JP6684323B2 - Planar antenna device, wireless terminal measuring device including the same, and wireless terminal measuring method - Google Patents

Description

  The present invention relates to a planar antenna device, a wireless terminal measuring device including the same, and a wireless terminal measuring method.

  2. Description of the Related Art In recent years, with the progress of multimedia, wireless terminals (smartphones, etc.) in which an antenna for wireless communication such as cellular and wireless LAN is mounted have been actively produced. In the future, in particular, there is a demand for wireless terminals that transmit and receive wireless signals compatible with IEEE 802.11ad, 5G cellular, and the like that use broadband signals in the millimeter wave band.

  In a wireless terminal manufacturing plant, for example, the output level and the reception sensitivity of a transmission radio wave determined for each communication standard are measured with respect to a plurality of antennas included in a wireless terminal adopting a MIMO (Multi Input Multi Output) method. Alternatively, beam forming measurement is performed, and a performance test is performed to determine whether or not the measurement results satisfy a predetermined standard. Here, the beam forming is a technique capable of changing the shape and direction of a beam of a radio signal by controlling the amplitude and phase of the radio signal transmitted and received by a plurality of antennas.

  Conventionally, when performing the above performance test, one wireless terminal as a device under test (DUT) is placed in a shield box or an anechoic chamber, and the control terminal and antenna terminal of the DUT are coaxial. There was work to connect to the measuring instrument with a cable. In the present situation where the inspection of tens of thousands of DUTs is required per day, the inspection time required for one unit is very limited, and efficient measurement in a short time is required.

  However, it is possible to shorten the measurement time by the measuring device by speeding up or parallelizing the CPU built in the measuring device, but regarding the connection time by the coaxial cable between the DUT and the measuring device, the coaxial cable is Since it is physically connected by, it is difficult to significantly reduce the time.

  Further, when the antenna of the DUT radiates radio signals in the K and Ka band bands (18 GHz to 40 GHz), in the configuration in which the antenna terminal of the DUT and the measuring device are connected by the coaxial cable, the signal from the antenna However, there was a problem that the loss was large when it was transmitted by the coaxial cable and accurate measurement could not be performed.

  Therefore, there has been proposed a measuring instrument that performs a performance test of the DUT by transmitting and receiving a radio signal to and from the DUT and does not require a coaxial cable connection between the DUT and the measuring instrument. In such a measuring instrument, when the polarization of the DUT is unknown, a circular polarization antenna or a measurement antenna capable of receiving two orthogonal polarizations is used. On the other hand, when the polarized wave of the DUT is known as linearly polarized wave, the linearly polarized wave antenna can be similarly used as the measurement antenna. Moreover, it is desirable that the measuring equipment be small. For this reason, it is assumed that the measurement antenna is not a three-dimensional antenna such as a horn antenna, but a plane antenna made of a printed circuit board or the like.

In the configuration of transmitting and receiving radio signals to and from the DUT antenna using the measurement antenna, the radiation surface of the measurement antenna and the radiation surface of the DUT antenna are arranged in parallel. However, if multiple reflection occurs such that signal components of opposite phases cancel each other out between the two antennas arranged in parallel, an ideal flat characteristic is obtained near the use frequency of the transmission characteristic S ₂₁ by the two antennas. In comparison, a dent (amplitude error) of about several dB may appear.

2. Description of the Related Art In recent years, in wireless terminals such as smartphones, in order to suppress power consumption and prolong battery life, control is performed to operate an internal amplifier with high efficiency in a non-linear region. For a DUT that distorts an input signal due to the non-linearity of such an amplifier, when a performance test is performed in a state where there is an amplitude error in the transmission characteristic S ₂₁ between the measurement antenna and the DUT antenna, transmission / reception characteristic measurement or The measurement accuracy of the beam forming measurement is significantly deteriorated.

  Therefore, it is necessary to reduce the multiple reflection that occurs between the antenna of the DUT and the antenna for measurement, and a method such as Patent Document 1 has been proposed.

JP, 2016-201608, A

  As shown in Patent Document 1, by covering the entire surface of the antenna with a radio wave absorber, it is possible to reduce the intensity of reflected waves and reduce multiple reflections. However, since the radio wave absorber is present above the antenna element, there is a problem that the radio wave itself, which is originally desired to be emitted, is also absorbed by the radio wave absorber. When the DUT is measured using such an antenna, the sensitivity of the measurement is reduced, and it may be difficult to perform the measurement such as the spurious measurement that requires a high dynamic range.

  The present invention has been made in order to solve such a conventional problem, and is a planar antenna device capable of suppressing an amplitude error caused by multiple reflection occurring between an antenna of a wireless terminal and the same, An object of the present invention is to provide a wireless terminal measuring device and a wireless terminal measuring method.

In order to solve the above problems, a planar antenna device according to the present invention is a planar antenna having an antenna substrate including a dielectric substrate, an antenna element formed on a first surface of the antenna substrate, and the antenna substrate. A radio wave absorber that surrounds the first surface of the antenna element in a direction other than the desired radiation direction, and the antenna of the wireless terminal and the planar antenna that face each other in close proximity to the first surface of the antenna substrate have a space. to be coupled, the planar antenna and the antenna is disposed face to face at close range is not a radiation far-field region, the wave absorber and the antenna elements that are located on a first surface of the antenna substrate structure Is.

  With this configuration, the planar antenna device according to the present invention can suppress an amplitude error caused by multiple reflection that occurs with the antenna of the wireless terminal.

Further, in the planar antenna device according to the present invention, the planar antenna is a circularly polarized antenna element having a predetermined polarization rotation direction and a surface opposite to the first surface of the dielectric substrate. A ground plane conductor to be superposed on the second surface side, one end side of each of which is connected to the ground plane conductor, penetrates the dielectric substrate along its thickness direction, and each other end side of the dielectric substrate is A plurality of metal posts that extend to the first surface and are provided at a predetermined interval so as to surround the antenna element, and form a cavity, and the plurality of metal posts on the first surface side of the dielectric substrate. And a frame-shaped conductor provided with a rim having a predetermined width in the antenna element direction and short-circuiting each other end side along the arrangement direction thereof, and resonating with the cavity and the frame-shaped conductor. The vessel, By adjusting the structural parameters of the oscillator and the antenna element, the resonance frequency of the resonator is set to a desired value, the structural parameters, internal dimension Lw of the cavity, the rim width L of the frame-like conductor _{R 1} , the number of turns of the antenna element, the basic length a 0 of the antenna element, and the element width W of the antenna element, and the rim width L _R of the frame-shaped conductor is the surface of the dielectric substrate. The width may be approximately ¼ of the wavelength of the surface wave propagating along.

  With this configuration, the planar antenna device according to the present invention can suppress the generation of surface waves and make the radiation characteristic of the antenna a desired characteristic.

  Further, in the planar antenna device according to the present invention, the antenna element is formed in a square spiral type or a circular spiral type having an end portion on the center side of a spiral, and the antenna formed in the square spiral type or the circular spiral type. A configuration may further be provided, in which one end side is connected to the center side end portion of the spiral of the element and a power supply pin that is provided so as to penetrate the dielectric substrate and the ground plane conductor is provided.

  Further, a wireless terminal measuring apparatus according to the present invention, the plurality of planar antenna apparatus according to any one of the above, the direction of the beam of the signal under measurement transmitted from the antenna of the wireless terminal capable of controlling the beam direction A beam direction control unit for controlling, a signal receiving unit for receiving the measured signal controlled by the beam direction control unit by the plurality of planar antenna devices, and the measured signal received by the signal receiving unit And an analysis processing section that performs analysis processing according to claim 1, wherein the analysis processing section measures the power of the signal under measurement received by the signal receiving section by each of the planar antenna devices, and the power measurement section. A beam direction estimation unit that estimates the direction of the beam of the signal under measurement transmitted from the antenna based on the power measured by the unit; and the beam direction estimation unit. Direction of the beam of more estimated the signal to be measured, and the beam steering determines beam direction determining section for determining whether or not coincides with the direction of the controlled the beam by the portion, which is configured to include a.

  With this configuration, the wireless terminal measuring device according to the present invention can perform measurement including beamforming measurement on the wireless terminal while the positional relationship between the wireless terminal and the plurality of planar antenna devices is fixed.

  Further, with this configuration, the wireless terminal measuring device according to the present invention can reduce multiple reflection of the signal under measurement between the antenna of the wireless terminal and the planar antenna device. That is, the wireless terminal measuring device according to the present invention suppresses an amplitude error caused by multiple reflections generated between the antenna of the wireless terminal and the planar antenna device, and performs measurement on the wireless terminal without lowering measurement sensitivity. It can be carried out.

  Further, in the wireless terminal measuring device according to the present invention, one surface on which the antenna is installed in the wireless terminal may not be parallel to the first surface of the antenna substrate of each of the planar antennas.

