Device, system and method for determining antenna coefficient

Abstract

The present invention relates to the field of antenna technology, and provides a device, system and method for determining antenna coefficients. The device includes a radiating unit and a balun. The radiating unit is connected to the balun. The balun is used to connect to a waveguide parameter measuring device. The radiating unit includes a first array, a second array and a radio frequency coaxial connector. The radio frequency coaxial connector is connected to the first array and the second array respectively through a first cable and a second cable; the radio frequency coaxial connector is connected to the balun; and the gap between the first array and the second array is less than 3 mm. By controlling the gap between the first array and the second array, the problem that the gap between the dipole feed source cannot be reduced is solved, so that the calculation model is closer to the real antenna, and the calculation value has a small error not only at the resonant frequency, but also in a wide frequency band that deviates from the resonant frequency, that is, a wide-band computable antenna is realized.

Description

Technical Field

[0001] The present invention relates to the field of antenna technology, and in particular to a device, system and method for determining antenna coefficients. Background Art

[0002] In the prior art, for antennas in the frequency band of 30MHz to 1000MHz, they usually include two parts: a balun (balanced-unbalanced converter) and a radiating unit. For the radiating unit part, the moment method can usually be used for precise calculation; the balun part usually cannot be accurately calculated using the moment method or other full-wave analysis methods. Generally, its S-parameters are measured by a vector network analyzer, and then the balun part is included in the analytical expression to approximate the actual antenna. In order to accurately measure the S-parameters, the part connecting the balun and the radiating unit needs to be designed as a standard RF connector.

[0003] However, due to the complex structure of the RF coaxial connector, the dipole feed gap in the theoretical calculation model is too large and difficult to reduce, which causes the error of the calculable antenna to increase sharply after it deviates from the resonant frequency, and the higher the frequency, the greater the error. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention provides a device, system and method for determining antenna coefficients.

[0005] In a first aspect, the present invention provides a device for determining an antenna coefficient, comprising a radiating unit and a balun, wherein the radiating unit is connected to the balun, and the balun is used to connect to a waveguide parameter measurement device, and the radiating unit comprises a first array, a second array and a radio frequency coaxial connector, wherein:

[0006] The RF coaxial connector is connected to the first array and the second array through a first cable and a second cable respectively; the RF coaxial connector is connected to the balun; and a gap between the first array and the second array is less than 3 mm.

[0007] In one embodiment, the balun includes a hybrid coupler and a third cable, wherein the first input end and the second input end of the hybrid coupler are respectively connected to a first positive connector and a second positive connector through the third cable; the load end of the hybrid coupler is connected to a first load, and the output end of the hybrid coupler is used to connect to the input end of the parameter measurement device.

[0008] In one embodiment, the radio frequency coaxial connector includes a first female connector and a second female connector, the first female connector is connected to the first male connector, and the second female connector is connected to the second male connector.

[0009] In one embodiment, the gap between the first array and the second array is 2-3 mm, and the length of the first cable or the length of the second cable is 5-10 cm.

[0010] In a second aspect, the present invention provides an antenna coefficient determination system, comprising the above-mentioned antenna coefficient determination device and a waveguide parameter measurement device, wherein the antenna coefficient determination device is connected to the waveguide parameter measurement device; the waveguide parameter measurement device is used to measure the S-parameters of the balun in the antenna coefficient determination device.

[0011] In a third aspect, the present invention provides a method for determining an antenna coefficient based on the above-mentioned antenna coefficient determination system, comprising:

[0012] Obtaining the S-parameters of the balun in the device for determining the antenna coefficient, and obtaining the simulated S-parameters between the first array and the second array;

[0013] Determine a calculated site insertion loss value based on the S-parameters and the simulated S-parameters;

[0014] Measure the actual field insertion loss between the two test antennas at the preset near-field distance;

[0015] Determine the absolute value of the difference between the calculated site insertion loss and the measured site insertion loss. When it is determined that the absolute value of the difference meets the test requirements, configure the transmitting antenna and the receiving antenna based on the test antenna, and when the distance between the transmitting antenna and the receiving antenna meets the preset distance condition, determine the antenna factor of the transmitting antenna or the receiving antenna based on the measured site insertion loss and the height information of the transmitting antenna and the receiving antenna obtained by the frequency scanning method.

