Four-port electronic calibration device

Abstract

A four-port electronic calibration device is used for verifying external connection ports of a vector network analyzer and comprises a shell, four interfaces, four load calibration units, a control processing unit, a switch connection unit and a data communication unit. And each interface is at least used for connecting a calibrated port of the vector network analyzer. And each interface is connected with one load calibration unit for carrying out load calibration on the calibrated port. The control processing unit is used for outputting a control instruction. And the switch connection unit responds to the control instruction and carries out load calibration or straight-through calibration on the calibrated port specified by the user. And the data communication unit is used for data transmission between the vector network analyzer and the control processing unit. The external port of the network analyzer is calibrated through the plurality of interfaces of the electronic calibration piece, that is, the plurality of calibration ports of the vector network analyzer can be verified in a time-sharing asynchronous manner, and the interfaces of the electronic calibration piece can also be used as expansion interfaces of the vector network analyzer.

Description

Technical Field

[0001] The present application relates to the technical field of communication test instruments and meters, and in particular to a four-port electronic calibration device. Background Art

[0002] As a universal S-parameter test instrument, the vector network analyzer (VNA) is widely used in research institutes, laboratories, and production lines for S-parameter measurements, such as those used for testing antennas, cavity filters, dielectric filters, circulators, couplers, splitters, and combiners. Before using a network analyzer for measurement, the test equipment and the device under test must be physically connected (either with a calibration device or the device under test) and calibrated separately. This is primarily due to inherent errors in the VNA, which require calibration to ensure measurement accuracy. VNA measurement errors include directivity error, source match error, reflection tracking error, load match error, and transmission tracking error. Directivity error, source match error, and reflection tracking error are errors associated with individual VNA ports and are determined by directly connecting different types of standard test pieces (OPEN, SHORTT, and LOAD). Load match error and transmission tracking error require external through-line cables (THRU). Therefore, when calibrating a multi-port vector network analyzer, a minimum set of OPEN, SHORTT, LOAD, and THRU standards is required. Currently, through-calibration between any ports of a vector network analyzer is performed by interpolating the electronic calibration components. This calibration method often ignores the differences between the individual ports, which can also cause measurement errors. Summary of the Invention

[0003] The main technical problem solved by this application is how to use electronic calibration components to calibrate multiple external ports of a vector network analyzer.

[0004] According to a first aspect, an embodiment provides a four-port electronic calibration device for calibrating a vector network analyzer, the four-port electronic calibration device comprising a housing; four interfaces provided on the housing; four load calibration units, a control processing unit, a switch connection unit, and a data communication unit provided within the housing;

[0005] The interface is at least used to connect to the calibrated port of the vector network analyzer when the vector network analyzer is calibrated;

[0006] Each of the load calibration units is connected to one of the interfaces, and the load calibration unit is used to perform load calibration on the calibrated port;

[0007] The control processing unit is connected to the load calibration unit, the switch connection unit, and the data communication unit, respectively, and is configured to output corresponding control instructions in response to a calibrated port and a calibration mode specified by a user; wherein the calibration mode includes a load calibration mode and a through calibration mode;

[0008] The switch connection unit is connected to each of the interfaces respectively; the switch connection unit includes a switch matrix composed of at least six switches, and is used to control the corresponding switches to switch in response to the control instruction. When the control instruction is a first instruction to perform load calibration on the calibrated port specified by the user, the interface connected to the calibrated port specified by the user is connected to the load calibration unit corresponding to the interface, so as to perform load calibration on the calibrated port specified by the user; when the control instruction is a second instruction to perform through calibration on two calibrated ports specified by the user, the two interfaces connected to the two calibrated ports specified by the user are connected, so as to perform through calibration on the two calibrated ports specified by the user;

[0009] The data communication unit is used to be electrically connected to the vector network analyzer being calibrated. The data communication unit is also electrically connected to the control processing unit and is used to transmit data between the vector network analyzer being calibrated and the control processing unit.

[0010] In one embodiment, the four-port electronic calibration device further includes a storage unit, and the control processing unit stores the calculated vector characteristic parameters of the designated port in the storage unit.

[0011] In one embodiment, the four-port electronic calibration device further includes an attenuator, and the attenuator is configured to be connected in series to any two paths connected by the interfaces through the switch connection unit.

[0012] In one embodiment, the attenuation of the attenuator is 5dB, 10dB, 20dB or 30dB.

[0013] In one embodiment, the data communication unit is a USB interface, and when the USB interface is electrically connected to the vector network analyzer to be calibrated, it also provides working power for the four-port electronic calibration device.

[0014] In one embodiment, the switch of the switch connection unit is a radio frequency switch; and the control processing unit is a single-chip microcomputer.

