TW202111338A - Antenna measurment system for mimo ota - Google Patents

Abstract

An antenna measurement system for MIMO OTA includes an anechoic chamber, a rotating base and a plurality of CATR units. The rotating base is used to place a DUT. The DUT includes a plurality of antennas to be tested. A signal source in each of the CATR units is configured to emit a first RF signal toward the corresponding concave mirror, the concave mirror reflecting the first RF signal into a second RF signal, wherein each of the second RF signals is substantially a uniform plane wave and each second RF signal is transmitted toward a platform of the rotating base, and the concave mirrors of any two CATR units are not disposed face to face.

Description

Antenna measurement system for multi-input multi-output air transmission

The invention relates to a measurement system, in particular to a multi-input multi-output air transmission measurement system applied in a multi-path environment.

Refer to Figure 1, which is a partial schematic diagram of an antenna test system disclosed in US Patent Application No. US 2012/0282863 A1 (hereinafter referred to as known technology). This known technology is to place a device under test 17 in an anechoic chamber 1. Six test antennas are used to surround the device under test 17 at equal intervals to measure the antenna characteristics of the device under test 17.

The disadvantages of this known technology are: (1) The test antenna 11 and the test antenna 12 are opposite to each other, so when measuring the receiving characteristics of the device under test 17, the electromagnetic waves emitted by the two opposite test antennas 11 and 12 are It will collide and interfere with each other and cause measurement errors. Similarly, the two opposite test antennas 13, 14 and the opposite two test antennas 15, 16 will have the same problem. (2) If the known technology uses far-field measurement technology, the distance r between any one of the test antennas 11, 12, 13, 14, 15, 16 and the device under test 17 must be much greater than 2D ² /λ, so that the electromagnetic waves arriving at the device under test 17 from each test antenna 11, 12, 13, 14, 15, 16 are approximately uniform plane waves. In a purely theoretical calculation, the parameter D is the maximum geometric diameter of the antenna 171 under test, and λ is the working wavelength of the antenna 171 under test during measurement. However, in practical applications, if the device under test 17 is a mobile phone, a tablet, or For notebook computers, the antenna 171 under test is connected to a circuit board (not shown in the figure) inside the device under test 17 to use this circuit board as a reference ground plane, which will make the entire device under test 17 participate in radiation, not just It is only the antenna 171 under test. Therefore, in order to correct the deviation between theory and practice, the parameter D should be corrected to the maximum geometric diameter of the device under test 17. In the era of 5G millimeter wave communication, the size of the smartphone corresponds to the parameter D is almost unchanged, but the millimeter wave wavelength λ is as small as millimeters, and 2D ² /λ will become very large after calculation. Therefore, the space of the anechoic chamber 1 used for 5G communication measurement is much larger than the 4G communication volume. Time measurement requirements, which will seriously increase the site requirements for the construction and increase the construction cost. (3). If the problem in item (2) above is to be solved, the known technology similar to Figure 1 has to use near-field measurement technology to replace far-field measurement technology. However, near-field measurement technology has been passive in the past. For antenna measurement, the phase of the non-uniform plane wave arriving at the device under test 17 must undergo complex calculations to convert to approximate far-field measurement results. Not only does it unavoidably introduce conversion calculation errors, but it also reduces the calculation time. Measurement efficiency, but the more difficult problem to overcome is that the near-field measurement is only suitable for passive measurement (the device under test 17 is turned off and the antenna 171 under test is measured with a conductive line connected to the instrument), and the device under test 17 cannot be measured. Active measurement (that is, the device under test 17 is turned on to enter the actual communication mode for measurement). The reason is that the near field measurement must know the phase of the electromagnetic wave during the measurement, and then use the method of numerical calculation to convert the data of the near field into the far field However, the electromagnetic waves of the device under test 17 in the active measurement are all signals after communication modulation, so it is difficult to calculate the phase of the electromagnetic waves before the unmodulation, and the more complicated the calculation process introduces the error and calculation time The demand is also greater, so the known technology cannot solve the space requirement of the anechoic chamber 1 during the active measurement of 5G millimeter wave.