  With this configuration, the wireless terminal measuring device according to the present invention can further suppress the amplitude error caused by the multiple reflection occurring between the plane antenna and the antenna of the wireless terminal.

  Further, in the wireless terminal measuring device according to the present invention, a normal line of the first surface of the antenna substrate of each of the planar antennas and a normal line of a radiation surface of each of the planar antennas are parallel to each other. The radiation direction may be the direction normal to the radiation surface of each planar antenna.

Further, in the wireless terminal measuring device according to the present invention, a planar antenna having an antenna substrate including a dielectric substrate, an antenna element formed on the first surface of the antenna substrate, and a first antenna of the antenna substrate. A radio wave absorber surrounding a plane other than a desired radiation direction of the antenna element, and the planar antenna is spatially coupled to the antenna of the wireless terminal that closely faces and faces the first plane of the antenna substrate. A plurality of planar antenna devices, a beam direction control unit for controlling the beam direction of the signal under measurement transmitted from the antenna of the wireless terminal capable of controlling the beam direction, and the beam direction control unit for controlling the beam direction. A signal receiving section for receiving a signal under measurement by the plurality of planar antenna devices, and an analysis process for the signal under measurement received by the signal receiving section. And an analysis processing unit that performs measurement, wherein the analysis processing unit is a power measurement unit that measures the power of the signal under measurement received by the signal reception unit by each of the planar antenna devices, and is measured by the power measurement unit. Based on the power, the beam direction estimation unit for estimating the beam direction of the measured signal transmitted from the antenna, and the beam direction of the measured signal estimated by the beam direction estimation unit is A beam direction determination unit that determines whether or not the beam direction is controlled by a beam direction control unit, and a wireless terminal measurement device, wherein the wireless terminal is further installed on the other surface side. A plurality of antennas including another antenna are provided, and the plurality of planar antennas are arranged at positions facing one surface of the wireless terminal, and are installed on one surface side of the wireless terminal. A first circularly polarized antenna that is spatially coupled to the antenna, and is spatially coupled to the antenna that is disposed at a position facing the other surface of the wireless terminal and is disposed on the other surface of the wireless terminal. The second circular polarization antenna may be configured such that the first circular polarization antenna and the second circular polarization antenna have different rotation directions of the predetermined polarization.

  With this configuration, the wireless terminal measuring device according to the present invention, without installing an object such as a shield material for blocking a signal between circularly polarized antennas having mutually different polarized wave rotation directions opposite to each other with the wireless terminal interposed therebetween, It is possible to maintain the isolation performance between the circularly polarized antennas facing each other.

  Further, in the wireless terminal measuring device according to the present invention, the other surface of the wireless terminal may not be parallel to the first surface of the antenna substrate of the second circularly polarized antenna.

  With this configuration, the wireless terminal measuring device according to the present invention can further suppress the amplitude error caused by the multiple reflection that occurs between the second circular polarization antenna and the antenna of the wireless terminal.

  In the wireless terminal measuring device according to the present invention, a normal line of a radiation surface of the antenna and a normal line of one surface or the other surface of the wireless terminal on which the antenna is installed are parallel to each other, and a radiation direction of the antenna. May be in the direction normal to the radiation surface of the antenna.

  Further, a wireless terminal measuring method according to the present invention is a wireless terminal measuring method using any one of the above wireless terminal measuring apparatuses, wherein a measured signal transmitted from the antenna of the wireless terminal capable of controlling a beam direction is used. A beam direction control step of controlling the beam direction of the beam, a signal reception step of receiving the signals under measurement controlled by the beam direction control step by the plurality of planar antenna devices, and the signal reception step received by the signal reception step. An analysis processing step of performing analysis processing on the signal under measurement, wherein the analysis processing step measures the power of the signal under measurement received in the signal receiving step by each of the planar antenna devices. And based on the power measured by the power measuring step, the target transmitted from the antenna. The beam direction estimation step of estimating the beam direction of the constant signal, and the beam direction of the measured signal estimated by the beam direction estimation step match the beam direction controlled by the beam direction control step. And a beam direction determining step for determining whether or not the beam is present.

  With this configuration, the wireless terminal measuring method according to the present invention can perform the measurement including the beamforming measurement on the wireless terminal while the positional relationship between the wireless terminal and the plurality of planar antenna devices is fixed.

  Further, with this configuration, the wireless terminal measuring method according to the present invention can reduce multiple reflection of the signal under measurement between the antenna of the wireless terminal and the planar antenna device. That is, the wireless terminal measuring device according to the present invention can suppress the amplitude error caused by the multiple reflection occurring between the antenna of the wireless terminal and the planar antenna device, and perform the measurement for the wireless terminal.

  The present invention provides a planar antenna device capable of suppressing an amplitude error caused by multiple reflections occurring between an antenna of a wireless terminal, a wireless terminal measuring device including the planar antenna device, and a wireless terminal measuring method. is there.

It is a block diagram which shows the structure of the wireless terminal measuring device which concerns on embodiment of this invention. It is a perspective view showing the composition of the plane antenna device concerning the embodiment of the present invention. It is sectional drawing (E surface sectional drawing) which shows an example of the positional relationship of the planar antenna apparatus and DUT which concern on embodiment of this invention. It is sectional drawing (E surface sectional drawing) which shows a mode that electromagnetic waves are radiated from the antenna of DUT toward the planar antenna apparatus which concerns on embodiment of this invention. FIG. 5 is a cross-sectional view (E-plane cross-sectional view) showing how electromagnetic waves diffusely reflected by the planar antenna device according to the embodiment of the present invention enter the DUT. It is sectional drawing (E surface sectional drawing) which shows a mode that the electromagnetic wave diffuse-reflected by DUT enters into the planar antenna of the planar antenna device which concerns on embodiment of this invention. It is a perspective view which shows the structure of the circular polarization antenna with which the wireless terminal measuring device which concerns on embodiment of this invention is equipped. (A) is a front view showing the configuration of the LHCP of the circular polarization antenna according to the embodiment of the present invention, and (b) is a front view of the configuration of the RHCP of the circular polarization antenna according to the embodiment of the present invention. It is a rear view which shows the structure of the circular polarization antenna in embodiment of this invention. 8A is an enlarged sectional view taken along line 4A-4A of FIG. 8A, and FIG. 8B is an enlarged sectional view taken along line 4B-4B of the modification of FIG. 8A. FIG. 9 is an enlarged sectional view taken along line 5-5 of FIG. (A) is an enlarged front view showing a configuration of a main part of a circular polarization antenna according to an embodiment of the present invention, and (b) is a configuration of a modified example of a main part of the circular polarization antenna according to the embodiment of the present invention. It is an enlarged front view showing. FIG. 8 is an enlarged front view showing the configuration of another modification of the main part of the circularly polarized wave antenna according to the embodiment of the present invention. It is a characteristic view when the configuration of the main part of the circularly polarized wave antenna according to the embodiment of the present invention is removed. It is a characteristic view when the structure of the principal part of the circular polarization antenna in the embodiment of the present invention is used. FIG. 4 is a cross-sectional view of a configuration of an experimental system for measuring S ₂₁ of the planar antenna device and the DUT according to the embodiment of the present invention as seen from directly above. It is a graph showing the measurement results of the S ₂₁ of the planar antenna device and the DUT according to embodiments of the present invention. It is a perspective view showing composition of a shield box with which a wireless terminal measuring device concerning an embodiment of the present invention is provided. It is a perspective view which shows the internal structure of the shield box with which the wireless terminal measuring device which concerns on embodiment of this invention is equipped. It is a perspective view which shows the structure of the antenna holding part with which the wireless terminal measuring device which concerns on embodiment of this invention is equipped. It is a top view for explaining movement of an antenna holding part with which a wireless terminal measuring device concerning an embodiment of the present invention is provided. It is a schematic diagram which shows an example of the positional relationship of the circularly polarized wave antenna and antenna of DUT in embodiment of this invention. 6 is a flowchart for explaining a process of a wireless terminal measuring method by the wireless terminal measuring device according to the embodiment of the present invention.

  Embodiments of a wireless terminal measuring device and a wireless terminal measuring method according to the present invention will be described below with reference to the drawings. The dimensional ratio of each component on each drawing does not always match the actual dimensional ratio.

  As shown in FIG. 1, the wireless terminal measuring device 1 according to the present embodiment is for performing measurement of transmission / reception characteristics, beam forming measurement, etc. with respect to a DUT 100 having at least one antenna 110 capable of controlling a beam direction. is there. For example, the wireless terminal measuring device 1 includes a shield box 50 accommodating the plurality of planar antenna devices 10, a measuring unit 51, a display unit 52, and an operating unit 53. The antenna 110 constitutes a phased array antenna whose beam direction is controllable.

  The DUT 100 is, for example, a wireless terminal such as a smartphone capable of performing millimeter wave communication compatible with 5G.

