JP7246785B1 - Near-field air probe and inspection equipment - Google Patents

Abstract

A near-field air probe and a testing device capable of measuring communication characteristics of a communication module as a DUT in the near field as well as in the far field are provided. A near-field air probe has a radome base, a connector section, a probe section, and a radome. The connector section is provided on the radome base and receives a signal from the network analyzer. The probe section has a plate-like base material and a conductor. A substrate has a first surface and a second surface opposite the first surface and is fixed to the radome base. The conductor is provided on the base material and emits a signal input to the connector portion as a traveling wave type radio wave. The radome covers the probe portion together with the radome base. The radome has a transmission surface having radio wave permeability along the radio wave emission direction, and a surface of the base material facing the first surface and the second surface, which is opposed to the first surface and the second surface, respectively. and an inclined surface formed of an inclined electromagnetic wave absorbing material. [Selection drawing] Fig. 7

Description

The present invention relates to a near-field air probe and an inspection device.

In recent years, antennas for mobile communication systems have been integrated into semiconductor chips. Such a communication module (antenna module) as a DUT (Device Under Test) is required to be shipped after inspection of communication characteristics and the like. For example, mass-produced communication modules are preferably tested for their communication performance before being attached to various devices.

JP 2019-097147 A

When measuring the electric field intensity, magnetic field intensity, etc. of the radio wave radiating source, it is necessary to avoid the influence of the electromagnetic coupling between the communication module as the DUT and the probe (coupler). For this reason, the distance between the communication module as the DUT and the probe (coupler) is measured by taking the distance that becomes the far field. That is, communication characteristics of communication modules are usually measured in the far field. However, if communication characteristics can be measured in a near field closer to the measuring equipment, more communication modules can be tested in a smaller space. In the near field, the electric field and the magnetic field of the DUT and the probe are mixed, so that it is difficult to measure communication characteristics compared to the far field.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a near-field air probe and a testing apparatus capable of measuring the communication characteristics of a communication module as a DUT not only in the far field but also in the near field.

A near-field air probe according to an aspect of the present invention includes a radome base made of an electromagnetic wave absorbing material, a connector section, a probe section, and a radome. The connector section is provided on the radome base and receives a signal from the network analyzer. The probe section has a plate-like base material and a conductor. A substrate has a first surface and a second surface opposite the first surface and is fixed to the radome base. The conductor is provided on the base material and emits a signal input to the connector portion as a traveling wave type radio wave. The radome covers the probe portion together with the radome base. The radome has a transmission surface having radio wave permeability along the radio wave emission direction, and a surface of the base material facing the first surface and the second surface, which is opposed to the first surface and the second surface, respectively. and an inclined surface formed of an inclined electromagnetic wave absorbing material. The dimension along the plate thickness of the end surface of the substrate facing the transmission surface of the radome is larger than λ/2, which is half the wavelength λ of the lowest frequency to be measured among radio waves.

According to the present invention, it is possible to provide a near-field air probe and a testing apparatus capable of measuring the communication characteristics of a communication module as a DUT not only in the far field but also in the near field.

1 is a schematic block diagram showing an inspection device according to an embodiment; FIG. Schematic which shows the near-field air probe of the test|inspection apparatus which concerns on embodiment. FIG. 3 is a schematic view of the near-field air probe viewed from the direction indicated by arrow III in FIG. 2; FIG. 3 is a schematic view of the near-field air probe viewed from the direction indicated by arrow IV in FIG. 2; FIG. 5 is a schematic diagram showing an example of the antenna section of the near-field air probe shown in FIGS. 2 to 4; FIG. Schematic diagram showing the electromagnetic field of a DUT and a near-field air probe. FIG. 4 is an explanatory diagram showing a state of reflection of radio waves in a radome; 5 is a graph showing the relationship between frequency and transmission characteristics according to the distance relationship between the DUT and the near-field air probe; 5 is a graph showing the relationship between the distance relationship between the DUT and the near-field air probe and the transmission characteristics; Schematic which shows a part of inspection apparatus which concerns on embodiment.

