A calibration system and calibration method for an FDD transceiver

Abstract

The application provides a kind of calibration system and calibration method of FDD transceiver, system includes tight field module, for the plane wave test environment of the transmitting array surface and receiving array surface of FDD unit to be measured;Switching matrix is connected with the test interface of FDD unit to be measured, and the time multiplexing of multiple calibration paths is realized by switching switch state;Measurement and control module includes instrument group and host computer, instrument group is connected with FDD unit to be measured by switching matrix, for executing calibration test and gain calibration, host computer is connected with tight field module, switching matrix and instrument group respectively, for coordinating and controlling the automatic execution of the calibration test of transmitting array surface, the calibration test of receiving array surface and gain calibration.Tight field module provides plane wave test environment for transmitting array surface and receiving array surface, combined with the time multiplexing of multiple calibration paths of switching matrix, realize the unified calibration of transmitting array surface and receiving array surface of FDD transceiver in single set of OTA calibration device.

Description

Technical Field

[0001] This invention relates to the field of wireless communication, and more particularly to a calibration system and calibration method for an FDD transceiver. Background Technology

[0002] In existing satellite and millimeter-wave communication systems, transceivers generally use over-the-air (OTA) calibration to perform amplitude and phase consistency calibration and gain calibration on the transmitting and receiving arrays. Since these systems typically operate in a frequency division duplex (FDD) architecture with separate transmitting and receiving bands, such as the Ku band (13.7–14.5 GHz transmitting band and 10.7–12.7 GHz receiving band) and Ka band (27.5–31 GHz transmitting band and 17.7–21.2 GHz receiving band) commonly used in satellite communications, there is a significant frequency gap between the transmitting and receiving bands, making it impossible to share the same RF link for measurement.

[0003] Therefore, existing technologies typically require separate OTA calibration devices for the transmitting and receiving arrays, employing two compact field systems and corresponding instruments to test the transceiver link separately. This significantly increases the hardware cost of the calibration system. Furthermore, the independent calibration processes for the transmitting and receiving arrays make unified scheduling difficult, further complicating the calibration operation and reducing overall calibration efficiency. Therefore, it is necessary to propose a device and method capable of simultaneously calibrating both the transmitting and receiving arrays of an FDD transceiver in a single compact field environment to address the aforementioned problems. Summary of the Invention

[0004] The purpose of this invention is to solve the problems of high cost and high calibration complexity caused by the need to build two independent OTA calibration devices due to the separation of the transmit and receive frequency bands in the existing FDD transceiver calibration technology.

[0005] A first aspect of the present invention provides a calibration system for an FDD transceiver, comprising: Compact field module, which is used to provide a plane wave test environment for the transmitting and receiving arrays of the FDD unit under test; A switch matrix is ​​connected to the test interface of the FDD unit under test, and time-division multiplexing of multiple calibration paths is achieved by switching the switch states; The measurement and control module includes an instrument group and a host computer. The instrument group is connected to the FDD unit under test through the switch matrix and is used to perform calibration tests and gain calibration. The host computer is communicatively connected to the compact field module, the switch matrix and the instrument group respectively, and is used to coordinate and control the automated execution of calibration tests of the transmitting array, calibration tests of the receiving array and gain calibration.

[0006] Furthermore, the compaction field module includes a displacement mechanism, which drives the FDD unit under test to move independently in two mutually perpendicular directions to achieve alignment switching between the transmitting array and the receiving array.

[0007] Furthermore, the compacted field module includes a feed source and a reflective surface; The reflective surface is used to collimate the radiation signal from the feed source into a plane wave to illuminate the receiving array, or to converge the radiation signals from each element of the transmitting array to the feed source; the feed source is connected to the instrument group through the switching matrix.

[0008] Furthermore, the instrument group includes a vector network analyzer, a signal generator, and a spectrum analyzer; The vector network analyzer is used for amplitude-phase consistency calibration and pattern testing; the signal source and the spectrum analyzer are used together for absolute gain calibration.

[0009] Furthermore, the switch matrix includes a first switch, a second switch, a third switch, a fourth switch, a fifth switch, a sixth switch, and a seventh switch; One end of the first switch is connected to the FDD unit under test, and the other end is connected to the fourth switch through the vector network analyzer; the other end of the fourth switch is connected to the feed source through the third switch and the second switch respectively; the fourth switch is also connected to the fifth switch; the fifth switch is connected to the signal source through the sixth switch and to the spectrum analyzer through the seventh switch respectively.