  The antenna 110 radiates radio waves of linear polarization such as vertical polarization and horizontal polarization. Further, the antenna 110 may have a configuration capable of temporally switching the polarization direction of the linearly polarized wave.

  As shown in FIGS. 2 and 3, the planar antenna device 10 includes a planar antenna 11 and a radio wave absorber 12. The planar antenna 11 is, for example, a patch antenna or a circular polarization antenna described later, and has an antenna substrate 13 including a dielectric substrate and an antenna element 14 formed on one surface 13a of the antenna substrate 13. The radio wave absorber 12 is arranged so as to surround the one surface 13 a of the antenna substrate 13 except for the desired radiation direction of the antenna element 14. A region denoted by reference numeral 113 in FIG. 3 shows an example of a range in a desired radiation direction of the antenna element 14.

  An antenna 110 including a plurality of antenna elements 112 is installed on one surface 111a of the DUT substrate 111 of the DUT 100. The one surface 111a of the DUT substrate 111 and the one surface 13a of the antenna substrate 13 of the planar antenna 11 closely face and oppose each other, whereby the antenna 110 of the DUT 100 and the planar antenna 11 are spatially coupled.

  The radio wave absorber 12 is composed of, for example, four wall portions 15 that surround the antenna element 14 from four directions. The height of each wall portion 15 needs to be a height that does not block an arbitrary straight line from the area of the effective area of the planar antenna 11 to the area of the effective area of the antenna 110 of the DUT 100. The desired radiation direction corresponds to the direction of this arbitrary straight line, for example.

  Of the region of the electromagnetic field radiated from the antenna 110 of the DUT 100, the region close to the antenna 110 is called a reactive near-field region in which the electromagnetic field component that does not contribute to the radiation is the main, and the region from the radiation surface of the antenna 110. The area where the directivity does not change with distance is called the radiation far field area. A region between the reactive near-field region and the radiation far-field region is a region called a radiation near-field region in which the directivity changes according to the distance.

The radiation near-field region is defined as a position that is apart from the radiation surface of the antenna 110 by a distance R that satisfies the following equation (1) with respect to the aperture length D of the antenna 110. Where λ is the free space wavelength.

  Hereinafter, the principle that multiple reflection can be suppressed between the planar antenna device 10 and the DUT 100 will be described. Here, it is assumed that the planar antenna 11 and the antenna 110 are installed facing each other at a short distance that is not a radiation far field region.

  When the radio wave absorber 12 is not attached to the planar antenna 11, the electromagnetic wave radiated from the antenna 110 is incident on the planar antenna 11 while being diffused in all directions, as indicated by an arrow in FIG. Of these, the electromagnetic wave incident on the area of the effective area of the planar antenna 11 is received by the planar antenna 11. Other electromagnetic waves are diffusely reflected by the antenna substrate 13 and the like. Note that FIG. 4A shows only the radiation direction of the electromagnetic wave radiated from one of the plurality of antenna elements 14 forming the antenna 110.

  Electromagnetic waves reflected without being received by the planar antenna 11 are diffused and reflected by the antenna substrate 13 of the planar antenna 11 and enter the DUT 100, as indicated by the arrows in FIG. Of these, the electromagnetic wave incident on the area of the effective area of the antenna 110 is received by the antenna 110. Other electromagnetic waves are diffusely reflected by the DUT substrate 111 of the DUT 100 and the like. Note that FIG. 5A shows only a reflected wave of a part of the electromagnetic waves radiated from the antenna 110 in FIG. 4A.

  Further, a part of the electromagnetic wave reflected without being received by the antenna 110 is again incident on the planar antenna 11 and received, as indicated by an arrow in FIG. That is, as shown in FIG. 4A, FIG. 5A, and FIG. 6A, the reflection of the electromagnetic wave is repeated a plurality of times between the planar antenna device 10 and the DUT 100. At this time, the planar antenna 11 receives a composite wave of the electromagnetic wave first directly radiated from the antenna 110 and the electromagnetic wave reflected between the planar antenna 11 and the DUT 100 and received after the second time.

Since the phase relationship between the signal received by the planar antenna 11 first and the signal received by the planar antenna 11 after the second time is determined by the installation distance between the planar antenna 11 and the DUT 100, this installation distance changes. In that case, the transmission characteristic S ₂₁ between the planar antenna 11 and the antenna 110 becomes wavy.

  On the other hand, as shown in FIG. 2, when the radio wave absorber 12 is attached to the planar antenna 11, the electromagnetic waves radiated from the antenna 110 are almost the same until they enter the planar antenna 11 (see FIG. 4). (B)), most of the electromagnetic waves diffusely reflected by the planar antenna 11 are absorbed by the radio wave absorber 12 and the intensity is reduced (FIG. 5 (b)). The broken lines in the arrows in FIGS. 4B and 5B represent electromagnetic waves that have been obstructed by the radio wave absorber 12 and have reduced strength.

Further, the electromagnetic wave diffusely reflected by the DUT 100 is absorbed by the radio wave absorber 12 even while being incident on the planar antenna 11, so that the strength is further reduced (FIG. 6B). In this way, the electromagnetic wave received by the planar antenna 11 after the second time is greatly reduced by the radio wave absorber 12, so that the signal received by the planar antenna 11 is mainly the first received signal. Therefore, it is possible to reduce the waviness of the transmission characteristic S ₂₁ when the installation distance between the planar antenna 11 and the DUT 100 is changed.

  Hereinafter, the configuration of a circular polarization antenna as an example of the planar antenna 11 will be described. 7 to 11 show the basic structure of a circularly polarized antenna.

  That is, FIG. 7 is a perspective view shown for explaining the configuration of the circularly polarized antenna 20. 8A and 8B are front views shown for explaining the configuration of the circularly polarized antenna 20. Further, FIG. 9 is a rear view shown for explaining the configuration of the circularly polarized antenna 20. Further, FIG. 10A is an enlarged cross-sectional view taken along line 4A-4A of FIG. Further, FIG. 10B is an enlarged cross-sectional view taken along line 4B-4B in the modified example of FIG. 8A. Further, FIG. 11 is an enlarged sectional view taken along line 5-5 of FIG.

  As shown in FIGS. 7 to 11, the circularly polarized antenna 20 of the present embodiment basically includes a dielectric substrate 21, a ground plane conductor 22 superposed on one surface 21a of the dielectric substrate 21, and a dielectric substrate 21. A circularly polarized antenna element 23 is formed on the opposite surface 21b of the body substrate 21 and has a predetermined polarization rotation direction. The antenna element 23 is an example of the antenna element 14 described above. Further, the antenna substrate 13 described above includes all the configurations of the circularly polarized antenna 20 except the antenna element 23. The one surface 13 a of the antenna substrate 13 corresponds to the opposite surface 21 b of the dielectric substrate 21. The opposite surface 21b is also referred to as a first surface, and the one surface 21a is also referred to as a second surface.

  Further, a power feeding portion 26 for feeding an excitation signal to the antenna element 23 is formed on the opposite side of the dielectric substrate 21 with the ground plane conductor 22 interposed therebetween. The power feeding unit 26 includes a power feeding dielectric substrate 27 and a power feeding line 28 of a microstrip line that is formed on a surface of the power feeding dielectric substrate 27 on the opposite side of the ground plane conductor 22 and that grounds the ground plane conductor 22. .

  As the dielectric substrate 21 and the power feeding dielectric substrate 27, a material such as RO4003 (Rogers) having a low loss in the quasi-millimeter wave band can be used.

As a material for the dielectric substrate 21 and the power feeding dielectric substrate 27, a material having a low loss and a dielectric constant of about 2 to 5 can be used. For example, a glass cloth Teflon substrate or various thermosetting resin substrates can be used. Become a candidate. For example, in the configuration shown in FIG. 10A, the dielectric constants of the dielectric substrate 21 and the feeding dielectric substrate 27 are both 3.62, the height h ₁ of the dielectric substrate 21 is 1.1 mm, and the feeding power is 1.1 mm. The height h ₂ of the dielectric substrate 27 can be set to 0.3 mm or the like.

  The antenna element 23 is, for example, a right-handed rectangular spiral (see FIG. 8A) or a left-handed rectangular spiral (see FIG. 8B) formed on the opposite surface 21b side of the dielectric substrate 21 by a pattern printing technique. It is an unbalanced antenna.

  Further, the circularly polarized wave antenna 20 has one end connected to a side end portion (feeding point) on the spiral center side of the antenna element 23, penetrates the dielectric substrate 21 in the thickness direction thereof, and forms a hole 22 a of the ground plane conductor 22. A power supply pin (feed pin) 25 that passes through in a non-conductive manner and further penetrates through the power supply dielectric substrate 27 that constitutes the power supply unit 26 and projects the other end side on the surface thereof.