[0015] In one embodiment, the four-port electronic calibration device further includes a temperature control unit for adjusting the operating temperature of the load calibration unit to maintain the operating temperature within a preset temperature threshold range.

[0016] In one embodiment, the temperature control unit includes a temperature sensor and a heating circuit; the temperature sensor is used to monitor the temperature, and the heating circuit is used to increase the temperature.

[0017] In one embodiment, the four-port electronic calibration device further includes a radio frequency switch circuit board, and the four load calibration units, the switch connection unit, the temperature sensor and the heating circuit are arranged on the radio frequency switch circuit board; the heating circuit includes a heating resistor.

[0018] In one embodiment, the load calibration unit includes at least one of a test SHORT circuit, a test OPEN circuit and a test LOAD circuit; the load calibration mode is used to connect the test SHORT circuit, the test OPEN circuit and / or the test LOAD circuit to the interface to perform load calibration on the calibrated port.

[0019] According to the four-port electronic calibration device of the above embodiment, when calibrating multiple external ports of a vector network analyzer, each external port of the vector network analyzer can be checked in a time-sharing asynchronous manner, and the number of external ports of the vector network analyzer can also be expanded. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a structural block diagram of an electronic calibration component in an embodiment;

[0021] Figure 2 This is a schematic diagram of the structural connection of a load calibration unit in one embodiment;

[0022] Figure 3 1 is a flow chart of a port calibration method according to an embodiment;

[0023] Figure 4 This is a schematic diagram of the structural connection of a four-port electronic calibration device in one embodiment;

[0024] Figure 5 A schematic diagram of the structural connection of a switch connection unit in an embodiment;

[0025] Figure 6 is a circuit connection diagram of a switch connection unit in one embodiment;

[0026] Figure 7 A schematic diagram of the arrangement of electronic components of a radio frequency switch circuit board in one embodiment. DETAILED DESCRIPTION

[0027] The present application is further described in detail below by means of specific embodiments in conjunction with the accompanying drawings. Similar elements in different embodiments are numbered with associated similar elements. In the following embodiments, many detailed descriptions are provided to enable the present application to be better understood. However, those skilled in the art will readily appreciate that some of the features may be omitted in different circumstances, or may be replaced by other elements, materials, or methods. In some cases, some operations related to the present application are not shown or described in the specification. This is to avoid the core portion of the present application being overwhelmed by excessive descriptions. For those skilled in the art, it is not necessary to describe these related operations in detail. They can fully understand the related operations based on the description in the specification and the general technical knowledge in the art.

[0028] In addition, the features, operations, or characteristics described in the specification may be combined in any appropriate manner to form various embodiments. Furthermore, the steps or actions in the method description may be reordered or adjusted in a manner readily apparent to those skilled in the art. Therefore, the various sequences in the specification and drawings are provided solely for the purpose of clearly describing a particular embodiment and are not intended to be mandatory, unless otherwise specified.

[0029] Component numbers used herein, such as "first" and "second," are used solely to distinguish the components being described and do not convey any sequential or technical meaning. References to "connection" and "coupling" herein, unless otherwise specified, include both direct and indirect connections (couplings).

[0030] In an embodiment of the present application, the electronic calibration component includes multiple interfaces. When calibrating multiple external ports of a vector network analyzer, each external port is connected to an interface of the electronic calibration component. By connecting the interface of the electronic calibration component to the load calibration unit, each external port of the vector network analyzer can be calibrated in a time-sharing asynchronous manner. This eliminates the need to manually connect the external ports of the vector network analyzer to the electronic standard component for calibration, thereby improving the calibration efficiency and accuracy of the vector network analyzer. Furthermore, the multiple interfaces of the electronic calibration component can also serve as external ports of the vector network analyzer to expand the number of external ports of the vector network analyzer.

[0031] Example 1:

[0032] Please refer to Figure 1, is a block diagram of the structure of an electronic calibration component in one embodiment. This electronic calibration component 1 is used to calibrate a vector network analyzer 2 and includes at least three interfaces 11, a load calibration unit 12 equal in number to the number of interfaces 11, a control processing unit 13, a switch connection unit 14, and a data communication unit 15. Each interface 11 is used to connect to at least one calibrated port of the vector network analyzer 2 during calibration. The load calibration unit 12 is used to perform load calibration on the calibrated port. The control processing unit 13 is used to output corresponding control instructions in response to a user-specified calibrated port and a calibration mode, which includes a load calibration mode and a through calibration mode. The switch connection unit 14 comprises a switch matrix consisting of at least four switches. The switch connection unit 14 controls the switching of corresponding switches in response to control instructions. When the control instruction is a first instruction to perform load calibration on a user-specified calibrated port, the switch connection unit 14 connects the interface 11 connected to the user-specified calibrated port with the load calibration unit 12 corresponding to the interface 11, thereby performing load calibration on the user-specified calibrated port. When the control instruction is the second instruction for performing through-calibration on the two user-specified ports being calibrated, the two interfaces 11 connected to the two user-specified ports are connected to perform through-calibration on the two user-specified ports. The data communication unit 15 is electrically connected to the vector network analyzer 2 being calibrated. The data communication unit 15 is also electrically connected to the control processing unit 13 for data transmission between the vector network analyzer 2 being calibrated and the control processing unit 13.