In order to solve the aforementioned problems of the known technology, the present invention proposes a method that saves the space of the anechoic chamber compared with the far-field measurement, and does not require the complexity of converting the near field to the far field. For calculation, it is suitable for both active and passive measurement, as well as a test system that can avoid electromagnetic interference between multiple test antennas.

The antenna measurement system for multi-input multi-output air transmission of the present invention includes an electric wave anechoic chamber, a rotating base and a plurality of short-distance field antenna units.

The rotating base is arranged in the anechoic chamber, and the rotating base includes a platform surface for placing a device to be tested, and the device to be tested includes a plurality of antennas to be tested.

Each narrow field antenna unit includes a signal feed, a concave mirror, and a connecting arm for fixing the signal feed and the concave mirror. The signal feed in each narrow field antenna unit is used to face the corresponding The concave mirror emits a first radio frequency signal, and the concave mirror is disposed facing the platform surface of the rotating base to reflect the first radio frequency signal into a second radio frequency signal toward the platform surface of the rotating base, wherein each The two radio frequency signals are substantially uniform plane waves, and the concave mirrors of any two reduced-distance field antenna units are not arranged face to face.

Preferably, the anechoic chamber is substantially a cube, and includes a first top corner, a second top corner, a third top corner, a fourth top corner, a first bottom corner, and a second bottom corner , A third bottom corner, a fourth bottom corner. The first apex angle, the platform surface of the rotating base, and the third bottom angle are sequentially arranged along a straight line; the second apex angle, the platform surface of the rotating base, and the fourth bottom angle are sequentially arranged along a straight line; The order is arranged along a straight line; the third apex angle, the platform surface of the rotating base and the first bottom angle are arranged in sequence along a straight line; the fourth apex angle, the platform surface of the rotating base and the first bottom angle are arranged in sequence along a straight line; The three bottom corners are arranged in sequence along a straight line. its In this case, the number of the shortened field antenna units is two, which are located at the first top corner and the second bottom corner respectively.

Preferably, the anechoic chamber is substantially a cube, and includes a first top corner, a second top corner, a third top corner, a fourth top corner, a first bottom corner, and a second bottom corner , A third bottom corner, a fourth bottom corner. The first apex angle, the platform surface of the rotating base, and the third bottom angle are sequentially arranged along a straight line; the second apex angle, the platform surface of the rotating base, and the fourth bottom angle are sequentially arranged along a straight line; The order is arranged along a straight line; the third apex angle, the platform surface of the rotating base and the first bottom angle are arranged in sequence along a straight line; the fourth apex angle, the platform surface of the rotating base and the first bottom angle are arranged in sequence along a straight line; The three bottom corners are arranged in sequence along a straight line. Wherein, the number of the reduced-distance field antenna units is three, which are respectively located at the first top corner, the second bottom corner, and the middle of the line connecting the third bottom corner and the fourth top corner.

Preferably, the anechoic chamber is substantially a cube, and includes a first top corner, a second top corner, a third top corner, a fourth top corner, a first bottom corner, and a second bottom corner , A third bottom corner, a fourth bottom corner. The first apex angle, the platform surface of the rotating base, and the third bottom angle are sequentially arranged along a straight line; the second apex angle, the platform surface of the rotating base, and the fourth bottom angle are sequentially arranged along a straight line; The order is arranged along a straight line; the third apex angle, the platform surface of the rotating base and the first bottom angle are arranged in sequence along a straight line; the fourth apex angle, the platform surface of the rotating base and the first bottom angle are arranged in sequence along a straight line; The three of the two bottom corners are arranged in sequence along a straight line, and the number of the reduced-distance field antenna units is four, which are respectively located at the first top corner, the second bottom corner, the third top corner, and the fourth bottom corner.

Preferably, the anechoic chamber is substantially a cube, and includes a first top corner, a second top corner, a third top corner, a fourth top corner, a first bottom corner, and a second bottom corner , A third bottom corner, a fourth bottom corner. The first apex angle, the platform surface of the rotating base, and the third bottom angle are sequentially arranged along a straight line; the second apex angle, the platform surface of the rotating base, and the fourth bottom angle are sequentially arranged along a straight line; The order is arranged along a straight line; the third apex angle, the platform surface of the rotating base and the first bottom angle are arranged in sequence along a straight line; the fourth apex angle, the platform surface of the rotating base and the first bottom angle are arranged in sequence along a straight line; The three bottom corners are arranged in sequence along a straight line. Among them, the number of the shortened field antenna units is six, which are located in the middle of the line connecting the first top corner, the second bottom corner, the third top corner, the fourth bottom corner, the second top corner, and the second bottom corner. , And the middle of the line between the third top corner and the third bottom corner.