[0010] Furthermore, the FDD unit under test includes an RF transmit test port, an RF receive test port, an IF transmit test port, and an IF receive test port. The IF receive test port is connected to the seventh switch, the IF transmit test port is connected to the sixth switch, and both the RF transmit test port and the RF receive test port are connected to the first switch.

[0011] Furthermore, a first channel is provided between the first switch and the radio frequency transmitting test port, and a second channel is provided between the first switch and the radio frequency receiving test port. A first amplifier is provided in the first channel, and a second amplifier is provided in the second channel. A third channel and a fourth channel are provided between the second switch and the third switch, and a third amplifier is provided in the third channel.

[0012] A second aspect of the present invention provides a calibration method for an FDD transceiver, employing any of the calibration systems described above for an FDD transceiver, comprising: The displacement mechanism in the compressed field module is controlled to move the FDD unit under test to the target alignment position, and the switch matrix is ​​controlled to switch to the corresponding calibration path to perform the calibration of the transmitting array, the absolute gain calibration of the transmitting array, the calibration of the receiving array, and the absolute gain calibration of the receiving array in sequence.

[0013] Furthermore, when performing calibration tests on the launch array, the first switch is switched to the first channel; The excitation signal of the vector network analyzer is input to the compact field module through the first switch and the first channel. The second switch and the third switch switch the signal to the third channel. The signal processed by the compact field module is returned to the vector network analyzer through the third channel, the third switch and the fourth switch for single-channel amplitude and phase calibration. Each array element is activated sequentially to obtain the array amplitude and phase, and array calibration is completed. The second switch and the third switch are switched to the fourth channel. The signal output by the compact field module is returned to the vector network analyzer via the fourth channel, the third switch and the fourth switch for transmission pattern testing.

[0014] Furthermore, when performing absolute gain calibration of the transmission array, the second switch and the third switch are switched to the fourth channel; The signal source inputs a known power excitation signal to the compact field module via the sixth switch. After processing, the signal is transmitted sequentially to the spectrum analyzer via the fourth channel, the third switch, the fourth switch, the fifth switch, and the seventh switch. The spectrum analyzer calculates the absolute gain of the transmitting array based on the link loss.

[0015] Furthermore, when performing calibration tests on the receiving array, the first switch is switched to the second channel; The excitation signal of the vector network analyzer is sequentially input to the compact field module via the fourth switch, the third switch, the fourth channel, and the second switch. The processed signal is returned to the vector network analyzer via the radio frequency receiver measurement port, the second channel, and the first switch for single-channel amplitude and phase calibration. The amplitude and phase of each array element are acquired sequentially to complete the array calibration; After the entire antenna array is activated, a receiver pattern test is performed.

[0016] Furthermore, when performing absolute gain calibration of the receiving array, the second switch and the third switch are switched to the fourth channel; The signal source sequentially inputs a known power excitation signal to the compact field module via the sixth switch, the fifth switch, the fourth switch, the third switch, the fourth channel, and the second switch. After processing, the signal is transmitted sequentially to the spectrum analyzer via the intermediate frequency receiving test port and the seventh switch. The spectrum analyzer calculates the absolute gain of the receiving array based on the link loss.

[0017] Compared to existing technologies, this invention offers at least the following advantages: By providing a plane wave testing environment for both the transmitting and receiving arrays through a compact field module, and combining this with the time-division multiplexing of multiple calibration paths using a switching matrix, unified calibration of the FDD transceiver's transmitting and receiving arrays is achieved within a single OTA calibration device. This improves upon the hardware redundancy of existing technologies that require the construction of two independent calibration systems, and reduces the construction cost of the calibration system. Simultaneously, the coordinated control of the compact field module, switching matrix, and instrument group by the host computer automates the entire process of amplitude and phase calibration and gain calibration, effectively reducing the complexity of manual operation and improving calibration efficiency. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the module of the calibration system for an FDD transceiver in one embodiment of the present invention; Figure 2 This is a schematic diagram of the internal structure of the compression field module in one embodiment of the present invention; Figure 3 This is a detailed schematic diagram of the switch matrix in one embodiment of the present invention; Figure 4 This is a link diagram during the calibration of the transmission array in one embodiment of the present invention; Figure 5 This is a link diagram for calculating the absolute gain calibration of the transmitting array in one embodiment of the present invention; Figure 6 This is a link diagram during receiver array calibration in one embodiment of the present invention; Figure 7 This is a link diagram for calculating the absolute gain calibration of the receiving array in one embodiment of the present invention; Among them, 1-compressed field module; 11-FDD unit under test; 12-feed source; 13-reflecting surface; 141-moving motor; 142-turntable; 2-switch matrix; 21-first amplifier; 22-second amplifier; 23-third amplifier; 31-first channel; 32-second channel; 33-third channel; 34-fourth channel. Detailed Implementation

[0020] The present invention will now be described in more detail with reference to the accompanying drawings, which illustrate preferred embodiments of the invention. It should be understood that those skilled in the art can modify the invention described herein while still achieving its advantageous effects. Therefore, the following description should be understood as being broadly known to those skilled in the art and is not intended to limit the invention.

