CN114414904A

CN114414904A - 5G NR basic station OTA amplitude and phase conformance test calibrating device

Info

Publication number: CN114414904A
Application number: CN202210143542.9A
Authority: CN
Inventors: 宫长波; 杨奎; 李峰; 李荣明
Original assignee: Nanjing Rflight Communication Electronic Corp
Current assignee: Nanjing Rflight Communication Electronic Corp
Priority date: 2022-02-16
Filing date: 2022-02-16
Publication date: 2022-04-29

Abstract

The invention provides a calibration device for 5G NR base station OTA amplitude-phase consistency test, belonging to the technical field of calibration test of a plurality of radiation units of a base station. Wherein, the device of the invention comprises: the system comprises a microwave camera obscura and a base station, wherein a plurality of probes are arranged in the microwave camera obscura, each probe corresponds to one radiation unit of the base station, and all the probes are connected into a switch matrix so as to switch the corresponding probes to receive signals and complete the test of amplitude and phase data of all channels of the base station. The invention adopts the space radiation (OTA) mode to calibrate the amplitude-phase consistency, does not need a complex switch network for closed-loop test, has simple system connection, can comprehensively calibrate each link influencing the amplitude-phase consistency among the antenna array units, greatly improves the test efficiency, and is very suitable for production debugging on a production line.

Description

5G NR basic station OTA amplitude and phase conformance test calibrating device

Technical Field

The invention belongs to the technical field of calibration and test of a plurality of radiation units of a base station, and particularly relates to a calibration device for testing OTA amplitude-phase consistency of a 5G NR base station.

Background

The 5G NR base station has a plurality of antenna radiation elements, and different beam directions are formed by phase weighting between the elements. Only if the amplitude and phase differences between the elements are accurately known, the corresponding compensation can be accurately made, and thus, accurate beam forming can be realized. How to accurately realize the amplitude-phase difference test among the units, or called amplitude-phase consistency balancing test, is the key to ensure the performance of the 5G NR base station.

The method mainly comprises two types of closed loop test mode and space test (OTA) mode for The inter-unit amplitude-phase consistency balancing test. For closed loop test, the method has the advantages of stable work, high precision and no influence of external environment, but the method does not contain the influence of amplitude-phase consistency tolerance, installation error, inconsistent connecting cables and the like of the antenna, so the final trimming of the amplitude-phase consistency of the whole antenna system is not realized by the test method.

Therefore, for the whole antenna array, the calibration of the amplitude-phase consistency by adopting a space radiation (OTA) mode is a necessary test link, and based on the calibration, the invention provides a calibration device for the 5G NR base station OTA amplitude-phase consistency test.

Disclosure of Invention

The invention aims to at least solve one technical problem in the prior art and provides a calibration device for testing the OTA amplitude-phase consistency of a 5G NR base station.

The invention provides a calibration device for 5G NR base station OTA amplitude-phase consistency test, which is characterized by comprising: the system comprises a microwave camera obscura and a base station, wherein a plurality of probes are arranged in the microwave camera obscura, each probe corresponds to one radiation unit of the base station, and all the probes are connected into a switch matrix so as to switch the corresponding probes to receive signals and complete the test of amplitude and phase data of all channels of the base station.

Optionally, the distance between the probe and the radiation unit ranges from 3 λ to 10 λ, where λ is the operating wavelength of the base station antenna.

Optionally, a probe mounting base plate is fixed to the upper end of the top wall of the microwave camera bellows, and the plurality of probes are arranged on one side, facing the inside of the microwave camera bellows, of the probe mounting base plate.

Optionally, the probes are dual-polarized probes, and each probe corresponds to two switch matrix channels.

Optionally, the radiation unit is dual-polarized at ± 45 °.

Optionally, the probe is further connected to a horn antenna, so that a consistency error of each probe channel is measured through the horn antenna before the test.

Optionally, a fan is arranged in the microwave camera bellows to cool the equipment in the microwave camera bellows.

Optionally, a ventilation waveguide window is further disposed on the top wall and/or the bottom wall of the microwave dark box, so as to ventilate through the ventilation waveguide window.

Optionally, a shielding door and an equipment inlet and outlet are further arranged on the side wall of the microwave dark box.