An inspection apparatus 10 according to an embodiment will be described with reference to FIGS. 1 to 9. FIG.

As shown in FIG. 1, an inspection apparatus 10 according to this embodiment has a near-field air probe 12 and a network analyzer 14 .

The near-field air probe 12 according to the present embodiment inspects a DUT (Device Under Test) 18, which is an object to be measured, together with a network analyzer 14 that inputs a predetermined signal to an RF connector section 24, which will be described later, of the near-field air probe 12. Used when In this embodiment, the DUT 18 will be described as a communication module (antenna module) in which an antenna is integrated with a semiconductor chip, that is, a communication device with a built-in antenna.

FIG. 2 shows a schematic side view of the near-field air probe 12 according to the present embodiment. FIG. 3 shows a schematic view of the near-field air probe 12 from the direction indicated by arrow III in FIG. FIG. 4 shows a schematic view of the near-field air probe 12 from the direction indicated by arrow IV in FIG.

As shown in FIGS. 2 to 4, the near-field air probe 12 according to this embodiment includes a radome base 22, an RF connector section (feeding section) 24, an antenna section (probe section) 26, and a radome 28. have.

The radome base 22 is formed, for example, as a substantially rectangular plate. An RF connector section 24 is provided on one surface 22a side of the radome base 22 (the outer surface side of the near-field air probe 12), and on the other surface 22b side (the inner surface side of the near-field air probe 12). is provided with an antenna section 26 . The radome base 22 is preferably made of the same material as the radome 28, which will be described later.

For the RF connector section 24, for example, a 2.92 mm connector with an upper limit frequency of 40 GHz, a 1.85 mm connector with an upper limit frequency of 65 GHz, or the like is used. As the 2.92 mm connector with an upper limit frequency of 40 GHz, a connector called a K connector or its equivalent can be used. A 1.85 mm connector with an upper frequency limit of 65 GHz can use what is called a V-connector or its equivalent. Also, if the upper frequency limit of interest is even higher, a suitable connector with an upper frequency limit of, for example, 120 GHz may be used.

A connector including a cable (cable connector) connected to the RF connector section 24 is connected to the network analyzer 14 .

The antenna section 26 has a thin plate-like base material 32 and conductors 34a and 34b formed on the base material 32, and is formed in a flat shape. The conductors 34a and 34b emit the signal input to the connector portion 24 as traveling-wave radio waves.

FIG. 5 is a schematic diagram showing a state in which one surface (first surface) 32a of the base material 32 of the antenna section 26 is viewed. A solid line in FIG. 5 indicates the edge of the conductor 34a present on the one surface 32a side of the substrate 32. As shown in FIG. A dashed line indicates the edge of the conductor 34b present on the other surface (second surface) 32b side of the substrate 32. As shown in FIG. As shown in FIG. 5, the antenna section 26 is formed as a traveling wave type (non-resonant type) planar antenna. In the example of the present embodiment, an antipodal type Vivaldi antenna, which is a type of tapered slot antenna (TSA), will be described as an example.

A substantially rectangular dielectric substrate, for example, is used as the base material 32 . The base material 32 is formed as a thin plate with a thickness of several millimeters or less. The substrate 32 has a pair of surfaces 32a, 32b on which conductors 34a, 34b are formed on at least one side, which is larger than the areas of the end surfaces 33a, 33b, 33c, 33d. The base material 32 is arranged perpendicular to the other surface 22 b of the radome base 22 .

The conductors 34a on one surface 32a of the base material 32 and the conductors 34b on the other surface 32b are formed such that the radio wave radiating positions are symmetrical or substantially symmetrical vertically in FIG. The conductors 34a and 34b may be made of a conductive substance such as a metal material having a thickness of about several μm, or may be formed to a thickness of several μm by sputtering or the like. By forming the conductors 34a and 34b into thin films, it is possible to reduce the area that is perpendicular to the electromagnetic field radiated from the DUT 18 and that may affect the transmission characteristics S21, which will be described later.