[0033] In one embodiment, the load calibration mode not only includes single-port calibration of the external port (the port to be calibrated) of vector network analyzer 2, but also includes single-port calibration of interface 11 of electronic calibration component 1 when it is used as an extended external port (the port to be calibrated) of vector network analyzer 2. In one embodiment, the through calibration mode directly connects the external port of vector network analyzer 2 through the electronic calibration component 1 to perform through calibration on the two directly connected external ports.

[0034] In one embodiment, the control processing unit 13 is further configured to calculate vector characteristic parameters of a specified port in a specified calibration mode, and the data communication unit 15 transmits the vector characteristic parameters of the specified port calculated by the control processing unit 13 to the vector network analyzer 2 being calibrated, so that the vector network analyzer 2 being calibrated can update its own parameters when performing vector characteristic measurements on the network under test.

[0035] In one embodiment, the electronic calibration component 1 further includes a storage unit 16, and the control processing unit 13 stores the calculated vector characteristic parameters of a designated port (used as an external port for vector network analysis) in the storage unit 16. In one embodiment, the switch connection unit 14 includes a switch matrix consisting of at least six switches. The electronic calibration component 1 further includes an attenuator 17, which is configured to be connected in series to a path connecting any two interfaces 11 through the switch connection unit 14. The control processing unit 13 calculates the vector characteristic parameters of the designated port in a through calibration mode with attenuation, compares the vector characteristic parameters in the through calibration mode with attenuation with the vector characteristic parameters in the through calibration mode without attenuation, and determines whether the electronic calibration component has completed calibration of the vector network analyzer 2 based on the comparison result.

[0036] In one embodiment, data communication unit 15 is a USB module. When electrically connected to the vector network analyzer 2 being calibrated, the USB module also provides power to the electronic calibration component 1. In one embodiment, the USB module includes a type connector. In one embodiment, the electronic calibration component 1 also includes a temperature control unit for regulating the operating temperature of the load calibration unit 12 to maintain within a preset temperature threshold range. In one embodiment, the switch of the switch connection unit 14 is a radio frequency switch.

[0037] In one embodiment, different interfaces of the electronic calibration component are also used to connect to the device under test and the vector network analyzer respectively, establishing a direct connection between the external port of the vector network analyzer and the device under test, thereby expanding the number of external ports of the vector network analyzer.

[0038] Please refer to Figure 2 , is a schematic diagram of the structural connection of a load calibration unit in one embodiment. The load calibration unit 12 includes at least one of a test short circuit 21, a test open circuit 22, and a test load circuit 23. The test short circuit 21, the test open circuit 22, and the test load circuit 23 are electrically connected to the interface 11 via a connection switch circuit 24. In the load calibration mode, the connection switch circuit 24 responds to a control electrical signal from the control processing unit 13 to connect one of the test short circuit 21, the test open circuit 22, and the test load circuit 23 to the interface 11, thereby connecting the test short circuit 21, the test open circuit 22, or the test load circuit 23 to the interface to calibrate the interface 11.

[0039] Please refer to Figure 3 , is a flow chart of a port calibration method according to an embodiment, which is used to calibrate a vector network analyzer using an electronic calibration component. The electronic calibration component includes at least three interfaces, a load calibration unit having the same number of interfaces, a control processing unit, and a switch connection unit. The port calibration method includes:

[0040] Step 101: Preset the connection interface and calibration mode.

[0041] The electronic calibration component receives instructions for a calibrated port and a calibration mode specified by a user through a calibration display interface of a vector network analyzer, wherein the calibration mode includes a load calibration mode and a through calibration mode.

[0042] Step 102: Verify the interface and obtain calibration information.

[0043] It is determined whether the interface of the electronic calibration component is connected to the designated calibrated port. If so, calibration information is sent to the control processing unit of the electronic calibration component, wherein the calibration information includes the calibrated port and calibration mode designated by the user.

[0044] Step 103: Output control instructions.