Optionally, when the amplitude and phase data are tested, the base station antenna is placed in the microwave dark box, and a wave-absorbing material is used in the microwave dark box.

The invention provides a calibration device for 5G NR base station OTA amplitude and phase consistency test, comprising: a plurality of probes are arranged in the microwave camera bellows and the microwave camera bellows, and each probe corresponds to one radiation unit of the base station; and all the probes are connected into a switch matrix to switch the corresponding probes to receive signals and complete the test of amplitude and phase data of all channels of the base station. The invention adopts the space radiation (OTA) mode to calibrate the amplitude-phase consistency, does not need a complex switch network for closed-loop test, has simple system connection, can comprehensively calibrate each link influencing the amplitude-phase consistency among the antenna array units, greatly improves the test efficiency, and is very suitable for production debugging on a production line.

Drawings

FIG. 1 is a schematic view of the overall structure of a microwave dark box according to an embodiment of the present invention;

FIG. 2 illustrates the probe consistency calibration principle according to an embodiment of the present invention;

FIG. 3 is a schematic view of a probe calibration according to an embodiment of the present invention;

FIG. 4 is probe amplitude test data according to an embodiment of the present invention;

FIG. 5 is a graph of probe amplitude compensation data according to an embodiment of the present invention;

fig. 6 shows the principle of testing the radiating elements of the 5G NR base station according to an embodiment of the present invention;

fig. 7 is a schematic diagram of an amplitude test of a 5G NR base station radiating element according to an embodiment of the present invention;

fig. 8 is a schematic diagram of a phase test of a radiation unit of a 5G NR base station according to an embodiment of the present invention.

Detailed Description

In order to make the technical solutions of the present invention better understood, the present invention will be described in further detail with reference to the accompanying drawings and specific embodiments. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the described embodiments of the invention without any inventive step, are within the scope of protection of the invention.

Unless otherwise specifically stated, technical or scientific terms used herein shall have the ordinary meaning as understood by those of ordinary skill in the art to which this invention belongs. The use of "including" or "comprising" and the like in this disclosure does not limit the presence or addition of any number, step, action, operation, component, element, and/or group thereof or does not preclude the presence or addition of one or more other different numbers, steps, actions, operations, components, elements, and/or groups thereof. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number and order of the indicated features.

In some descriptions of the invention, unless expressly stated or limited otherwise, the terms "mounted," "connected," or "fixed" and the like are not restricted to physical or mechanical connections, but may include electrical connections, whether direct or indirect through an intermediate medium, whether internal to two elements or an interactive relationship between two elements. Also, the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate an orientation or positional relationship based on that shown in the drawings, and are used only to indicate a relative positional relationship, which may also be changed accordingly when the absolute position of the object being described is changed.

It should be noted that, for the 5G NR base station antenna, only if the amplitude and phase differences between the radiation elements are precisely known, the corresponding compensation can be accurately made, so as to achieve precise beam forming. Therefore, how to accurately implement an amplitude-phase difference test between antenna units, or referred to as an amplitude-phase consistency balancing test, is key to ensuring the performance of the 5G NR base station. And, the consistency of the signals received by the probe is required to be ensured firstly, and the difference of the corresponding channels of the probe is eliminated, so that the probe is required to be calibrated. Based on this, the invention provides a calibration device for testing the OTA amplitude-phase consistency of a 5G NR base station.

As shown in fig. 1 to 8, the present invention provides a calibration apparatus for 5G NR base station OTA amplitude-phase consistency test, including: the microwave dark box 110 and the microwave dark box 110 are internally provided with a plurality of probes 111, each probe corresponds to one radiation unit of the base station, and all the probes are connected to one switch matrix so as to switch the corresponding probes to receive signals and complete the test of amplitude and phase data of all channels of the base station.

It should be noted that, before testing, errors of the system itself need to be eliminated, that is, amplitude-phase consistency between probes is removed. Therefore, in order to eliminate consistency errors among probe groups, the probe of the embodiment is connected with the horn antenna to test each probe channel, namely the horn antenna is needed only when the probe consistency is calibrated, so that the probe channel with large amplitude-phase difference is checked through the horn antenna, errors caused by loosening of the cable and the interface are eliminated, and finally, after the amplitude phases of all the probes are collected, compensation data are obtained through normalization. And then, the base station is placed in a microwave dark box for calibration test, and the probe compensation data is subtracted from the tested data to obtain the radiation unit inter-phase data.