When the conductors 34a and 34b are viewed from one side of the substrate 32, the width W of the slot 35 extends from the other side 22b of the radome base 22 (the proximal end surface 33d of the substrate 32) to the distal end surface 33a. Gradually widens as you go. The antenna section 26 radiates waves in a wide frequency band from between the slots 35 in a single direction.

In this embodiment, the antenna unit 26 is formed to be able to inspect a frequency band including radio waves in the so-called millimeter wave band (28 GHz and its surroundings), which is used in, for example, a fifth-generation mobile communication system called 5G. .

It should be noted that, for example, in the fifth generation mobile communication system, there is information that extension to, for example, about 90 GHz is being considered as the millimeter wave band. The near-field air probe 12 according to the present embodiment can inspect radio waves in a frequency band including about 90 GHz by appropriately setting the shape, size, material, etc. of the antenna portion 26 and the RF connector portion 24, that is, , is formed so as to be able to inspect radio waves of frequencies from about 28 GHz to about 90 GHz.

Further, the antenna unit 26 may be capable of inspecting a frequency band in a submillimeter wave band (300 GHz to 3000 GHz) with a wavelength of about 0.1 to 1 mm.

In this embodiment, an example of using a Vivaldi antenna as an antipodal tapered slot antenna will be described. A slot 35 that gradually widens as it separates from the radome base 22 is formed on one surface 32a of the base material 32. Conductors 34a and 34b may be formed.

In addition, the antenna section 26 includes a ground (GND) plate (not shown) at the connection section between the RF connector section 24 and the conductors 34a and 34b to prevent standing waves from being generated and affecting the measurement of the DUT 18. have The ground plate may be provided as a thin film on the substrate 32 in parallel with the conductors 34a and 34b on the DUT 18 side so as to suppress electromagnetic coupling between the DUT 18 side and the RF connector section 24 side.
Further, an electromagnetic wave absorbing material, for example, may be arranged on the base material 32 of the antenna section 26 .

Radome 28 is formed to cover antenna section 26 . The radome 28 is formed in a cylindrical shape with a bottom. The radome 28 has a tubular portion 42 made of an electromagnetic wave absorbing material and a tip portion (transmissive surface) 44 made of a radio wave transparent material.

The cylindrical portion 42 is made of, for example, ferrite or a material (magnetic material) having a function equivalent to ferrite as an electromagnetic wave absorbing material. In the present embodiment, the cylindrical portion 42 is made of a material that does not cause loss or modification of electromagnetic waves in a required frequency band (for example, 28 to 60 GHz) in the millimeter wave band. The cylindrical portion 42 is formed in a size that does not cause loss and modification of electromagnetic waves in a necessary frequency band (for example, 28 to 60 GHz) in the millimeter wave band.
In addition to the magnetic material, the electromagnetic wave absorbing material may be, for example, a conductive material, a dielectric absorbing material, or the like.

The tubular portion 42 has a first inclined portion 43 a facing one surface 32 a of the base material 32 and a second inclined portion 43 b facing the other surface 32 b of the base material 32 .

The first inclined portion 43a faces the one surface 32a of the base material 32, but has an inner side surface (inclined surface) that is not parallel but inclined. In the present embodiment, the inner side surface of the first inclined portion 43a and the outer side surface opposite to the inner side surface are shown to be parallel to simplify the explanation. It doesn't have to be. For example, the first inclined portion 43a becomes closer to the one surface 32a of the substrate 32 as it approaches the distal end surface 33a from the proximal end surface 33d of the substrate 32 . Similarly, the second inclined portion 43b has an inner side surface (inclined surface) that faces the other surface 32b of the base material 32 but is not parallel but inclined. In the present embodiment, the inner surface of the second inclined portion 43b and the outer surface opposite to the inner surface are shown to be parallel for the sake of simplicity of explanation. It doesn't have to be. For example, the second inclined portion 43b becomes closer to the other surface 32b of the substrate 32 as it approaches the distal end surface 33a from the proximal end surface 33d of the substrate 32 . The first inclined portion 43a and the second inclined portion 43b may be flat surfaces or curved surfaces such as concave surfaces or convex surfaces.

