers, adapters, mixers, and amplifiers, although their characteristics are referred to as coupling, isolation, directivity, insertion loss, attenuation, gain, amplification factor, conversion loss, and efficiency, all fall under the scope of attenuation measurement. Calibrated standard attenuators can be used to measure receiver sensitivity and noise figure, extend the measurement range of parameters such as voltage, power, and spectrum, and simulate target distances in simulation technology. Therefore, attenuation measurement is an important parameter in radio metrology. Attenuation measurement requires an ideally matched system.

[0005] However, in practical applications, imperfect port matching of the device under test (DUT) can introduce significant attenuation measurement errors, necessitating specialized methods to improve port matching. For attenuation measurement systems in the low-frequency band (below 170 GHz), impedance matching devices can be used to improve system matching. However, for frequency bands above 170 GHz, there are currently no readily available and the system measurement errors introduced by mismatch cannot be eliminated. This invention designs a method and device for improving DUT matching, employing precision matching to absorb the load and coupling energy transmission to improve DUT matching in the attenuation measurement system, thereby enhancing the accuracy of attenuation measurements.

[0006] It should be noted that the above content falls within the inventor's technical knowledge and does not necessarily constitute prior art. Summary of the Invention

[0007] To address the aforementioned problems, the present invention aims to provide a method and apparatus for improving the impedance matching of a device under test (DUT) in an attenuation measurement system. This method utilizes a precision-matched load to improve the impedance matching of the DUT, achieving a voltage standing wave ratio (VSWR) at the load level and improving the accuracy of attenuation measurements. The DUT matching improvement apparatus developed using this method is directly connected to both ends of the DUT in the attenuation measurement system, thereby improving the impedance matching of the DUT.

[0008] To achieve the above objectives, this invention proposes a method for improving the matching of the device under test (DUT) in an attenuation measurement system. The core of this improvement method is to add a precision matching absorption load to the front-end transmission system of the DUT.

[0009] Energy is then transferred through a coupling hole on the wide side of the waveguide with a precisely matched absorbing load.

[0010] A transmission waveguide is then added above the coupling hole to transmit energy to the device under test in the positive direction.

[0011] By adding a precision matching absorption load in the opposite direction, energy is absorbed in the opposite direction, forming a device for improving the matching of the tested component in the attenuation measurement system, and ultimately improving the matching of the tested component in the attenuation measurement system.

[0012] An attenuation measurement system includes a device for improving the matching of the device under test (DUT) and is applied to the improvement method described above. The device includes an upper cavity waveguide, a lower cavity waveguide, and a precision matching absorption load.

[0013] The upper cavity waveguide and the lower cavity waveguide correspond to the two waveguide ports of the matching improvement device, respectively. Absorbing precision matching loads are added to the terminals of the upper cavity waveguide and the lower cavity waveguide to absorb the direct energy and achieve energy transmission through coupling.

[0014] Preferably, the improving device is made of copper with a gold-plated surface.

[0015] Preferably, the upper cavity waveguide and the lower cavity waveguide have the same parameters, and both are selected as standard waveguides. The parameters that need to be designed for the improved device include the wide side dimension a and narrow side dimension b of the waveguide aperture of the upper cavity waveguide and the lower cavity waveguide, the number N, spacing d, aperture r and distance s between the coupling holes on the coupling sheet and the waveguide edge.

[0016] Preferably, the parameters of the improved device are designed as follows:

[0017] S1: Determine the wide side dimension a and narrow side dimension b of the waveguide aperture.

[0018] Select the standard waveguide port width and narrow side dimensions based on the operating frequency of the attenuation measurement system attenuation aperture.

[0019] S2: Determine the initial value of the distance s between the coupling hole of the coupling plate and the edge of the waveguide. Choose s = a / 4 as its initial value.

[0020] S3: Determine the number and spacing of the coupling holes.

[0021] The number of coupling holes is determined based on the attenuation of the attenuator and the operating frequency band. The spacing between the coupling holes is selected as one-quarter of the wavelength inside the center frequency guide.

[0022] S4: Determine the initial value of the coupling hole diameter, which makes the attenuation introduced by coupling 3dB.