[0021] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0022] The invention is described more specifically by way of example in the following paragraphs with reference to the accompanying drawings. The advantages and features of the invention will become clearer from the following description. It should be noted that the drawings are in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the invention.

[0023] Example 1 This embodiment provides a calibration system for an FDD transceiver. Please refer to [link / reference]. Figures 1-3 ,include: The compacted field module 1 includes the FDD unit under test 11, which is used to provide a plane wave test environment for the transmitting and receiving arrays of the FDD unit under test 11.

[0024] Switch matrix 2 is connected to the test interface of the FDD unit under test 11, and time-division multiplexing of multiple calibration paths is achieved by switching the switch states.

[0025] The measurement and control module includes an instrument group and a host computer. The instrument group is connected to the FDD unit under test 11 through the switch matrix 2 and is used to perform calibration tests and gain calibration. The host computer is communicatively connected to the compact field module 1, the switch matrix 2 and the instrument group, and is used to coordinate and control the fully automated execution of the calibration test of the transmitting array, the calibration test of the receiving array and the gain calibration.

[0026] Please refer to Figure 1 The system mainly consists of three parts: a compacted field module 1, a switch matrix 2, and a measurement and control module. The compacted field module 1 collimates the signal radiated by the feed 12 into a plane wave through a reflector 13, providing a plane wave test environment that meets far-field conditions for the transmitting and receiving arrays of the FDD unit under test 11. The same compacted field module 1 can be used for the calibration and testing of both the transmitting and receiving arrays without the need for a separate calibration anechoic chamber. The switch matrix 2 is connected to each test interface of the FDD unit under test 11. By controlling the on / off state of the internal switches, it enables flexible switching and time-division multiplexing of the transmitting calibration path, receiving calibration path, and gain calibration path on a single hardware platform.

[0027] The measurement and control module consists of an instrument group and a host computer. The instrument group includes a vector network analyzer, a signal generator, and a spectrum analyzer, which are responsible for amplitude and phase consistency calibration, radiation pattern testing, and absolute gain calibration measurement, respectively. They are connected to the test interface of the FDD unit under test 11 through switch matrix 2. The host computer includes a switch and a control module. As the unified control center of the system, the host computer establishes communication connections with the compact field module 1, switch matrix 2, and the instrument group. According to the preset calibration process, it coordinates and controls the working status of each sub-module, thereby realizing the fully automated execution of the transmitting array calibration, receiving array calibration, and gain calibration process, effectively reducing manual intervention.

[0028] Furthermore, the compaction field module 1 includes a displacement mechanism, which drives the FDD unit under test 11 to move independently in two mutually perpendicular directions to achieve alignment switching between the transmitting array and the receiving array.

[0029] Since the transmitting and receiving arrays of the FDD unit under test 11 are spatially independent, when calibrating and testing the transmitting and receiving arrays separately, it is necessary to precisely align the corresponding arrays with the center of the quiet zone of the compressed field to ensure the consistency of the test environment and measurement accuracy. To this end, a displacement mechanism supports the independent movement of the FDD unit under test 11 in two mutually perpendicular directions. By adjusting the position, the transmitting or receiving array is sequentially aligned with the quiet zone of the reflector 13, thereby completing the rapid switching and alignment between the transmitting and receiving arrays without disassembling or reinstalling the unit under test, further improving the continuity and automation of the calibration process. In this embodiment, the displacement mechanism is controlled by a host computer sending control commands through a switch to achieve automated control of the displacement mechanism's movement process, thus completing the switching and alignment of the transmitting and receiving arrays without manual intervention. For details, please refer to... Figure 2 The displacement mechanism includes a moving motor 141 and a turntable 142. The moving motor 141 drives the FDD unit 11 under test to move independently in the mutually perpendicular X and Y axis directions to achieve precise alignment of the array. The turntable 142 supports the FDD unit 11 under test and works with the moving motor 141 to adjust the orientation of the FDD unit 11 under test, thus achieving the switching alignment of the transmitting and receiving arrays.

[0030] Furthermore, the compacted field module 1 includes a feed source 12 and a reflective surface 13.