In addition, in order to complete the test quickly, the probe is also connected to the switch matrix, the probe is switched quickly through the switch matrix, the base station synchronously opens the radiation units corresponding to the probe and closes other units, and the amplitude phase test work of all array surface units is completed in sequence, so that the test efficiency is greatly improved, and the method is very suitable for production debugging on a production line.

In the embodiment, the horn antenna is adopted to test each probe channel, the amplitude-phase consistency is calibrated in a space radiation (OTA) mode, a switch network with complex closed-loop test is not needed, the system connection is simple, and all links influencing the amplitude-phase consistency among antenna array units can be comprehensively calibrated.

For example, as shown in fig. 1 to 8, in the microwave dark box 110, using the mirror image principle, using probes with the same number as the number of radiation units, that is, M × N radiation units 120 of the base station antenna, using M × N probes 111 as mirror images, where the test distance between each probe 111 and the radiation unit 120 of the base station antenna is R, and switching the probes through a 2M × 2N channel matrix switch to complete the amplitude and phase test of each base station radiation unit (removing the probe consistency error), of course, in order to avoid the external environment interference, the test needs to be performed in a shielding dark box.

It should be noted that the number of probes in this embodiment is the same as the number of base station antenna radiation units.

It should be further noted that, the distance range between the probe and the base station antenna radiation unit in this embodiment is R, where R is 3 λ to 10 λ, and λ is the operating wavelength of the base station antenna. That is, the embodiment performs OTA calibration by mirror image method, and places the probe at a distance of 3-10 λ from the antenna radiation unit, and the distance between the probe and the antenna unit is equal.

Specifically, as shown in fig. 1 and 3, a probe mounting base plate 112 is fixed to an upper end of a top wall of the micro-chamber 110, that is, the top wall of the micro-chamber 110 is provided with a probe mounting opening 113, and a plurality of probes 111 are provided on a side of the probe mounting base plate 112 facing the interior of the micro-chamber 110.

It should be noted that the probe in this embodiment adopts a dual-polarized probe, the dual-polarized probe is used as a mirror image, each probe corresponds to two switch matrix channels, and each base station antenna radiation unit is a ± 45 ° dual-polarization.

Further, a fan (for example, a fan) is arranged in the microwave dark box of the embodiment to cool the equipment in the microwave dark box.

Furthermore, as shown in fig. 1, 7 and 8, in the present embodiment, when performing the amplitude and phase data test, the base station antenna 150 is disposed in the microwave dark box 110, and a wave-absorbing material is used in the microwave dark box to reduce the reflection level, and in addition, the base station antenna 150 is disposed in the microwave dark box 110 and connected to a power line and a control line to ensure the operation of the fan in the dark box.

Further, as shown in fig. 1, the top wall and the bottom wall of the microwave chamber 110 of the present embodiment are further provided with ventilation waveguide windows 114 for ventilation through the ventilation waveguide windows.

Further, as shown in fig. 1, a shielding door and an equipment access 115 are further disposed on a side wall of the dark microwave box 110 to facilitate the equipment access.

Further, as shown in fig. 1 and 3, the horn antenna 130 and the switch matrix 140 of the present embodiment are respectively connected to a vector network analyzer 160. Referring further to fig. 7, a schematic diagram of the amplitude test of the 5G NR base station radiating elements is shown, where the switch matrix 140 is a radio frequency switch matrix connected to a frequency spectrograph or a power meter. For another example, please further refer to fig. 8, which shows a schematic diagram of phase test of the 5G NR base station radiating unit, where the switch matrix 140 is a radio frequency switch matrix connected to the vector network analyzer test branch, and the 5G NR base station antenna 150 is connected to the vector network analyzer reference branch 170.

Based on the structure, the specific test flow for the OTA amplitude-phase consistency of the 5G NR base station is as follows:

1. the probe group is subjected to consistency calibration through a horn, errors of the system are eliminated, the testing principle is shown in fig. 2, the testing schematic diagram is shown in fig. 3, the horn and a switch matrix are respectively connected to two testing ports of a vector network analyzer (hereinafter referred to as vector network) Port1 and Port2, the horn is moved to be respectively arranged below each probe, testing is carried out through vector network S21, and finally amplitude and phase data of each probe are obtained, the testing amplitude data is shown in fig. 4, the data are concentrated near-41 dB, normalization operation is carried out on the data through-41 dB, and accordingly normalized compensation data are obtained, and as shown in fig. 5, when a radio frequency cable, the switch matrix and the probe at one end of the probe are not changed, the normalized compensation data of the probe can be reused without repeated testing.