[0023] S5: Use electromagnetic simulation software to perform simulation optimization and determine the final result.

[0024] S6: Add precision-matched absorbing loads to the terminals of the upper and lower cavity waveguides to convert them into two-port devices.

[0025] Preferably, step S3 is as follows:

[0026] The center frequency is calculated based on the starting frequency f1 and ending frequency f2 of the frequency band corresponding to the standard waveguide:

[0027] f0 = (f1 + f2) / 2;

[0028] Then calculate the wavelength in vacuum corresponding to f0:

[0029] λ0=c / f0,

[0030] c is the speed of light in a vacuum; then according to the formula:

[0031]

[0032] Calculate the corresponding inductance wavelength λ g In the formula, a is the width of the standard waveguide in this frequency band, and finally, one-quarter of the wavelength inside the guide is taken as the initial value of the coupling aperture spacing d.

[0033] Preferably, in S1, the attenuator operates in the frequency band below 110GHz according to GB11450.2-89, and in the frequency band above 110GHz according to IEEE1785.1.

[0034] The method and equipment for improving the matching of the tested component in an attenuation measurement system proposed in this invention can bring the following beneficial effects:

[0035] 1. The improved method and equipment of this invention use a precision-matched load to improve the impedance matching of the device under test (DUT), achieving a voltage standing wave ratio (VSWR) at the load level and improving the accuracy of attenuation measurement. The DUT matching improvement equipment developed using this method is directly connected to both ends of the DUT in the attenuation measurement system, improving the impedance matching of the DUT.

[0036] 2. The improved method and equipment of this invention address the problem of the lack of mature impedance tuners in the frequency band above 170GHz. This invention provides a feasible matching improvement scheme, fills the technical gap in port matching correction in attenuation measurement in this frequency band, and expands the feasible range of high-frequency attenuation measurement.

[0037] 3. The improved method and equipment of the present invention adopts a standard waveguide and coupling hole structure, combined with a precision absorption load, which does not require complex external adjustment devices, has a compact structure, high processing feasibility, and is easy to integrate into existing attenuation measurement systems;

[0038] 4. The improved method and equipment of the present invention, through reasonable design of the number, spacing and aperture distribution of coupling holes, can achieve stable attenuation of about 3dB and good matching in a wide frequency band, and is suitable for attenuation measurement in multiple frequency bands and wide frequency ranges.

[0039] 5. The design process of the improved method and equipment of this invention provides clear parameter selection principles and optimization steps, and combines electromagnetic simulation software for verification and optimization, ensuring the scientific nature and reliability of the design, and facilitating practical engineering application and promotion.

[0040] 6. The improved method and equipment of this invention, after improving and matching the test component in the attenuation measurement system, reduces system reflection and makes signal transmission more stable, which is conducive to improving the dynamic range and repeatability of the measurement system, and provides more reliable technical support for applications such as high-precision attenuation measurement, receiver sensitivity testing, and noise figure measurement. Attached Figure Description

[0041] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings:

[0042] Figure 1 This is a schematic diagram of the device for improving the matching of the tested component in the attenuation measurement system of the present invention. Detailed Implementation

[0043] To more clearly illustrate the overall concept of the present invention, a detailed description will be provided below with reference to the accompanying drawings and examples.

[0044] A method for improving the matching of a device under test (DUT) in an attenuation measurement system is proposed. The core of this method is to add a precision matching absorbing load to the front-end transmission system of the DUT to achieve impedance matching at the load level. Then, energy is transmitted through a series of coupling holes on the wide side of the waveguide of the precision matching absorbing load, resulting in approximately 3dB of energy attenuation. A transmission waveguide is then added above the coupling holes to transmit energy to the DUT in the forward direction. A precision matching absorbing load is added in the reverse direction to absorb energy in the opposite direction, forming a matching improvement device for the DUT in the attenuation measurement system, ultimately improving the DUT matching in the attenuation measurement system.

[0045] A device for improving the matching of the test object in an attenuation measurement system, applied to the above-mentioned improvement method, such as... Figure 1 As shown, the improved device includes an upper cavity waveguide, a lower cavity waveguide, and a precision-matched absorption load.