Preferably, the anechoic chamber further includes a plurality of screw holes, and the connecting arm of each reduced-distance field antenna unit includes a first arm portion and a second arm portion, and each first arm portion is fixed to the anechoic chamber, each The second arm part of a connecting arm is connected with the concave mirror.

Preferably, the concave mirror can rotate relative to the second arm portion of the connecting arm.

Preferably, the antenna measurement system for multi-input multi-output air transmission further includes a first support plate, the first support plate is non-conductor, low permittivity (permittivity), low dielectric loss (dielectric loss) Material, the first support plate is fixed to a wall plate of the anechoic chamber, and is used to support the weight of a corresponding one of the short-distance field antenna units, and the first support plate supports the The shortened field antenna unit is located in the middle of the line connecting the third top corner and the third bottom corner.

Preferably, the antenna measurement system for multi-input multi-output air transmission further includes a second support plate that is also non-conductor, low dielectric constant, and low dielectric loss, and the second support plate is fixed to the anechoic chamber. The wall plate is used to support the weight of the corresponding one of the short-distance field antenna units, and the short-distance field antenna unit supported by the second support plate is located in the middle of the line connecting the second top corner and the second bottom corner s position.

Preferably, the antenna measurement system for multi-input multi-output air transmission further includes a first support column and a second support column substantially in a T shape or an inverted L shape, and the first support plate is a non-conductor, A material with low dielectric constant and low dielectric loss. The first support column is fixed on a bottom plate of the anechoic chamber to support the weight of a corresponding one of the narrow-distance field antenna units, and is supported by the first support column. The short-distance field antenna unit is located in the middle of the line connecting the third apex angle and the third bottom angle, the second supporting column is also a non-conductor, low dielectric constant, and low dielectric loss material, and the second supporting column is fixed On the bottom plate of the anechoic chamber, it is used to support the weight of another corresponding narrow-range field antenna unit, and the narrow-range field antenna unit supported by the second support column is located at the second top corner and the second bottom The position in the middle of the line of the corner.

The effect of the present invention is to use the concave mirror of the telescopic field antenna unit to reflect the non-uniform plane wave (the first radio frequency signal) from the signal feed into a uniform plane wave (the second radio frequency signal), without limitation as shown in the prior art technique shown in Figure 1. The parameter r must be much larger than 2D ² /λ to reach the device under test to reach the limit of the uniform plane wave. Therefore, the problem of large space requirement of the anechoic chamber for far-field measurement or complex calculation of near-field measurement and not suitable for active measurement is improved; In addition, the present invention also considers the spatial configuration of the plurality of short-distance field antenna units in the anechoic chamber, so as to avoid the collision and interference of the second radio frequency signals reflected by any two short-distance field antenna units during the multiple-input multiple-output (MIMO) test. problem.

1‧‧‧Anechoic Chamber

11~16‧‧‧Test antenna

17‧‧‧Device to be tested

171‧‧‧Antenna to be tested

2‧‧‧Anechoic Chamber

200‧‧‧Wall Panel

201‧‧‧Bottom plate

21‧‧‧The first vertex

22‧‧‧Second top corner

23‧‧‧The third vertex

24‧‧‧The fourth vertex

25‧‧‧First bottom corner

26‧‧‧Second bottom corner

27‧‧‧The third bottom corner

28‧‧‧Fourth bottom corner

3‧‧‧Rotating base

31‧‧‧Platform

4‧‧‧Reduced Field Antenna Unit

41‧‧‧Signal feed

42‧‧‧Concave mirror

43‧‧‧Connecting arm

431‧‧‧First arm

4311‧‧‧Screw

4312‧‧‧Fixed metal sheet

432‧‧‧Second Arm

5‧‧‧Device to be tested

51‧‧‧Antenna to be tested

111‧‧‧First RF signal

112‧‧‧Second RF signal

291, 293‧‧‧Location

20‧‧‧Screw hole

61‧‧‧First support plate

62‧‧‧Second support plate

71‧‧‧First support column

72‧‧‧Second Support Column

Figure 1 is a partial schematic diagram of the conventional technology.