[0045] The control processing unit outputs corresponding control instructions in response to the calibrated port and calibration mode specified by the user.

[0046] Step 104: Execute the control instruction.

[0047] The switch connection unit controls the corresponding switch to switch in response to the control instruction, so that when the control instruction is a first instruction to perform load calibration on the user-specified calibrated port, the interface connected to the user-specified calibrated port is connected to the load calibration unit corresponding to the interface, so as to perform load calibration on the user-specified calibrated port. When the control instruction is a second instruction to perform through-calibration on two user-specified calibrated ports, the two interfaces connected to the two user-specified calibrated ports are connected, so as to perform through-calibration on the two user-specified calibrated ports.

[0048] Step 105: perform verification.

[0049] The first vector characteristic parameter measured by the vector network analyzer through the electronic calibration component on the designated calibrated port in the designated calibration mode is calculated.

[0050] Step 106: Update interface parameters.

[0051] The first vector characteristic parameter is used to update the self-parameter corresponding to the parameter type of the first vector parameter recorded by the vector network analyzer. The self-parameter is a parameter related to the self-characteristics of the vector network analyzer used by the vector network analyzer when measuring the vector characteristics of the network under test.

[0052] In one embodiment, the electronic calibration component further includes an attenuator, which is configured to be connected in series to a path connecting any two interfaces through a switch connection unit. The port calibration method further includes:

[0053] Step 107: Connect an attenuator.

[0054] After completing the calibration of the designated calibrated port in the designated calibration mode, the control processing unit outputs a calibration confirmation instruction. In response to the calibration confirmation instruction, the switch connection unit connects the attenuator in series to the path connecting the two interfaces connected to the two calibrated ports designated by the user.

[0055] Step 108: Obtain through calibration parameters.

[0056] Calculate the vector characteristic parameters of the specified port in the through calibration mode with attenuation, and compare the vector characteristic parameters in the through calibration mode with attenuation with the vector characteristic parameters in the through calibration mode without attenuation. Based on the comparison results, determine whether the electronic calibration component has completed the calibration of the vector network analyzer.

[0057] The electronic calibration component disclosed in this embodiment includes at least three interfaces connected to the calibrated ports of a vector network analyzer, a load calibration unit, a control processing unit, a switch connection unit, and a data communication unit. The load calibration unit performs load calibration on the calibrated port, the control processing unit outputs corresponding control instructions based on the calibrated port and calibration mode specified by the user, the switch connection unit connects the load calibration unit and the interface or any two interfaces in response to the control instructions, and the data communication unit is used for data transmission between the vector network analyzer and the control processing unit. By calibrating the external ports of the network analyzer through the multiple interfaces of the electronic calibration component, not only can the multiple calibration ports of the vector network analyzer be verified in a time-sharing asynchronous manner, but the interfaces of the electronic calibration component can also be used as calibration ports of the vector network analyzer to expand the number of its external ports.

[0058] Example 2:

[0059] Please refer to Figure 4, is a schematic diagram of the structural connection of a four-port electronic calibration device in one embodiment. The four-port electronic calibration device 100 is used as an electronic calibration component to calibrate a vector network analyzer 2. The device includes a housing and four interfaces (a first interface 31, a second interface 32, a third interface 33, and a fourth interface 34) disposed therein, four load calibration units (a first load calibration unit 35, a second load calibration unit 36, a third load calibration unit 37, and a fourth load calibration unit 38), a control processing unit 13, a switch connection unit 14, and a data communication unit 15. In one embodiment, the four load calibration units and the switch connection unit 14 are disposed on an RF switch circuit board 200. Each interface is connected to a load calibration unit: the first interface 31 is connected to the first load calibration unit 35, the second interface 32 is connected to the second load calibration unit 36, the third interface 33 is connected to the third load calibration unit 37, and the fourth interface 34 is connected to the fourth load calibration unit 38. Each interface is at least configured to connect to a calibrated port of the vector network analyzer 2 during calibration. Each load calibration unit is configured to perform load calibration on the calibrated port. The control processing unit 13 is configured to output corresponding control instructions based on a user-specified calibrated port and a calibration mode, which includes a load calibration mode and a through-calibration mode. The switch connection unit 14 controls the corresponding switch in response to the control instruction. When the control instruction is a first instruction to perform load calibration on the user-specified calibrated port, the interface connected to the user-specified calibrated port is connected to the load calibration unit corresponding to the interface, thereby performing load calibration on the user-specified calibrated port. When the control instruction is a second instruction to perform through-calibration on two user-specified calibrated ports, the two interfaces connected to the two user-specified calibrated ports are connected, thereby performing through-calibration on the two user-specified calibrated ports. The data communication unit 15 is configured to electrically connect to the vector network analyzer 2 being calibrated. The data communication unit 15 is also electrically connected to the control processing unit 13 and is configured to transmit data between the vector network analyzer 2 being calibrated and the control processing unit 13. In one embodiment, the four-port electronic calibration device is further configured to connect to the vector network analyzer 2 and the device under test (DUT) via at least two interfaces, respectively, so that the vector network analyzer 2 can monitor the DUT. In one embodiment, the control processing unit 15 is a single-chip microcomputer (MCU). In one embodiment, the data communication unit 15 is a USB interface. In one embodiment, the four-port electronic calibration device obtains operating power via the USB interface.

