JP2020022141A - Planar antenna device, wireless terminal measuring device including the same, and wireless terminal measuring method - Google Patents

Abstract

To provide a planar antenna device capable of suppressing an amplitude error caused by multiple reflection occurring between an antenna and a wireless terminal, a wireless terminal measurement device including the same, and a wireless terminal measurement method.SOLUTION: The planar antenna device includes: an antenna substrate 13 including a dielectric substrate; a planar antenna 11 having an antenna element 14 formed on one surface 13a of the antenna substrate 13; and a radio wave absorber 12 surrounding one side 13a of the antenna substrate 13 other than a desired radiation direction of the antenna element 14. An antenna 110 of a DUT 100 and the planar antenna 11 that are opposed to and close to one surface 13a of the antenna substrate 13 are spatially coupled.SELECTED DRAWING: Figure 3

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 development of multimedia, wireless terminals (smartphones and the like) equipped with antennas for wireless communication such as cellular and wireless LAN have been actively produced. In the future, in particular, wireless terminals that transmit and receive wireless signals corresponding to IEEE802.11ad, 5G cellular, and the like that use broadband signals in the millimeter wave band are required.

  In a wireless terminal manufacturing plant, for example, measurement of the output level of a transmission radio wave and the reception sensitivity specified for each communication standard for a plurality of antennas provided in a wireless terminal employing a MIMO (Multi Input Multi Output) method. Also, beamforming measurement is performed, and a performance test is performed to determine whether the measurement result satisfies a predetermined standard. Here, the beamforming is a technology that can change the shape and direction of a beam of a radio signal by controlling the amplitude and phase of a 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 the antenna terminal of the DUT are coaxial. The work of connecting to a measuring instrument by a cable was performed. In the current situation where inspection of tens of thousands of DUTs can be required per day, the inspection time required for one device is very limited, and efficient measurement in a short time is required.

  However, it is possible to shorten the measurement time by the measuring instrument by increasing the speed of the CPU built in the measuring instrument or by parallelizing the measuring instrument. It is difficult to greatly reduce the time since they are physically connected.

  When the antenna of the DUT emits radio signals in the K and Ka band bands (18 GHz to 40 GHz), the configuration in which the antenna terminal of the DUT is connected to the measuring instrument with a coaxial cable, the signal from the antenna is not used. However, there is a problem that the loss is large when transmitted over a coaxial cable, and accurate measurement cannot 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 device, when the polarization of the DUT is not known, a circularly polarized antenna or a measuring antenna that can receive two orthogonally polarized waves is used. On the other hand, when the polarization of the DUT is known as linear polarization, a linear polarization antenna can be used for the measurement antenna as well. Also, 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 flat antenna manufactured on a printed circuit board or the like.

In a configuration in which the measurement antenna is used to transmit and receive a radio signal to and from the DUT antenna, the radiation surface of the measurement antenna and the radiation surface of the DUT antenna are arranged in parallel. However, the parallel-arranged two antennas between antiphase multiple reflection as signal components to each other are canceled in occurs, to use around the frequency of the transmission characteristic S ₂₁ by two antennas, the ideal flat characteristic In some cases, a dent (amplitude error) of about several dB may appear.

2. Description of the Related Art In recent years, wireless terminals such as smartphones have been controlled to operate an internal amplifier with high efficiency in a non-linear region in order to suppress power consumption and extend battery life. Relative DUT giving distortion to the input signal by nonlinearity of such an amplifier, when performance tested in the presence of amplitude errors in the transmission characteristic S ₂₁ between the measuring antenna and the DUT antenna, Ya reception characteristic measurement The measurement accuracy of the beam forming measurement is significantly reduced.

  For this reason, it is necessary to reduce the multiple reflections generated between the antenna of the DUT and the antenna for measurement. For example, a method as disclosed in Patent Document 1 has been proposed.

JP-A-2006-160608

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

  The present invention has been made to solve such a conventional problem, and a planar antenna device capable of suppressing an amplitude error caused by multiple reflection occurring between an antenna of a wireless terminal and a flat antenna device. It is an object of the present invention to provide a wireless terminal measurement device provided with a wireless terminal measurement method.

  In order to solve the above problems, a planar antenna device according to the present invention includes: a planar antenna having an antenna substrate including a dielectric substrate; an antenna element formed on a first surface of the antenna substrate; And a radio wave absorber surrounding the antenna element in a direction other than a desired radiation direction on the first surface of the antenna substrate. It is a structure which is combined in a typical manner.

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

Further, in the planar antenna device according to the present invention, the planar antenna is the 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 superposed on the second surface side, one end of each is connected to the ground plane conductor, penetrates the dielectric substrate along its thickness direction, and the other end of the dielectric substrate is A plurality of metal posts that extend to a first surface and are provided at predetermined intervals so as to surround the antenna element, thereby forming a cavity; and the plurality of metal posts on a first surface side of the dielectric substrate. And a frame-like conductor provided with a rim having a predetermined width in the direction of the antenna element. Comprising a 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, the number of turns of the antenna elements, the antenna base length of the element a0, include at least one element width W of the antenna elements and the rim width L _R of the frame-like conductor, the surface of the dielectric substrate May be approximately １ ／ of the wavelength of the surface wave propagating along the axis.

  With this configuration, the planar antenna device according to the present invention can suppress the generation of surface waves, and can make the radiation characteristics 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 shape or a circular spiral shape having a center end portion of a spiral, and the antenna formed in the square spiral shape or the circular spiral shape is provided. One end of the element may be connected to a center side end of the spiral and may further include a power supply pin provided through the dielectric substrate and the ground plane conductor.

  Further, the wireless terminal measurement device according to the present invention, the plurality of planar antenna devices according to any of the above, the beam direction 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 signal under measurement controlled by the beam direction control unit by the plurality of planar antenna devices, and a signal to be measured received by the signal receiving unit. An analysis processing unit that performs an analysis process by using the 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 A beam direction estimating unit that estimates a direction of a beam of the signal under measurement transmitted from the antenna based on the power measured by the unit; and a beam direction estimating 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 measurement device according to the present invention can perform measurement including beamforming measurement on the wireless terminal in a state where the positional relationship between the wireless terminal and the plurality of planar antenna devices is fixed.