[0016] In one embodiment, the distance condition includes that the distance between the transmitting antenna and the receiving antenna is greater than 8 to 10 times the wavelength of the microwave.

[0017] In one embodiment, the antenna coefficient of the transmitting antenna or the receiving antenna is determined based on the measured value of the site insertion loss and the height information of the transmitting antenna and the receiving antenna obtained by the frequency sweeping method, including:

[0018] Based on the measured insertion loss value of the site and the height information of the transmitting antenna and the receiving antenna obtained by the frequency sweep method, the antenna factor of the transmitting antenna or the receiving antenna is determined by the following calculation formula;

[0019]

[0020] Among them, F a is the antenna factor, L SIL It is the measured value of site insertion loss, in dB;

[0021] E D The determination is divided into the following situations:

[0022] A) Antenna coefficient for horizontal polarization:

[0023]

[0024] B) Antenna coefficient for vertical polarization:

[0025]

[0026] d1 and d2 are:

[0027] d1=[R 2 +(h1-h2) 2 ] 1 / 2

[0028] d2=[R 2 +(h1+h2) 2 ] 1 / 2

[0029] Where:

[0030] R——horizontal projection distance between antenna center points, m;

[0031] h1 and h2 are the heights of the transmitting antenna reference point and the receiving antenna reference point, respectively, in m;

[0032] and ——The minimum and maximum height values ​​for the height scan of the receiving antenna, m;

[0033]

[0034] Where:

[0035] f M ——Frequency, MHz.

[0036] C) Free space antenna coefficient:

[0037]

[0038] In one embodiment, determining the calculated value of site insertion loss according to the S-parameter and the simulated S-parameter includes:

[0039] The site insertion loss calculation value is determined using the following calculation formula according to the S-parameters and the simulated S-parameters;

[0040]

[0041] Among them, L cis the calculated value of site insertion loss, e 12 、e 21 、e 22 is the S-parameter calculated by the moment method; where: p 21 、p 22 It can be calculated by the following formula:

[0042]

[0043] Among them, S 11 , S 12 , S 13 , S 21 , S 22 , S 23 , S 31 , S 32 , S 33 is the scattering parameters collected at the first input end, the second input end and the output end of the balun in the first measurement process;

[0044] q 21 ,q 11 It can be calculated by the following formula

[0045]

[0046] Among them, S 11 , S 12 , S 13 , S 21 , S 22 , S 23 , S 31 , S 32 , S 33 These are the scattering parameters collected at the first input end, the second input end, and the output end of the balun in the second measurement process.

[0047] The antenna coefficient determination device, system and determination method provided by the present invention solve the problem that the gap of the dipole feed source cannot be reduced by controlling the gap between the first array and the second array, thereby making the calculation model closer to the real antenna, and the calculation value has a small error not only at the resonant frequency, but also in a wide frequency band that deviates from the resonant frequency, that is, a wide-band computable antenna is realized. The wide-band computable antenna can not only be used for performance verification at the resonant frequency, but can also be directly used as a standard antenna to carry out antenna value transfer, or directly applied to occasions where the antenna value requires very high accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0049] Figure 1 It is a structural schematic diagram of a device for determining antenna coefficients provided by the present invention;

[0050] Figure 2 is a schematic diagram of the structure of the balun provided by the present invention;

[0051] Figure 3 It is a flow chart of the method for determining antenna coefficients provided by the present invention. DETAILED DESCRIPTION

[0052] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0053] Combine the following Figure 1 to Figure 3 The invention describes an apparatus, system and method for determining antenna coefficients.