Figure 2 is a schematic diagram of the first preferred embodiment of the present invention.

Figure 3 is a schematic diagram illustrating the reduced-range field antenna unit of the first preferred embodiment.

Figure 4 is a schematic diagram of a second preferred embodiment of the present invention.

Figure 5 is a schematic diagram of the third preferred embodiment of the present invention.

Figure 6 is a schematic diagram of a fourth preferred embodiment of the present invention.

Fig. 7 is a schematic diagram illustrating a method of fixing the distance field antenna unit and the anechoic chamber of any preferred embodiment.

Fig. 8 is a schematic diagram illustrating another method of fixing the distance field antenna unit and the anechoic chamber of any preferred embodiment.

Figure 9 is a schematic diagram illustrating that the first preferred embodiment further includes a first support plate.

Figure 10 is a schematic diagram illustrating that the first preferred embodiment further includes a second Support board.

Figure 11 is a schematic diagram illustrating an embodiment in which a T-shaped first support column is used instead of the first support plate.

Figure 12 is a schematic diagram illustrating an embodiment in which a T-shaped second support column is used instead of the second support plate.

Fig. 13 is a schematic diagram illustrating an embodiment of replacing the first support plate with an L-shaped first support column.

Figure 14 is a schematic diagram illustrating an embodiment in which the second support plate is replaced by an L-shaped second support column.

2 and 3, the first preferred embodiment of the antenna measurement system for multi-input multi-output air transmission of the present invention includes an anechoic chamber 2, a rotating base 3, and a plurality of narrow field antenna units 4.

The rotating base 3 is disposed in the anechoic chamber 2. The rotating base 3 includes a platform surface 31 for placing a device under test 5, and the device under test 5 includes a plurality of antennas 51 under test.

In the first preferred embodiment, the anechoic chamber 2 is substantially a cube, and includes a first apex 21, a second apex 22, a third apex 23, a fourth apex 24, and a first apex angle. A bottom corner 25, a second bottom corner 26, a third bottom corner 27, and a fourth bottom corner 28. The first vertex 21, the platform surface 31 of the rotating base 3, and the third bottom corner 27 are sequentially arranged along a straight line; the second vertex 22, the platform surface 31 of the rotating base 3, and the The four bottom corners 28 are arranged in sequence along a straight line; the third top corner 23, the platform surface 31 of the rotating base 3, and the first bottom corner 25 are arranged in sequence along Arranged in a straight line; the fourth top corner 24, the platform surface 31 of the rotating base 3 and the second bottom corner 26 are arranged in a straight line in sequence.

Each narrow field antenna unit 4 includes a signal feed 41, a concave mirror 42 and a connecting arm 43 for fixing the signal feed 41 and the concave mirror 42. The signal feed 41 in each narrow field antenna unit 4 is used to transmit a first radio frequency signal 111 toward the corresponding concave mirror 42. The concave mirror 42 is arranged facing the platform surface 31 of the rotating base 3 for the The first radio frequency signal 111 is reflected to become a second radio frequency signal 112 facing the platform surface 31 of the rotating base 3, wherein each second radio frequency signal 112 is substantially a uniform plane wave, and any two narrow field antenna units 4 The concave mirror 42 is not arranged face to face.

The theoretical definition of a uniform plane wave means that the field vector of the electromagnetic field changes only along its propagation direction. In an infinite plane perpendicular to the wave propagation direction, the direction, amplitude and phase of the electric field strength E and the magnetic field strength H remain unchanged. However, In practical communication applications, it can only substantially approach a uniform plane wave. Therefore, in this specification, the electric field strength E and the magnetic field strength H of the second radio frequency signal when it propagates into the quiet zone of the anechoic chamber 2 The amplitude difference is less than 1dB, and the phase difference is less than 22.5 degrees.

Among them, the number of the shortened field antenna units 4 is six, which are located at the first apex angle 21, the second apex angle 26, the third apex angle 23, the fourth apex angle 28, the second apex angle 22, and the second apex angle. The middle of the line of the bottom corner 26 (position 293), and the middle of the line of the third top corner 23 and the third bottom corner 27 (position 291).