[0031] The reflector 13 is used to collimate the radiation signal of the feed source 12 into a plane wave to illuminate the receiving array of the FDD unit under test 11, or to converge the radiation signals of each element of the transmitting array of the FDD unit under test 11 to the feed source 12; the feed source 12 is connected to the instrument group through the switch matrix 2.

[0032] Specifically, in this embodiment, the FDD unit under test 11 includes four interfaces: RF transmit test port (RF_TX), RF receive test port (RF_RX), IF transmit test port (IF_TX), and IF receive test port (IF_RX). Their functions are as follows: RF_TX is used for calibrating the transmit multi-antenna array and radiation pattern test, RF_RX is used for calibrating the receive multi-antenna array and radiation pattern test, and these two parts are directly connected to the vector network calibrator. IF_TX is used for calibrating the absolute gain of the transmit link (the transmit link includes the frequency conversion part), and IF_RX is used for calibrating the absolute gain of the receive link (the receive link includes the frequency conversion part).

[0033] The feed 12 operates in a frequency band covering both the transmit and receive frequencies of the FDD unit under test (FDD) 11, enabling the same compact hardware setup to meet calibration and testing requirements for both transmit and receive frequencies. The feed 12 is connected to the instrument group via a switch matrix 2, allowing the instrument group to flexibly switch the signal transmission or reception path according to the needs of the current calibration task. This seamlessly integrates the feed 12 into various test procedures, including transmit calibration, receive calibration, and gain calibration. In this embodiment, the feed 12 is a broadband feed horn, covering the entire transmit and receive frequency bands.

[0034] The reflector 13 is the core component of the compact field module 1. It adopts a high-precision curved surface structure and can collimate or converge the incident signal using the reflection characteristics of electromagnetic waves. In the receiving array calibration scenario, the feed 12 radiates the signal to the reflector 13, which collimates the signal into a high-quality plane wave and illuminates the receiving array of the FDD unit under test 11, simulating far-field incident conditions. In the transmitting array calibration scenario, each element of the transmitting array of the FDD unit under test 11 radiates radio frequency signals in sequence. The reflector 13 converges the radiated signals of each element to the feed 12, which then receives the signals, thereby realizing the measurement of the radiation characteristics of each element one by one.

[0035] Furthermore, the instrument group includes a vector network analyzer, a signal generator, and a spectrum analyzer.

[0036] The vector network analyzer is used for amplitude-phase consistency calibration and radiation pattern testing; the signal source and the spectrum analyzer are used together for absolute gain calibration measurement.

[0037] Specifically, the vector network analyzer has the ability to simultaneously measure signal amplitude and phase. During the amplitude and phase consistency calibration of the transmit and receive arrays, the vector network analyzer acts as both the excitation source and the receiver. By scanning and measuring each array element channel one by one, it obtains the amplitude differences and phase deviations between channels, providing accurate measurement data for subsequent amplitude and phase compensation correction. Furthermore, after completing array calibration, the vector network analyzer is also used for radiation pattern testing of the transmit and receive arrays, providing measurement data for evaluating the beam pointing, gain distribution, and sidelobe characteristics of the antenna array.

[0038] The signal generator and spectrum analyzer work together to perform absolute gain calibration measurements on the transmitting and receiving arrays. In the transmit gain calibration scenario, the signal generator provides a known power excitation signal to the FDD unit under test (FDD) 11. The spectrum analyzer accurately measures the signal power received by the feed 12 after over-the-air transmission, thereby calculating the absolute gain of the transmit channel. In the receive gain calibration scenario, the signal generator radiates a known power standard signal to the receiving array through the feed 12. The spectrum analyzer measures the output signal power of the receiving channel of the FDD unit under test (FDD) 11, thus completing the absolute gain calibration of the receiving channel. These three instruments work together, covering all the measurement capabilities required for FDD transceiver calibration.

[0039] For further details, please refer to... Figure 1 and Figure 3 The switch matrix 2 includes a first switch, a second switch, a third switch, a fourth switch, a fifth switch, a sixth switch, and a seventh switch.

[0040] One end of the first switch is connected to the FDD unit 11 under test, and the other end is connected to the fourth switch through the vector network analyzer; the other end of the fourth switch is connected to the feed source 12 through the third switch and the second switch respectively; the fourth switch is also connected to the fifth switch; the fifth switch is connected to the signal source through the sixth switch and to the spectrum analyzer through the seventh switch respectively.