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

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

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

  Further, in the wireless terminal measuring device according to the present invention, the normal of the first surface of the antenna substrate of each of the planar antennas is parallel to the normal of the radiation surface of each of the planar antennas, May be a normal direction of a radiation surface of each of the planar antennas.

  Further, in the wireless terminal measuring device according to the present invention, the wireless terminal further has a plurality of antennas including another antenna installed on the other surface side, and the plurality of planar antennas are provided on one surface of the wireless terminal. A first circularly polarized antenna spatially coupled to the antenna disposed on one side of the wireless terminal, and a first circularly polarized antenna disposed spatially opposite to the other side of the wireless terminal; A second circular polarized antenna spatially coupled to the antenna installed on the other side of the wireless terminal, wherein the first circular polarized antenna and the second circular polarized antenna The configuration may be such that the direction of rotation of the predetermined polarization is different.

  With this configuration, the wireless terminal measurement device according to the present invention does not install an object that blocks a signal such as a shield material between circularly polarized antennas having different rotation directions of polarized waves that face each other across the wireless terminal, Isolation performance between opposed circularly polarized antennas can be maintained.

  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 an amplitude error caused by multiple reflections generated between the second circularly polarized antenna and the antenna of the wireless terminal.

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

  Also, a wireless terminal measurement method according to the present invention is a wireless terminal measurement method using any one of the above wireless terminal measurement devices, wherein a signal under test transmitted from the antenna of the wireless terminal capable of controlling a beam direction is provided. A beam direction control step of controlling the direction of the beam, a signal receiving step of receiving the signal under measurement controlled by the beam direction control step by the plurality of planar antenna devices, and the signal received by the signal receiving step An analysis processing step of performing analysis processing on the signal under measurement, wherein the analysis processing step is a power measuring step of measuring the power of the signal under measurement received in the signal receiving step by each of the planar antenna devices. And the power transmitted from the antenna based on the power measured in the power measuring step. A beam direction estimating step of estimating the beam direction of the constant signal, and the beam direction of the signal under measurement estimated by the beam direction estimating step coincides with the beam direction controlled by the beam direction control step. And a beam direction determining step of determining whether or not there is a beam direction.

  With this configuration, the wireless terminal measurement method according to the present invention can perform measurement including beamforming measurement on the wireless terminal in a state where 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 reflections of the signal under measurement between the antenna of the wireless terminal and the planar antenna device. That is, the wireless terminal measurement device according to the present invention can perform measurement on the wireless terminal while suppressing an amplitude error caused by multiple reflection occurring between the antenna of the wireless terminal and the planar antenna device.

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

FIG. 1 is a block diagram illustrating a configuration of a wireless terminal measurement device according to an embodiment of the present invention. 1 is a perspective view illustrating a configuration of a planar antenna device according to an embodiment of the present invention. It is sectional drawing (E surface sectional drawing) which shows an example of the positional relationship between the planar antenna device and DUT which concern on embodiment of this invention. It is sectional drawing (E side sectional drawing) which shows a mode that an electromagnetic wave is radiated | emitted from the antenna of DUT toward the planar antenna device which concerns on embodiment of this invention. FIG. 5 is a cross-sectional view (E-plane cross-sectional view) illustrating a state in which an electromagnetic wave diffusely reflected by the planar antenna device according to the embodiment of the present invention is incident on a DUT. It is sectional drawing (E surface sectional drawing) which shows a mode that the electromagnetic wave diffuse-reflected by the DUT is incident on the planar antenna of the planar antenna device according to the embodiment of the present invention. It is a perspective view showing the composition of the circular polarization antenna with which the radio terminal measuring device concerning an embodiment of the present invention is provided. (A) is a front view showing the configuration of the LHCP of the circularly polarized antenna in the embodiment of the present invention, and (b) is a front view of the RHCP configuration of the circularly polarized antenna in the embodiment of the present invention. It is a rear view showing the composition of the circularly polarized wave antenna in an embodiment of the present invention. FIG. 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 in a 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 the circularly polarized antenna in the embodiment of the present invention, and (b) is a configuration of a modification of a main part of the circularly polarized antenna in the embodiment of the present invention. FIG. It is an enlarged front view which shows the structure of the other modification of the principal part of the circularly polarized wave antenna in embodiment of this invention. FIG. 4 is a characteristic diagram when a configuration of a main part of the circularly polarized wave antenna according to the embodiment of the present invention is omitted. It is a characteristic diagram at the time of using the structure of the principal part of the circularly polarized wave antenna in the embodiment of the present invention. It is a sectional view from above the configuration of the experimental system for measuring the S ₂₁ of a planar antenna device and the DUT according to embodiments of the present invention. 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 showing the internal structure of the shield box with which the wireless terminal measuring device concerning the embodiment of the present invention is provided. It is a perspective view showing composition of an antenna holding part with which a wireless terminal measuring device concerning an embodiment of the present invention is provided. It is a top view for explaining movement of the antenna holding part with which the wireless terminal measuring device concerning the embodiment of the present invention is provided. FIG. 2 is a schematic diagram illustrating an example of a positional relationship between a circularly polarized antenna and an antenna of a DUT according to the embodiment of the present invention. 5 is a flowchart for explaining processing of a wireless terminal measurement method by the wireless terminal measurement device according to the embodiment of the present invention.

  Hereinafter, embodiments of a wireless terminal measurement device and a wireless terminal measurement method according to the present invention will be described with reference to the drawings. Note that the dimensional ratio of each component on each drawing does not always match the actual dimensional ratio.

