Antenna performance test device for IoT communication equipment

Abstract

The present invention discloses an antenna performance testing device for Internet of Things communication equipment, comprising a multi-probe anechoic chamber, a shielding box, a first link switching switch, a signal adjustment device and a signal measuring instrument, wherein the multi-probe anechoic chamber comprises a central turntable for placing the device to be tested, a plurality of detection antennas arranged in a circle around the central turntable in the vertical direction, and a communication antenna arranged around the central turntable, wherein the detection antenna and the communication antenna are respectively connected to the first link switching switch through a anechoic chamber waveguide port via a radio frequency cable. The present invention can realize the measurement of antenna performance. The present invention can realize the connection of different links through the multi-probe anechoic chamber, the shielding box, the first link switching switch, the signal adjustment device and the signal measuring instrument, so that the signal measuring instrument can be connected to different links, thereby realizing signal measurement during antenna communication.

Description

Technical Field

[0001] The present invention relates to the field of active testing of antennas in Internet of Things communication systems, and in particular to a performance testing device for antennas of Internet of Things communication equipment. Background Art

[0002] Traditionally, IoT device wireless communication system performance testing, exemplified by mainstream mobile communications systems like 2G, 3G, 4G, and now 5G, has well-established test methods and standards for antenna performance testing. Standards such as the international CTIA standard and China's YD / T1484 series define comprehensive and systematic testing methods and standards for wireless terminal antenna performance. For these tests, sophisticated instruments and equipment are available, providing comprehensive solutions that easily test active antenna performance. By using standardized testing instruments to evaluate both terminal and base station antenna performance, the performance of the entire communication system can be assessed.

[0003] With the development of the Internet of Things (IoT), more and more IoT communication technologies are being applied to all aspects of life. However, since some of these technologies are still in their early stages of application, it is difficult to find affordable testing equipment for RF-related performance. Even for some proprietary communication protocols, there is no testing equipment that can simulate a base station or provide corresponding performance testing such as modem and demodulation during active antenna performance testing. To address this issue, most IoT product developers and designers currently rely on application-layer performance testing, such as actual communication distance or throughput testing, or use auxiliary testing methods such as passive antenna efficiency and gain testing. Furthermore, existing methods and devices for testing antenna performance of communication devices using anechoic chambers exist. However, these methods can only qualitatively evaluate antenna performance and cannot quantitatively determine the radiated power and sensitivity of the device under test. They cannot even accurately determine the communication distance between the communication systems under test, but only provide relative communication distance performance based on the test equipment.

[0004] Faced with the complex and diverse IoT communication technologies, existing technologies lack the affordable and adaptable instrumentation and demodulation capabilities to perform active antenna performance testing. IoT product developers and designers struggle to afford the high equipment costs, and testing labs are unable to purchase equipment tailored to each communication protocol.

[0005] Some existing technologies require connecting to an internal RF communication interface, which means some terminals must be disassembled to connect to the internal antenna interface. Testing the passive antenna performance or communication range requires disconnecting the existing antenna and connecting a test antenna or test cable. These testing methods require disassembling the device, or even damaging it, which is unacceptable in some situations.

[0006] Existing technologies cannot provide complete and specific performance data of the communication system under test. They can only obtain a qualitative judgment of the antenna performance relative to the performance of the test system. They cannot make a quantitative judgment or quantitatively determine the antenna active performance, and cannot obtain specific data on the antenna active EIS and EIRP performance parameters.

[0007] Furthermore, in real-world engineering applications, many IoT devices under test lack underlying software support in some specialized scenarios. For example, software for reading the received signal strength (RSSI) value or reading the data being sent and received is unavailable. Consequently, testing that requires reading the RSSI value or the success rate of received signals often lacks software support, leading to software limitations that prevent existing testing methods from being supported. Summary of the Invention

[0008] To this end, it is necessary to provide an IoT communication equipment antenna performance test device to solve the problem that the existing technology cannot conveniently test the performance of the IoT system antenna.

[0009] To achieve the above-mentioned objectives, the present invention provides an antenna performance testing device for Internet of Things communication equipment, comprising a multi-probe anechoic chamber, a shielding box, a first link switching switch, a signal adjustment device and a signal measuring instrument, wherein the multi-probe anechoic chamber comprises a central turntable for placing the device to be tested, a plurality of detection antennas arranged in a circle around the central turntable in the vertical direction, and a communication antenna arranged around the central turntable, the detection antenna and the communication antenna are respectively connected to the first link switching switch through a radio frequency cable and then through a anechoic chamber waveguide port; the two output ends of the first link switching switch are connected to the two input ends of the signal adjustment device, the shielding box is provided with a test bracket and a signal coupling plate for placing and fixing the object to be tested, the signal coupling plate is connected to the signal adjustment device through a radio frequency cable, and the output end of the signal adjustment device is connected to the signal measuring instrument; the signal adjustment device is used to switch and adjust the signal input from the input end and input it into the signal measuring instrument.