[0041] Specifically, the switch matrix 2 is composed of multiple switches, and the flexible configuration and time-division multiplexing of the calibration path are achieved through the coordinated switching of each switch. Specifically, one end of the first switch is connected to the RF test interface of the FDD unit under test 11, and the other end is connected to the vector network analyzer. The other end of the vector network analyzer is then connected to the fourth switch, thus forming the main amplitude and phase measurement path between the FDD unit under test 11 and the vector network analyzer. The other end of the fourth switch is connected to the feed source 12 via the third and second switches, respectively. The third and second switches are set in parallel to select different air interface transmission paths according to test needs during amplitude and phase calibration, allowing the feed source 12 to flexibly access the measurement loop of the vector network analyzer.

[0042] Furthermore, the fourth switch is connected to the fifth switch. The fifth switch, acting as the pivot node in the absolute gain calibration path, has one end connected to the signal source via the sixth switch and the other end connected to the spectrum analyzer via the seventh switch. During absolute gain calibration, the signal source and spectrum analyzer can be connected to their respective test paths through the coordinated operation of the fifth, sixth, and seventh switches, enabling precise measurement of the absolute gain of the transmit or receive channel. These switches together form a complete and flexible switch matrix 2, supporting various test scenarios for amplitude and phase calibration and absolute gain calibration on a single hardware platform.

[0043] Furthermore, the FDD unit under test 11 includes an RF transmit test port, an RF receive test port, an IF transmit test port, and an IF receive test port. The IF receive test port is connected to the seventh switch, the IF transmit test port is connected to the sixth switch, and both the RF transmit test port and the RF receive test port are connected to the first switch.

[0044] Specifically, each interface is connected to the corresponding switch in switch matrix 2 according to the signal type and calibration task, thereby achieving calibration test coverage at both the RF and IF levels. The RF transmit and receive test ports are both connected to the first switch. During amplitude and phase consistency calibration of the transmit or receive array, the RF signals from each element channel of the transmit or receive array are connected to the first switch via the corresponding test port, and then the amplitude and phase are measured by a vector network analyzer, achieving accurate acquisition of the amplitude and phase characteristics of each RF channel.

[0045] The intermediate frequency (IF) transmit test port and the IF receive test port correspond to the signal injection and signal measurement paths in the absolute gain calibration scenario, respectively. The IF transmit test port is connected to the sixth switch. During transmit gain calibration, the signal source injects an IF excitation signal of known power into the transmit link of the FDD unit under test 11 via the sixth switch, driving the transmit array to complete air interface radiation. The IF receive test port is connected to the seventh switch. During receive gain calibration, the spectrum analyzer measures the power of the IF signal output from the receive link of the FDD unit under test 11 via the seventh switch, thereby completing the absolute gain calibration of the receive channel. The reasonable division of labor among the above four test interfaces enables the orderly and coordinated execution of RF amplitude and phase calibration and IF gain calibration within the unified switch matrix 2 framework.

[0046] Furthermore, a first channel 31 is provided between the first switch and the radio frequency transmitting test port, and a second channel 32 is provided between the first switch and the radio frequency receiving test port. A first amplifier 21 is provided in the first channel 31, and a second amplifier 22 is provided in the second channel 32.

[0047] A third channel 33 and a fourth channel 34 are provided between the second switch and the third switch, and a third amplifier 23 is provided in the third channel 33.

[0048] In one possible embodiment, please refer to Figure 3The switch matrix has eleven external ports, each connected to a corresponding module in the system according to its function. Port 1 and Port 2 are connected to the RF transmit test port (RF_TX) and RF receive test port (RF_RX) of the FDD unit under test 11, respectively, and are connected to the first switch via the first channel 31 containing the first amplifier 21 and the second channel containing the second amplifier 22, respectively. Port 3 is connected to a test interface of a vector network analyzer. Port 4 is directly connected to the feed source. Port 5 is connected to one end of the third amplifier, and Port 6 is connected to the other end of the third amplifier. Port 7 is connected to another test interface of the vector network analyzer. Port 8 is connected to the intermediate frequency transmit test port (IF_TX) of the FDD unit under test 11. Port 9 is connected to a signal source. Port 10 is connected to the intermediate frequency receive test port (IF_RX) of the FDD unit under test 11. Port 11 is connected to a spectrum analyzer.

[0049] The switch matrix 2 has a dedicated signal conditioning channel on the critical path to meet the differentiated requirements for signal power and quality under different calibration scenarios. Between the first switch and the FDD unit under test 11, a first channel 31 and a second channel 32 are established according to the different functions of the RF transmit and receive test ports. The first channel 31 is located between the first switch and the RF transmit test port, and includes a first amplifier 21 for power compensation of the RF signals output from each element channel of the transmit array. This compensates for path loss during signal transmission through the test port and cables, ensuring that the vector network analyzer can receive signals that meet the measurement dynamic range requirements. The second channel 32 is located between the first switch and the RF receive test port, and includes a second amplifier 22 for power adjustment of the excitation signal injected into the receive link during amplitude and phase calibration of the receive array, ensuring the consistency of test signals for each receive channel.