[0046] The upper and lower cavity waveguides correspond to the two waveguide ports of the matching improvement device. The upper and lower cavity waveguides have the same parameters and are both standard waveguides. Absorbing precision matching loads are added to the terminals of the upper and lower cavity waveguides to absorb direct energy and achieve energy transmission through coupling.

[0047] The improved equipment is made of copper with a gold-plated surface, such as... Figure 1 As shown in the figure, P4 and P3 are two waveguide ports of the upper cavity waveguide, and P1 and P2 are two waveguide ports of the lower cavity waveguide. The main parameters that need to be designed include the wide side dimension a, the narrow side dimension b of the waveguide port, the number N of coupling holes on the coupling plate, the spacing d, the aperture r, and the distance s between the coupling hole and the edge of the waveguide.

[0048] The design principles for each parameter are as follows:

[0049] S1: Determine the wide side dimension a and narrow side dimension b of the waveguide port.

[0050] Select the standard waveguide port width and narrow side dimensions according to the operating frequency of the attenuator in the attenuation measurement system. For frequency bands below 110 GHz, refer to GB11450.2-89; for frequency bands above 110 GHz, refer to IEEE1785.1.

[0051] S2: Determine the initial value of the distance s between the coupling hole of the coupling plate and the edge of the waveguide. Usually, s = a / 4 is chosen as its initial value.

[0052] S3: Determine the number and spacing of the coupling holes.

[0053] The number of coupling holes is determined based on the attenuator's attenuation and the operating frequency band, typically with an initial value of N = 14. If the hole diameter is too large, the number of coupling holes can be increased appropriately. The spacing between the coupling holes is usually chosen to be one-quarter of the wavelength within the center frequency band. The center frequency is calculated based on the starting frequency f1 and ending frequency f2 of the corresponding frequency band for this standard waveguide.

[0054] f0 = (f1 + f2) / 2;

[0055] Then calculate the corresponding wavelength in vacuum:

[0056] λ0=c / f0,

[0057] Where c is the speed of light in a vacuum; and according to the formula:

[0058]

[0059] Calculate the corresponding inductance wavelength λ g Finally, one-quarter of the inner wavelength is taken as the initial value of the coupling aperture spacing d.

[0060] S4: Determine the initial value of the coupling hole diameter, which makes the attenuation introduced by coupling approximately 3dB.

[0061] S5: After obtaining the initial values ​​of the above parameters, use electromagnetic simulation software to perform simulation optimization and determine the final result.

[0062] S6: Add precision-matched absorbing loads to the terminals of the upper and lower cavity waveguides to convert them into two-port devices.

[0063] Taking the 140GHz to 220GHz frequency band as an example, this paper details the specific process of improving the matching of the device under test in an attenuation measurement system with a nominal attenuation of 3dB designed using this invention.

[0064] The standard waveguide for the 140GHz–220GHz band is the WM-1295 standard waveguide, with a wide side a = 1.2954mm and a narrow side b = 0.6477mm. The commonly used waveguide flange for this band is the UG-387 standard flange. When designing the attenuator, the main factors to determine are the number N of coupling holes on the coupling plate, the spacing d, the hole diameter r, and the distance s between the hole and the waveguide edge.

[0065] The specific design method for the standard is as follows:

[0066] S01: Determine the wide side dimension a and narrow side dimension b of the waveguide port. Select the standard wide side and narrow side dimensions of the waveguide port according to the operating frequency of the designed attenuator. For the 140GHz~220GHz frequency band, refer to the IEEE1785.1 waveguide standard to determine that the wide side a = 1.2954mm and the narrow side b = 0.6477mm.

[0067] S02: Determine the initial value of the distance s between the coupling hole of the coupling plate and the edge of the waveguide. If s = a / 4 is selected, then its initial value is 0.323mm.

[0068] S03: Determine the spacing d of the coupling holes using the following method:

[0069] The starting frequency f1 = 140 GHz and the ending frequency f2 = 220 GHz of the 140 GHz to 220 GHz band are used to calculate the center frequency according to the following formula.