[0054] Figure 1 A schematic diagram showing the structure of a device for determining antenna coefficients according to the present invention is shown in FIG. Figure 1 The structure includes a radiation unit 11 and a balun 12. The radiation unit 11 is connected to the balun 12. The balun 12 is used to connect to a waveguide parameter measurement device 13. The radiation unit 11 includes a first array 111, a second array 112 and a radio frequency coaxial connector 113, wherein:

[0055] The RF coaxial connector is connected to the first array and the second array through the first cable 114 and the second cable 115 respectively; the RF coaxial connector is connected to the balun; the ratio of the gap between the first array and the second array to the length of the first cable or the length of the second cable is in the range of 10 / 2 to 10 / 6. Furthermore, the gap between the first array and the second array is 2 to 3 mm, and the length of the first cable or the length of the second cable is 5 to 10 cm.

[0056] In this regard, it should be noted that in the present invention, see Figure 2, buy or develop a 0 / 180° hybrid coupler, and make a box with insulating materials, connect a 50Ω load to its ∑ port; the △ port is the input / output port; connect long cables of about 1m in length to ports A and B, and install QMA (male) connectors at the ends (left side) respectively. The balun includes a hybrid coupler and a third cable. The first input end and the second input end of the hybrid coupler are connected to the first male connector and the second male connector respectively through the third cable; the load end of the hybrid coupler is connected to the first load, and the output end of the hybrid coupler is used to connect the input end of the parameter measurement device.

[0057] Cut to form at least 40 half-steel wires of equal length, and require that their phase difference is less than 1° at 1 GHz; two of them are called equivalent replacement cables (i.e., the first cable and the second cable mentioned above), and each half-steel wire in these two equivalent replacement cables is installed with a female SMA connector at both ends; one end of the remaining half-steel wire is installed with a QMA (male) connector.

[0058] See also Figure 1 , an insulating material (as shown by the dotted line in the figure) is used to form a corresponding shape, and the semi-steel wires of the two equivalent replacement cables are bent into corresponding shapes and then inserted into the insulating material.

[0059] Install the two female SMA connectors (i.e., the first female connector and the second female connector) of the equivalent replacement cable to the left QMA connector (i.e., the first positive connector and the second positive connector) of the port of the detachable balun manufactured above, and the connector at the other end of the equivalent replacement cable is connected to the two arrays respectively.

[0060] Accordingly, the present invention provides a system for determining an antenna coefficient, the system comprising the above-mentioned device for determining an antenna coefficient and a waveguide parameter measuring device, the device for determining an antenna coefficient is connected to the waveguide parameter measuring device; the waveguide parameter measuring device is used to measure the S-parameters of the balun in the device for determining an antenna coefficient. Based on the S-parameters of the balun in the device for determining an antenna coefficient measured by the waveguide parameter measuring device, and obtaining the simulated S-parameters between the first array and the second array, the calculated value of the site insertion loss is determined. The calculated value of the insertion loss can participate in the process of judging whether the antenna meets the preset requirements.

[0061] Accordingly, based on the parameter measurement of the antenna coefficient determination system, a method for determining the antenna coefficient is provided, see Figure 3 , the method comprising:

[0062] 31. Obtaining the S-parameters of the balun in the device for determining the antenna coefficient, and obtaining the simulated S-parameters between the first array and the second array;

[0063] 32. Determine the calculated value of site insertion loss based on S-parameters and simulated S-parameters;

[0064] 33. Measure the actual value of site insertion loss between the two test antennas at the preset near-field distance;

[0065] 34. Determine the absolute value of the difference between the calculated site insertion loss and the measured site insertion loss. When it is determined that the absolute value of the difference meets the test requirements, configure the transmitting antenna and the receiving antenna based on the test antenna. When the distance between the transmitting antenna and the receiving antenna meets the preset distance condition, determine the antenna factor of the transmitting antenna or the receiving antenna based on the measured site insertion loss and the height information of the transmitting antenna and the receiving antenna obtained by the frequency scanning method.

[0066] In this regard, it should be noted that the waveguide parameter measurement device uses a fully 3-port calibrated vector network analyzer.

[0067] Using a fully 3-port calibrated vector network analyzer, we measured Figure 2 All S-parameters of the 3-port of the balun (a total of 9 sets of data). If a 2-port network analyzer is used, three measurements are required. The above 9 S-parameters are converted into 4 S-parameters according to the following formula.