[0050] In addition, a third channel 33 and a fourth channel 34 are provided between the second and third switches. These two channels are used to handle the signal transmission between the feed 12 and the vector network analyzer. The third channel 33 is equipped with a third amplifier 23, which is used to amplify and compensate the over-the-air transmission signal in specific calibration scenarios to overcome the path attenuation caused by transmission in a confined field space and improve the measurement signal-to-noise ratio. The fourth channel 34 serves as a direct path without an amplifier. The two channels can be flexibly selected by switching according to the actual signal level requirements, thereby taking into account the different signal gain requirements in different test scenarios.

[0051] Example 2 This embodiment provides a calibration method for an FDD transceiver, using the FDD transceiver calibration system described in Embodiment 1. Please refer to [link / reference]. Figure 1 ,include: The displacement mechanism in the compact field module 1 is controlled to move the FDD unit 11 under test to the target alignment position. The switch matrix 2 is controlled to switch to the corresponding calibration path. Through the air interface signal transmission between the compact field module 1 and the FDD unit 11 under test and the wired signal transmission of the switch matrix 2, the calibration test of the transmitting array, the absolute gain calibration of the transmitting array, the calibration test of the receiving array, and the absolute gain calibration of the receiving array are performed in sequence.

[0052] For details, please refer to Figure 4 When the calibration test of the launch array is performed, the first switch is switched to the first channel 31.

[0053] The excitation signal of the vector network analyzer is input to the compact field module 1 via the first switch and the first channel 31. The second switch and the third switch switch the signal to the third channel 33. The signal processed by the compact field module 1 is returned to the vector network analyzer via the third channel 33, the third switch and the fourth switch for single-channel amplitude and phase calibration.

[0054] Each array element is activated sequentially to obtain the array amplitude and phase, thus completing the array calibration.

[0055] The second switch and the third switch are switched to the fourth channel 34. The signal output by the compact field module 1 is returned to the vector network analyzer via the fourth channel 34, the third switch and the fourth switch for transmission pattern testing.

[0056] Please refer to Figure 5 When the absolute gain of the launch array is calibrated, the second switch and the third switch are switched to the fourth channel 34.

[0057] The signal source inputs an excitation signal with known power to the compact field module 1 via the sixth switch. After processing, the signal is transmitted sequentially to the spectrum analyzer via the fourth channel 34, the third switch, the fourth switch, the fifth switch, and the seventh switch. The spectrum analyzer calculates the absolute gain of the transmitting array based on the link loss.

[0058] Please refer to Figure 6 When the receiving array is being calibrated, the first switch is switched to the second channel 32.

[0059] The excitation signal of the vector network analyzer is sequentially input to the compact field module 1 via the fourth switch, the third switch, the fourth channel 34, and the second switch. The processed signal is returned to the vector network analyzer via the radio frequency receiving port, the second channel 32, and the first switch for single-channel amplitude and phase calibration.

[0060] The amplitude and phase of each array element are acquired sequentially to complete the array calibration.

[0061] After the entire antenna array is activated, a receiver pattern test is performed.

[0062] Please refer to Figure 7 When performing absolute gain calibration of the receiving array, the second switch and the third switch are switched to the fourth channel 34.

[0063] The signal source sequentially inputs a known power excitation signal to the compact field module 1 via the sixth switch, the fifth switch, the fourth switch, the third switch, the fourth channel 34, and the second switch. After processing, the signal is transmitted sequentially to the spectrum analyzer via the intermediate frequency receiving test port and the seventh switch. The spectrum analyzer calculates the absolute gain of the receiving array based on the link loss.

[0064] Example 3 This embodiment explains the calibration and testing process and the absolute gain calibration process through specific implementation steps: Please refer to Figure 4 The test of the launch array pattern and the test of the single-channel calibration path are performed according to the following steps, based on the current link calibration method: The switch matrix section retains only the first to fourth switches and only the vector network analyzer function.

[0065] If a single-channel calibration test is to be performed, the transmitting array is first moved to the center of the compact field by a moving motor. The vector network analyzer transmits power, for example, 10dBm, through Port 21. The signal passes through the air interface and feed source, enters the second switch, and is amplified by the third channel 33 (this channel contains an amplifier to improve the signal-to-noise ratio; if the signal-to-noise ratio of the entire link is sufficient, the second and third switches can be omitted). After being amplified, it enters the vector network analyzer's Port 22 through the third and fourth switches to complete the amplitude and phase calibration of a single branch.