[0060] Please refer to Figure 5, is a schematic diagram of the structural connection of a switch connection unit in one embodiment. In one embodiment, the switch connection unit is a switch matrix consisting of a first RF switch 41, a second RF switch 42, a third RF switch 43, a fourth RF switch 44, a fifth RF switch 45, and a sixth RF switch 46. The first load calibration unit 35 is connected to the first interface 31, the second load calibration unit 36 is connected to the second interface 32, the third load calibration unit 37 is connected to the third interface 33, and the fourth load calibration unit 38 is connected to the fourth interface 34. In one embodiment, the four-port electronic calibration device further includes an attenuator 17, which is configured to be connected in series to a path connecting any two interfaces through the switch connection unit 14. The control processing unit 13 calculates the vector characteristic parameters of the designated port in the through calibration mode with attenuation, compares the vector characteristic parameters in the through calibration mode with attenuation with the vector characteristic parameters in the through calibration mode without attenuation, and determines whether the electronic calibration device has completed the calibration of the vector network analyzer based on the comparison result.

[0061] In one embodiment, the first RF switch 41 is connected to the first interface 31, the fifth RF switch 45, the sixth RF switch 46, and the third RF switch 43, respectively. The first RF switch 41 is used to connect or disconnect the third RF switch 43 with the fifth RF switch 45, the sixth RF switch 46, and the first interface 31, respectively. The second RF switch 42 is connected to the third interface 33, the fourth RF switch 44, the fifth RF switch 45, and the sixth RF switch 46, respectively. The second RF switch 42 is used to connect or disconnect the fourth RF switch 44 with the third interface 33, the fifth RF switch 45, and the sixth RF switch 46. The third RF switch 43 is connected to the first RF switch 41 and the fourth RF switch 44, respectively. The fourth RF switch 44 is connected to the third RF switch 43, the second RF switch 42, and the attenuator 17, respectively. The third RF switch 43 and the fourth RF switch 44 are used to connect the attenuator 17 between the first RF switch 41 and the second RF switch 42, or to electrically isolate the attenuator. The fifth RF switch 45 is connected to the second interface 32, the first RF switch 41, and the second RF switch 42, respectively. The fifth RF switch 45 is used to connect or disconnect the second interface 32 with the first RF switch 41 and the second RF switch 42. The sixth RF switch 46 is connected to the fourth interface 34, the second RF switch 42, and the first RF switch 41, respectively. The sixth RF switch 46 is used to connect or disconnect the fourth interface 34 with the second RF switch 42 and the first RF switch 41.

[0062] Please refer to Figure 6, is a circuit connection diagram of a switch connection unit in one embodiment. In one embodiment, the first RF switch 41 and the second RF switch 42 are single-pole, multi-throw (SP4T) RF switches, each including one moving terminal and three fixed terminal connections. The third RF switch 43, the fourth RF switch 44, the fifth RF switch 45, and the sixth RF switch 46 are single-pole, double-throw (SPDT) RF switches, each including one moving terminal and two fixed terminal connections. An SP4T is a one-to-four switch, comprising a common port (moving terminal connection) and four conducting ports (fixed terminal connection). The common port can conduct electricity with any of the conducting ports, but the four conducting ports cannot conduct electricity with each other. An SPDT is a one-to-two switch, comprising a common port (moving terminal connection) and two conducting ports (fixed terminal connection). The common port can conduct electricity with any of the conducting ports, but the two conducting ports cannot conduct electricity with each other.

[0063] The common port of the first RF switch 41 is connected to the common port of the third RF switch 43. The three conductive ports of the first RF switch 41 are respectively connected to the first interface, one conductive port of the fifth RF switch 45, and one conductive port of the sixth RF switch 46. The common port of the second RF switch 42 is connected to the common port of the fourth RF switch 44. The three conductive ports of the second RF switch 42 are respectively connected to the third interface, one conductive port of the fifth RF switch 45, and one conductive port of the sixth RF switch 46. One conductive port of the third RF switch 43 is connected to one conductive port of the fourth RF switch 44. The common port of the fifth RF switch 45 is connected to the second interface. The two conductive ports of the fifth RF switch 45 are respectively connected to one conductive port of the first RF switch 41 and one conductive port of the second RF switch 42. The common port of the sixth RF switch 46 is connected to the fourth interface. The two conductive ports of the sixth RF switch 46 are respectively connected to one conductive port of the first RF switch 41 and one conductive port of the second RF switch 42.