[0010] Furthermore, the multi-probe anechoic chamber further includes an antenna switching switch for detecting antenna selection, one end of the antenna switching switch is connected to the detection antenna, and the other end is connected to the first link switching switch through the anechoic chamber waveguide port.

[0011] Furthermore, the signal adjustment device includes a first combiner, a second combiner, a third combiner, a load, a second link switching switch, a first link signal control device, and a second link signal control device; the first combiner is connected to the signal coupling board and divides the signal path of the signal coupling board into two paths, one of which is connected to the second combiner as a signal output, and the other is connected to the output end of the second link signal control device; the second combiner divides the signal into two paths, one of which is connected to the input end of the first link signal control device and then the output end of the first link signal control device is connected to the first link switching switch, and the other is connected to the second link switching switch and then to the signal measuring instrument; the third combiner is connected to the first link switching switch and divides the signal into two paths, one of which is connected to the second link switching switch and the other is connected to the input end of the second link signal control device, and the second link switching switch is connected to the load. The first link signal control device and the second link signal control device are used for unidirectional transmission of the link signal and signal size adjustment.

[0012] Furthermore, the signal adjustment device also includes a first fixed attenuator, a second fixed attenuator, a third fixed attenuator, a fourth fixed attenuator, a fifth fixed attenuator and a sixth fixed attenuator; the first combiner is connected to the signal coupling board through the first fixed attenuator; one path of the first combiner is connected to the second combiner through the second fixed attenuator, and the other path of the first combiner is connected to the output end of the second link signal control device through the third fixed attenuator; one path of the second combiner is connected to the input end of the first link signal control device through the fourth fixed attenuator; the output end of the first link signal control device is connected to the first link switching switch through the fifth fixed attenuator, and the other path of the second combiner is connected to the second link switching switch through the sixth fixed attenuator and then connected to the signal measuring instrument; the third combiner is connected to the first link switching switch and divides the signal into two paths, one path is connected to the second link switching switch, and the other path is connected to the input end of the second link signal control device, and the second link switching switch is connected to the load.

[0013] Furthermore, the first link signal control device and the second link signal control device have the same structure, including a signal input end and a signal output end, and a first isolator, an adjustable signal amplifier, an adjustable attenuator and a second isolator are respectively connected in series between the two ends.

[0014] Furthermore, a switch capable of short-circuiting the signal is connected in parallel to the adjustable signal amplifier, and is used to short-circuit the adjustable signal amplifier to reduce active noise caused by the amplifier.

[0015] Furthermore, it also includes a control and test system, which is connected to the multi-probe anechoic chamber, the shielding box, the first link switch, the signal adjustment device and the signal measuring instrument.

[0016] Furthermore, the test bracket is an electromagnetic transparent material bracket.

[0017] Furthermore, the signal measuring instrument is a spectrum analyzer or an oscilloscope.

[0018] Furthermore, the number of the detection antennas is more than 5.

[0019] Different from the existing technology, the above technical solution can realize switching of different angles through a multi-probe anechoic chamber, and then realize the connection of different links through a multi-probe anechoic chamber, a shielding box, a first link switching switch, a signal adjustment device and a signal measuring instrument. In this way, the signal measuring instrument can be connected to different links, thereby realizing signal measurement during antenna communication. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic structural diagram of the device for testing the antenna performance of IoT communication equipment according to the present invention;

[0021] Figure 2 It is a structural schematic diagram of the signal adjustment device of the present invention;

[0022] Figure 3 Schematic diagram of the structure of the link signal control device of the present invention;

[0023] Figure 4 This is a diagram of the interaction of the return method;

[0024] Figure 5 This is a schematic diagram of the waveform collected by the signal measuring instrument;

[0025] Figure 6 A schematic diagram for determining whether the communication between the communication device A under test and the device B under test is normal.

[0026] Description of reference numerals:

[0027] 1. Multi-probe anechoic chamber;

[0028] 101. Center turntable;

[0029] 102. Antenna switch;

[0030] 112. Detection antenna;

[0031] 111. Communication antenna;

[0032] 2. Shielding box;

[0033] 202, test bracket;

[0034] 201, signal coupling board;

[0035] 3. First link switch;

[0036] 4. Control and test system;

[0037] 5. Signal measuring instruments;

[0038] 6. Signal adjustment device;

[0039] 601, first fixed attenuator; 602, second fixed attenuator; 603, third fixed attenuator; 604, fourth fixed attenuator; 605, fifth fixed attenuator; 606, sixth fixed attenuator;

[0040] 607, load;

[0041] 610, first link signal control device; 620, second link signal control device;

[0042] 631, first combiner; 632, second combiner; 633, third combiner;

[0043] 641, second link switching switch;

[0044] 611. First isolator; 612. Adjustable signal amplifier; 613. Adjustable attenuator; 614. Second isolator; 615. Switch. DETAILED DESCRIPTION

[0045] In order to explain the technical content, structural features, achieved objectives and effects of the technical solution in detail, the following is a detailed description in conjunction with specific embodiments and accompanying drawings.