[0066] Turn on antennas 0 through N in sequence (N is the size of the antenna array, which varies depending on the product). Repeat the above steps to obtain the amplitude and phase of the entire antenna array, and then complete the array calibration.

[0067] After array calibration is completed, with the entire antenna array activated, the same airflow direction will guide the signal through channel 34 to the vector network analyzer for pattern testing. (With the entire array activated, channel 33 may become saturated.) The above completes the array calibration and radiation pattern test of the launch array.

[0068] Please refer to Figure 5 After completing the above calibration and pattern test, the absolute gain calibration link of the transmission array needs to be performed, and the second to seventh switches are retained.

[0069] Before performing absolute gain calibration, path loss needs to be calibrated, including: the absolute path loss Loss_if_t (negative value) from the signal source through the sixth switch to IF_TX, the spatial loss from the transmitter array to the spectrum analyzer entrance, and the corresponding switching loss Loss_TX on the path; The signal source transmits power within SUB6G (e.g., 3.8GHz), for example, the signal source output power Pout=10dBm, and the transmitting array uses calibrated amplitude and phase configuration, with the array fully open.

[0070] By adjusting the attenuators inside the array, the gain of the transmitting array reaches the preset value TX_Gain. The signal pin is then acquired using a spectrum analyzer, thus completing the array gain calibration. The calculation is as follows: Pout+Loss_if_t+TX_Gain+Loss_TX = Pin By traversing different frequency points, the absolute gain calibration of the transmitting section is completed.

[0071] Please refer to Figure 6 The receiver array pattern test and single-channel calibration path test of the link are performed according to the following steps based on the current link calibration method: The switch matrix section retains only the first to fourth switches and only the vector network analyzer function.

[0072] If a single-channel calibration test is to be performed, the receiving array is moved to the center position of the compressed field array by a moving motor. The vector network analyzer transmits power, for example, 10dBm, through Port22. The signal passes through the air interface and feed source, then enters the third and fourth switches, and is amplified by the fourth channel 34 (where the output power of the vector network analyzer can be relatively large without the need for an amplifier). After amplification, the signal enters Port21 of the vector network analyzer through the third and fourth switches to complete the amplitude and phase calibration of a single branch.

[0073] Turn on antennas 0 through N in sequence (N is the size of the antenna array, which varies depending on the product). Repeat the above steps to obtain the amplitude and phase of the entire antenna array, and then complete the array calibration.

[0074] After the array calibration is completed, once the entire antenna array is turned on, the same flow direction will be used to enter the vector network analyzer through the fourth channel for pattern testing.

[0075] The above completes the array calibration of the receiving array and the radiation pattern test.

[0076] Please refer to Figure 7 After completing the above calibration and pattern test, the absolute gain calibration of the receiver array needs to be performed, keeping switches 2-7 intact.

[0077] Before performing absolute gain calibration, path loss needs to be calibrated, including: the absolute path loss Loss_if_r (negative value) of the signal from the IF_RX output through the seventh switch to the spectrum analyzer, the spatial loss from the receiving array to the spectrum analyzer input, and the corresponding switching loss Loss_RX on the path. The signal source transmits power within the pre-conversion frequency (e.g., 30GHz). For example, the signal source output power Pout = 10dBm. The receiving array uses calibrated amplitude and phase configurations, and the array is fully open.

[0078] By adjusting the attenuators inside the array to achieve the preset gain RX_Gain, and then acquiring the signal pin using a spectrum analyzer, the array gain calibration is complete. The calculation is as follows: Pout+Loss_RX+RX_Gain+Loss_if _r= Pin By traversing different frequency points, the absolute gain calibration of the receiving section is completed.

[0079] The above examples illustrate the present invention only to aid in understanding it and are not intended to limit the scope of the invention. Those skilled in the art can make various simple deductions, modifications, or substitutions based on the principles of this invention.