  The power feeding unit 26 is not limited to the above microstrip line configuration, and may be an unbalanced type power feeding line such as a coaxial cable, a coplanar line having the ground plane conductor 22 as a ground, or a microstrip line. Any configuration may be used as long as power is supplied from the other end side of the. The circularly polarized antenna 20 having the configuration shown in FIG. 8A is fed from the feeding pin 25, so that the main polarized wave from the antenna element 23 rotates in the counterclockwise direction (left hand circular polarization). LHCP) radio waves can be emitted. On the other hand, the circularly polarized wave antenna 20 having the configuration shown in FIG. 8B is fed from the feeding pin 25, so that the main polarized wave is rotated clockwise from the antenna element 23 (right hand circular circular). It is possible to radiate radio waves of polarization (RHCP). In addition, in the drawings after FIG. 9, only the configuration in which the main polarization is LHCP is shown unless otherwise specified.

  However, in a circularly polarized antenna having only this structure, a surface wave along the surface of the dielectric substrate 21 is excited, so that the desired characteristics cannot be obtained as a circularly polarized antenna due to the influence of the surface wave.

  Therefore, in the circularly polarized antenna 20 of the present embodiment, a structure for suppressing the excitation of the surface wave along the surface of the dielectric substrate 21 is shown in FIGS. 10A and 11 in addition to the above structure. As described above, a cavity structure constituted by a plurality of metal posts 30 is adopted.

  Specifically, for example, a plurality of columnar metal posts 30 are connected at one end side to the ground plane conductor 22, penetrate the dielectric substrate 21 in the thickness direction thereof, and at the other end sides thereof are made of a dielectric material. A cavity is formed by extending to the opposite surface 21b of the substrate 21 and being provided at predetermined intervals so as to surround the antenna element 23.

  Further, in addition to the above-mentioned cavity structure, the circularly polarized antenna 20 of the present embodiment is such that the other end side of the plurality of metal posts 30 is sequentially short-circuited to the opposite surface 21b side of the dielectric substrate 21 along the arrangement direction. In addition, the frame-shaped conductor 32 is provided so as to extend from the connection position with each metal post 30 toward the antenna element 23 by a predetermined distance.

  Then, in the circularly polarized wave antenna 20 of the present embodiment, the surface wave can be suppressed by the synergistic effect of this cavity structure and the frame-shaped conductor 32. That is, the circularly polarized wave antenna 20 of the present embodiment is provided with the above-mentioned cavity structure and the frame-shaped conductor 32, so that the leakage of radio waves from the side surface of the antenna is significantly increased as compared with the conventional general planar antenna. Can be suppressed.

  As shown in FIG. 10B, the plurality of metal posts 30 form a plurality of holes 301 penetrating the dielectric substrate 21, and the inner walls of the plurality of holes 301 are plated (through-hole plating). As a result, a plurality of hollow metal posts 30 'can be realized.

  In this case, the lower ends of the plurality of hollow metal posts 30 'formed by through-hole plating are connected to the ground plane conductor 22 via lands 302 formed on the one surface 21a side of the dielectric substrate 21 by the pattern printing technique. Has been done.

  Hereinafter, in order to explain the effect of suppressing the surface wave by the above-mentioned cavity structure and the frame-shaped conductor 32, the simulation result of the structural parameters of each part and the characteristics of the circularly polarized antenna 20 obtained by changing the structural parameters. Will be described.

  First, elements that can be structural parameters of each part will be described.

  The frequency of use of the circularly polarized antenna 20 is 18 to 40 GHz in the K and Ka band bands, and the rectangular spiral of the antenna element 23 has a basic length of a0, and the a0 and a line having an arbitrary multiple thereof are 90 degrees. Are arranged for each angle.

  A typical example of such a square spiral is shown in FIG. That is, in this example, the element width W is set to 0.25 mm, the basic length a0 is set to 0.45 mm, and the line lengths of 2a0, 2a0, 3a0, 3a0, 4a0, and 4a0 are set for each 90-degree angle. Is 3a0, and is a nine-turn (nine-turn spiral) square spiral.

  The square spiral shown in FIG. 12B is a case where the basic length a0 ′ is made longer than the basic length a0 in FIG. 12A and the number of turns is reduced.

  In this example, the element width W is 0.25 mm, the basic length a0 'is 0.7 mm, and the line lengths are 2a0', 2a0 ', 3a0', 3a0 ', and 4a0' for every 90 degree angle. The line length is set to about 1.5a0 ', and a total of eight turns (eight-turn spiral) rectangular spiral is used.

  In this case, the final line length is selected to be about 1.5a0 'so as to optimize the axial ratio of circularly polarized waves and the reflection characteristics.

  In the following description and embodiments, an example of a rectangular spiral is shown as the antenna element 23 that should be adopted in the circularly polarized antenna 20.

  However, as shown in FIG. 13, as the antenna element 23 to be adopted in the circular polarization antenna 20, a circular spiral antenna element 23 can be used instead of the rectangular spiral.

  The circular spiral antenna element 23 shown in FIG. 13 has a radius initial value SR = 0.2 mm from the reference point, an element width W = 0.35 mm, a spiral interval d = 0.2 mm, and a winding number 2.125. This is the case of the antenna element 23 having a circular spiral, and even when the antenna element 23 having such a circular spiral is used for the circularly polarized antenna 20, the same result as that when the above-mentioned rectangular spiral antenna element 23 is used is obtained. Has been obtained.

  Further, the outer shape of the dielectric substrate 21 is a square centered on the spiral center of the antenna element 23, and as shown in FIGS. 8A and 8B, the length of one side thereof is L (hereinafter referred to as the outer length). ), And the outer shape of the cavity is also a concentric square.

Further, as shown in FIGS. 10A and 10B, the cavity has an inner dimension Lw. Further, the frame-shaped conductor 32 is provided with a rim having a predetermined width (hereinafter, referred to as a rim width) L _R extending inward from the inner wall of the cavity.

  The diameter of each of the plurality of metal posts 30 forming the cavity is 0.3 mm, and the interval between the metal posts 30 is 0.9 mm.

  FIG. 14 shows a simulation result of a radiation characteristic of a vertical surface (yz plane in FIGS. 7 and 8) in the case where the cavity formed by the plurality of metal posts 30 and the frame-shaped conductor 32 are not provided.

  In FIG. 14, F1 and F1 ′ are characteristics of the main polarization (left-hand circular polarization: LHCP) and cross polarization (right-hand circular polarization: RHCP) when the external length L = 18 mm, and F2, F2 'is the characteristic of the main polarization and the cross polarization when the external length L = 24 mm.

  Here, the radiation characteristics required for a circularly polarized wave antenna are symmetric and broad single-peaked characteristics with respect to the main polarization with respect to the 0 ° direction, and cross-polarization (or zero for perfect circular polarization). ), The radiation intensity needs to be sufficiently lower than the main polarization in a wide angle range.

  On the other hand, the characteristics F1 and F2 of the main polarization in FIG. 14 are both asymmetric and have a large variation in gain, and regarding cross polarization, the main polarization is near -60 ° and -40 °. It can be seen that the radiation level is equivalent or close to it.

  Such disturbance of the radiation characteristic is caused by the influence of the above-mentioned surface wave.

FIG. 15 shows the external lengths L = 18 mm and L = 24 mm when a cavity having an inner dimension Lw = 9 mm is provided by a plurality of metal posts 30 and a frame-shaped conductor 32 having a rim width L _R = 1.2 mm is further provided. The simulation results are shown for the main polarization characteristics F3 and F4 and the cross polarization characteristics F3 ′ and F4 ′ in the case.

  As is clear from FIG. 15, the main polarization characteristics F3 and F4 are symmetrical and broad single-peak characteristics around the 0 ° direction, and the cross polarization characteristics F3 ′ and F4 ′ are also wide angle ranges. In Fig. 7, the radiation intensity is sufficiently lower than those of the main polarizations F3 and F4, and the change is slow, and it can be seen that the desired characteristics required for the circular polarization antenna described above are obtained.

  Further, as a result of simulations of several various radiation characteristics similar to the above performed by changing the structural parameters of each part, the radiation characteristics in the case where the frame-shaped conductor 32 does not exist are the outer length L of the dielectric substrate 21 and the cavity. The dependence on the inner dimension Lw is shown, and in general, when the outer shape length L is large (L = 24, 18 mm), the main polarization characteristic becomes 3 as the cavity inner dimension Lw increases from 3 to 10 mm. It has been found that the ridge shape approaches the unimodal shape.

  Further, when the outer shape length L of the dielectric substrate 21 is relatively small (L = 12 mm), the main polarization characteristic approaches from a double-peaked shape to a single-peaked shape as the cavity inner dimension Lw increases from 3 to 10 mm. It turns out.

  However, in any case, the cross polarization violence is large and the difference with the main polarization component is small in any of the use angle ranges, the polarization selectivity is low, and the desired characteristics as shown in FIG. It is known that it will not reach.