[0046] References to "embodiments" herein mean that the specific features, structures, or characteristics described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the word "embodiment" in various places in the specification does not necessarily refer to the same embodiment, nor does it particularly limit its independence or relevance to other embodiments. In principle, in this application, as long as there are no technical contradictions or conflicts, the various technical features mentioned in the embodiments can be combined in any manner to form a corresponding implementable technical solution.

[0047] Unless otherwise defined, the technical terms used herein have the same meanings as those generally understood by those skilled in the art to which this application belongs; the use of relevant terms herein is only for describing specific embodiments and is not intended to limit this application.

[0048] In the description of this application, the term "and / or" is used to describe a logical relationship between objects, indicating that three relationships can exist. For example, A and / or B means: A exists, B exists, and both A and B exist. In addition, the character " / " in this document generally indicates that the objects before and after are in a logical "or" relationship.

[0049] In this application, terms such as "first" and "second" are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual quantity, priority or sequence relationship between these entities or operations.

[0050] Without further limitations, in this application, the words "include", "comprise", "have" or other similar expressions used in the sentences are intended to cover non-exclusive inclusion. These expressions do not exclude the presence of additional elements in the process, method or product including the elements, so that the process, method or product including a series of elements may include not only those defined elements, but also other elements not explicitly listed, or elements inherent to such process, method or product.

[0051] Consistent with the understanding in the Examination Guidelines, in this application, expressions such as "greater than," "less than," and "exceed" are understood to exclude the number itself; expressions such as "above," "below," and "within" are understood to include the number itself. Furthermore, in the description of the embodiments of this application, "multiple" means more than two (including two), and similar expressions related to "multiple" are also understood in this manner, such as "multiple groups," "multiple times," etc., unless otherwise specifically defined.

[0052] In the description of the embodiments of the present application, the space-related expressions used, such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "vertical", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicate the orientation or position relationship based on the orientation or position relationship shown in the specific embodiments or drawings, and are only for the convenience of describing the specific embodiments of the present application or facilitating the reader's understanding, and do not indicate or imply that the device or component referred to must have a specific position, a specific orientation, or be constructed or operated in a specific orientation. Therefore, it should not be understood as a limitation on the embodiments of the present application.

[0053] Unless otherwise expressly specified or limited, in the description of the embodiments of the present application, the terms "installed", "connected", "connected", "fixed", "set", etc. used should be understood in a broad sense. For example, the "connection" can be a fixed connection, a detachable connection, or an integrated setting; it can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. For those skilled in the art of the present application, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0054] See also Figures 1 to 6 The present invention provides an IoT system antenna testing device and method, which can be used to quantitatively test the performance of IoT communication system antennas. This method and corresponding device are economical and applicable. They can be used to measure the performance of a wide variety of IoT communication technology standards without disassembling the device antenna, enabling active, quantitative measurement of the antenna performance of the communication device to obtain EIS and EIRP performance information. Furthermore, the test can ultimately provide a complete and accurate understanding of the performance of the receiving and transmitting devices of the communication system under test. Furthermore, in situations where software support for reading RSSI values ​​and signal read success rates is unavailable, a method for determining signal read success is provided.

[0055] like Figure 1 As shown, a test device based on a multi-probe anechoic chamber system includes a multi-probe anechoic chamber 1, which is used to measure the receiving performance EIS and radiated power performance EIRP of the communication system under test; wherein the multi-probe anechoic chamber includes a circle of detection antennas 112, the number of detection antennas is N, and N can be an integer greater than or equal to 5. The multi-probe anechoic chamber 1 also includes a communication antenna 111 for testing signal connection, which is a small multi-band antenna placed inside the central turntable near the test center where the object to be tested is placed. It is connected to the external signal through the anechoic chamber waveguide port via a radio frequency cable. The multi-probe anechoic chamber 1 also includes a central turntable 101 for placing the device to be tested; and the device to be tested A placed on the central turntable; the multi-probe anechoic chamber 1 includes an antenna switching switch 102 for detecting antenna selection, one end of which is connected to the detection antenna, and the other end is connected to the external signal of the anechoic chamber through the anechoic chamber waveguide port.

[0056] The test apparatus based on the multi-probe anechoic chamber system also includes a shielding box 2, placed outside the multi-probe anechoic chamber. Inside, there are a test bracket 202 for holding the DUT (device under test) and a signal coupling board 201. The test bracket is preferably made of electromagnetically transparent material to reduce the signal impact on the antenna performance of the device under test B. The signal coupling board 201 is electrically connected to the outside of the shielding box via a radio frequency cable.