  As shown in FIG. 1, a wireless terminal measuring apparatus 1 according to the present embodiment performs measurement of transmission / reception characteristics, beamforming measurement, and the like for a DUT 100 having at least one antenna 110 capable of controlling a beam direction. is there. For example, the wireless terminal measurement device 1 includes a shield box 50 in which a plurality of planar antenna devices 10 are accommodated, a measurement unit 51, a display unit 52, and an operation unit 53. The antenna 110 constitutes a phased array antenna whose beam direction can be controlled.

  The DUT 100 is a wireless terminal such as a smartphone that can perform 5G-compatible millimeter-wave communication.

  The antenna 110 emits radio waves of linear polarization such as vertical polarization and horizontal polarization. Further, the antenna 110 may be configured to be capable of temporally switching the polarization direction of the linear polarization.

  The planar antenna device 10 includes a planar antenna 11 and a radio wave absorber 12, as shown in FIGS. The planar antenna 11 is, for example, a patch antenna or a circularly polarized antenna described later, and includes 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 disposed on one surface 13 a of the antenna substrate 13 so as to surround the antenna element 14 in a direction other than a desired radiation direction. 3 indicates an example of a range of a desired radiation direction of the antenna element 14.

  On one surface 111a of the DUT substrate 111 of the DUT 100, an antenna 110 including a plurality of antenna elements 112 is installed. The one surface 111a of the DUT substrate 111 and the one surface 13a of the antenna substrate 13 of the planar antenna 11 are closely opposed to each other, so that the antenna 110 of the DUT 100 and the planar antenna 11 are spatially coupled.

  The radio wave absorber 12 is constituted by, for example, four walls 15 surrounding the antenna element 14 from all sides. The height of each wall portion 15 needs to be a height that does not block any 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, for example, the direction of this arbitrary straight line.

  Among the regions of the electromagnetic field radiated from the antenna 110 of the DUT 100, a region close to the antenna 110 is called a reactive near-field region in which an electromagnetic field component that does not contribute to the radiation is main. A region in which the directivity does not change with distance is called a radiant far-field region. Further, a region between the reactive near-field region and the radiation far-field region is 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 separated from the radiation surface of the antenna 110 by a distance R satisfying the following expression (1) with respect to the opening length D of the antenna 110. Here, λ is a free space wavelength.

  Hereinafter, the principle of suppressing multiple reflection 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 radiating 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 arrows in FIG. Among them, 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. FIG. 4A shows only the radiation direction of the electromagnetic wave radiated from one of the plurality of antenna elements 14 constituting the antenna 110.

  The electromagnetic wave reflected without being received by the planar antenna 11 is diffusely reflected by the antenna substrate 13 or the like of the planar antenna 11 and enters the DUT 100 as indicated by an arrow in FIG. Among them, 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 board 111 of the DUT 100 and the like. Note that FIG. 5A illustrates only a reflected wave related to a part of the electromagnetic waves radiated from the antenna 110 in FIG.

  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 shown by an arrow in FIG. That is, as shown in FIG. 4A, FIG. 5A, and FIG. 6A, the reflection of the electromagnetic wave between the planar antenna device 10 and the DUT 100 is repeated a plurality of times. At this time, the planar antenna 11 receives a composite wave of the electromagnetic wave directly radiated directly from the antenna 110 and the electromagnetic wave reflected between the planar antenna 11 and the DUT 100 and received for the second and subsequent times.

Since the phase relationship between the signal received by the planar antenna 11 first and the signal received by the planar antenna 11 for the second and subsequent times is determined by the installation distance between the planar antenna 11 and the DUT 100, the installation distance varies. If you, the transmission characteristic _{S 21} between the plane antenna 11 and the antenna 110 becomes wavy it.

  On the other hand, as shown in FIG. 2, when the radio wave absorber 12 is attached to the planar antenna 11, the electromagnetic wave radiated from the antenna 110 is almost the same up to the point where the electromagnetic wave enters the planar antenna 11 (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. 5B). 4 (b) and 5 (b) indicate electromagnetic waves whose strength has been reduced due to interference with the radio wave absorber 12.

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 intensity is further reduced (FIG. 6B). As described above, since the electromagnetic waves received by the planar antenna 11 for the second time and thereafter are greatly reduced by the radio wave absorber 12, the signal received by the planar antenna 11 is mainly the signal received first. Therefore, it is possible to reduce the waviness of the transmission characteristic S ₂₁ in the case of changing the installation distance of the planar antenna 11 and the DUT 100.

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

  That is, FIG. 7 is a perspective view shown for explaining the configuration of the circularly polarized wave antenna 20. FIGS. 8A and 8B are front views illustrating the configuration of the circularly polarized antenna 20. FIG. FIG. 9 is a rear view for explaining the configuration of the circularly polarized wave antenna 20. FIG. 10A is an enlarged cross-sectional view taken along the line 4A-4A in FIG. FIG. 10B is an enlarged cross-sectional view taken along line 4B-4B in the modification of FIG. 8A. 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 according to 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 formed on the opposite surface 21 b of the body substrate 21 and having a predetermined polarization rotation direction. The antenna element 23 is an example of the antenna element 14 described above. The antenna substrate 13 already described includes all components of the circularly polarized antenna 20 except the antenna element 23. One surface 13a of the antenna substrate 13 corresponds to the opposite surface 21b 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, on the opposite side of the dielectric substrate 21 with the ground plane conductor 22 interposed therebetween, a feeder 26 for feeding an excitation signal to the antenna element 23 is formed. The power supply unit 26 includes a power supply dielectric substrate 27 and a microstrip line power supply line 28 formed on the surface of the power supply dielectric substrate 27 opposite to the ground plane conductor 22 and grounding the ground plane conductor 22. .

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

As the material of the dielectric substrate 21 and the power supply dielectric substrate 27, any 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. 10 (a), both the dielectric constant of the dielectric substrate 21 and the feeding dielectric substrate 27 and 3.62, 1.1 mm height _{h 1} of the dielectric substrate 21, a power supply the height _{h 2} of the dielectric substrate 27 may be, eg, 0.3 mm.

  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.