For example, in FIG. 2, a short-range field antenna unit 4 is provided at the first apex 21, then the third bottom corner 27 cannot be provided with a short-distance field antenna unit 4; the third apex 23 is provided with a short-distance field antenna unit 4, Then the distance field antenna unit 4 cannot be set at the second bottom corner 25; for the same reason, the position 291 is set If there is a short-distance field antenna unit 4, the position 292 cannot be provided with the short-distance field antenna unit 4. In this way, it is possible to avoid the problem of destructive interference of the two second radio frequency signals 112 when the concave mirrors 42 of any two narrow-field antenna units 4 are arranged face to face.

Refer to FIG. 4, which is a schematic diagram of the second preferred embodiment of the present invention. The second preferred embodiment is similar to the first preferred embodiment. The difference is that the number of the reduced-range field antenna units 4 is four, respectively Located at the first top corner 21, the second bottom corner 26, the third top corner 23 and the fourth bottom corner 28.

Refer to FIG. 5, which is a schematic diagram of the third preferred embodiment of the present invention. The third preferred embodiment is similar to the second preferred embodiment, but the difference lies in that the number of the reduced field antenna units 4 is three. They are located at the first top corner 21, the second bottom corner 26, and the middle 291 of the line connecting the third bottom corner 27 and the fourth top corner 24, respectively.

Refer to FIG. 6, which is a schematic diagram of the fourth preferred embodiment of the present invention. The fourth preferred embodiment is similar to the third preferred embodiment, but the difference lies in that the number of the narrow field antenna units 4 is two, respectively Located at the first top corner 21 and the second bottom corner 26.

Referring to FIG. 7, the anechoic chamber 2 of any of the foregoing preferred embodiments further includes a plurality of screw holes 20, and the connecting arm 43 of each reduced-distance field antenna unit 4 includes a first arm 431 and a second arm. 432. Each first arm 431 is fastened to the wall plate 200 of the anechoic chamber 2 with screws 4311, and the second arm 432 of each connecting arm 43 is connected to the concave mirror 42, and the concave mirror 42 can be opposite to each other. The second arm 432 of the connecting arm 43 rotates to adjust the direction of the second radio frequency signal 112, and the second arm 432 can also rotate about the Z-direction axis relative to the first arm 431.

Referring to FIG. 8, the reduced-range field antenna unit 4 further includes a fixed metal sheet 4312 compared to that of FIG. 7. The fixed metal sheet 4312 and the first arm portion 431 are respectively located on both sides of the wall plate 200 of the anechoic chamber 2. Two screws 4311 connect the first arm 431, the wall plate 200 and the fixed metal sheet 4312 all three are locked and fixed. In addition, the actual application is not limited to the use of screws 4311 for locking, and it can also be fixed by direct welding.

2 and 9, FIG. 9 shows that the first preferred embodiment further includes a first support plate 61, the first support plate 61 is a non-conductor, low dielectric constant, low dielectric loss material to reduce the electromagnetic wave The first support plate 61 is fixed to the wall plate 200 of the anechoic chamber 2 to support the weight of the corresponding one of the retracted field antenna units 4, and the retracted field supported by the first support plate 61 The antenna unit 4 is located at a position 291 in the middle of the line connecting the third top corner 23 and the third bottom corner 27.

2 and FIG. 10, FIG. 10 shows that the first preferred embodiment further includes a second support plate 62 that is also a non-metallic conductor, low dielectric constant, and low dielectric loss. The second support plate 62 is fixed to the wall plate 200 of the anechoic chamber 2 to support the weight of the corresponding other short-distance field antenna unit 4, and the short-distance field antenna supported by the second support plate 62 The unit 4 is located at a position 293 in the middle of the line connecting the second top corner 22 and the second bottom corner 26.

Referring to Figures 2, 11, and 12, it is explained that the first support plate 61 and the second support plate 62 (see Figures 9 and 10) can also be replaced by a first support post 71 and a second support post 72, respectively. A supporting column 71 and the second supporting column 72 are substantially T-shaped, and are arranged and fixed on a bottom plate 201 of the anechoic chamber 2, and the reduced-distance field antenna unit 4 supported by the first supporting column 71 is Located at a position 291 in the middle of the line between the third top corner 23 and the third bottom corner 27, the reduced-distance field antenna unit 4 supported by the second supporting column 72 is located at the second top corner 22 and the second bottom corner 26 Position 293 in the middle of the line.