A third inclined portion 43c and a fourth inclined portion 43d are formed in the circumferential direction between the first inclined portion 43a and the second inclined portion 43b. The third inclined portion 43c is not parallel to the end surface 33b adjacent to the tip end surface 33a of the base material 32, but is inclined. For example, the distance of the third inclined portion 43c to the end face 33b of the base material 32 decreases as the base end face 33d of the base material 32 approaches the tip end face 33a. The fourth inclined portion 43d is adjacent to the tip end face 33a of the base material 32 and is not parallel to the end face 33c opposite to the end face 33b but inclined. For example, the distance of the fourth inclined portion 43d to the end face 33c of the base material 32 decreases as the base end face 33d of the base material 32 approaches the tip end face 33a.

The tip portion 44 is provided in a state of closing one end of the tubular portion 42 . The tip portion 44 is made of, for example, a radio wave transparent material and formed into a flat plate shape. For the tip portion 44, for example, fibers such as resin and paper are preferably used. As the resin material of the tip portion 44, it is preferable to use PTFE or polypropylene, which suppresses attenuation and has excellent high-frequency characteristics. The outer surface of the distal end portion 44 and the inner surface of the distal end portion 44 facing the distal end surface 33a of the antenna portion 26 are parallel to each other. The tip portion 44 may have radio wave permeability along the radio wave emitting direction.

2 and 3, the size of the tip portion 44 of the radome 28 in the direction along the plate thickness of the tip end surface 33a of the base material 32 is made larger than the plate thickness of the tip end surface 33a of the base material 32. bottom. The size of the distal end portion 44 of the radome 28 in the direction along the plate thickness of the distal end face 33a of the substrate 32 should be slightly wider than half the wavelength λ of the lowest frequency to be measured in the radio waves, that is, λ/2. Just do it. Experimental results show that the broadband performance of the near-field air probe 12 can be impaired when the size of the tip end 44 of the radome 28 in the direction along the plate thickness of the tip end face 33a of the base material 32 is λ/2 or less. is obtained from

The other end of the tubular portion 42 has an opening 42a. The radome base 22 is fitted to the other end of the tubular portion 42 . That is, the radome base 22 is fitted to the other end of the tubular portion 42 . The fitting relationship between the radome 28 and the radome base 22 is sufficient as long as the influence of the electromagnetic field outside the cylindrical portion 42 of the radome 28 can be suppressed.

The opening 42a of the cylindrical portion 42 has a size that does not induce resonance with the wavelength of the measurement frequency.

As shown in FIG. 1, the network analyzer 14 has a signal source 62, a switch 64, receivers 66a, 66b, 66c, and directional couplers 68a, 68b. A reference signal receiver 66a is connected to both branches of the switch 64 from the signal source 62 via directional couplers 68a and 68b. One branch of the switch 64 connected to the signal source 62 is connected to the near-field air probe 12 through the first port 14 a of the network analyzer 14 . A connection destination of the near-field air probe 12 is connected to a reflected signal receiver 66b via a directional coupler 68a. DUT 18 is connected to the other branch of switch 64 via second port 14b of network analyzer 14 . A receiver 66c for transmission signals is connected to the connection destination of the DUT 18 via a directional coupler 68b.

FIG. 6 shows the near-field air probe 12 when an appropriate signal is output from the signal source 62 of the network analyzer 14 with the tip 44 of the near-field air probe 12 brought close to the DUT 18 at an appropriate distance. It is a schematic diagram showing an electromagnetic field formed on the outer circumference.

The near-field air probe 12 is used facing or in contact with the DUT 18 in a predetermined direction. The radio wave radiation direction by the antenna section 26 of the near-field air probe 12 and the radio wave radiation direction by the DUT 18 are parallel. Moreover, it is preferable that the axis along the radio wave radiation direction of the antenna section 26 of the near-field air probe 12 coincides with the epicenter of the radio wave of the DUT 18 .