[0057] The multi-probe anechoic chamber system-based test device includes a first link switch 3, which is placed outside the multi-probe anechoic chamber 1. It includes four ports, a, a', b, and b', and can be controlled to achieve a first state a-a' or b-b' connection; it can also be controlled to achieve a second state a-b' or b-a' connection.

[0058] The multi-probe darkroom system-based test device includes a signal adjustment device 6, which enables signal selection and switching and adjusts the path signal level to ensure stable and accurate test connections. It contains four ports: A, B, C, and D. Port A is connected to the signal coupling board 201 of the shielding box 2; port B is connected to port a' of the first link switch 3; port C is connected to port b' of the first link switch 3; and port D is connected to the signal measuring instrument 5.

[0059] The multi-probe anechoic chamber system-based testing device includes a signal measuring instrument 5, which can measure the signal power value during the test. The signal measuring instrument 5 can also support time domain signal measurement to determine whether the communication connection is normal. The signal measuring instrument can be a spectrum analyzer or an oscilloscope.

[0060] The multi-probe anechoic chamber system-based testing device includes a control and testing system 4, which can execute the testing method of the present invention. The control and testing system is connected to the multi-probe anechoic chamber 1, the first link switch 3, the signal adjustment device 6, and the signal measuring instrument 5 via control cables. This system can control the device, obtain information, and calculate test results.

[0061] like Figure 2As shown, the signal conditioning device 6 includes a first fixed attenuator 601, a second fixed attenuator 602, a third fixed attenuator 603, a fourth fixed attenuator 604, a fifth fixed attenuator 605, and a sixth fixed attenuator 606; a first combiner 631, a second combiner 632, and a third combiner 633; ​​a load 607; a second link switch 641; a first link signal control device 610, and a second link signal control device 620. The first fixed attenuator 601, the second fixed attenuator 602, and the third fixed attenuator 603 are respectively connected to the three ports of the first combiner 631. For the sake of distinction, the three ports are designated as a signal port, another signal port, and a common port. The two signal ports can be connected to signal lines, respectively, and the common port can then combine two signals for output. A combiner is a unit composed of multiple filters. It is a multi-port network in which all ports are dual-function input / output ports, capable of combining or splitting wireless signals for output. The fixed attenuator in the present invention mainly provides fixed attenuation for the line and ensures load matching at the port of the first combiner 631, thereby preventing impedance changes of the signal coupling plate in the shielding box caused by different terminals B under test from causing signal reflections and affecting the test results. The first combiner 631 splits the signal path of the signal coupling board 201 into two paths, one of which is connected to the second combiner 632 as a signal output through the third fixed attenuator 603; the other is connected to the output end of the second link signal control device 620 through the second fixed attenuator 602. The second combiner 632 splits the signal into two paths, one of which is connected to the input end of the first link signal control device 610 through the fourth fixed attenuator 604, and the other is connected to the second link switch 641 through the fifth fixed attenuator 605, so as to measure the signal level of the signal coupling board 201. The third combiner 633 is connected to the first link switch 3 through the D port, which can split the signal of the anechoic chamber into two paths. One path is connected to the link switch 641 through the sixth fixed attenuator 606 to measure the signal level of the antenna in the anechoic chamber, and the other path is connected to the input end of the second link signal control device 620, thus establishing a signal path between the antenna in the anechoic chamber and the shielding box.

[0062] In addition, the load 607 is connected to the port b' of the second link switch 641, which can realize the load connection of the second combiner 632 or the third combiner 633 signal when it is not connected to the signal measuring instrument 5, ensuring the matching of the signal path and preventing signal reflection from affecting the test results.

[0063] The first link signal control device 610 and the second link signal control device 620 have the same structure and are used for unidirectional transmission of link signals and signal size adjustment. They include two ports, namely a signal input port (IN port) and a signal output port (OUT port). Figure 3 As shown, a first isolator 611, an adjustable signal amplifier 612, an adjustable attenuator 613, and a second isolator 614 are connected in series between the two ports. Furthermore, a switch 615 capable of short-circuiting the signal is connected in parallel to the adjustable signal amplifier 612 to ensure that the adjustable signal amplifier 612 is short-circuited when the signal strength meets the requirement, thereby reducing the active noise introduced by the amplifier 612.

[0064] It should be noted that the control and test system 4 is configured to facilitate switching control. In some embodiments, manual switching control is also possible. The control and test system 4 can directly connect to the various modules and units in the signal conditioning device 6 to implement control. Alternatively, relay control can be implemented through an intermediate control component 650. Specifically, the control and test system 4 sends a signal to the intermediate control component 650, which responds to the signal and implements control of the various modules and units in the signal conditioning device 6.

