A fast and efficient array beam squint angle calibration method for equivalent isotropically radiated power test

Abstract

The application discloses a kind of fast and efficient array beam deflection angle calibration methods for equivalent isotropically radiated power test, including pre-calibration stage and calibration stage;Pre-calibration stage, a standard antenna under test is used as reference, placed in the quiet zone of compact range;In the case of unfocused feed, rotate reference 0 and 20, record the two sets of data;In the case of defocus, rotate reference 0, θ m , 30 and get the corresponding S 21 , record the three sets of data;Get the expression of two deflection angle fitting functions;Calibration stage places the problematic device in the quiet zone of compact range, and positions the feed according to the feed deflection angle 0, 20, -20, respectively, to obtain the corresponding S 21 ;The three sets of test values are brought into the unfocused compact range angle power fitting function and the defocused compact range angle power fitting function, to obtain the peak deflection angle and deflection direction of the problematic device.The application realizes the angle calibration of production line test equipment, with the characteristics of convenience and efficiency.

Description

Technical Field

[0001] This invention relates to the field of compact field production line testing technology, and specifically to a fast and efficient array beam deflection calibration method for equivalent omnidirectional radiated power testing. Background Technology

[0002] The continuous innovation of 5G and even 6G has greatly promoted the development of the Internet of Things (IoT), while also placing higher demands on the quantity and quality of communication devices. In recent years, an increasing number of high-gain antenna arrays have been applied to various communication devices and terminal equipment. With the increase in commercial frequencies and the expansion of bandwidth, the miniaturization of communication devices has become a major trend, bringing with it many manufacturing and assembly challenges. Among these, the most serious problem is the shift in the maximum radiation direction of the high-gain antenna array within the device. Even a small angle (generally less than 30°) can significantly affect the air interface radiation performance of the device, such as peak equivalent isotropic radiated power (EIRP). Traditional antenna pattern measurement methods can be used to calibrate the angle, such as in far-field measurements and multi-probe systems, but these increase measurement costs and complexity. Furthermore, as the number of products under test increases, traditional testing methods increase testing costs and reduce the efficiency of commercial product testing. Therefore, air interface test production line testing systems with efficient angle calibration methods are of significant development potential.

[0003] Currently, common testing solutions are mainly divided into far-field testing and near-field testing, but neither is suitable for production line testing scenarios. Far-field testing requires meeting antenna far-field conditions, thus demanding too much testing space and imposing excessive space costs on the production line. Near-field testing includes near-field scanning, near-field multi-probe testing, and reflector compact field testing. Near-field scanning uses a mechanical scanning frame, which is the most time-consuming and inefficient. The platform setup costs for near-field multi-probe and reflector compact field testing are too high, and they are also unsuitable for large-scale equipment testing.

[0004] Transmission compaction is a feasible production line testing solution, but existing transmission compaction systems lack angle calibration capabilities. This is primarily because both the feed antenna and the transmission collimator in a transmission compaction system are symmetrical structures, resulting in a symmetrical plane wave quiet zone. This lack of angular direction determination capability further complicates the issue, as the relationship between angle and received power is unknown. Summary of the Invention

[0005] To overcome the above technical problems, the present invention aims to provide a fast and efficient array beam deflection calibration method for equivalent omnidirectional radiated power testing. This method combines a transmission-type compact field structure, obtains the relationship between the peak radiation offset angle of the antenna under test and the received power based on the characteristics of the radiation field distribution of the transmission collimator, and utilizes the defocusing principle to combine the non-defocused and defocused compact field to obtain a novel testing method. This method can realize the angle calibration of production line testing equipment and has the characteristics of convenience and efficiency.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A fast and efficient array beam deflection calibration method for equivalent isotropic radiated power testing, comprising a pre-calibration stage and a calibration stage;

[0008] During the pre-calibration phase, a standard antenna under test was used as a reference and placed in the test quiet zone. With the feed unfocused, the reference was rotated by 0° and 20°, and the two sets of data were recorded. The measured two-port network parameters S were also recorded. 21 The numerical value represents the level of energy received by the antenna under test in a compact field; in the case of defocusing, rotating the reference element 0, θ m , 30° and obtain the corresponding S 21 Record these three sets of data; using the five sets of data obtained from the pre-calibration, obtain the expressions for two deflection angle fitting functions, namely the non-defocused compact field angle power fitting function and the defocused compact field angle power fitting function.