[0064] In one embodiment, the attenuator 17 (ATT) is connected to a fixed terminal of the third RF switch 43 and a fixed terminal of the fourth RF switch 44. In one embodiment, the attenuation of the attenuator 17 is 5 dB, 10 dB, 20 dB, or 30 dB.

[0065] like Figure 2As shown, the first load calibration unit, the second load calibration unit, the third load calibration unit and the fourth load calibration unit respectively include a connection switch circuit 24 and a test SHORT circuit 21, a test OPEN circuit 22 and a test LOAD circuit 23. The test SHORT circuit 21, the test OPEN circuit 22 and the test LOAD circuit 23 are respectively connected to the connection switch circuit 24. Among them, OPEN means that the RF microstrip line is directly open-circuited (test OPEN circuit), SHORT (test SHORT circuit) means that the RF microstrip line is directly short-circuited to ground, and LOAD (test LOAD circuit) is composed of a 50Ω load. In one embodiment, as Figure 6 As shown, the connection switch circuit 24 is a single-pole, multi-throw (SP4T) RF switch, comprising a moving terminal and four fixed terminals. The moving terminal of the SP4T RF switch of the switch circuit 24 is connected to a port of the four-port electronic calibration device, while the four fixed terminals are respectively connected to the test short circuit circuit 21, the test open circuit 22, the test load circuit 23, and the switch connection unit. In one embodiment, the test load circuit is a 50Ω load. In one embodiment, the test short circuit is a RF microstrip line directly short-circuited to ground. In one embodiment, the test open circuit RF microstrip line is directly open-circuited.

[0066] In one embodiment, the four-port electronic calibration device can realize the connection of a test SHORT circuit, a test OPEN circuit, or a test LOAD circuit for any interface connected to a vector network analyzer, so as to realize pre-test calibration of the vector network analyzer. The four-port electronic calibration device can also realize physical direct connection of any two interfaces, so that the vector network analyzer can not only perform a separate calibration on the interface to be tested (external interface), but also realize direct connection calibration of two interfaces to be tested. In addition, the interface of the four-port electronic calibration device can also be used for the external interface of the vector network analyzer to expand the number of external interfaces of the vector network analyzer. In one embodiment, at least two interfaces of the four-port electronic calibration device are respectively connected to the external interface of the vector network analyzer and the device to be tested, so as to realize free conversion between calibration and measurement while ensuring that the physical connection method does not change. In one embodiment, the attenuator with a preset attenuation amount can realize free loading and isolation according to the test requirements by setting the conduction of the third radio frequency switch and the fourth radio frequency switch.

[0067] like Figure 4 As shown, in one embodiment, the four-port electronic calibration device further includes a temperature control unit 18 connected to the control processing unit 13. The temperature control unit 18 includes a heating circuit and a temperature sensor for maintaining a stable operating temperature of the four load calibration units in the four-port electronic calibration device.

[0068] In one embodiment, the four-port electronic calibration device further includes a storage unit connected to the control processing unit 10, and the parameter storage unit is used to store electrical parameter data related to the testing and calibration of the vector network analyzer 2, wherein the electrical parameter data includes S parameters and attenuation parameter data of OPEN calibration, SHORTT calibration, LOAD calibration and / or THRU calibration of each interface.

[0069] The four-port electronic calibration device disclosed in this embodiment is used to calibrate the external connection ports of a vector network analyzer, and includes a housing, four interfaces, four load calibration units, a control processing unit, a switch connection unit, and a data communication unit. Each interface is used to connect at least to the calibrated port of the vector network analyzer. Each interface is connected to a load calibration unit for performing load calibration on the calibrated port. The control processing unit is used to output corresponding control instructions in response to the calibrated port and calibration mode specified by the user. The switch connection unit performs load calibration or through-calibration on the calibrated port specified by the user in response to the control instruction. The data communication unit is used to transmit data between the vector network analyzer and the control processing unit. By calibrating the external ports of the network analyzer through the multiple interfaces of the electronic calibration component, not only can the multiple calibration ports of the vector network analyzer be calibrated in a time-sharing asynchronous manner, but the interfaces of the electronic calibration component can also be used as calibration ports of the vector network analyzer to expand the number of its external ports. Furthermore, when used as an external port for expansion of a vector network analyzer, since there is no plugging and unplugging operation during the calibration and testing process, the physical connection method between the test interface of the vector network analyzer and the device under test will not change, thereby greatly reducing the calibration error of the vector network analyzer caused by the difference when plugging and unplugging the port.