2. Placing the base station antenna in a camera bellows, connecting a power line and a control line, and ensuring the work of a fan in the camera bellows;

3. the test principle of controlling the switch matrix and the base station antenna radiation units can refer to fig. 6, a frequency spectrograph or a power meter is used for receiving in the amplitude test process, as shown in fig. 7, only one radiation unit works at the same time in the test, and the switches are switched to corresponding probes for signal receiving when other units are in a closed state. In the phase test process, the vector network is used for receiving, as shown in fig. 8, a reference branch is led out from the base station, a hop end of a front panel of the vector network is connected to an R1 receiver, a probe receives a signal and is connected to a Port2, the vector network test parameter is S21, and probe compensation operation is performed on the data obtained by the test.

4. Generating an amplitude error and phase error calibration data matrix according to the array plane antenna balancing data format, and balancing the radiation array plane;

5. and (3) testing the balanced array antenna in the step (3) again, judging whether the amplitude phase error of each radiation unit meets the index requirement, and if not, repeating the iteration process again until the requirement is met.

6. After the test is finished, the polarization of the probe is changed, the calibration operation is repeated for the other polarization of the base station radiation unit, the dual-polarization probe can be used under the condition, and meanwhile, the channels of the switch matrix are doubled, so that the two polarization tests can be finished in one process, and the test efficiency can be improved.

The invention provides a calibration device for testing the OTA amplitude-phase consistency of a 5G NR base station, which has the following beneficial effects compared with the prior art: the invention adopts the space radiation (OTA) mode to calibrate the amplitude-phase consistency, does not need a complex switch network for closed-loop test, has simple system connection, can comprehensively calibrate each link influencing the amplitude-phase consistency among the antenna array units, greatly improves the test efficiency, and is very suitable for production debugging on a production line.

It will be understood that the above embodiments are merely exemplary embodiments taken to illustrate the principles of the present invention, which is not limited thereto. It will be apparent to those skilled in the art that various modifications and improvements can be made without departing from the spirit and substance of the invention, and these modifications and improvements are also considered to be within the scope of the invention.

Claims

1. A5G NR base station OTA amplitude and phase consistency test calibration device is characterized by comprising: the system comprises a microwave camera obscura and a base station, wherein a plurality of probes are arranged in the microwave camera obscura, each probe corresponds to one radiation unit of the base station, and all the probes are connected into a switch matrix so as to switch the corresponding probes to receive signals and complete the test of amplitude and phase data of all channels of the base station.

2. The apparatus of claim 1, wherein the probe is located at a distance from the radiating element in a range from 3 λ to 10 λ, λ being an operating wavelength of the base station antenna.

3. The apparatus of claim 1, wherein a probe mounting base plate is secured to an upper end of the top wall of the microwavable chamber, the probe mounting base plate being configured with the plurality of probes on a side thereof facing an interior of the microwavable chamber.

4. The apparatus of claim 1, wherein the probes are dual polarized probes, and each probe corresponds to two switch matrix channels.

5. The apparatus of claim 1, wherein the radiating elements are + 45 ° dual polarized.

6. The apparatus of claim 1, wherein said probe further engages a horn antenna to measure each of said probe channel uniformity errors prior to testing by said horn antenna.

7. The apparatus according to any one of claims 1 to 6, wherein a fan is provided in the microwave camera chamber to cool the equipment in the microwave camera chamber.

8. The apparatus of claim 7, wherein the top and/or bottom walls of the microwavable chamber further comprise a ventilation waveguide window for ventilation therethrough.

9. The apparatus according to any one of claims 1 to 6, wherein a shielding door and an equipment access port are further provided on the side wall of the microwave dark box.

10. The apparatus of any one of claims 1 to 6, wherein the base station antenna is placed in the microwave dark box during the amplitude and phase data test, and a wave-absorbing material is used in the microwave dark box.