The rim width L _R of 1.2 mm corresponds to approximately 1/4 of the wavelength of the surface wave propagating along the surface of the dielectric substrate 21. That is, the length of the rim width L _R = 1.2 mm is λg / 4 (λg is a guide wavelength) at which the impedance becomes infinite with respect to the surface wave when the post wall side is viewed from the tip side. To form a transmission line of.

  Therefore, the current does not flow along the surface of the dielectric substrate 21, and the current blocking action suppresses the excitation of the surface wave, thus preventing the radiation characteristic from being disturbed.

Therefore, when the circularly polarized antenna 20 is applied to a frequency band other than the above, the rim width L _R may be changed and set according to the frequency.

  By the way, the circularly polarized wave antenna 20 of the present embodiment constitutes a resonator by providing a cavity made of a plurality of metal posts 30 and a frame-shaped conductor 32 on the dielectric substrate 21, and the resonator is excited by the antenna element 23. You can think that you are doing.

  Since the circularly polarized antenna 20 of the present embodiment constitutes a resonator, there is a resonance frequency, and at that resonant frequency, the input impedance of the circularly polarized antenna 20 becomes very large and radiation is stopped.

  In this case, the resonance frequency of the resonator is determined by the structural parameters of the resonator and the circularly polarized antenna element 23.

As described above, the structural parameters are the inner dimension Lw of the cavity, the rim width L _R , the number of turns of the antenna element 23, the basic length a0 of the antenna element 23, the element width W of the antenna element 23, and the like.

  Therefore, in the frequency characteristic of the antenna gain, a sharp deep drop (notch) occurs near the resonance frequency. This resonance frequency can be set to a desired value by adjusting the above structural parameters.

  Hereinafter, the result of an experiment using the experimental system shown in FIG. 16 for suppressing multiple reflections by the planar antenna device 10 of the present embodiment will be described. 16 is a sectional view of the experimental system as seen from directly above. Here, a 4 × 4 patch antenna array 100 ′ was used as the DUT, and the 4 × 4 patch antenna array 100 ′ was attached and fixed to a fixing jig 101 made of Teflon (registered trademark). This 4 × 4 patch antenna array 100 ′ is capable of independently turning on / off power feeding to each element of the 16 antenna elements 112, and by feeding only some elements, it is smaller than 4 × 4. It is also possible to simulate various array antennas.

As the plane antenna 11 of the plane antenna device 10, the circular polarization antenna 20 shown in FIG. The experiment was performed by measuring the transfer characteristic S ₂₁ with the vector network analyzer (VNA) 102 while changing the distance d between the antenna substrate 13 and the DUT substrate 111 of the planar antenna device 10. The measurement frequency was 28 GHz.

FIG. 17 shows an experimental result when power is supplied to all the antenna elements 112 of the 4 × 4 patch antenna array 100 ′ and an experimental result when power is supplied only to the central 2 × 2 element of the 4 × 4 patch antenna array 100 ′. Shows. Further, FIG. 17 shows the result when the radio wave absorber 12 is attached to the circular polarization antenna 20 by a solid line, and the result when the radio wave absorber 12 is not attached to the circular polarization antenna 20 by a broken line. From the result of FIG. 17, regardless of the number of feedings of the antenna element 112, when the electromagnetic wave absorber 12 is not attached to the circularly polarized wave antenna 20, the level of S ₂₁ is greatly undulated according to the change of the distance d. I understand. On the other hand, when the electromagnetic wave absorber 12 is attached to the circularly polarized wave antenna 20, it can be seen that the waviness at the level of S ₂₁ is small.

From the above measurement results, it can be confirmed that by attaching the radio wave absorber 12 to the circularly polarized antenna 20, it is possible to obtain the effect of suppressing the corrugation of S ₂₁ due to the multiple reflection between the planar antenna device 10 and the DUT. It was

  Hereinafter, the configuration of the shield box 50 will be described. As shown in FIGS. 18 and 19, the shield box 50 shields the DUT 100 from surrounding electromagnetic waves, and mainly includes a housing 120, a tray 121, and an antenna holding portion 122.

  The size of the housing 120 is, for example, width 560 mm, depth 620 mm, and height 560 mm. The housing 120 is made of a conductive metal such as iron, stainless steel, aluminum, copper, brass, or an alloy thereof, and has an electromagnetic wave shielding function with respect to the outside. The housing 120 can be manufactured by bending a metal plate made of any of these materials, but may make a hole by punching the plate made of any of these materials for weight reduction and resource saving. . Alternatively, a mesh material may be adopted instead of the plate from the beginning. If the size of the holes or the mesh is sufficiently smaller than the wavelength of the radio wave of the signal under measurement output by the DUT 100 (for example, 1/10 wavelength or less), the shielding performance of the shield box can be maintained.

  In the shield box 50, the electromagnetic waves generated by the antenna 110 of the DUT 100 or the planar antenna device 10 are suppressed from being reflected inside the shield box 50, and the electromagnetic waves are prevented from leaking out of the shield box 50. A radio wave absorber for is provided along the inner wall surface.

  The tray 121 is a drawer-like member for mounting the DUT 100, and has polyethylene and polyacetal (POM) with a relatively low relative dielectric constant and a low dielectric loss at least over the entire thickness direction of the place where the DUT 100 is mounted. It is made of synthetic resin such as or Teflon (registered trademark).

  The tray 121 is attached to two air cylinders 130 installed on both sides of the housing 120. The tray 121 is pulled out from the housing 120 by the reciprocating motion of the air cylinders 130 in the Y-axis direction, and is placed on the mounting surface 121 a on the DUT 100. Can be placed on the mounting surface 121a and the DUT 100 placed on the mounting surface 121a can be stored inside the housing 120. The size of the DUT 100 that can be mounted on the mounting surface 121a is, for example, 38 mm to 221 mm in width and 123 mm to 306 mm in height.

  As shown in FIGS. 19 and 20, the antenna holding part 122 includes, for example, two antenna guides 123 extending in the X-axis direction and two antenna guides 124 extending in the Y-axis direction, and the shield box 50. A plurality of planar antenna devices 10 are held inside. Each of the antenna guides 123 and 124 is formed of a synthetic resin such as polyethylene, polyacetal (POM), or Teflon (registered trademark) having a relatively low relative dielectric constant and a small dielectric loss.

  The antenna holding unit 122 is arranged inside the shield box 50, for example, above and below the DUT 100. By the antenna holding portion 122, the positional relationship between the antenna 110 of the DUT 100 and the plurality of planar antenna devices 10 is fixed when the DUT 100 is housed in the shield box 50.

  FIG. 20 shows the positional relationship between the DUT 100 and the antenna holding portion 122 arranged above the DUT 100. As shown in FIG. 20, the two antenna guides 123 extending in the X-axis direction have, for example, a gap 123a into which the planar antenna device 10 can be inserted from the side (Y-axis direction) and a radiation surface of the planar antenna device 10. It has an opening 123b for exposing. Similarly, the two antenna guides 124 extending in the Y-axis direction are for exposing the gap 124a into which the planar antenna device 10 can be inserted from the side (X-axis direction) and the radiation surface of the planar antenna device 10, for example. It has an opening 124b. The planar antenna device 10 is arranged such that the radiation surface side (that is, the opposite surface 21b side) faces one surface of the DUT 100.

  The antenna holding unit 122 can arrange an arbitrary number of planar antenna devices 10 at arbitrary positions of the antenna guides 123 and 124. As described above, since the circularly polarized antenna 20 has very little leakage of radio waves from the side surface of the antenna, when the circularly polarized antenna 20 is adopted as the planar antenna 11, the planar antennas are used in the antenna guides 123 and 124. It is also possible to place the devices 10 close together.

  In the example shown in FIG. 20, although the openings 123b and 124b are also provided on the one surface 21a side opposite to the radiation surface of the planar antenna device 10, the opening portion on the one surface 21a side is not provided. The flat antenna device 10 may be configured so as to entirely cover the one surface 21a side.

  Further, the antenna holding part 122 arranged below the DUT 100 has the same configuration as the antenna holding part 122 arranged above the DUT 100, and the plane antenna device 10 has a radiation surface side (that is, the opposite surface 21b side). Hold it facing the DUT 100.

  Note that, in FIG. 20, arrows pointing from the respective antennas 110 of the DUT 100 to the planar antenna device 10 indicate an example of beam directions.

  The two antenna guides 123 extending in the X-axis direction can be translated in the Y-axis direction. Similarly, the two antenna guides 124 extending in the Y-axis direction can be moved in parallel in the X-axis direction. Further, the entire antenna holding portion 122 arranged above and below the DUT 100 can be moved in parallel in the Z-axis direction.