[0009] The calibration phase includes data sampling and corresponding test data post-processing steps. The device under test (DUT) is placed in the test quiet zone, and feed antennas one, two, and three are positioned at these three locations according to feed angles of 0°, 20°, and -20°, respectively. The corresponding two-port parameters S are then measured. 21 The three sets of two-port parameters S measured at the three locations 21 The test values ​​are then substituted into the unfocused compact field angle power fitting function and the focused compact field angle power fitting function. Solving the functions yields the peak offset angle and deflection direction of the test piece.

[0010] The two fitting functions in the pre-calibration stage are obtained by analyzing the relationship between the positions of feed antenna one and feed antenna two and different deflection angles, combined with the peak EIRP test index. The specific design steps are as follows:

[0011] The production line testing indicator, the formula for calculating peak equivalent isotropic radiated power, is as follows:

[0012] EIRP(dBm) = P(dBm) + Gain(dBi)

[0013] Where P is the transmit power of the compact field and Gain is the gain of the antenna under test. Since P is the rated power, the antenna gain, which corresponds to the received power in the test quiet zone, becomes the main factor affecting the peak EIRP.

[0014] This paper utilizes the angular rotation characteristics of a high-gain antenna within a quiet zone to simulate the main lobe beam deflection phenomenon caused by manufacturing and assembly factors in reality. The high-gain antenna is a linear array, but this method can also be extended to area arrays. Through the projection principle, i.e., the change characteristics of received power satisfy the projection area mapping relationship with the deflection angle, the following relationship is found between the deflection angle of the high-gain antenna under test and the test quiet zone:

[0015] S 21 (θ)=M p ×cos(θ)+Q original

[0016] This analytical expression is the angle power fitting function for the unfocused compact field, where θ is the deflection angle, and M... p Q is the projection coefficient. original S is the initial projection constant. 21 The parameters of the two-port network between the compressed field and the antenna under test are related to the received power of the compressed field as follows:

[0017] P R =PR×P=|S 21 | 2 P

[0018] Where P R For the received power, it can be seen from this equation that: S 21 Each power level corresponds one-to-one with the received power, using S... 21 As a primary indicator for evaluating peak equivalent isotropic radiated power, however, due to limitations in the size of the test quiet zone, the above deflection angle and S 21 The relationship is limited to 0-20° and it does not have the ability to distinguish the direction of main lobe deflection;

[0019] Next, by moving the compact field feed antenna along the vertical axis, the propagation direction of the quiet zone was deflected, and the relationship between the quiet zone deflection characteristics and the feed tilt angle was investigated, thus obtaining the connection between the feed tilt angle and the deflection angle of the device under test.

[0020] When the feed tilt angle equals the antenna deflection angle, the received power can be restored to its normal value. Utilizing this characteristic, the feed tilt angle can be rationally designed to expand the angle calibration range to 30°. The relationship between its deflection angle and the compact field is as follows:

[0021]

[0022] This analytical expression is the power fitting function for the off-focus compaction field angle, where θ m M is the initial deflection angle. d M u They are 0-θ m θ m The projection factor at -30°, Q d Q u Using the initial projection constants and the angle power fitting function of the unbiased compact field, a calibration range of 0-30° is obtained, and the direction of the deflection angle can be identified:

[0023] When the feed tilt angle and the antenna deflection angle are equal in value but opposite in direction, the obtained S 21 The value is significantly lower than when both are in the same direction, meaning the direction of the antenna deflection angle is determined by different feed tilt angles.

[0024] The post-processing steps in the calibration phase are specifically as follows:

[0025] Step 1: Measure the S-axis of the feed antenna. 21 Substituting the angle power fitting function into the non-deflection compact field, if the solved angle value is between 0-20°, then it is the measured offset angle of the main radiation direction of the device under test; the S values ​​measured by feed antennas two and three... 21 The values ​​are compared. If the value of feed antenna 2 is larger, the main radiation direction will shift counterclockwise. If the value of feed antenna 3 is larger, the main radiation direction will shift clockwise.

[0026] Step Two: If the angle value obtained by the angle power fitting function of the undeflected compacted field in Step One is greater than 20°, then substitute it into the angle power fitting function of the deflected compacted field and solve for the main radiation direction offset angle of the device under test; similarly, use the S values ​​measured by feed antenna two and feed antenna three... 21 The values ​​are compared. If the value of feed antenna 2 is larger, the main radiation direction will shift counterclockwise. If the value of feed antenna 3 is larger, the main radiation direction will shift clockwise.

[0027] The feed antenna one, feed antenna two, and feed antenna three are three different test positions, and their directions are directly facing the compact field transmission collimator.