[0065] The following is an explanation of the device and method. The method for measuring the equivalent radiated power (EIRP) of IoT communication equipment based on the device includes the following steps:

[0066] 1. Before testing, all parts of the path are calibrated and confirmed, including the air path loss between the test antenna in the darkroom and the center path of the test turntable, including the loss of each part of the link. The link loss value of each part in the signal adjustment device 6 is calibrated. Since the two paths of the combiner have the characteristics of equal amplitude and phase, in order to simplify the description, this embodiment assumes its performance under ideal conditions. In actual engineering applications, it is necessary to calibrate the loss values ​​of the two ports of each combiner separately. The specific calibration method can adopt the existing calibration method and is not detailed here.

[0067] 2. Place the device A under test at the center of the turntable of the multi-probe anechoic chamber 1, and place the auxiliary device B under test in the test bracket 202 in the shielding box 2, and keep its relative position to the signal coupling board 201 unchanged.

[0068] 3. Control the central turntable 101 to the first Phi angle and the antenna switch 102 to the first Theta angle; control the first link switch 3 to achieve the connection mode of a-b' and b-a'; set the adjustable attenuator 613 and amplifier 612 in the first link signal control device 610 and the second link signal control device 620 to an initial value to ensure that the communication link loss has a relatively ideal initial value;

[0069] 4. Control the wireless information interaction between the device A under test and the device B under test, and control the connection mode of the second link switching switch 641 to the connection state of a-a' and b-b'. In the current state of the first link switching switch 3 and the second link switching switch 641, the communication antenna 111 is connected to one signal end of the second combiner 632, and then connected to the signal coupling board 201 through the second combiner 632. The signal measuring instrument 5 is connected to the other signal end of the second combiner 632, and the signal of the detection antenna can enter the signal measuring instrument 5 through the third combiner 633. Set the acquisition frequency of the signal measuring instrument 5 to be the same as the output signal frequency of the device B under test, and measure the power value. According to this power value and the link insertion loss, the power value radiated by the communication antenna 111 can be calculated, and the loss value of the first link signal control device 610 can be adjusted according to the power value measured by the instrument to ensure that the device A under test has sufficient receiving signal strength and the link stability during the test.

[0070] 5. Control the device A under test to continuously radiate signals at maximum power, and control the connection mode of the second link switch 641 to the connection state of a-b' and b-a'. In the current state of the first link switch 3 and the second link switch 641, the communication antenna 111 is connected to a signal end of the second combiner 632, and then connected to the signal coupling board 201 through the second combiner 632. The signal measuring instrument 5 is connected to a signal end of the third combiner 633, and the signal of the detection antenna 112 can enter the signal measuring instrument 5 through the third combiner 633. The acquisition frequency of the signal measuring instrument 5 is set to be the same as the output signal frequency of the device A under test, and the measured power value is recorded as Power_eirp. Based on this power value and the link insertion loss, the radiation power value of the signal coupling board 201 can be calculated. The loss value of the second link signal control device 620 is adjusted according to the power value measured by the instrument to ensure that the device B under test has sufficient received signal strength and ensure link stability during the test.

[0071] 6. Calculate the EIRP at this angle (theta，phi) The value is as follows:

[0072] EIRP (theta，phi) =Power_eirp+S 21 (OTA, f)+S 21 (tx, f)

[0073] Where: EIRP (theta，phi) --(theta, phi) angle equivalent radiated power value (unit: dBm); Power_eirp is the power value measured by the current signal measuring instrument 5 (unit: dBm); S 21(OTA, f) is the spatial loss value between the current angle detection antenna 112 and the device under test A in the anechoic chamber and the total loss of the switch and related lines (unit: dB); S 21 (tx, f) is the total value of other losses in the link, mainly including the total value of the second link switch 641, the fixed attenuator 606, the third combiner 633, the first link switch 3 and related line losses (unit: dB).

[0074] 7. Control antenna switch 102 to set the Theta angle to a second angle different from the first Theta angle, and repeat steps 4 to 7 to complete EIRP measurements for all second Theta angles. Of course, the Theta angles may also include a third, fourth, or more angles.

[0075] 8. Control the switching center turntable 101 to rotate to another second Phi angle, which is different from the first Phi angle. Repeat 4 to 8 to complete the EIRP measurement of all Phi and theta angles. That is, complete all Theta angle measurements at each Phi angle. Then, the EIRP at each angle can be calculated. (theta，phi) , and finally record and save all angle EIRP data.

[0076] The above embodiment controls the Phi angle of the central turntable and the Theta angle of the antenna switch; then controls wireless information exchange between devices A and B to measure power status and ultimately measure equivalent radiated power. Furthermore, the Phi and Theta angles can be changed to measure equivalent radiated power at various angles.