  In addition, the circularly polarized antenna 20 has one end connected to a side end (feed point) on the spiral center side of the antenna element 23, penetrates the dielectric substrate 21 in the thickness direction thereof, and forms the hole 22 a of the ground plane conductor 22. A feed pin (feed pin) 25 which passes non-conductively and further penetrates the feed dielectric substrate 27 constituting the feed unit 26 and has the other end protruding from the surface thereof is provided.

  The power supply section 26 is not limited to the configuration of the microstrip line described above, but may be an unbalanced power supply line, for example, 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 of the device. The circularly polarized antenna 20 having the configuration shown in FIG. 8A is supplied with power from the power supply pin 25, so that the rotation direction of the main polarized wave is counterclockwise from the antenna element 23 (left hand circular polarization: LHCP) radio waves. On the other hand, in the circularly polarized antenna 20 having the configuration shown in FIG. 8B, the power is supplied from the feed pin 25, so that the rotation direction of the main polarized wave from the antenna element 23 is clockwise circularly (right hand circular). polarization (RHCP) radio waves. In the drawings after FIG. 9, only the configuration of the main polarization is LHCP unless otherwise specified.

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

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

  More specifically, for example, one end of each of the plurality of columnar metal posts 30 is connected to the ground plane conductor 22, penetrates the dielectric substrate 21 along the thickness direction, and the other end of each of the plurality of columns is a dielectric. A cavity is formed by extending at a predetermined interval so as to extend to the opposite surface 21 b of the substrate 21 and surround the antenna element 23.

  Furthermore, in addition to the above-described cavity structure, the circularly polarized antenna 20 of the present embodiment sequentially short-circuits the other ends of the plurality of metal posts 30 on the opposite surface 21b side of the dielectric substrate 21 along the direction in which they are arranged. A frame-shaped conductor 32 is provided extending from the connection position with each metal post 30 toward the antenna element 23 by a predetermined distance.

  In the circularly polarized wave antenna 20 of the present embodiment, a surface wave can be suppressed by a synergistic effect of the cavity structure and the frame-shaped conductor 32. In other words, the circularly polarized antenna 20 of the present embodiment includes the above-described cavity structure and the frame-shaped conductor 32, so that the leakage of radio waves from the side surface of the antenna is significantly reduced as compared with a conventional general planar antenna. Can be suppressed.

  As shown in FIG. 10B, the plurality of metal posts 30 are formed with 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). Thereby, it can also be realized as a plurality of hollow metal posts 30 '.

  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 21 a side of the dielectric substrate 21 by a pattern printing technique. Has been made.

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

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

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

  A typical example of such a rectangular spiral is shown in FIG. That is, in this example, the element width W is 0.25 mm, the basic length a0 is 0.45 mm, and hereafter, the line length is 2a0, 2a0, 3a0, 3a0, 4a0, 4a0 at every 90 ° angle, and the final line length is Is 3a0, and a 9-turn (nine-turn spiral) square spiral is used.

  The square spiral shown in FIG. 12B is a case where the basic length a0 ′ is 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 hereafter, the line length is 2a0', 2a0 ', 3a0', 3a0 ', 4a0' for each 90-degree angle. The line length is about 1.5a0 ', and the whole is a square spiral of eight turns (eight-turn spiral).

  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 to be employed in the circularly polarized antenna 20.

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

  The circular spiral antenna element 23 shown in FIG. 13 has, for example, 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 number of turns of 2.125. This is the case of the antenna element 23 using a circular spiral. Even when such an antenna element 23 using a circular spiral is used for the circularly polarized antenna 20, almost the same result as when the antenna element 23 using a square spiral described above is used. Have been obtained.

  The outer shape of the dielectric substrate 21 is a square centered on the spiral center of the antenna element 23. As shown in FIGS. 8A and 8B, the length of one side 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, a predetermined width extending from the cavity inner wall to the inside (hereinafter, referred to as rim width) rim having L _R is provided.

  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 plane (yz plane in FIGS. 7 and 8) in a 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 the characteristics of the main polarization (left-hand circular polarization: LHCP) and cross polarization (right-hand circular polarization: RHCP) when the outer length L is 18 mm. F2 'is the characteristic of the main polarization and the cross polarization when the outer length L is 24 mm.

  Here, the radiation characteristic required for a circularly polarized antenna is a single-peak characteristic that is symmetric and broad around the 0 ° direction for the main polarized wave, and is a cross polarized wave (zero for a perfect circularly polarized wave). ) Requires that the radiation intensity be sufficiently lower than the main polarization over 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 significant gain in the gain. In addition, regarding the cross polarization, the main polarization has a main polarization near -60 ° and -40 °. It can be seen that the radiation level is equal to or close to it.

  Such disturbance of the radiation characteristics is caused by the influence of the surface wave described above.

FIG. 15 shows a case where a plurality of metal posts 30 are provided with a cavity having an inner dimension Lw = 9 mm, and a frame-shaped conductor 32 having a rim width L _{R of} 1.2 mm is provided. Simulation results are shown for the main polarization characteristics F3 and F4 and the cross polarization characteristics F3 'and F4' in the case of the above.

  As is clear from FIG. 15, the characteristics F3 and F4 of the main polarization are symmetric and broad single-peak characteristics around the 0 ° direction, and the characteristics F3 ′ and F4 ′ of the cross polarization also have a wide angle range. , The radiation intensity is sufficiently low with sufficiently lower radiation intensity than the main polarized waves F3 and F4, and it can be seen that the desired characteristics required for the circularly polarized antenna are obtained.

  In addition, as a result of a simulation of various radiation characteristics similar to the above, which were performed by changing the structural parameters of each part, the radiation characteristics without the frame-shaped conductor 32 were determined by the outer length L of the dielectric substrate 21 and the cavity. The dependence on the inner dimension Lw is shown. Generally speaking, when the outer dimension L is large (L = 24, 18 mm), the main polarization characteristic becomes 3 as the inner dimension Lw of the cavity increases from 3 to 10 mm. It has been found that the peak shape approaches a single peak shape.