[0028] The beneficial effects of this invention are:

[0029] This invention combines a transmission compact field design, resulting in a compact structure and a simple and efficient method. Only five sets of data need to be measured in the pre-calibration stage and three sets of data are needed in the calibration stage to obtain the specific deflection angle of the problematic device. Moreover, it can achieve production line-based product testing without the need for complex equipment and facilities, effectively improving testing efficiency and reducing testing costs. It meets the market needs of most existing wireless equipment manufacturers and therefore has high commercial value. Attached image description:

[0030] Figure 1 This is a schematic diagram of a commercial test solution for calibrating antenna angles in conjunction with a test conveyor belt.

[0031] Figure 2 This is a schematic diagram of the non-biased compact field sampling method during the pre-calibration stage.

[0032] Figure 3 This is a schematic diagram of the off-focus compaction field sampling measures during the pre-calibration stage.

[0033] Figure 4 This is a schematic diagram of the compacted field sampling measures during the calibration phase.

[0034] Figure 5 This is a comparison chart of the angle power fitting function for the unbiased compact field.

[0035] Figure 6 This is a comparison chart of the angle power fitting function for the focal compression field. Detailed Implementation

[0036] The present invention will be further described in detail below with reference to the embodiments.

[0037] A fast and efficient array beam deflection calibration method for equivalent isotropic radiated power testing, comprising a pre-calibration stage and a calibration stage;

[0038] During the pre-calibration phase, a standard antenna under test (meaning an antenna with a standard beam direction selected from a batch of antennas under test before the pre-calibration experiment, serving as the reference antenna in the pre-calibration; during the pre-calibration experiment, this antenna is rotated to simulate an antenna under test with angular deflection) is used as a reference and placed parallel to the compacted field collimator in a quiet region (e.g., ...). Figure 2 θ1 (where θ1 is the initial angle 0°); with the feed unfocused, rotate the reference element counterclockwise by 0° and 20° around the horizontal axis of the antenna under test, and record these two sets of data (record the measured two-port network parameters S). 21 The numerical value represents the level of energy received by the antenna under test in a compact field; in the case of defocusing, (such as...) Figure 3 In the context of θ3 (which is the initial angle 0°), rotate the reference element 0, θ m , 30° and obtain the corresponding S 21Record these three sets of data; using the five sets of data obtained from the pre-calibration, obtain the expressions for two deflection angle fitting functions, namely the non-defocused compact field angle power fitting function and the defocused compact field angle power fitting function.

[0039] The calibration phase (at this point, the antenna under test has completely unknown beam direction; therefore, the purpose of this phase is to detect their deflection angles) includes data sampling steps and corresponding test data post-processing steps. The device under test (DUT) 6 is placed in the test quiet zone. Feed antennas one, two, and three are set up according to feed deflection angles of 0°, 20°, and -20° (feed antennas are compact field radiating antennas; their deflection angles need to be obtained through compact field testing; this can be understood as the DUT transmitting information and the feed antenna receiving information, with two-port parameters S). 21 (That is, the numerical value representing the received information), located at these three positions respectively, and the corresponding two-port parameter S is measured. 21 These three sets of test values ​​(three sets of two-port parameters S measured at three locations) 21 The test value is substituted into the unbiased compact field angle power fitting function and the biased compact field angle power fitting function. Solving the function will yield the peak offset angle and deflection direction of the test part 6.

[0040] like Figure 1 As shown, this invention utilizes the proposed antenna angle calibration method and combines it with the production line testing conditions of the transmission compact field to obtain a fast and efficient test calibration scheme.

[0041] 1, 2, and 3 represent three feed antennas placed in three different test positions, with their orientation facing the compact field collimator. In the diagram, 4 is the transmission collimator, 5 is the shaded area of ​​the test quiet zone, 6 is the test device with antenna radiation peak offset due to assembly or manufacturing defects, 7 is the mechanical rotating conveyor belt, and 8 is the standard test device without antenna radiation peak offset.

[0042] The dark graphic above the device under test (DUT) in the figure is a schematic diagram of the antenna radiation pattern. The main lobe of the radiation pattern of the standard DUT 8 is vertical, which meets the product requirements. However, the main lobe of the radiation pattern of the problematic DUT 6 has a significant deviation angle, thus greatly affecting its radiation performance (peak EIRP). Its deflection angle needs to be calibrated. This can be achieved by simultaneously feeding the antennas to obtain the corresponding received power. Using these three sets of data, the corresponding deflection angle can be obtained according to the theoretical model curve.

[0043] The effective calibration range of this design is -30° to 30°. The device under test can be a linear array or a square array antenna. The entire calibration process is fast and efficient, meeting the calibration needs of the future market for miniaturized communication devices.