[0070] Example 3:

[0071] Please refer to Figure 7 , is a schematic diagram of the electronic components of an RF switch circuit board in one embodiment. The RF switch circuit board 200 is provided with a control and power supply connection socket 50, at least one temperature sensor 51, multiple heating circuits 52, an attenuator 17, four load calibration units, and the switch connection unit described in Example 2. The control and power supply connection socket 50 is used to connect to the control processing unit of the four-port electronic calibration device via a connecting cable. The four load calibration units are arranged axially symmetrically on the RF switch circuit board 200 and are electrically connected to the interface of the four-port electronic calibration device via microstrip lines.

[0072] In one embodiment, the heating circuit 52 is heated by a heating resistor. In one embodiment, an even number of temperature sensors 51 are provided on the RF switch circuit board 200, symmetrically arranged on the RF switch circuit board 200. In one embodiment, the heating resistors are 619Ω 0402 resistors, with a supply voltage of 5V and a heating power of 1.7W. When the switch connection unit is powered by the USB interface of a vector network analyzer, its power supply capacity is 5V and 500mA, totaling 2.5W (a common USB interface). The remaining 0.8W is consumed by power-consuming components such as the control processing unit (MCU) and the switch circuit. The MCU controls the heating resistor's supply voltage to be shut off. The MCU reads the temperature at any time using the temperature sensor 51 and sets a temperature range (e.g., 33°C to 35°C) as the operating temperature for the electronic calibration component (for testing the short circuit, open circuit, and load circuit). Within this temperature range, the electronic calibration component achieves the highest accuracy. When the MCU reads that the operating temperature of the switch connection unit is less than 33°C, heating is enabled. When the MCU reads that the operating temperature of the switch connection unit is between 33°C and 35°C, heating is stopped.

[0073] In one embodiment, the heating circuit 52 includes a plurality of heating resistors that are evenly arranged on the RF switch circuit board to achieve synchronous heating of the entire RF switch circuit board, making the heating effect more balanced and achieving a temperature stable state in the shortest time.

[0074] In one embodiment, the MCU indicates the temperature through red and green indicator lights. When the temperature of the RF switch circuit board is read to be less than 33°C, the MCU controls the red light to light up and the green light to turn off; when the temperature of the RF switch circuit board is read to be between 33°C and 35°C, the green light is turned on and the red light is turned off.

[0075] In one embodiment, a DC blocking capacitor 53 is provided on the microstrip line connecting the load calibration unit and the interface to protect the radio frequency chip.

[0076] In one embodiment, the open circuit test circuit in the load calibration unit implements an open load by leaving the pin floating. In one embodiment, the load circuit test circuit in the load calibration unit connects two 0201 packaged 100Ω resistors in parallel to form a 50Ω load at the end of the RF trace. The short circuit test circuit implements a short load by drilling a GND via from the pin to ground.

[0077] In one embodiment, the six switches of the switch connection unit are electrically connected via microstrip lines. In one embodiment, the control processing unit of the four-port electronic calibration device is a single-chip microcomputer (MCU). In one embodiment, the data communication unit 11 of the four-port electronic calibration device is a USB interface.

[0078] In one embodiment, the attenuator is respectively connected to the third RF switch 43 and the fourth RF switch 44 of the switch connection unit. In one embodiment, the attenuation of the attenuator is 5dB, 10dB, 20dB or 30dB. In one embodiment, the fixed attenuator is a verification component, which is similar to the straight-through state between the ports, except that the third RF switch 43 and the fourth RF switch 44 simultaneously turn on the attenuator path, and any two interfaces in the four-port electronic calibration device can directly switch to the path that turns on the attenuator. In one embodiment, when writing the calibration component parameter data, the S21 parameter of the attenuator path is also written into the memory of the storage unit. After calibrating the network using the electronic calibration component, the S21 parameter of the attenuation path is remeasured and compared with the S21 parameter stored in the memory. This can be used to evaluate whether the four-port electronic calibration device has completed the calibration of the network analyzer and to determine whether the calibration is correct.

[0079] In one embodiment, the switch connection unit includes a first RF switch circuit 41 , a second RF switch circuit 42 , a third RF switch 43 , a fourth RF switch 44 , a fifth RF switch 45 and a sixth RF switch 46 electrically connected via microstrip lines.

[0080] In one embodiment, the housing 100 is a shielding shell. In one embodiment, the attenuation circuit 17 is disposed in the middle of the RF switch circuit board 200 .