  When the outer length L of the dielectric substrate 21 is relatively small (L = 12 mm), the main polarization characteristic approaches a single-peak shape from a bimodal shape as the cavity inner size Lw increases from 3 to 10 mm. It turns out that.

  However, in any case, the cross polarization is largely ramped up, the difference from 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 has been found not to be reached.

Note that the rim width _LR of 1.2 mm corresponds to approximately １ ／ of the wavelength of the surface wave propagating along the surface of the dielectric substrate 21. That is, when the rim width L _R = 1.2 mm is viewed from the front end side to the post wall side, the length of λg / 4 (λg is the guide wavelength) at which the impedance becomes infinite with respect to the surface wave. Is formed.

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

Therefore, when applying a circularly polarized wave antenna 20 to the other frequency bands other than those described above may be changed setting the rim width L _R in accordance with the frequency.

  Incidentally, the circularly polarized antenna 20 of the present embodiment forms a resonator by providing a cavity formed by a plurality of metal posts 30 and a frame-shaped conductor 32 on a dielectric substrate 21, and the resonator is excited by an antenna element 23. You can think that you are.

  Since the circularly polarized antenna 20 of the present embodiment constitutes a resonator, there is a resonance frequency, and at that resonance frequency, the input impedance of the circularly polarized antenna 20 becomes very large, and radiation does not occur.

  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.

The structural parameters, as described above, internal dimension Lw of the cavity, in addition to the rim width L _R, the number of turns of the antenna element 23, the basic length a0 of the antenna element 23, and the like element width W of the antenna element 23.

  Therefore, the frequency characteristic of the antenna gain has a sharp notch near the resonance frequency. This resonance frequency can be set to a desired value by adjusting the above structural parameters.

  Hereinafter, the results of an experiment performed on the suppression of multiple reflection by the planar antenna device 10 of the present embodiment using the experimental system shown in FIG. 16 will be described. FIG. 16 is a cross-sectional view of the experimental system as viewed from directly above. Here, a 4 × 4 patch antenna array 100 ′ was used as a 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 ′ can independently supply power to each of the 16 antenna elements 112, and is smaller than 4 × 4 by supplying power to only some of the elements. It is also possible to simulate a simple array antenna.

Further, as the planar antenna 11 of the planar antenna device 10, the circularly polarized antenna 20 shown in FIG. 7 and the like was used. Experiments while changing the distance d between the antenna substrate 13 and the DUT board 111 of the planar antenna device 10 was carried out by measuring the transmission characteristic _{S 21} in a vector network analyzer (VNA) 102. 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 to only the central 2 × 2 element of the 4 × 4 patch antenna array 100 ′. Is shown. FIG. 17 shows the result when the radio wave absorber 12 is attached to the circularly polarized antenna 20 by a solid line, and the result when the radio wave absorber 12 is not attached to the circularly polarized antenna 20 by a broken line. From the results of FIG 17, regardless of the feeding speed of the antenna element 112, if the circularly polarized antenna 20 is not attached to the wave absorber 12 according to the change of the distance d, the level of S ₂₁ is wavy large You can see that. On the other hand, in the case of attaching the electromagnetic wave absorber 12 to a circularly polarized wave antenna 20, the waving of the level of S _21, it is seen that the smaller.

From the above measurement results, it can be confirmed that attaching the radio wave absorber 12 to the circularly polarized antenna 20 has an effect of suppressing the waving of S ₂₁ due to multiple reflection between the planar antenna device 10 and the DUT. 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 unit 122.

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

  In the shield box 50, the reflection of the electromagnetic waves generated by the antenna 110 or the planar antenna device 10 of the DUT 100 in the shield box 50 is suppressed, and the electromagnetic waves are prevented from leaking out of the shield box 50. Radio wave absorber is provided along the inner wall surface.

  The tray 121 is a drawer-shaped member on which the DUT 100 is placed. The tray 121 has a relatively low dielectric constant and a small dielectric loss, such as polyethylene or polyacetal (POM), at least over the entire thickness direction of the place where the DUT 100 is placed. And a synthetic resin such as Teflon (registered trademark).

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

  As shown in FIGS. 19 and 20, the antenna holding unit 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. Inside, a plurality of planar antenna devices 10 are held. Each of the antenna guides 123 and 124 is made of a synthetic resin such as polyethylene, polyacetal (POM), or Teflon (registered trademark) having a relatively low dielectric constant and a small dielectric loss.

  The antenna holding units 122 are arranged in the shield box 50, for example, above and below the DUT 100. The antenna holder 122 fixes the positional relationship between the antenna 110 of the DUT 100 and the plurality of planar antenna devices 10 when the DUT 100 is accommodated in the shield box 50.

  FIG. 20 illustrates a positional relationship between the DUT 100 and the antenna holding unit 122 disposed above the DUT 100. As shown in FIG. 20, the two antenna guides 123 extending in the X-axis direction are, 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 exposure. Similarly, the two antenna guides 124 extending in the Y-axis direction have, for example, a gap 124a into which the planar antenna device 10 can be inserted from the side (X-axis direction) and a radiation surface of the planar antenna device 10 for exposing the radiation surface. 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 the 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 radio wave leakage from the side of the antenna, when the circularly polarized antenna 20 is adopted as the planar antenna 11, the planar antenna It is also possible to arrange the device 10 in close proximity.

  In the example shown in FIG. 20, the openings 123b and 124b are provided also on the one surface 21a side opposite to the radiation surface of the planar antenna device 10, but without providing the opening on the one surface 21a side. The configuration may be such that the entire surface 21a side of the planar antenna device 10 is covered.

  The antenna holder 122 disposed below the DUT 100 has the same configuration as the antenna holder 122 disposed above the DUT 100, and the radiation surface side (that is, the opposite surface 21b side) of the planar antenna device 10 is It is held so as to face the DUT 100.

  Note that, in FIG. 20, an arrow from each antenna 110 of the DUT 100 toward the planar antenna device 10 indicates an example of a beam direction.