[0070] f0 = (f1 + f2) / 2 = 180 GHz

[0071] Calculate the wavelength in free space corresponding to the center frequency:

[0072] λ0=c / f0=1.666mm

[0073] Calculate one-quarter of the wavelength inside the standard waveguide corresponding to this frequency point:

[0074]

[0075] S04: Determine the coupling aperture diameter r and the number N. Taking into account factors such as coupling aperture processing, select the number of coupling apertures as N=14 in this frequency band. The coupling aperture diameter adopts Chebyshev distribution, and a series of coupling aperture diameters can be calculated.

[0076] S05: Use electromagnetic simulation software to perform simulation optimization and determine the final result.

[0077] S06: Add precision-matched absorbing loads to the terminals of the upper and lower cavity waveguides to convert them into two-port devices.

[0078] The above description is merely an embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A method for improving the matching of the test piece in an attenuation measurement system, characterized in that, The core of the improvement method is to add a precision-matched absorption load to the front-end transmission system of the device under test. Energy is then transferred through a coupling hole on the wide side of the waveguide with a precisely matched absorbing load. Then, a transmission waveguide is added above the coupling hole to transmit energy to the device under test in the positive direction; By adding a precision matching absorption load in the opposite direction, energy is absorbed in the opposite direction, forming a device for improving the matching of the tested component in the attenuation measurement system, and ultimately improving the matching of the tested component in the attenuation measurement system.

2. A device for improving the matching of a test component in an attenuation measurement system, applied to the improvement method described in claim 1, characterized in that, The improvement device includes an upper cavity waveguide, a lower cavity waveguide, and a precision-matched absorption load; The upper cavity waveguide and the lower cavity waveguide correspond to the two waveguide ports of the matching improvement device, respectively. Absorbing precision matching loads are added to the terminals of the upper cavity waveguide and the lower cavity waveguide to absorb the direct energy and achieve energy transmission through coupling.

3. The device for improving the matching of the tested component in an attenuation measurement system according to claim 2, characterized in that, The upper and lower cavity waveguides have the same parameters and are both selected as standard waveguides. The parameters that need to be designed for the improved equipment include the wide side dimension a and narrow side dimension b of the waveguide aperture of the upper and lower cavity waveguides, the number N, spacing d, aperture r and distance s between the coupling holes on the coupling plate and the waveguide edge.

4. The device for improving the matching of the tested component in an attenuation measurement system according to claim 3, characterized in that, The parameters of the improved equipment are designed as follows: S1: Determine the wide side dimension a and the narrow side dimension b of the waveguide aperture; Select the standard waveguide port width and narrow side dimensions based on the operating frequency of the attenuation measurement system attenuation aperture. S2: Determine the initial value of the distance s between the coupling hole of the coupling plate and the edge of the upper / lower cavity waveguide. Choose s = a / 4 as its initial value. S3: Determine the number and spacing of the coupling holes; The number of coupling holes is determined based on the attenuation of the attenuator and the operating frequency band. The spacing between the coupling holes is selected as one-quarter of the wavelength inside the center frequency guide. S4: Determine the initial value of the coupling hole diameter, which makes the attenuation introduced by coupling 3dB. S5: Use electromagnetic simulation software to perform simulation optimization and determine the final result; S6: Add precision-matched absorbing loads to the terminals of the upper and lower cavity waveguides to convert them into two-port devices.

5. The device for improving the matching of the tested component in an attenuation measurement system according to claim 4, characterized in that, S3 is specifically as follows: The center frequency is calculated based on the starting frequency f1 and ending frequency f2 of the frequency band corresponding to the standard waveguide: f0 = (f1 + f2) / 2; Then calculate the wavelength in vacuum corresponding to f0: λ0=c / f0, c is the speed of light in a vacuum; then according to the formula: Calculate the corresponding inductance wavelength λ g In the formula, a is the width of the standard waveguide in this frequency band, and finally, one-quarter of the wavelength inside the guide is taken as the initial value of the coupling aperture spacing d.

6. The device for improving the matching of the tested component in an attenuation measurement system according to claim 5, characterized in that, The attenuator in S1 operates in the frequency band below 110GHz, referring to GB11450.2-89, and in the frequency band above 110GHz, referring to IEEE1785.

1.

7. The device for improving the matching of the tested component in an attenuation measurement system according to claim 6, characterized in that, The improved equipment is made of copper with a gold-plated surface.

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