[0077] The following describes the steps for measuring the equivalent radiation sensitivity (EIS) using the device:

[0078] The method for measuring the equivalent radiation sensitivity (EIS) of an antenna of an Internet of Things communication device based on the device includes the following steps:

[0079] 1. Similar to the above embodiment, before testing, all parts of the path are calibrated and confirmed, including the air path loss between the test antenna in the darkroom and the center path of the test turntable, as well as the loss of each part of the link. The link loss value of each part in the signal adjustment device 6 is calibrated. Since the two paths of the combiner have the characteristics of equal amplitude and phase, in order to simplify the description, this embodiment assumes its performance under ideal conditions. In actual engineering applications, it is necessary to calibrate the loss values ​​of the two ports of each combiner separately. The specific calibration method is not detailed here.

[0080] 2. Place the device A under test at the center of the turntable of the multi-probe anechoic chamber 1, and place the auxiliary device B under test in the test bracket 202 in the shielding box 2, and keep its relative position to the signal coupling board 201 unchanged.

[0081] 3. Control central turntable 101 to the first Phi angle, control antenna switch 102 to the first Theta angle, and control first link switch 3 to the a-a', b-b' connection. Furthermore, set the adjustable attenuator 613 and amplifier 612 in first link signal control device 610 and second link signal control device 620 to initial values ​​to ensure a relatively ideal initial value for communication link loss.

[0082] 4. Control the wireless information interaction between the device under test A and the device under test B, and control the connection mode of the second link switching switch 641 to be a-b', b-a' connection state. In the current connection state of the first link switching switch 3 and the second link switching switch 641, the communication antenna 111 is connected to the common end of the third combiner 633, and one signal end of the third combiner 633 is connected to the signal measuring instrument 5. The signal of the communication antenna 111 can enter the signal measuring instrument 5 through the third combiner 633. The other signal end of the third combiner 633 is connected to the first combiner 631 and then to the signal coupling board 201. Set the acquisition frequency of the signal measuring instrument 5 to be the same as the output signal frequency of the device under test A, and measure the power value. Based on this power value and the link insertion loss, the radiation power value of the signal coupling board 201 can be calculated. According to the power value measured by the instrument, the loss value of the second link signal control device 620 is adjusted to ensure that the device under test B has sufficient received signal strength and the link stability during the test process.

[0083] 5. Control the second link switching switch 641 to lock the connection state of a-a' and b-b'; at this time, the signal measuring instrument 5 is connected to a signal end of the second combiner 632, and the signal of the signal coupling board 201 can enter the signal measuring instrument 5 through the first combiner 631 and the second combiner 632. Set the acquisition frequency of the signal measuring instrument 5 to be the same as the output signal frequency of the device B under test, and read the power value Power_eis of the signal measuring instrument 5 at this time. Based on this power value and the link insertion loss, the power value radiated by the detection antenna 112 can be calculated, and the loss value of the first link signal control device 610 can be adjusted according to the power value measured by the instrument to ensure that the device A under test has sufficient receiving signal strength and the link stability in the initial state of the test.

[0084] 6. Increase the loss value of the first link signal control device 610 according to a certain step value to reduce the power value radiated by the detection antenna 112, and determine whether the communication performance between the device under test A and the device under test B meets the preset worst-case requirements. If the preset requirements are met, further increase the loss value of the first link signal control device 610 until the preset requirements are met. Record the Power_eis and the loss value S of the link signal control device 610 at this time 21 (610, f).

[0085] 7. Calculate the EIS angle (theta，phi) The value is as follows:

[0086] EIS (theta，phi) =Power_eis-S 21 (OTA, f)-S 21 (610, f)-S 21 (rx, f)

[0087] Where: EIS (theta，phi) is the equivalent radiant sensitivity value at the (theta, phi) angle (unit: dBm); Power_eis is the power value measured by the current signal measuring instrument 5 (unit: dBm); S 21 (OTA, f) is the spatial loss value between the current angle detection antenna 112 and the device under test A in the anechoic chamber and the total loss of the antenna switch and related lines (unit: dB); S 21 (610, f) is the loss value of the link signal control device 610, including the total loss value of its internal isolator, adjustable amplifier, and adjustable attenuator (unit: dB); S 21 (rx, f) is the total value of other loss calibration in the link, mainly including the second link switch 641, the third fixed attenuator 603 and the fourth fixed attenuator 604, the second combiner 632, the first link switch 3 and the total value of related line losses (unit: dB).

[0088] 8. Control the antenna switch 102 so that the Theta angle is another second angle, and repeat steps 4 to 8 to complete all EIS measurements with the Theta angle being another second angle.

[0089] 9. Control the switching center turntable 101 to rotate until the Phi angle is another second angle, repeat 4 to 9, and complete the EIS measurement of all Phi and theta angles; record the EIS measurement results of all angles. The above embodiment can complete the EIS measurement of the antenna system.

[0090] The following describes a method for measuring the communication distance of an IoT communication device using a device.