  Therefore, by moving the positions of the antenna guides 123 and 124 according to the mounting position and size of the DUT 100 without strict positioning when mounting the DUT 100 on the mounting surface 121a of the tray 121. It is possible to dispose the plurality of planar antenna devices 10 held by the antenna holding unit 122 at desired positions with respect to the plurality of antennas 110 of the DUT 100. For example, it is possible to arrange the planar antenna device 10 directly above each antenna 110 of the DUT 100.

  For example, as shown in FIG. 21 (a), the DUT 100 is placed in the center of the placement surface 121 a of the tray 121, and as shown in FIG. 21 (b), the DUT 100 is placed from the center of the placement surface 121 a of the tray 121. Whether the DUT 100 having a large size is placed on the placement surface 121a of the tray 121 as shown in FIG. The positions of the antenna guides 123 and 124 can be moved according to the positions.

  As shown in FIG. 1, the measurement unit 51 includes a signal transmission unit 60, a signal reception unit 61, a coupler 62, a SW 63, a beam direction control unit 64, an analysis processing unit 65, a storage unit 66, The DUT 100 is provided with a measurement control unit 67, and performs measurement of transmission / reception characteristics such as output level and reception sensitivity of transmission radio waves, and beamforming measurement.

  The signal transmitting unit 60 outputs a test signal from each planar antenna device 10 toward each antenna 110 of the DUT 100 housed in the shield box 50.

  The signal receiving unit 61 is configured to receive the signal under measurement transmitted from the antenna 110 of the DUT 100 by the plurality of planar antenna devices 10.

  The test signal includes a control signal for performing various controls corresponding to the communication standard of the DUT 100, such as setting the DUT 100 to the call connection state with respect to the wireless terminal measuring device 1 of the present embodiment. Further, the signal under measurement is a response signal from the DUT 100 to the test signal output from the wireless terminal measurement device 1 of the present embodiment, a signal whose amplitude and phase are controlled by the beam direction control unit 64 described later, or the like. is there.

  The coupler 62 is a wideband directional coupler that allows the output frequency of the test signal output from the signal transmission unit 60 to pass, and is configured by, for example, a Wilkinson-type distributor. The coupler 62 is connected to the planar antenna device 10 by a coaxial cable, inputs the test signal output from the signal transmission unit 60 to the planar antenna device 10, and receives the test signal from each DUT 100 received by each planar antenna device 10. The signal under measurement can be input to the signal receiving section 61.

  The SW 63 has either a state in which the output side of the signal receiving unit 61 is connected to a transmission / reception characteristic measuring unit 68 described later, or a state in which the output side of the signal receiving unit 61 is connected to a beamforming measuring unit 69 described later. Is configured to take.

  The beam direction control unit 64 outputs a control signal for controlling the shape and direction of the beam of the signal under measurement transmitted from the antenna 110 of the DUT 100 to the DUT 100 via the control terminal 40 of the shield box 50. ing. For example, the beam direction control unit 64 can control the amplitude and phase of the signal under measurement so as to realize the shape and direction of the beam set by the operation unit 53. The signal under measurement whose beam direction is controlled to a desired direction by the beam direction control unit 64 is received by the signal reception unit 61 by the plurality of planar antenna devices 10.

  The analysis processing section 65 is configured to perform analysis processing on the signal under measurement received by the signal receiving section 61, and includes a transmission / reception characteristic measuring section 68 and a beamforming measuring section 69.

  The transmission / reception characteristic measurement unit 68, for example, in the state where the output side of the signal reception unit 61 is connected by the SW 63, includes, for example, modulation accuracy (EVM), transmission power level, transmission spectrum mask, error vector amplitude, adjacent channel leakage power, and spurious emission. It is designed to make measurements. Furthermore, the transmission / reception characteristic measuring unit 68 can execute minimum input sensitivity, maximum input level, adjacent channel elimination, non-adjacent channel elimination, etc. as analysis processing relating to the MIMO reception test. The beamforming measurement unit 69 also includes a power measurement unit 69a, a beam direction estimation unit 69b, and a beam direction determination unit 69c. The measurement by the transmission / reception characteristic measurement unit 68 and the measurement by the beamforming measurement unit 69 are mainly performed in the radiation near-field region or the reactive near-field region.

  The power measuring unit 69a is configured to measure the power of the signal under measurement received by the signal receiving unit 61 by each planar antenna device 10 in a state where the output side of the signal receiving unit 61 is connected by the SW 63. Further, the power measuring unit 69a stores the power measured for each planar antenna device 10 in the storage unit 66 as a function of the position of the planar antenna device 10.

  The beam direction estimation unit 69b is configured to estimate the shape and direction of the beam of the signal under measurement transmitted from the antenna 110, based on the power measured by the power measurement unit 69a for each planar antenna device 10. This estimation is performed, for example, by interpolating the power stored in the storage unit 66 as a function of the position of the planar antenna device 10 by an arbitrary interpolation method.

  The beam direction determination unit 69c determines whether or not the beam direction of the signal under measurement estimated by the beam direction estimation unit 69b matches the beam direction controlled by the beam direction control unit 64. ing.

  The measurement control unit 67 is configured by, for example, a microcomputer including a CPU, a ROM, a RAM, a HDD that configures the storage unit 66, a personal computer, or the like, and controls the operation of each unit that configures the measurement unit 51.

  The signal transmission unit 60, the signal reception unit 61, the SW 63, the beam direction control unit 64, and the analysis processing unit 65 should be configured by digital circuits such as FPGA (Field Programmable Gate Array) and ASIC (Application Specific Integrated Circuit). Alternatively, a predetermined program stored in the storage unit 66 in advance may be executed by the measurement control unit 67 to be configured as software. Alternatively, the signal transmission unit 60, the signal reception unit 61, the SW 63, the beam direction control unit 64, and the analysis processing unit 65 can be configured by appropriately combining hardware processing by a digital circuit and software processing by a predetermined program. Is. The measurement control unit 67 can also receive a new program or a program whose version has been changed from the outside, and can add or update the storage unit 66.

  The display unit 52 is composed of a display device such as an LCD or a CRT, and based on a control signal from the measurement control unit 67, soft keys, pull-down menus, texts for displaying measurement results, setting measurement conditions, and the like. It is designed to display operation targets such as boxes.

  The operation unit 53 is for inputting an operation by the user, and is configured by, for example, a touch panel provided on the surface of the display screen of the display unit 52. Alternatively, the operation unit 53 may include an input device such as a keyboard or a mouse. In addition, the operation unit 53 may be configured by an external control device that performs remote control by a remote command or the like. The input operation by the operation unit 53 is detected by the measurement control unit 67. The user uses the operation unit 53 to select a communication standard supported by the DUT 100 from a plurality of communication standards, input the position of the planar antenna device 10 in the antenna holding unit 122, and the antenna 110 of the DUT 100. It is possible to set the shape and direction of the beam of the signal under measurement transmitted from.

  22A and 22B show an example of the positional relationship between the plurality of circularly polarized antennas 20 and the plurality of antennas 110 of the DUT 100 in the wireless terminal measuring device 1 of the present embodiment. Here, the illustration of the antenna holder 122 and the radio wave absorber 12 is omitted. In the following description, the case where the antenna 110 is installed on each of the one surface 111a side and the other surface 111b side of the DUT 100 will be described as an example, but the antenna 110 is installed only on the one surface 111a side or the other surface 111b side of the DUT 100. The configuration is also included in the scope of the present invention.

  The plurality of circularly polarized antennas 20 are arranged at positions facing one surface 111a of the DUT 100 and are spatially coupled to the antenna 110 installed on the one surface 111a side of the DUT 100, and the DUT 100. The second circularly polarized wave antenna 20b is disposed at a position facing the other surface 111b of the DUT 100 and is spatially coupled to the antenna 110 installed on the side of the other surface 111b of the DUT 100. If the DUT 100 has the antenna 110 only on the one surface 111a side, the second circular polarization antenna 20b can be omitted. Similarly, when the DUT 100 has the antenna 110 only on the side of the other surface 111b, the first circular polarization antenna 20a can be omitted.

  That is, the opposite surface 21b of the first circularly polarized wave antenna 20a faces the radiation surface 110a of the antenna 110 of the DUT 100 and the one surface 111a of the DUT 100. The opposite surface 21b of the second circular polarization antenna 20b faces the radiation surface 110a of the antenna 110 of the DUT 100 and the other surface 111b of the DUT 100.

  Further, the opposite surface 21b of each circularly polarized antenna 20 may be arranged not by being parallel to the radiation surface 110a of each antenna 110 of the DUT 100 but by an inclination angle θ. That is, the normal line of the one surface 111a or the other surface 111b of the DUT 100 on which the plurality of antennas 110 are installed and the normal line of the opposite surface 21b of each circular polarization antenna 20 intersect.

  Here, the normal line N2 of the radiation surface 110a of each antenna 110 is parallel to the normal line of the one surface 111a or the other surface 111b of the DUT 100 in which the plurality of antennas 110 are installed. The radiation direction of each antenna 110 is the normal line direction of the radiation surface 110a of each antenna 110.