Referring to Figs. 2, 13, and 14, the first support column 71 and the second support column 72 can also be replaced with an inverted L shape.

The effect of the present invention is that the concave mirror 42 of the retracted field antenna unit 4 is used to reflect the non-uniform plane wave (the first radio frequency signal 111) from the signal feed 41 into a uniform plane wave (the second radio frequency signal 112). Fig. 1 The conventional technical parameter r must be much larger than 2D ² /λ to reach the device under test 5 to reach the limit of the uniform plane wave. Therefore, the far-field measurement anechoic chamber 2 has a large space requirement or the near-field measurement calculation is complicated and unsuitable. The problem of active measurement; in addition, the present invention also considers the spatial configuration of the plurality of short-range field antenna units 4 in the anechoic chamber 2 to avoid reflections of any two short-range field antenna units 4 during multiple input multiple output (MIMO) testing. The second radio frequency signals 112 collide and interfere with each other.

2‧‧‧Anechoic Chamber

21‧‧‧The first vertex

22‧‧‧Second top corner

23‧‧‧The third vertex

24‧‧‧The fourth vertex

25‧‧‧First bottom corner

26‧‧‧Second bottom corner

27‧‧‧The third bottom corner

28‧‧‧Fourth bottom corner

3‧‧‧Rotating base

31‧‧‧Platform

4‧‧‧Reduced Field Antenna Unit

5‧‧‧Device to be tested

51‧‧‧Antenna to be tested

111‧‧‧First RF signal

112‧‧‧Second RF signal

291, 292, 293, 294‧‧‧ location

Claims (10)