  The two antenna guides 123 extending in the X-axis direction can be moved in parallel 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, it is possible to move the entire antenna holding unit 122 disposed above and below the DUT 100 in parallel in the Z-axis direction.

  Therefore, even if the DUT 100 is not strictly positioned when placed on the placement surface 121a of the tray 121, the positions of the antenna guides 123 and 124 can be moved according to the placement position and size of the DUT 100. The plurality of planar antenna devices 10 held by the antenna holding unit 122 can be arranged at desired positions with respect to the plurality of antennas 110 of the DUT 100. For example, the planar antenna device 10 can be arranged directly above each antenna 110 of the DUT 100.

  For example, as shown in FIG. 21A, the DUT 100 is placed at the center of the placing surface 121a of the tray 121, and as shown in FIG. 21B, the DUT 100 is placed at the center of the placing surface 121a of the tray 121. Regardless of whether the DUT 100 is placed at a deviated position or the large DUT 100 is placed on the placement surface 121a of the tray 121 as shown in FIG. It is possible to move the positions of the antenna guides 123 and 124 according to the position.

  As shown in FIG. 1, the measuring unit 51 includes a signal transmitting unit 60, a signal receiving unit 61, a coupler 62, an SW 63, a beam direction control unit 64, an analysis processing unit 65, a storage unit 66, A measurement control section 67 is provided to measure the transmission / reception characteristics of the DUT 100 with respect to the output level of transmission radio waves, the reception sensitivity, and the like, and to perform 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.

  Note that 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 in a call connection state with the wireless terminal measurement device 1 of the present embodiment. The signal under measurement is a response signal from the DUT 100 to a test signal output from the wireless terminal measurement device 1 of the present embodiment, a signal whose amplitude and phase are controlled by a beam direction control unit 64 described later, and the like. is there.

  The coupler 62 is a broadband 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 via a coaxial cable, inputs a test signal output from the signal transmission unit 60 to the planar antenna device 10, and receives a test signal from the DUT 100 received by each planar antenna device 10. The signal under measurement can be input to the signal receiving unit 61.

  The SW 63 sets 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 beam forming 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 beam shape and direction 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 receiving unit 61 by the plurality of planar antenna devices 10.

  The analysis processing unit 65 performs an analysis process on the signal under measurement received by the signal receiving unit 61, and includes a transmission / reception characteristic measurement unit 68 and a beamforming measurement unit 69.

  When the output side of the signal receiving unit 61 is connected by the SW 63, the transmission / reception characteristic measuring unit 68 measures, for example, modulation accuracy (EVM), transmission power level, transmission spectrum mask, error vector amplitude, adjacent channel leakage power, and spurious radiation. It is designed to perform measurements and the like. Further, the transmission / reception characteristic measurement unit 68 can execute minimum input sensitivity, maximum input level, adjacent channel removal, non-adjacent channel removal, and the like as analysis processing relating to a MIMO reception test. Further, beamforming measuring section 69 includes a power measuring section 69a, a beam direction estimating section 69b, and a beam direction determining section 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 measures 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 estimating unit 69b estimates the shape and direction of the beam of the signal to be measured transmitted from the antenna 110 based on the power measured for each planar antenna device 10 by the power measuring unit 69a. This estimation is performed by, for example, interpolating the power as a function of the position of the planar antenna device 10 stored in the storage unit 66 using an arbitrary interpolation method.

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

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

  Note that the signal transmitting unit 60, the signal receiving unit 61, the SW 63, the beam direction control unit 64, and the analysis processing unit 65 are configured by digital circuits such as an FPGA (Field Programmable Gate Array) and an ASIC (Application Specific Integrated Circuit). Alternatively, a predetermined program stored in the storage unit 66 in advance is executed by the measurement control unit 67, so that it can 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. It is. Note that the measurement control unit 67 can also receive or add a new program or a version-changed program from the outside, and add or update the storage unit 66.

  The display unit 52 is configured by a display device such as an LCD or a CRT, and displays soft keys, pull-down menus, and text keys for displaying measurement results and setting measurement conditions based on a control signal from the measurement control unit 67. The operation target such as a box is displayed.

  The operation unit 53 is for performing an operation input 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. The operation unit 53 may be configured by an external control device that performs remote control using 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 among a plurality of communication standards, input the position of the planar antenna device 10 in the antenna holding unit 122, It is possible to set the shape and direction of the beam of the signal to be measured transmitted from.

  FIGS. 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 measurement device 1 of the present embodiment. Here, illustration of the antenna holder 122 and the radio wave absorber 12 is omitted. In the following, a case where the antenna 110 is installed on 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 one surface 111a side or the other surface 111b side of the DUT 100. Such a configuration is also included in the scope of the present invention.

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

  That is, the first circularly polarized wave antenna 20a has the opposite surface 21b opposed to the radiation surface 110a of the antenna 110 of the DUT 100 and the one surface 111a of the DUT 100. In the second circularly polarized antenna 20b, the opposite surface 21b 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 to be parallel to the radiation surface 110a of each antenna 110 of the DUT 100 but to be inclined by the inclination angle θ. That is, the normal of one surface 111a or the other surface 111b of the DUT 100 on which the plurality of antennas 110 are installed and the normal of the opposite surface 21b of each circularly polarized antenna 20 intersect.

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

  The normal N1 to the opposite surface 21b of each circularly polarized antenna 20 and the normal to the radiation surface of each circularly polarized antenna 20 are parallel. The radiation direction of each circularly polarized antenna 20 is the normal direction of the radiation surface of each circularly polarized antenna 20.

  That is, as shown in FIG. 22A, the radiation direction of the measured signal 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 to be measured radiated from the radiation surface 110a of the antenna 110 is reflected between the circularly polarized antenna 20 and the antenna 110, travels toward the inner wall surface 50a of the shield box 50, and is 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, travels toward the inner wall surface 50a of the shield box 50, and is absorbed by the inner wall surface 50a. In this manner, multiple reflection of the test signal between the circularly polarized antenna 20 and the antenna 110 is suppressed. As described above, by arranging the circularly polarized antenna 20 at an angle, multiple reflection can be further suppressed.