[0044] like Figure 2The figure shows the non-defocused compact field sampling method during the pre-calibration stage. 1 is the feed antenna placed at the center of the compact field, 4 is the compact field collimator, and 8 is the standard test piece used in the pre-calibration stage. As shown, the standard test piece is rotated around a horizontal axis at two angles, 0° and 20°, and the S values ​​corresponding to these two angles are measured. 21 The numerical values ​​can be used to calculate the parameters of the angle power fitting function for a deflection-free compaction field.

[0045] like Figure 3 The diagram shows a schematic of the off-focus compact field sampling method during the pre-calibration stage. 2 represents a feed antenna moving along the positive vertical axis with a feed angle of -20°, 4 is the compact field collimator, and 8 is the standard test piece used in the pre-calibration stage. As shown, the standard test piece rotates around the horizontal axis at three angles: 0° and θ. m And 30°, and tested to obtain the S corresponding to these three angles. 21 The numerical values ​​can be used to calculate the parameters of the power fitting function for the deflected compaction field angle.

[0046] like Figure 4 The diagram shows the data sampling steps during the calibration phase, illustrating the compact field sampling method. 1, 2, and 3 represent the feed antenna, for example... Figure 1 The structure in the figure can be tested by placing the three feed antennas in three different positions, or by assembling the three antennas into a linear array and placing them in corresponding positions. The results are the same, but the latter saves more time and steps. 4 represents the compact field collimator, and 6 represents the component under test (DUT) with a problem where the antenna radiation peak shifts due to assembly or manufacturing defects. As shown in the figure, the DUT is placed in the compact field quiet zone, and the corresponding three S values ​​are obtained through testing the antennas at three positions. 21 Numerical value.

[0047] The post-processing steps in the calibration phase are as follows:

[0048] Step 1: Measure the S-values ​​obtained from the feed antenna-1 21 Substituting the angle power fitting function into the non-deflection compact field, if the solved angle value is between 0 and 20°, then it is the measured offset angle of the main radiation direction of the device under test; the S measured by feed antenna 2 and feed antenna 3... 21 The values ​​are compared. If the value of feed antenna 2 is larger, the main radiation direction will shift counterclockwise. If the value of feed antenna 3 is larger, the main radiation direction will shift clockwise.

[0049] Step 2: If the angle value obtained by the angle power fitting function of the undeflected compacted field in Step 1 is greater than 20°, then substitute it into the angle power fitting function of the deflected compacted field and solve for the offset angle of the main radiation direction of the device under test; similarly, use the S values ​​measured by feed antenna 2 and feed antenna 3 to... 21The values ​​are compared. If the value of feed antenna 2 is larger, the main radiation direction will shift counterclockwise. If the value of feed antenna 3 is larger, the main radiation direction will shift clockwise.

[0050] Figure 5 This is a comparison graph of the fitting function for the angle power of a deflection-free compaction field. The solid line represents the test data, and the dashed line represents the fitting curve of the fitting function. The graph shows that the fitting function has excellent fitting characteristics within the range of 0-20°. Only two sets of test position data are needed to calibrate the angle of the test piece.

[0051] Figure 6 This is a comparison graph of the fitting function for the angle power of the focused, compressed field. The solid line represents the test data, and the dashed line represents the fitting curve of the fitting function. The graph shows that the fitting function has excellent fitting characteristics within the range of 20°-30°. Only three sets of test position data are needed to calibrate the angle of the test piece and to calibrate the direction of the deflection angle based on two opposite focusing positions.

Claims

1. A fast and efficient array beam deflection calibration method for equivalent isotropic radiated power testing, characterized in that, Includes a pre-calibration phase and a calibration phase; During the pre-calibration phase, a standard antenna under test was used as a reference and placed in the test quiet zone (5). With the feed unfocused, the reference was rotated by 0° and 20°, and the two sets of data were recorded. The measured two-port network parameters S were also recorded. 21 The numerical value represents the level of energy received by the antenna under test in a compact field; in the case of defocusing, rotating the reference element 0, θ m , 30° and obtain the corresponding S 21 Record these three sets of data; Using the five sets of data obtained from pre-calibration, expressions for two deflection angle fitting functions were obtained: the non-defocused compact field angle power fitting function and the defocused compact field angle power fitting function. The calibration phase includes data sampling steps and corresponding test data post-processing steps. The test device (6) is placed in the test quiet area (5). Feed antenna one (1), feed antenna two (2) and feed antenna three (3) are positioned at these three locations according to the feed angles of 0°, 20° and -20°, respectively, and the corresponding two-port parameters S are measured. 21 The three sets of two-port parameters S measured at the three locations 21 The test value is then substituted into the unfocused compact field angle power fitting function and the focused compact field angle power fitting function. Solving the function will yield the peak offset angle and deflection direction of the test piece (6).