[0068]

[0069] In the formula, S 11 , S 12 , S 13 , S 21 , S 22 , S 23 , S 31 , S 32 , S 33 are the scattering parameters collected at the first input end, the second input end and the output end of the balun measurement process.

[0070] In the present invention, the method of moments is used to perform simulation according to the length and diameter of the array to obtain four S-parameters between two arrays.

[0071] In the present invention, the calculated value of site insertion loss is determined based on the S-parameters and the simulated S-parameters, including:

[0072] The calculated value of site insertion loss is determined using the following calculation formula based on the S-parameters and simulated S-parameters;

[0073]

[0074] Among them, L c is the calculated value of site insertion loss, e 12 、e 21、e 22 is the S-parameter calculated by the moment method; where: p 21 、p 22 It can be calculated by the following formula:

[0075]

[0076] Among them, S 11 , S 12 , S 13 , S 21 , S 22 , S 23 , S 31 , S 32 , S 33 is the scattering parameters collected at the first input end, the second input end and the output end of the balun in the first measurement process;

[0077] q 21 ,q 11 It can be calculated by the following formula

[0078]

[0079] Among them, S 11 , S 12 , S 13 , S 21 , S 22 , S 23 , S 31 , S 32 , S 33 These are the scattering parameters collected at the first input end, the second input end, and the output end of the balun in the second measurement process.

[0080] In an open test field, a computable dipole antenna is set up using the near-field method at a preset near-field distance, and accurate installation and alignment are performed to perform measurement verification to obtain the actual insertion loss value of the site. The distance between the transmitting and receiving antennas is less than 20cm, and the height from the ground is more than 1.6m; the purpose is to eliminate the error of the measurement system. Before measurement, the cable needs to be accurately calibrated. For a computable biconical antenna, the distance between the transmitting and receiving antennas generally needs to be more than 5m.

[0081] When the absolute value of the difference between the measured value and the calculated value is less than the preset value, such as less than 0.5db, the antenna can be considered to meet the design requirements; otherwise, it is necessary to return to the above steps to check one by one or redesign and process.

[0082] In the present invention, when the antenna meets the design requirements, within a wide frequency band of 10 MHz to 1100 MHz, and the spacing between the transmitting antenna and the receiving antenna is greater than 8 to 10 times the microwave wavelength, based on the measured value of the site insertion loss and the height information of the transmitting antenna and the receiving antenna obtained by the frequency sweep method, the antenna coefficient of the transmitting antenna or the receiving antenna is determined by the following calculation formula;

[0083]

[0084] Among them, F a is the antenna factor, L SIL It is the measured value of site insertion loss, in dB;

[0085] E D The determination is divided into the following situations:

[0086] A) Antenna coefficient for horizontal polarization:

[0087]

[0088] B) Antenna coefficient for vertical polarization:

[0089]

[0090] d1 and d2 are:

[0091] d1=[R 2 +(h1-h2) 2 ] 1 / 2

[0092] d2=[R 2 +(h1+h2) 2 ] 1 / 2

[0093] Where:

[0094] R——horizontal projection distance between antenna center points, m;

[0095] h1 and h2 are the heights of the transmitting antenna reference point and the receiving antenna reference point, respectively, in m; and ——The minimum and maximum height values ​​for the height scan of the receiving antenna, m;

[0096]

[0097] Where:

[0098] f M - frequency, MHz;

[0099] C) Free space antenna coefficient:

[0100]

[0101] The antenna coefficient determination device, system and determination method provided by the present invention solve the problem that the gap of the dipole feed source cannot be reduced by controlling the gap between the first array and the second array, thereby making the calculation model closer to the real antenna, and the calculation value has a small error not only at the resonant frequency, but also in a wide frequency band that deviates from the resonant frequency, that is, a wide-band computable antenna is realized. The wide-band computable antenna can not only be used for performance verification at the resonant frequency, but can also be directly used as a standard antenna to carry out antenna value transfer, or directly applied to occasions where the antenna value requires very high accuracy.