  Further, the normal line N1 of the opposite surface 21b of each circular polarization antenna 20 and the normal line of the radiation surface of each circular polarization antenna 20 are parallel. The radiation direction of each circular polarization antenna 20 is the normal direction of the radiation surface of each circular polarization antenna 20.

  That is, as shown in FIG. 22A, the radiation direction of the signal under measurement radiated from the radiation surface 110a of the antenna 110 is not parallel to the normal direction N1 of the opposite surface 21b of the circularly polarized antenna 20. . Therefore, the signal under measurement radiated from the radiation surface 110a of the antenna 110 is reflected between the circularly polarized antenna 20 and the antenna 110 toward the inner wall surface 50a of the shield box 50 and absorbed by the inner wall surface 50a. . In this way, multiple reflection of the signal under measurement between the circularly polarized antenna 20 and the antenna 110 is suppressed.

  Similarly, as shown in FIG. 22B, the radiation direction of the test signal radiated from the antenna element 23 of the circularly polarized antenna 20 is not parallel to the normal direction N2 of the radiation surface 110a of the antenna 110. . Therefore, the test signal radiated from the circularly polarized antenna 20 is reflected between the circularly polarized antenna 20 and the antenna 110 toward the inner wall surface 50a of the shield box 50 and absorbed by the inner wall surface 50a. In this way, multiple reflection of the test signal between the circularly polarized antenna 20 and the antenna 110 is suppressed. In this way, by arranging the circularly polarized wave antenna 20 so as to be inclined, it is possible to further suppress multiple reflection.

  The circularly polarized wave antenna 20 is configured to be able to favorably receive the signal under measurement regardless of the linear polarization direction of the linearly polarized wave of the signal under measurement transmitted from the antenna 110. Further, the circularly polarized antenna 20 has a characteristic that it is difficult to receive a signal from the circularly polarized antenna whose polarization rotation direction is different from that of itself.

  In this embodiment, the first circular polarization antenna 20a and the second circular polarization antenna 20b have different polarization rotation directions. For example, the main polarization of the first circular polarization antenna 20a can be RHCP, and the main polarization of the second circular polarization antenna 20b can be LHCP. Alternatively, conversely, the main polarization of the first circular polarization antenna 20a can be LHCP and the main polarization of the second circular polarization antenna 20b can be RHCP.

  In this way, the first circularly polarized wave antenna 20a and the second circularly polarized wave antenna 20b are made to have different polarization rotation directions, so that a certain circularly polarized wave antenna 20 transmits as shown in FIG. It is possible to suppress the received test signal from being received by another circularly polarized antenna 20 that faces the DUT 100.

  The location and the number of circularly polarized antennas 20 in the shield box 50 are not limited to the examples shown in FIGS. 19, 20, and 22.

  In the wireless terminal measuring device 1 of the present embodiment, the first circular polarization antenna 20a and the second circular polarization antenna 20b whose main polarization directions are different from each other face each other across the DUT 100, so that the first circular polarization Good isolation performance can be obtained between the wave antenna 20a and the second circular polarization antenna 20b.

  Hereinafter, an example of the process of the wireless terminal measuring method using the wireless terminal measuring device 1 according to the present embodiment will be described with reference to the flowchart of FIG. Note that, here, it is assumed that the output side of the signal receiving unit 61 is connected to the beamforming measuring unit 69 by the SW 63.

  First, the user places the DUT 100 on the placing surface 121a of the tray 121, and the DUT 100 placed on the tray 121 is accommodated in the shield box 50 by operating the operation unit 53 (step S1).

  Next, the desired shape and direction of the beam of the signal under measurement transmitted from the antenna 110 capable of controlling the beam direction of the DUT 100 is input by the user operating the operation unit 53 (step S2).

  Next, the beam direction control unit 64 controls the beam shape and direction of the signal under measurement transmitted from the antenna 110 capable of controlling the beam direction of the DUT 100 to the state input in step S2 (beam direction control step S3).

  Next, the signal receiving section 61 receives the signal under measurement controlled in step S3 by the plurality of planar antenna devices 10 (signal receiving step S4).

  Next, the beam forming measurement unit 69 performs the analysis processing of the following steps S5 to S7 on the signal under measurement received in step S4 (analysis processing step).

  First, the power measuring unit 69a measures the power of the signal under measurement received by each planar antenna device 10 in step S4 (power measuring step S5).

  Next, the beam direction estimation unit 69b estimates the beam shape and direction of the signal under measurement transmitted from the antenna 110 based on the power measured in step S5 (beam direction estimation step S6).

  Next, the beam direction determination unit 69c determines whether or not the beam direction of the signal under measurement estimated in step S6 matches the beam direction controlled in step S3 (beam direction determination step S7). ).

  Next, the display unit 52 displays the determination result obtained in step S7 (step S8).

  When the DUT 100 is provided with a plurality of antennas 110 capable of controlling the beam direction, the measurement control unit 67 determines whether or not the determination processing in step S7 has been performed for all the antennas 110 (step S9). ). In the case of a negative determination, the processing from step S2 to step S8 is repeated, and the shape and direction of the beam of the signal under measurement is calculated for each antenna 110. If the determination is affirmative, the process ends.

  As described above, the planar antenna device 10 according to the present embodiment is provided with the radio wave absorber 12 surrounding the antenna substrate 13 in a direction other than the desired radiation direction of the antenna element 14, so that the planar antenna device 10 is generated between the antenna 110 of the DUT 100. It is possible to suppress the amplitude error caused by the multiple reflection.

  Further, in the planar antenna device 10 according to the present embodiment, the metal posts 30 penetrating the dielectric substrate 21 are arranged so as to surround the antenna element 23 to form a cavity structure, and the tips of the metal posts 30 are arranged in the arrangement direction. And a frame-shaped conductor 32 that is short-circuited and extends a predetermined distance in the direction of the antenna element 23. As a result, the planar antenna device 10 can suppress the generation of surface waves and make the radiation characteristic of the antenna a desired characteristic.

  Further, since the wireless terminal measuring device 1 according to the present embodiment can suppress the generation of surface waves of the planar antenna device 10, each planar antenna device 10 is not affected by the other planar antenna device 10 and the antenna 110 of the antenna 110 is not affected. Radiation properties can be measured.

  Further, in the wireless terminal measuring device 1 according to the present embodiment, it is possible to arrange an arbitrary number of planar antenna devices 10 at arbitrary positions of the antenna guides 123 and 124, so that the DUT 100 and the plurality of planar antenna devices 10 are arranged. Measurements including beamforming measurement for the DUT 100 can be performed with the positional relationship between and fixed.

  In addition, the wireless terminal measuring device 1 according to the present embodiment changes the height of the antenna guides 123 and 124 to measure the transmission / reception characteristics in the radiative near-field region or the reactive near-field region and the beamforming measurement. It can be carried out.

  Further, since the wireless terminal measuring device 1 according to the present embodiment can move the antenna holding part 122 according to the position where the DUT 100 is placed on the placing surface 121a of the tray 121, the DUT 100 on the placing surface 121a is moved. It is not necessary to perform strict positioning of the DUT 100, and various DUTs 100 having different sizes and shapes can be easily set.

  Further, in the wireless terminal measuring device 1 according to the present embodiment, the one surface 111a on which the antenna 110 is installed in the DUT 100 and the one surface 13a of the antenna substrate 13 of the planar antenna 11 can be arranged not to be parallel, and the planar antenna 11 and the DUT100 can be arranged. It is possible to further suppress the amplitude error caused by the multiple reflection that occurs between the antenna 110 and the antenna 110.

  In the wireless terminal measuring device 1 according to the present embodiment, the radiation direction of the signal under measurement radiated from the radiation surface 110a of the antenna 110 is parallel to the normal direction of the one surface 13a of the antenna substrate 13 of the planar antenna 11. Not arrangements are also possible. In this case, the multiple reflection of the signal under measurement between the antenna 110 and the planar antenna 11 can be further reduced. That is, the wireless terminal measuring device 1 according to the present embodiment can perform measurement on the DUT 100 while suppressing the amplitude error caused by the multiple reflection that occurs between the antenna 110 and the planar antenna 11.

  Further, in the wireless terminal measuring device 1 according to the present embodiment, the radiation direction of the test signal radiated from the antenna element 14 of the planar antenna 11 may be arranged not parallel to the normal direction of the radiation surface of the antenna 110. Therefore, the multiple reflection of the test signal between the antenna 110 and the planar antenna 11 can be further reduced.

  In the wireless terminal measuring device 1 according to the present embodiment, the first circular polarization antenna 20a and the second circular polarization antenna 20b that face each other with the DUT 100 in between have different polarization rotation directions, and thus face each other. The isolation performance between the opposing circular polarization antennas 20 can be maintained without installing an object such as a shield material that blocks signals between the circular polarization antennas 20.