2. The fast and efficient array beam deflection calibration method for equivalent isotropic radiated power testing according to claim 1, characterized in that, The two fitting functions in the pre-calibration stage are obtained by analyzing the relationship between the positions of feed antenna one (1) and feed antenna two (2) and different deflection angles, combined with the peak EIRP test index. The specific design steps are as follows: The production line testing indicator, the formula for calculating peak equivalent isotropic radiated power, is as follows: EIRP(dBm) = P(dBm) + Gain(dBi) Where P is the transmit power of the compact field and Gain is the gain of the antenna under test. Since P is the rated power, the antenna gain, which corresponds to the received power in the test quiet zone (5), becomes the main factor affecting the peak EIRP. The angular rotation characteristics of a high-gain antenna in the quiet zone are used to simulate the main lobe beam deflection phenomenon caused by manufacturing and assembly factors in reality. The high-gain antenna is a linear array. This method can also be extended to a surface array. Through the projection principle, that is, the change characteristics of the received power satisfy the projection area mapping relationship with the deflection angle, the following relationship exists between the deflection angle of the high-gain antenna under test and the test quiet zone (5) through calculation: S 21 (θ)=M p ×cos(θ)+Q original This analytical expression is the angle power fitting function for the unfocused compact field, where θ is the deflection angle, and M... p Q is the projection coefficient. original S is the initial projection constant. 21 The parameters of the two-port network between the compressed field and the antenna under test are related to the received power of the compressed field as follows: P R =PR×P=|S 21 | 2 P Where P R For the received power, it can be seen from this equation that: S 21 Each power level corresponds one-to-one with the received power, using S... 21 As the main indicator for evaluating peak equivalent isotropic radiated power, however, due to the limitation of the size of the test quiet zone (5), the above deflection angle and S 21 The relationship is limited to 0-20° and it does not have the ability to distinguish the direction of main lobe deflection; Next, by moving the compact field feed antenna along the vertical axis, the propagation direction of the quiet zone was deflected, and the relationship between the deflection characteristics of the quiet zone and the feed tilt angle was investigated, thus obtaining the connection between the feed tilt angle and the deflection angle of the device under test (6).

3. The fast and efficient array beam deflection calibration method for equivalent isotropic radiated power testing according to claim 2, characterized in that, When the feed tilt angle equals the antenna deflection angle, the received power can be restored to its normal value. Utilizing this characteristic, the feed tilt angle can be rationally designed to expand the angle calibration range to 30°. The relationship between its deflection angle and the compact field is as follows: This analytical expression is the power fitting function for the off-focus compaction field angle, where θ m M is the initial deflection angle. d M u 0-θ m θ m The projection factor at -30°, Q d Q u Using the initial projection constants and the angle power fitting function of the unbiased compact field, a calibration range of 0-30° is obtained, and the direction of the deflection angle can be identified: When the feed tilt angle and the antenna deflection angle are equal in value but opposite in direction, the obtained S 21 The value is significantly lower than when both are in the same direction, meaning the direction of the antenna deflection angle is determined by different feed tilt angles.

4. A fast and efficient array beam deflection calibration method for equivalent isotropic radiated power testing according to claim 1, characterized in that, The post-processing steps in the calibration phase are specifically as follows: Step 1: Measure the S value obtained from feed antenna 1 (1) 21 Substituting the angle power fitting function of the non-deflection compact field, if the angle value obtained is between 0 and 20°, then it is the measured offset angle of the main radiation direction of the device under test; the S measured by feed antenna two (2) and feed antenna three (3) 21 Compare the values. If the value of feed antenna 2 (2) is larger, the main radiation direction will shift counterclockwise. If the value of feed antenna 3 (3) is larger, the main radiation direction will shift clockwise. Step 2: If the angle value obtained by the angle power fitting function of the undeflected compacted field in Step 1 is greater than 20°, then substitute it into the angle power fitting function of the deflected compacted field and solve for the offset angle of the main radiation direction of the device under test; similarly, the S measured by feed antenna 2 (2) and feed antenna 3 (3) 21 The values ​​are compared. If the value of feed antenna 2 (2) is larger, the main radiation direction will shift counterclockwise. If the value of feed antenna 3 (3) is larger, the main radiation direction will shift clockwise.

5. A fast and efficient array beam deflection calibration method for equivalent isotropic radiated power testing according to claim 4, characterized in that, The feed antenna one (1), feed antenna two (2) and feed antenna three (3) are three different test positions, and their directions are directly opposite the compact field transmission collimator (4).

Images