[0102] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for determining antenna coefficients based on an antenna coefficient determination system, characterized in that: The antenna coefficient determination system includes an antenna coefficient determination device and a waveguide parameter measurement device, wherein the antenna coefficient determination device is connected to the waveguide parameter measurement device; the waveguide parameter measurement device is used to measure the S-parameter of the balun in the antenna coefficient determination device; the antenna coefficient determination device includes a radiation unit and a balun, wherein the radiation unit is connected to the balun, and the balun is used to connect to the waveguide parameter measurement device, characterized in that the radiation unit includes a first array, a second array and a radio frequency coaxial connector, wherein: The RF coaxial connector is connected to the first array and the second array through a first cable and a second cable respectively; the RF coaxial connector is connected to the balun; the gap between the first array and the second array is less than 3 mm; The balun comprises a hybrid coupler and a third cable, wherein the first input end and the second input end of the hybrid coupler are respectively connected to a first positive connector and a second positive connector through the third cable; the load end of the hybrid coupler is connected to a first load, and the output end of the hybrid coupler is used to connect to the input end of the waveguide parameter measurement device; The radio frequency coaxial connector comprises a first female connector and a second female connector, the first female connector is connected to the first male connector, and the second female connector is connected to the second male connector; The gap between the first array and the second array is 2-3 mm, and the length of the first cable or the length of the second cable is 5-10 cm; The method comprises: Obtaining the S-parameters of the balun in the device for determining the antenna coefficient, and obtaining the simulated S-parameters between the first array and the second array; Determine a calculated site insertion loss value based on the S-parameters and the simulated S-parameters; Measure the actual field insertion loss between the two test antennas at the preset near-field distance; Determine the absolute value of the difference between the calculated site insertion loss and the measured site insertion loss, and when it is determined that the absolute value of the difference meets the test requirements, configure the transmitting antenna and the receiving antenna based on the test antenna, and when the distance between the transmitting antenna and the receiving antenna meets the preset distance condition, determine the antenna factor of the transmitting antenna or the receiving antenna based on the measured site insertion loss and the height information of the transmitting antenna and the receiving antenna obtained by the frequency sweeping method; The method of determining the antenna coefficient of the transmitting antenna or the receiving antenna based on the measured value of the site insertion loss and the height information of the transmitting antenna and the receiving antenna obtained by the frequency sweeping method includes: Based on the measured value of the site insertion loss and the height information of the transmitting antenna and the receiving antenna obtained by the frequency sweep method, the antenna factor of the transmitting antenna or the receiving antenna is determined by the following calculation formula; Among them, F a is the antenna factor, L SIL It is the measured value of site insertion loss, in dB; E D The determination is divided into the following situations: A) Antenna coefficient for horizontal polarization: B) Antenna coefficient for vertical polarization: d1 and d2 are: d1=[R 2 +(h1-h2) 2 ] 1 / 2 Where: R——horizontal projection distance between the center points of the antennas, in meters; h1 and h2 are the heights of the transmitting antenna reference point and the receiving antenna reference point, respectively, in meters; and ——The minimum and maximum height values ​​of the receiving antenna height scan, in meters; Where: f M - frequency, MHz; C) Free space antenna coefficient: The determining of the calculated value of site insertion loss according to the S-parameter and the simulated S-parameter includes: The site insertion loss calculation value is determined using the following calculation formula according to the S-parameters and the simulated S-parameters; Among them, L c is the calculated value of site insertion loss, e 11 、e 12 、e 21 、e 22 is the S-parameter calculated by the moment method; where: p 21 、p 22 Calculated by the following formula: Among them, S 11 , S 12 , S 13 , S 21 , S 22 , S 23 , S 31 , S 32 , S 33 is the scattering parameters collected at the first input end, the second input end and the output end of the balun in the first measurement process; q 21 ,q 11 Calculated by the following formula Among them, S 11 , S 12 , S 13 , S 21 , S 22 , S 23 , S 31 , S 32 , S 33 These are the scattering parameters collected at the first input end, the second input end, and the output end of the balun in the second measurement process.

2. The method for determining the antenna coefficient according to claim 1, characterized in that: The distance condition includes that the distance between the transmitting antenna and the receiving antenna is greater than 8 to 10 times the wavelength of the microwave.

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