As described above, the tubular portion 42 of the radome 28 is made of an electromagnetic wave absorbing material, so it absorbs the radio waves from the near-field air probe 12 and causes heat loss. Further, the cylindrical portion 42 of the radome 28 absorbs radio waves not only from the near-field air probe 12 but also from the DUT 18, causing heat loss. The cylindrical portion 42 of the radome 28 prevents unnecessary electromagnetic coupling from the DUT 18 to the antenna portion 26 of the near-field air probe 12 and prevents unnecessary electromagnetic coupling from the antenna portion 26 of the near-field air probe 12 to the DUT 18. to prevent In this way, the near-field air probe 12 can avoid electromagnetic coupling with the side surfaces of the antenna section 26 (one side 32a and the other side 32b of the substrate 32) by the tubular portion 42 of the radome 28. .

FIG. 7 is a schematic diagram showing an example of reflection of radio waves radiated from the antenna section 26 and an example of reflection of radio waves radiated from the DUT 18 .

For example, when radio waves from the antenna section 26 hit the inner surface of the first inclined portion 43a of the radome 28, part of the radio waves are reflected at a reflection angle θ1 that is the same as the incident angle θ1. Therefore, the reflected radio waves are not reflected in the same direction, and it is possible to prevent the radio waves from reflecting and resonating within the radome 28 . When radio waves (unnecessary electromagnetic waves from the DUT 18) hit the outside of the second inclined portion 43b of the radome 28, part of the radio waves is reflected at a reflection angle .theta.2 that is the same as the incident angle .theta.2. Therefore, by forming the inner side of the radome 28 as an inclined surface with respect to the one surface 32a and the other surface 32b of the antenna section 26, resonance can be prevented. Therefore, it is possible to prevent unnecessary signals from being input during the measurement of S12.

Part of the radio wave from the antenna section 26 is not absorbed by the tubular portion 42 of the radome 28, and the radiated radio wave can be emitted at an angle θ1 with respect to the outer surface of the first inclined portion 43a of the radome 28. Also, part of the radio wave from the DUT 18 is not absorbed by the cylindrical portion 42 of the radome 28, and the radiated radio wave can travel toward the antenna portion 26 at an angle θ2 with respect to the inner surface of the first inclined portion 43a of the radome 28. However, since part of the radio wave from the DUT 18 passes through the tubular portion 42, which is an electromagnetic wave absorbing material, it may be negligibly small compared to the radio wave entering from the tip portion 44, and may cause resonance as described above. is prevented.

Here, the S parameter that is the reflection characteristic (reflection coefficient) of the DUT 18 is assumed to be S11, and the S parameter that is the transmission characteristic (transmission coefficient) is assumed to be S21. The network analyzer 14 detects, as the reflection characteristics S11, the amplitude data of the reflected signal with respect to the incident signal at each frequency and the amount of phase change at each frequency of the reflected signal with respect to the incident signal. Further, as shown in FIG. 8, the network analyzer 14 detects, as the transmission characteristics S21, the amplitude data of the transmission signal with respect to the incident signal at each frequency and the amount of phase change at each frequency of the transmission signal with respect to the incident signal.

The distance d between the DUT 18 and the tip 44 of the radome 28 of the near-field air probe 12 is 0, that is, the contact state is defined as the distance d0 (not shown). As shown in FIG. 6, the network analyzer 14 was used to detect the transmission characteristics S21 at the positions where the distance d is d0, a certain distance d1, a certain distance d2=2·d1, and a certain distance d3=3·d1. That is, an appropriate signal was output from the signal source 62 of the network analyzer 14, the signals were received by the receivers 66a, 66b, 66c, and the transmission characteristic S21 was detected.