[0081] The radio frequency switch circuit board disclosed in this embodiment is provided with a control and power supply connection socket, a temperature sensor, a heating circuit, an attenuator, four load calibration units and a switch connection unit. The control and power supply connection socket is used to connect to the control processing unit of the four-port electronic calibration device through a connecting cable. The temperature sensor is used to monitor the operating temperature of the load calibration unit. The heating circuit is used to heat the radio frequency switch circuit board. The four load calibration units are respectively electrically connected to the four interfaces of the four-port electronic calibration device, and each interface of the four-port electronic calibration device is used at least to connect to the calibrated port of the vector network analyzer when the vector network analyzer is calibrated. The switch connection unit is connected to each interface and is used to switch the connection between the two interfaces respectively connected to the two calibrated ports. Since the temperature sensor and the heating circuit are provided on the radio frequency switch circuit board, the operating temperature range of the load calibration unit can be maintained, thereby improving the measurement accuracy of the vector network analyzer.

[0082] The above specific examples are used to illustrate the present application, which is only used to help understand the present application and is not intended to limit the present application. For those skilled in the art of the present application, based on the concept of the present application, they can also make some simple deductions, modifications or substitutions.

Claims

1. A four-port electronic calibration device for calibrating a vector network analyzer, characterized in that: The four-port electronic calibration device includes a housing; four interfaces are provided on the housing; four load calibration units, a control processing unit, a switch connection unit and a data communication unit are provided in the housing; The interface is at least used to connect to the calibrated port of the vector network analyzer when the vector network analyzer is calibrated; Each of the load calibration units is connected to one of the interfaces, and the load calibration unit is used to perform load calibration on the calibrated port; The control processing unit is connected to the load calibration unit, the switch connection unit, and the data communication unit, respectively, and is configured to output corresponding control instructions in response to a calibrated port and a calibration mode specified by a user; wherein the calibration mode includes a load calibration mode and a through calibration mode; The switch connection unit is connected to each of the interfaces respectively; the switch connection unit includes a switch matrix composed of at least six switches, and is used to control the corresponding switches to switch in response to the control instruction. When the control instruction is a first instruction to perform load calibration on the calibrated port specified by the user, the interface connected to the calibrated port specified by the user is connected to the load calibration unit corresponding to the interface, so as to perform load calibration on the calibrated port specified by the user; when the control instruction is a second instruction to perform through calibration on two calibrated ports specified by the user, the two interfaces connected to the two calibrated ports specified by the user are connected, so as to perform through calibration on the two calibrated ports specified by the user; The data communication unit is used to be electrically connected to the vector network analyzer being calibrated. The data communication unit is also electrically connected to the control processing unit and is used to transmit data between the vector network analyzer being calibrated and the control processing unit.

2. The four-port electronic calibration device according to claim 1, wherein: A storage unit is also included, and the control processing unit stores the calculated vector characteristic parameters of the designated port in the storage unit.

3. The four-port electronic calibration device according to claim 1, wherein: It also includes an attenuator, which is configured to be connected in series to a path connecting any two of the interfaces through the switch connection unit.

4. The four-port electronic calibration device according to claim 3, wherein: The attenuation of the attenuator is 5dB, 10dB, 20dB or 30dB.

5. The four-port electronic calibration device according to claim 1, wherein: The data communication unit is a USB interface. When the USB interface is electrically connected to the vector network analyzer to be calibrated, it also provides working power for the four-port electronic calibration device.

6. The four-port electronic calibration device according to claim 1, wherein: The switch of the switch connection unit is a radio frequency switch; and the control processing unit is a single-chip microcomputer.

7. The four-port electronic calibration device according to claim 1, wherein: It also includes a temperature control unit for adjusting the operating temperature of the load calibration unit to maintain it within a preset temperature threshold range.

8. The four-port electronic calibration device according to claim 7, wherein: The temperature control unit includes a temperature sensor and a heating circuit; the temperature sensor is used to monitor the temperature, and the heating circuit is used to increase the temperature.

9. The four-port electronic calibration device according to claim 8, wherein: It also includes a radio frequency switch circuit board, on which the four load calibration units, the switch connection unit, the temperature sensor and the heating circuit are arranged; and the heating circuit includes a heating resistor.

10. The four-port electronic calibration device according to any one of claims 1 to 9, characterized in that: The load calibration unit includes at least one of a test SHORT circuit, a test OPEN circuit, and a test LOAD circuit; The load calibration mode is used to connect the test SHORT circuit, the test OPEN circuit, or / the test LOAD circuit to the interface to perform load calibration on the calibrated port.

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