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

  In the present embodiment, the first circularly polarized wave antenna 20a and the second circularly polarized wave 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, by making the rotation directions of the polarized waves different between the first circularly polarized antenna 20a and the second circularly polarized antenna 20b, as shown in FIG. It is possible to suppress the received test signal from being received by another circularly polarized antenna 20 facing the DUT 100.

  The location and the number of the 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 measurement device 1 of the present embodiment, the first circularly polarized antenna 20a and the second circularly polarized antenna 20b having different rotation directions of the main polarization are opposed to each other with the DUT 100 interposed therebetween. Good isolation performance can be obtained between the wave antenna 20a and the second circularly polarized wave antenna 20b.

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

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

  Next, a 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 are input by the operation of the operation unit 53 by the user (step S2).

  Next, the beam direction control unit 64 controls the 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 to the state input in step S2 (beam direction control step). S3).

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

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

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

  Next, the beam direction estimation unit 69b estimates the shape and direction of the beam 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 result of the determination in step S7 (step S8).

  When the DUT 100 includes 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 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 are 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 includes the radio wave absorber 12 that surrounds the antenna element 14 in a direction other than the desired radiation direction of the antenna element 14, so that the antenna 10 can be generated between the antenna 110 and the DUT 100. Amplitude error caused by multiple reflections can be suppressed.

  In the planar antenna device 10 according to the present embodiment, the metal posts 30 penetrating through the dielectric substrate 21 are arranged so as to surround the antenna element 23 to form a cavity structure. And a frame-shaped conductor 32 extending a predetermined distance in the direction of the antenna element 23 is provided. Thereby, the planar antenna device 10 can suppress the generation of the surface wave, and can make the radiation characteristic of the antenna a desired characteristic.

  In addition, the wireless terminal measurement device 1 according to the present embodiment can suppress the generation of surface waves of the planar antenna device 10, so that each planar antenna device 10 is not affected by the other planar antenna device 10 and the antenna 110 The radiation characteristics can be measured.

  In the wireless terminal measurement device 1 according to the present embodiment, since the arbitrary number of planar antenna devices 10 can be arranged at arbitrary positions of the antenna guides 123 and 124, the DUT 100 and the plurality of planar antenna devices 10 In a state where the positional relationship with the DUT 100 is fixed, measurement including beamforming measurement for the DUT 100 can be performed.

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

  In addition, the wireless terminal measurement device 1 according to the present embodiment can move the antenna holding unit 122 in accordance with the position where the DUT 100 is placed on the placement surface 121a of the tray 121, so that the DUT 100 on the placement surface 121a can be moved. It is not necessary to strictly position the DUT 100, and various DUTs 100 having different sizes and shapes can be easily set.

  In addition, the wireless terminal measurement device 1 according to the present embodiment can be arranged such that 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 flat antenna 11 are not parallel. It is possible to further suppress an amplitude error caused by multiple reflection occurring between the antenna 110 and the antenna 110.

  Further, in the wireless terminal measurement 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. Other arrangements are also possible. In this case, 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 measurement device 1 according to the present embodiment can perform measurement on the DUT 100 while suppressing an amplitude error caused by multiple reflection occurring between the antenna 110 and the planar antenna 11.

  In addition, the wireless terminal measurement device 1 according to the present embodiment can also be arranged such that the radiation direction of the test signal radiated from the antenna element 14 of the planar antenna 11 is not parallel to the normal direction of the radiation surface of the antenna 110. Thus, 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 circularly polarized antenna 20a and the second circularly polarized antenna 20b that face each other with the DUT 100 interposed therebetween have different rotation directions of polarization, and therefore, are opposed to each other. The isolation performance between the opposed circularly polarized antennas 20 can be maintained without installing an object such as a shield material between the circularly polarized antennas 20 to block a signal.

  Further, the wireless terminal measurement device 1 according to the present embodiment can be arranged such that the other surface 111b of the DUT 100 on which the antenna 110 is installed and the one surface 13a of the antenna substrate 13 of the second circularly polarized antenna 20b are not parallel. Amplitude errors caused by multiple reflections generated between the second circularly polarized antenna 20b and the antenna 110 of the DUT 100 can be further suppressed.

  Further, when the wireless terminal measurement device 1 according to the present embodiment employs the circularly polarized antenna 20 as the planar antenna 11, the measured signal radiated from the antenna 110 has a linear polarization (for example, a vertical polarization, Accurate measurement is possible regardless of the direction of horizontal polarization. Further, the wireless terminal measurement 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 placed on the placement surface 121a of the tray 121.

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

REFERENCE SIGNS LIST 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 circular polarized antenna 20a first circular polarized antenna 20b second circular polarized antenna Reference Signs List 21 dielectric substrate 21a second surface 22 ground plane conductor 25 power supply pin 30 metal post 32 frame-shaped conductor 61 signal receiving unit 64 beam direction control unit 65 analysis processing unit 69a power measurement unit 69b beam direction estimation unit 69c beam direction determination unit 100 DUT
110 Antenna 110a Radiation surface 111 DUT board 111a One surface 111b Other surface

In order to solve the above problems, a planar antenna device according to the present invention includes: a planar antenna having an antenna substrate including a dielectric substrate; an antenna element formed on a first surface of the antenna substrate; And a radio wave absorber surrounding the antenna element in a direction other than a desired radiation direction on the first surface of the antenna substrate. 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 It is.