Claims

1. A calibration system for an FDD transceiver, characterized by include: Compact field module, which is used to provide a plane wave test environment for the transmitting and receiving arrays of the FDD unit under test; A switch matrix is ​​connected to the test interface of the FDD unit under test, and time-division multiplexing of multiple calibration paths is achieved by switching the switch states; The measurement and control module includes an instrument group and a host computer. The instrument group is connected to the FDD unit under test through the switch matrix and is used to perform calibration tests and gain calibration. The host computer is communicatively connected to the compact field module, the switch matrix, and the instrument group, and is used to coordinate and control the automatic execution of the calibration test of the transmitting array, the calibration test of the receiving array, and the gain calibration. The compaction field module includes a displacement mechanism, which drives the FDD unit under test to move independently in two mutually perpendicular directions to achieve alignment switching between the transmitting array and the receiving array. The compact field module also includes a feed source and a reflector; the reflector is used to collimate the radiation signal from the feed source into a plane wave to illuminate the receiving array, or to converge the radiation signals from each element of the transmitting array to the feed source; the feed source is connected to the instrument group through the switch matrix; The instrument group includes a vector network analyzer, a signal generator, and a spectrum analyzer; The switch matrix includes a first switch, a second switch, a third switch, a fourth switch, a fifth switch, a sixth switch, and a seventh switch; One end of the first switch is connected to the FDD unit under test, and the other end is connected to the fourth switch through the vector network analyzer; the other end of the fourth switch is connected to the feed source through the third switch and the second switch respectively; the fourth switch is also connected to the fifth switch; the fifth switch is connected to the signal source through the sixth switch and to the spectrum analyzer through the seventh switch respectively.

2. The calibration system for an FDD transceiver as described in claim 1, characterized in that, The vector network analyzer is used for amplitude and phase calibration and radiation pattern testing; The signal source and the spectrum analyzer are used together for absolute gain calibration.

3. The calibration system for an FDD transceiver of claim 1, wherein, The FDD unit under test includes an RF transmit test port, an RF receive test port, an IF transmit test port, and an IF receive test port. The IF receive test port is connected to the seventh switch, the IF transmit test port is connected to the sixth switch, and both the RF transmit test port and the RF receive test port are connected to the first switch.

4. The calibration system for an FDD transceiver as described in claim 3, characterized in that, A first channel is provided between the first switch and the radio frequency transmitting test port, and a second channel is provided between the first switch and the radio frequency receiving test port. A first amplifier is provided in the first channel, and a second amplifier is provided in the second channel. A third channel and a fourth channel are provided between the second switch and the third switch, and a third amplifier is provided in the third channel.

5. A calibration method for an FDD transceiver, employing the calibration system for an FDD transceiver as described in any one of claims 1-4, characterized in that, The displacement mechanism in the compressed field module is controlled to move the FDD unit under test to the target alignment position, and the switch matrix is ​​controlled to switch to the corresponding path to perform the calibration test of the transmitting array, the absolute gain calibration of the transmitting array, the calibration test of the receiving array, and the absolute gain calibration of the receiving array in sequence.

6. The calibration method for an FDD transceiver as described in claim 5, characterized in that, When the calibration test of the launch array is performed, the first switch is switched to the first channel; The excitation signal of the vector network analyzer is input to the compact field module through the first switch and the first channel. The second switch and the third switch are switched to the third channel. The signal processed by the compact field module is returned to the vector network analyzer through the third channel, the third switch and the fourth switch for single-channel amplitude and phase calibration. Each array element is activated sequentially to obtain the array amplitude and phase, and array calibration is completed. The second switch and the third switch are switched to the fourth channel. The signal output by the compact field module is returned to the vector network analyzer via the fourth channel, the third switch and the fourth switch for transmission pattern testing.

7. The calibration method for an FDD transceiver as described in claim 6, characterized in that, When the absolute gain of the transmitting array is calibrated, the second switch and the third switch are switched to the fourth channel; The signal source inputs an excitation signal of known power to the compact field module via the sixth switch. After processing, the signal is transmitted sequentially to the spectrum analyzer via the fourth channel, the third switch, the fourth switch, the fifth switch, and the seventh switch. The spectrum analyzer calculates the absolute gain of the transmitting array based on the link loss.

8. The calibration method for an FDD transceiver as described in claim 7, characterized in that, When the calibration test of the receiving array is performed, the first switch is switched to the second channel; The excitation signal of the vector network analyzer is sequentially input to the compact field module via the fourth switch, the third switch and the fourth channel, and the second switch. The processed signal is returned to the vector network analyzer via the radio frequency receiver measurement port, the second channel and the first switch for single-channel amplitude and phase calibration. The amplitude and phase of each array element are acquired sequentially to complete the array calibration; After the entire antenna array is activated, a receiver pattern test is performed.

9. The calibration method for an FDD transceiver as described in claim 8, characterized in that, When performing absolute gain calibration of the receiving array, the second switch and the third switch are switched to the fourth channel; The signal source sequentially inputs an excitation signal of known power to the compact field module via the sixth switch, the fifth switch, the fourth switch, the third switch, the fourth channel, and the second switch. After processing, the signal is transmitted sequentially to the spectrum analyzer via the intermediate frequency receiving test port and the seventh switch. The spectrum analyzer calculates the absolute gain of the receiving array based on the link loss.

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