An antenna measurement system for multi-input and multi-output air transmission includes: an electric wave anechoic chamber; a rotating base set in the electric wave anechoic chamber, the rotating base includes a platform surface, and the platform surface is used for placing a waiting room. Test device, the device under test includes a plurality of antennas to be tested; and a plurality of short-distance field antenna units, each of the short-distance field antenna units includes a signal feed, a concave mirror, and one for fixing the signal feed and the concave mirror The signal feed in each narrow field antenna unit is used to transmit a first radio frequency signal toward the corresponding concave mirror, and the concave mirror is arranged facing the platform surface of the rotating base for the first radio frequency The signal is reflected as a second radio frequency signal toward the platform surface of the rotating base, wherein each second radio frequency signal is substantially a uniform plane wave, and the concave mirrors of any two narrow field antenna units are not arranged face to face. According to item 1 of the scope of patent application, the antenna measurement system for multi-input multi-output air transmission, wherein the anechoic chamber is essentially a cube, and includes a first vertex, a second vertex, and a third vertex. Top corner, a fourth top corner, a first bottom corner, a second bottom corner, a third bottom corner, a fourth bottom corner, the first top corner, the platform surface of the rotating base, and the third bottom corner The three bottom corners are arranged in sequence along a straight line, and the second top corner, the platform surface of the rotating base and the fourth bottom corner are sequentially arranged Arranged along a straight line, the third apex angle, the platform surface of the rotating base, and the first bottom angle are sequentially arranged along a straight line, the fourth apex angle, the platform surface of the rotating base, and the second The three bottom corners are arranged in sequence along a straight line, and the number of the reduced-distance field antenna units is two, which are respectively located at the first top corner and the second bottom corner. According to item 1 of the scope of patent application, the antenna measurement system for multi-input multi-output air transmission, wherein the anechoic chamber is essentially a cube, and includes a first vertex, a second vertex, and a third vertex. Top corner, a fourth top corner, a first bottom corner, a second bottom corner, a third bottom corner, a fourth bottom corner, the first top corner, the platform surface of the rotating base, and the third bottom corner The three bottom corners are arranged in sequence along a straight line, the second top corner, the platform surface of the rotating base, and the fourth bottom corner are arranged in sequence along a straight line. The platform surface and the first bottom corner are sequentially arranged along a straight line, and the fourth top corner, the platform surface of the rotating base, and the second bottom corner are sequentially arranged along a straight line. The number of distance field antenna elements is three, which are respectively located at the first top corner, the second bottom corner, and the middle of the line connecting the third bottom corner and the fourth top corner. According to item 1 of the scope of patent application, the antenna measurement system for multi-input multi-output air transmission, wherein the anechoic chamber is essentially a cube, and includes a first vertex, a second vertex, and a third vertex. Top corner, a fourth top corner, a first bottom corner, a second bottom corner, a third bottom corner, a fourth bottom corner, the first top corner, the platform surface of the rotating base, and the third bottom corner The three bottom corners are arranged in sequence along a straight line. The second top corner, the platform surface of the rotating base and the fourth bottom corner are arranged in sequence along a straight line. The platform surface and the first bottom corner are sequentially arranged along a straight line, the fourth top corner, the platform surface of the rotating base, and the second bottom corner are sequentially arranged along a straight line. The number of distance field antenna units is four, which are located at the first top corner, the second bottom corner, the third top corner, and the fourth bottom corner. According to item 1 of the scope of patent application, the antenna measurement system for multi-input multi-output air transmission, wherein the anechoic chamber is essentially a cube, and includes a first vertex, a second vertex, and a third vertex. Top corner, a fourth top corner, a first bottom corner, a second bottom corner, a third bottom corner, a fourth bottom corner, the first top corner, the platform surface of the rotating base, and the third bottom corner The three bottom corners are arranged in sequence along a straight line, the second top corner, the platform surface of the rotating base, and the fourth bottom corner are arranged in sequence along a straight line. The platform surface and the first bottom corner are in order Arranged along a straight line, the fourth top corner, the platform surface of the rotating base, and the second bottom corner are arranged in sequence along a straight line, wherein the number of the shortened field antenna units is six, which are located at The first top corner, the second bottom corner, the third top corner, the fourth bottom corner, the middle of the line between the second top corner and the second bottom corner, and the middle of the line between the third top corner and the third bottom corner. According to the first item of the scope of patent application, the antenna measurement system for multi-input multi-output air transmission, wherein the anechoic chamber also includes a plurality of screw holes, and the connecting arm of each shortened field antenna unit includes a first arm and A second arm part, each first arm part is fixed to the anechoic chamber, and the second arm part of each connecting arm is connected with the concave mirror. According to the sixth item of the scope of patent application, the antenna measurement system for multi-input multi-output air transmission, wherein the concave mirror can rotate relative to the second arm of the connecting arm. According to item 5 of the scope of patent application, the antenna measurement system for multi-input multi-output air transmission further includes a first support plate which is non-conductor, low permittivity, and low dielectric loss (dielectric loss) material, the first support plate is fixed to a wall plate of the anechoic chamber, used to support the weight of the corresponding one of the distance field antenna units, and the distance field supported by the first support plate The antenna unit is located in the middle of the line connecting the third top corner and the third bottom corner. According to item 8 of the scope of patent application, the antenna measurement system for multiple-input multiple-output air transmission further includes a second support plate that is also non-conductor, low dielectric constant, and low dielectric loss. The second support plate is fixed on The wall plate of the electric wave anechoic chamber is used to support the weight of another corresponding narrow-range field antenna unit, and the narrow-range field antenna unit supported by the second support plate is located at the second top corner and the second bottom corner The position in the middle of the connection. According to item 5 of the scope of patent application, the antenna measurement system for multi-input multi-output air transmission further includes a first support column and a second support column substantially in a T shape or an inverted L shape. The first support The plate is a non-conductor, low dielectric constant, and low dielectric loss material. The first support column is fixed on a bottom plate of the anechoic chamber to support the weight of a corresponding narrow-distance field antenna unit and is affected by the first The reduced-distance field antenna unit supported by a supporting column is located in the middle of the line connecting the third top corner and the third bottom corner, and the second supporting column is also a non-conductor, low dielectric constant, and low dielectric loss material. The second support column is fixed on the bottom plate of the anechoic chamber to support the weight of another corresponding narrow-range field antenna unit, and the narrow-range field antenna unit supported by the second support column is located on the second top. The position in the middle of the line between the corner and the second bottom corner.

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