[0091] According to the above steps, the EIRP and EIS values ​​of each angle of the device under test A based on the device under test B are completed respectively. Since the communication distance between the communication systems must also know the EIRP and EIS values ​​of the two devices in the communication system, the method steps for measuring accurate communication distance are as follows:

[0092] 1. According to the above steps, complete the EIRP and EIS of each angle of the device A based on the device B, and record the difference as EIRP DUT_A ,EIS DUT_A .

[0093] 2. Change the relative positions of the device under test A and the device under test B. Place the device under test B in the multi-probe anechoic chamber 1 and place the device under test A in the shielding box 3.

[0094] 3. Refer to the EIRP and EIS measurement method of device A to obtain the EIRP and EIS difference of device B at each angle based on device A and record them as EIRP DUT_B ,EIS DUT_B .

[0095] 4. Calculate the communication distance between two devices without obstruction according to the formula:

[0096]

[0097]

[0098] Where: R (A-B) The distance (in km) that the signal transmitted by device A to be received by device B under test can be transmitted; R (B-A) The distance (in km) that the signal transmitted by device B can be transmitted to device A under test; EIRP DUT_A(theta1，phi1) and EIS DUT_A(theta1，phi1) They are the equivalent radiated power and equivalent radiated sensitivity (in dBm) of the device under test in the direction of angle (theta1, phi1); EIRP DUT_B(theta2，phi2) and EIS DUT_B(theta2，phi2) are the equivalent radiated power and equivalent radiated sensitivity (in dBm) of the device B under test in the direction of angle (theta2, phi2); f is the communication frequency in GHz, and the communication distance between the two communication devices takes the minimum value: R = min (R (A-B) ,R (B-A) ). This completes the test of the communication distance.

[0099] In some embodiments, the determination of whether the communication performance between the device under test A and the device under test B meets the preset worst-case requirements includes the following steps: the device under test A sends specific information to the device under test B, and the device under test B is preset to send the original information back to the device under test A after receiving the information; after receiving the returned information, the device under test A compares it with the sent information to determine whether the device under test B has successfully received it. That is, a loopback judgment method is used for judgment, such as Figure 4 As shown in the figure, the loopback method involves sending specific information to the UUT. Upon receiving the information, the UUT is programmed to transmit the original information back to the sender. The sender then compares the returned information with the sent information to determine whether the UUT successfully received it. This method requires that the UUT's underlying software or application layer software supports automatic feedback.

[0100] Alternatively, in certain embodiments, determining whether the communication performance between device A and device B meets a preset worst-case scenario includes the following steps: sending specific information from device A to device B, reading the received information from device B via wired or wireless information exchange, and comparing the information with the transmitted information. This method employs a direct judgment method, which involves sending specific information to the device under test, reading the received information from the device under test via wired, wireless, or other information exchange, and comparing the information with the transmitted information. This method requires that the device under test physically and software-capable of reading information.

[0101] Some devices under test lack these conditions, or these conditions result in low test efficiency and high economic costs. For example, a switch panel in a smart home generates a relay on / off upon receiving a wireless control command. During testing, the success of wireless communication can be determined by checking whether the relay is on or off. However, this method can be extremely inconvenient during testing, especially when the device under test is placed in a darkroom.

[0102] Based on the above problem description, a judgment method is proposed based on the device of the present invention: the above method is that when performing EIS measurement, step 6 needs to determine whether the communication performance between the device A under test and the device B under test meets the preset worst-case requirements. The judgment method is to change the connection mode of the second link switching switch 641 to a-b', b-a', and the signal measuring instrument 5 sets the reading mode to the time domain scanning mode. At this time, the signal measuring instrument 5 is connected to the radio wave darkroom communication antenna 111. During the test, the communication antenna can first receive the electromagnetic signal 01 radiated by the detection antenna, and then receive the electromagnetic signal 02 radiated by the device A under test to form a complete signal communication process. Pre-record a normal and complete waveform of a communication link under normal communication conditions, including the time interval information of the waveform, the waveform amplitude information, the waveform width and other information. The normal and complete waveform should include all waveforms that successfully complete information interaction and can represent successful communication; during the EIS measurement process, the waveform conditions of the interaction process are read by the signal measuring instrument, and compared with all the recorded normal waveforms in sequence to determine whether the communication is successful. As Figure 5 and Figure 6 They respectively indicate that the communication antenna 111 receives the signals radiated by the detection antenna 112 and the device A under test. Since the amplitude values ​​of the two signals received by the communication antenna 111 are not exactly the same, it is possible to comprehensively judge which signal is radiated by the detection antenna and which signal is radiated by the device A under test through the amplitude value and the signal insertion loss between the detection antenna 112 and the communication antenna 111.