Further, in the wireless terminal measurement device according to the present invention, a planar antenna having an antenna substrate including a dielectric substrate, an antenna element formed on a first surface of the antenna substrate, and a first antenna of the antenna substrate A radio wave absorber surrounding a surface other than a desired radiation direction of the antenna element, and the antenna of the wireless terminal facing the first surface of the antenna substrate and facing the first surface is spatially coupled. A plurality of planar antenna devices, a beam direction control unit that controls the direction of the beam 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 that is controlled by the beam direction control unit A signal receiving unit that receives the signal under measurement by the plurality of planar antenna devices, and an analysis process on the signal under measurement received by the signal receiving unit Performing an analysis processing unit, wherein the analysis processing unit is a power measurement unit that measures the power of the signal under measurement received by the signal receiving unit by each of the planar antenna devices, is measured by the power measurement unit Based on the power, the beam direction estimating unit for estimating the direction of the beam of the signal under measurement transmitted from the antenna, the beam direction of the signal under measurement estimated by the beam direction estimating unit, the A beam direction determination unit that determines whether or not the direction of the beam is controlled by a beam direction control unit, and the wireless terminal is further installed on the other surface side. It has a plurality of antennas including another antenna, the plurality of planar antennas are arranged at a position facing one surface of the wireless terminal, and installed on one surface side of the wireless terminal A first circularly polarized antenna spatially coupled to the antenna; and a spatially coupled antenna disposed at a position facing the other surface of the wireless terminal and spatially coupled to the antenna installed on the other surface of the wireless terminal. And a second circularly polarized antenna, wherein the first circularly polarized antenna and the second circularly polarized antenna have different directions of rotation of the predetermined polarization.

Claims (10)

A planar antenna (11, 20) having an antenna substrate (13) including a dielectric substrate (21), and antenna elements (14, 23) formed on a first surface (13a, 21b) of the antenna substrate; ,
A radio wave absorber (12) surrounding a first direction of the antenna element other than a desired radiation direction of the antenna element;
A planar antenna device, wherein an antenna (110) of a wireless terminal (100) facing close to a first surface of the antenna substrate and the planar antenna are spatially coupled. The planar antenna,
A circular polarization type antenna element having a predetermined polarization rotation direction,
A ground plane conductor (22) superimposed on a second surface (21a) of the dielectric substrate opposite to the first surface;
One end of each is connected to the ground plane conductor, penetrates the dielectric substrate along its thickness direction, and the other end extends to the first surface of the dielectric substrate to surround the antenna element. A plurality of metal posts (30) forming a cavity,
A frame-shaped rim provided on the first surface side of the dielectric substrate, the other end of each of the plurality of metal posts being short-circuited along the direction in which the posts are arranged, and having a predetermined width in the antenna element direction. A conductor (32);
A resonator is constituted by the cavity and the frame-shaped conductor, and a structural parameter of the resonator and the antenna element is adjusted to set a resonance frequency of the resonator to a desired value. The frame includes at least one of an inner dimension Lw of the cavity, the rim width L _R of the frame-shaped conductor, the number of turns of the antenna element, a basic length a0 of the antenna element, and an element width W of the antenna element. the rim width L _R of Jo conductor, the planar antenna device according to claim 1, wherein a width of approximately 1/4 of the wavelength of a surface wave propagating along the dielectric surface of the substrate. The antenna element is formed in a square spiral shape or a circular spiral shape having a center end portion of the spiral,
A power supply pin (25) having one end connected to the center side end of the spiral of the antenna element formed in the square spiral shape or the circular spiral shape and provided through the dielectric substrate and the ground plane conductor is further provided. The planar antenna device according to claim 2, comprising: A plurality of planar antenna devices according to any one of claims 1 to 3,
A beam direction control unit (64) for controlling a direction of a beam of a signal under measurement transmitted from the antenna of the wireless terminal capable of controlling a beam direction;
A signal receiving unit (61) for receiving the signal under measurement controlled by the beam direction control unit with the plurality of planar antenna devices;
An analysis processing unit (65) that performs 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 estimating unit (69b) for estimating a direction of a beam of the signal under measurement transmitted from the antenna based on the power measured by the power measuring unit;
A beam direction determining unit (69c) for determining whether the direction of the beam of the signal under measurement estimated by the beam direction estimating unit matches the direction of the beam 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 is installed in the wireless terminal is not parallel to the first surface of the antenna substrate of each of the planar antennas.   The normal to the first surface of the antenna substrate of each of the planar antennas is parallel to the normal to the radiation surface of each of the planar antennas, and the radiation direction of each of the planar antennas is the normal to the radiation surface of each of the planar antennas. The wireless terminal measurement device according to claim 4, wherein the measurement is in a linear direction. The wireless terminal further has a plurality of antennas (110) including another antenna installed on the other surface (111b) side,
A first circularly polarized antenna (20a) disposed at a position facing one surface of the wireless terminal, and spatially coupled to the antenna installed on one surface of the wireless terminal; A second circularly polarized antenna (20b) disposed at a position facing the other surface of the wireless terminal, and spatially coupled to the antenna installed on the other surface side of the wireless terminal;
The wireless terminal measuring device according to claim 4, wherein the first circularly polarized antenna and the second circularly polarized antenna have different rotation directions of the predetermined polarization.   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. The normal to the radiation surface of the antenna and the normal to one surface or the other surface of the wireless terminal on which the antenna is installed are parallel to each other,
9. The wireless terminal measuring device according to claim 4, wherein a radiation direction of the antenna is a normal direction of a radiation surface of the antenna. A wireless terminal measurement method using the wireless terminal measurement device according to claim 4, wherein:
A beam direction control step (S3) of controlling a direction of a beam of a signal under measurement transmitted from the antenna of the wireless terminal capable of controlling a beam direction;
A signal receiving step (S4) of receiving the signal under measurement controlled by the beam direction control step by the plurality of planar antenna devices;
Analysis processing steps (S5 to S7) for performing analysis processing on the signal under measurement received in the signal reception step,
The analysis processing step includes:
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 estimation step (S6) of estimating a beam direction of the signal under measurement transmitted from the antenna based on the power measured in the power measurement step;
A beam direction determining step (S7) of determining whether the beam direction of the signal under measurement estimated by the beam direction estimating step matches the beam direction controlled by the beam direction controlling step; And a wireless terminal measurement method.

Images