Here, the near-field air probe 12 is affected by the area of the electromagnetic field component of the DUT 18 in the vicinity of the DUT 18, but as the distance d from the DUT 18 increases and the near-field air probe 12 separates from the DUT 18, the DUT 18 It shifts to the far field where the directivity of electromagnetic waves is determined. If the aperture diameter of the antenna is D, the distance d from the DUT 18, which is the far field, is generally given by
2D ² /λ<d
is represented as If the frequency is 28 GHz (wavelength λ is approximately 10.7 mm, for example) and the aperture diameter D is 15 mm, the far field will not shift unless d>60 mm, for example.

At this time, for example, if the frequency is 28 GHz, the wavelength is about 10 mm. Therefore, even if the distance between the tip portion 44 of the radome 28 and the tip end surface 33a of the substrate 32 is an appropriate distance such as 1 to 2 mm, for example, d1 = 1 mm, d2 = 2 mm, and d3 = 3 mm. In this case, any near-field air probe 12 is affected by the near-field of the DUT 18 .

As shown in FIG. 8, in the graph of the distance d0, when the DUT 18 of this embodiment was used, the amplitude [dB] tended to increase as the frequency increased. The same tendency was observed even when the distance d increased from d0 to d3. For example, when the graph of the distance d1 is multiplied by a predetermined coefficient, there is a tendency that the graphs of the other distances d2 and d3 match or substantially match. That is, when the near-field air probe 12 according to the present embodiment is used, as shown by the line La shown in FIG. Got. As shown by line Lb in FIG. 9, generally, the transmission characteristic S21 tends to decrease substantially linearly as it approaches the far field (for example, a region where distance d≧dn), but the near field ( For example, in the region where the distance d<dn), it is found that there is variation rather than being substantially linear.

Due to this tendency (the tendency indicated by symbol La), the characteristics of the DUT 18 can be measured even in the near field by using the near field air probe 12 according to this embodiment. Therefore, by using the near-field air probe 12 according to the present embodiment, the DUT 18 can be It is possible to prevent the influence in the near field of

In this embodiment, an example using the distance d between the DUT 18 and the tip 44 of the radome 28, which is the appearance of the near-field air probe 12, has been described. By reducing the distance between the tip side end face 33a of the antenna part 26 of the near-field air probe 12 and the tip face of the tip part 44 of the radome 28, the DUT 18 and the tip part 44 of the radome 28 of the near-field air probe 12 can be regarded as the distance between the DUT 18 and the tip side end face 33a of the antenna section 26 of the near-field air probe 12. As shown in FIG.

Further, when the distance between the tip portion 44 of the near-field air probe 12 and the DUT 18 is the distance in the far field, the distance between the DUT 18 and the tip end face 33a of the antenna section 26 of the near-field air probe 12 is the distance in the far field. distance. When the distance d is the distance dn in the far field (see FIG. 8), a graph of approximately the same shape as the distances d0, d1, d2 and d3 in the near field was obtained. That is, when the near-field air probe 12 according to the present embodiment is used, as shown in FIGS. 6, 8 and 9, when the distance d is increased, even in the far field, S21 tends to decrease substantially linearly. Got.

Due to this tendency, the characteristics of the DUT 18 can be measured not only in the near field but also in the far field by using the near-field air probe 12 according to this embodiment.

In this embodiment, an example in which the amplitude [dB] tends to increase as the frequency increases has been described, but depending on the DUT 18, the amplitude [dB] tends to decrease as the frequency increases.

Therefore, according to this embodiment, it is possible to provide the near-field air probe 12 and the inspection device 10 that can measure the communication characteristics of the communication module (DUT 18) as the DUT 18 in the near field as well as the far field.

The base material 32 and the conductors 34a and 34b of the antenna section 26 used in the present embodiment are not limited to the illustrated shapes, and any appropriate shape may be used. Also, the antenna section 26 may have various structures such as a structure in which the conductors 34 a and 34 b are sandwiched between the base material (dielectric substrate) 32 . In this case, the conductors 34a and 34b are provided on one surface 32a of one substrate 32, for example. That is, the antenna section 26 is appropriately formed according to the desired measurement frequency and the DUT 18 .