[0103] like Figure 5 As shown, Figure 5 The figure shows the waveform collected by the signal measuring instrument 5. The figure is just a simple and easy-to-understand description of the judgment method. The method used in actual engineering application is more complex and rigorous. Figure 6 As shown, Figure 6 This method is used to determine whether communication between devices A and B is normal, which is used to determine the EIS test. This method supplements EIS test step 6. After the determination is completed, the second link switch 641 needs to be switched to the connection mode a-a' or b-b' to continue the EIS measurement step.

[0104] It should be noted that although the above embodiments have been described herein, this does not limit the scope of patent protection of the present invention. Therefore, based on the innovative concept of the present invention, changes and modifications to the embodiments described herein, or equivalent structural or equivalent process transformations made using the contents of the present invention's specification and drawings, and direct or indirect application of the above technical solutions to other related technical fields, are all included in the scope of patent protection of the present invention.

Claims

1. The antenna performance test device for Internet of Things communication equipment is characterized by: It includes a multi-probe anechoic chamber, a shielding box, a first link switching switch, a signal adjustment device and a signal measuring instrument. The multi-probe anechoic chamber includes a central turntable for placing the device to be tested, a plurality of detection antennas arranged in a circle around the central turntable in the vertical direction, and a communication antenna arranged around the central turntable. The detection antenna and the communication antenna are respectively connected to the first link switching switch through a radio frequency cable and then through a darkroom waveguide port; the two output ends of the first link switching switch are connected to the two input ends of the signal adjustment device, and a test bracket and a signal coupling plate for placing and fixing the object to be tested and a signal coupling plate are provided in the shielding box. The signal coupling plate is connected to the signal adjustment device through a radio frequency cable, and the output end of the signal adjustment device is connected to the signal measuring instrument; the signal adjustment device is used to switch and adjust the signal input from the input end and input it into the signal measuring instrument; The signal adjustment device includes a first combiner, a second combiner, a third combiner, a load, a second link switch, a first link signal control device, and a second link signal control device; the first combiner is connected to the signal coupling board and divides the signal path of the signal coupling board into two paths, one of which is connected to the second combiner as a signal output, and the other is connected to the output end of the second link signal control device; the second combiner divides the signal into two paths, one of which is connected to the input end of the first link signal control device and then the output end of the first link signal control device is connected to the first link switch, and the other is connected to the second link switch and then to the signal measuring instrument; The third combiner is connected to the first link switch and divides the signal into two paths, one path is connected to the second link switch, and the other path is connected to the input end of the second link signal control device. The second link switch is connected to the load. The first link signal control device and the second link signal control device are used to perform unidirectional transmission of the link signal and adjust the signal level. The test object is used for auxiliary testing; The multi-probe anechoic chamber further includes an antenna switching switch for detecting antenna selection, one end of the antenna switching switch is connected to the detection antenna, and the other end is connected to the first link switching switch through the anechoic chamber waveguide port.

2. The IoT communication device antenna performance test device according to claim 1, characterized in that: The signal adjustment device further includes a first fixed attenuator, a second fixed attenuator, a third fixed attenuator, a fourth fixed attenuator, a fifth fixed attenuator, and a sixth fixed attenuator; the first combiner is connected to the signal coupling board via the first fixed attenuator; one path of the first combiner is connected to the second combiner via the second fixed attenuator, and another path of the first combiner is connected to the output end of the second link signal control device via the third fixed attenuator; and one path of the second combiner is connected to the input end of the first link signal control device via the fourth fixed attenuator; The output end of the first link signal control device is connected to the first link switching switch through a fifth fixed attenuator, and the other path of the second combiner is connected to the second link switching switch through a sixth fixed attenuator and then connected to the signal measuring instrument; the third combiner is connected to the first link switching switch and divides the signal into two paths, one path is connected to the second link switching switch, and the other path is connected to the input end of the second link signal control device, and the second link switching switch is connected to the load.

3. The IoT communication device antenna performance test device according to claim 1, characterized in that: The first link signal control device and the second link signal control device have the same structure, including a signal input end and a signal output end, with a first isolator, an adjustable signal amplifier, an adjustable attenuator and a second isolator connected in series between the two ends respectively.

4. The IoT communication device antenna performance test device according to claim 3, characterized in that: A switch capable of short-circuiting the signal is connected in parallel to the adjustable signal amplifier, and is used to short-circuit the adjustable signal amplifier to reduce active noise caused by the amplifier.

5. The IoT communication device antenna performance test device according to claim 1, characterized in that: It also includes a control and test system, which is connected to the multi-probe anechoic chamber, the shielding box, the first link switch, the signal adjustment device and the signal measuring instrument.

6. The IoT communication device antenna performance test device according to claim 1, characterized in that: The test bracket is an electromagnetic transparent material bracket.

7. The IoT communication device antenna performance test device according to claim 1, characterized in that: The signal measuring instrument is a spectrum analyzer or an oscilloscope.

8. The IoT communication device antenna performance test device according to claim 1, characterized in that: The number of the detection antennas is 5 or more.

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