  Further, in the wireless terminal measuring device 1 according to the present embodiment, the other surface 111b on which the antenna 110 is installed in the DUT 100 and the one surface 13a of the antenna substrate 13 of the second circular polarization antenna 20b can be arranged not parallel to each other, It is possible to further suppress the amplitude error caused by the multiple reflection that occurs between the second circularly polarized wave antenna 20b and the antenna 110 of the DUT 100.

  Further, in the wireless terminal measuring device 1 according to the present embodiment, when the circular polarization antenna 20 is used as the plane antenna 11, the linear polarization (for example, vertical polarization or Accurate measurement is possible regardless of the direction of horizontal polarization. Further, the wireless terminal measuring device 1 according to the present embodiment can reduce the fluctuation of the input / output power with respect to the horizontal installation angle of the DUT 100 mounted on the mounting surface 121a of the tray 121.

  Further, since the wireless terminal measuring device 1 according to the present embodiment measures in close proximity, accurate measurement can be performed without using an anechoic chamber.

1 Wireless Terminal Measuring Device 10 Planar Antenna Device 11 Planar Antenna 12 Radio Wave Absorber 13 Antenna Substrate 13a, 21b First Surface 14, 23 Antenna Element 20 Circularly Polarized Antenna 20a First Circularly Polarized Antenna 20b Second Circularly Polarized Antenna 21 Dielectric Substrate 21a Second Surface 22 Ground Plate Conductor 25 Feed Pin 30 Metal Post 32 Frame-shaped Conductor 61 Signal Receiving Section 64 Beam Direction Controlling Section 65 Analysis Processing Section 69a Power Measuring Section 69b Beam Direction Estimating Section 69c Beam Direction Determining Section 100 DUT
110 Antenna 110a Radiating surface 111 DUT substrate 111a One surface 111b Other surface

Claims (10)

A planar antenna (11, 20) having an antenna substrate (13) including a dielectric substrate (21) and an antenna element (14, 23) formed on the first surface (13a, 21b) of the antenna substrate. ,
A radio wave absorber (12) surrounding the first surface of the antenna substrate in a direction other than a desired radiation direction of the antenna element,
The antenna (110) of the wireless terminal (100) and the planar antenna, which face each other in close proximity to the first surface of the antenna substrate, are spatially coupled to each other , and the planar antenna and the antenna (110) radiate a far field region. A planar antenna device, wherein the antenna element and the radio wave absorber are arranged face to face with each other at a short distance, and the antenna element and the radio wave absorber are disposed on a first surface of the antenna substrate . The planar antenna is
A circularly polarized antenna element having a predetermined polarization rotation direction,
A ground plane conductor (22) superposed on the second surface (21a) side opposite to the first surface of the dielectric substrate;
One end of each is connected to the ground plane conductor, penetrates the dielectric substrate along its thickness direction, and the other end of each extends to the first surface of the dielectric substrate to surround the antenna element. A plurality of metal posts (30) forming a cavity by being provided at predetermined intervals,
A frame shape in which a rim having a predetermined width in the antenna element direction is provided on the first surface side of the dielectric substrate by short-circuiting the other end sides of the plurality of metal posts along the arrangement direction. A conductor (32),
A resonator is constituted by the cavity and the frame-shaped conductor, the structural parameters of the resonator and the antenna element are adjusted, and the resonant frequency of the resonator is set to a desired value. At least one of the inner dimension Lw of the cavity, the rim width L _R of the frame-shaped conductor, the number of turns of the antenna element, the basic length a0 of the antenna element, and the element width W of the antenna element, and the frame The planar antenna device according to claim 1, wherein the rim width L _R of the strip conductor is a width of about ¼ of a wavelength of a surface wave propagating along the surface of the dielectric substrate. The antenna element is formed in a square spiral type or a circular spiral type having an end portion on the center side of the spiral,
A feed pin (25) is further provided, one end of which is connected to an end portion of the spiral of the antenna element formed in the square spiral type or the circular spiral type on the center side of the spiral and penetrates through the dielectric substrate and the ground plane conductor. The planar antenna device according to claim 2, further comprising: A plurality of planar antenna devices according to any one of claims 1 to 3,
A beam direction control unit (64) for controlling the beam direction of the signal under measurement transmitted from the antenna (110) of the wireless terminal capable of controlling the beam direction;
A signal receiving unit (61) for receiving the signal under measurement controlled by the beam direction control unit by the plurality of planar antenna devices;
An analysis processing unit (65) for performing an analysis process on the signal under measurement received by the signal receiving unit,
The analysis processing unit,
A power measuring unit (69a) for measuring the power of the signal under measurement received by the signal receiving unit by each of the planar antenna devices;
A beam direction estimation unit (69b) that estimates the direction of the beam of the signal under measurement transmitted from the antenna (110) based on the power measured by the power measurement unit;
A beam direction determination unit (69c) for determining whether or not the beam direction of the signal under measurement estimated by the beam direction estimation unit matches the beam direction controlled by the beam direction control unit. And a wireless terminal measuring device. The wireless terminal measuring device according to claim 4, wherein one surface (111a) on which the antenna (110) is installed in the wireless terminal and the first surface of the antenna substrate of each of the planar antennas are not parallel to each other. .   The normal line of the first surface of the antenna substrate of each planar antenna and the normal line of the radiation surface of each planar antenna are parallel, and the radiation direction of each planar antenna is the normal of the radiation surface of each planar antenna. The wireless terminal measuring device according to claim 4 or 5, wherein the wireless terminal measuring device is in a line direction. A planar antenna (11, 20) having an antenna substrate (13) including a dielectric substrate (21) and an antenna element (14, 23) formed on the first surface (13a, 21b) of the antenna substrate. A radio wave absorber (12) surrounding the first surface of the antenna substrate other than a desired radiation direction of the antenna element, and the radio terminal (100 facing close to the first surface of the antenna substrate). A plurality of planar antenna devices in which the antenna (110) of 1) and the planar antenna are spatially coupled.
A beam direction control unit (64) for controlling the beam direction of the signal under measurement transmitted from the antenna (110) of the wireless terminal capable of controlling the beam direction;
A signal receiving unit (61) for receiving the signal under measurement controlled by the beam direction control unit by the plurality of planar antenna devices;
An analysis processing unit (65) for performing an analysis process on the signal under measurement received by the signal receiving unit,
The analysis processing unit,
A power measuring unit (69a) for measuring the power of the signal under measurement received by the signal receiving unit by each of the planar antenna devices;
A beam direction estimation unit (69b) that estimates the direction of the beam of the signal under measurement transmitted from the antenna (110) based on the power measured by the power measurement unit;
A beam direction determination unit (69c) for determining whether or not the beam direction of the signal under measurement estimated by the beam direction estimation unit matches the beam direction controlled by the beam direction control unit. A wireless terminal measuring device including,
The wireless terminal further has a plurality of antennas (110) including another antenna installed on the other surface (111b) side,
The plurality of planar antennas are arranged at positions facing one surface of the wireless terminal and are spatially coupled to the antenna (110) installed on one surface side of the wireless terminal. 20a) and a second circularly polarized wave antenna (20b ) arranged at a position facing the other surface of the wireless terminal and spatially coupled to the antenna (110) installed on the other surface side of the wireless terminal. ) And, including,
The first circular polarization antenna rotation direction of the predetermined polarization differs between said second circular polarization antenna no line terminal measuring device you characterized.   The wireless terminal measuring device according to claim 7, wherein the other surface of the wireless terminal and the first surface of the antenna substrate of the second circularly polarized antenna are not parallel to each other. A normal line of the radiation surface of the antenna (110) and a normal line of one surface or the other surface of the wireless terminal on which the antenna (110) is installed are parallel to each other,
Wireless terminal measuring device according to any one of the antenna (110) Radial said antenna (110) according to claim 8 from claim 4 characterized in that the normal direction of the emission surface of the. A wireless terminal measuring method using the wireless terminal measuring device according to any one of claims 4 to 9,
A beam direction control step (S3) for controlling the beam direction of the signal under measurement transmitted from the antenna (110) of the wireless terminal capable of controlling the beam direction;
A signal receiving step (S4) of receiving the signal under measurement controlled by the beam direction controlling step by the plurality of planar antenna devices,
An analysis processing step (S5 to S7) of performing an analysis processing on the signal under measurement received by the signal receiving step,
The analysis processing step,
A power measuring step (S5) of measuring the power of the signal under measurement received by each of the planar antenna devices in the signal receiving step,
A beam direction estimating step (S6) of estimating a beam direction of the signal under measurement transmitted from the antenna (110) based on the power measured by the power measuring step;
A beam direction determination step (S7) for determining whether or not the beam direction of the signal under measurement estimated by the beam direction estimation step matches the beam direction controlled by the beam direction control step. A method for measuring a wireless terminal, comprising:

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