An inspection apparatus 10 incorporating a plurality of near-field air probes 12 will be described below with reference to FIG. 10, illustration of the signal source 62 and the switch 64 of the network analyzer 14 is omitted.

The inspection apparatus 10 has a box 80 having radio wave shielding properties. The box 80 has a plurality of booths (object-to-be-measured placement sections) 82 partitioned so as not to interfere with each other.

A plurality of near-field air probes 12 connected to network analyzers 14 are arranged in each booth 82 .

Also, in each booth 82, a DUT 18 is arranged so that it can be taken in and out of each booth 82 for inspection. The booth 82 of the box 80 is formed so as to facilitate the insertion and removal of the DUT 18 while shielding radio waves from the near-field air probe 12 and the DUT 18 during inspection. As an example, the RF connector 86 of the cable connected to the DUT 18 is fixed to the door 84 through which the DUT 18 is put in and out. When the DUT 18 is to be tested, when it is connected to the RF connector 86 of the door 84, the near-field air probe 12 and the DUT 18 are adjusted to have a predetermined distance d (the distance affected by the near-field).

In this manner, the DUT 18 can be placed at a predetermined distance (or d0) in the near-field from the near-field air probe 12, and the communication characteristics of the DUT 18 can be tested. For this reason, the near-field air probe 12 according to this embodiment can be used, for example, when testing mass-produced DUTs (homogeneous or heterogeneous communication modules) 18 in a small space. Therefore, the inspection apparatus 10 according to this embodiment can inspect the communication characteristics of a large number of DUTs 18 at the same time or at the same time while saving space.

According to this embodiment, it is possible to provide the inspection device 10 capable of measuring the communication characteristics of the communication module (DUT 18) as the DUT 18 in the near field.

It should be noted that the present invention is not limited to the above-described embodiments, and various modifications can be made in the implementation stage without departing from the scope of the invention. Further, each embodiment may be implemented in combination as appropriate, in which case the combined effect can be obtained. Furthermore, various inventions are included in the above embodiments, and various inventions can be extracted by combinations selected from a plurality of disclosed constituent elements. For example, even if some constituent elements are deleted from all the constituent elements shown in the embodiments, if the problem can be solved and effects can be obtained, the configuration with the constituent elements deleted can be extracted as an invention.

DESCRIPTION OF SYMBOLS 10... Inspection apparatus 12... Near-field air probe 14... Network analyzer 22... Radome base 24... RF connector part 26... Antenna part 28... Radome 32... Base material 33a... Tip end face 33d... Base end face 34a, 34b Conductor 35 Slot 42 Cylindrical part 42a Opening 43a-43d Inclined part 44 Distal end (transmitting surface) 62 Signal source 64 Switch , 66a, 66b, 66c... receivers, 68a, 68b... directional couplers.

Claims (4)

a radome base formed of an electromagnetic wave absorbing material;
a connector section provided on the radome base and receiving a signal from a network analyzer;
A plate-like substrate having a first surface and a second surface opposite to the first surface and fixed to the radome base; and the first surface of the substrate and the a probe section provided on at least one of the second surfaces and having a conductor that emits a signal input to the connector section as a traveling wave type radio wave;
a transmission surface having radio wave permeability along the radio wave emission direction; a radome having an inclined surface formed of an electromagnetic wave absorbing material that is inclined with respect to
The near-field air probe, wherein the size in the direction along the plate thickness of the end surface of the base material facing the transmission surface of the radome is larger than λ/2, which is half the wavelength λ of the lowest frequency to be measured in the radio wave. . 2. A near-field air probe as recited in claim 1 , wherein said probe portion is formed as a tapered slot antenna. A near-field air probe according to claim 1 or claim 2,
and an object-to-be-measured placement unit that faces the transmission surface of the near-field air probe and in which a DUT, which is the object to be measured, is placed at a position in the near-field of the radio wave. 4. The inspection apparatus according to claim 3 , further comprising a network analyzer for inputting a predetermined signal to said connector portion of said near-field air probe.

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