JP2005227213A - Antenna evaluation device, and measuring method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antenna evaluation device capable of evaluating easily and precisely performance of a mobile terminal antenna in a multichannel wave propagation environment. <P>SOLUTION: An amplitude and a phase of a scatterer 102 comprising a plurality of antennas 102a-102g arranged on a circumference with an equal interval are controlled to control a property of the multichannel wave propagation environment constituted in the vicinity of the center part of a circle by an electromagnetic wave emitted from the scatterer 102. The measured antenna 110 such as a diversity antenna is arranged in the vicinity of the center part of the circle to evaluate the performance under the actual using environment. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention mainly relates to an apparatus for evaluating antenna characteristics of a radio apparatus and a measurement method using the apparatus.

  In recent years, mobile communication wireless terminals such as mobile phones have been rapidly developed. Radio waves that reach the wireless terminal from the base station become multiple waves due to reflection, scattering, or diffraction by the topography or structures of the propagation path. For this reason, when evaluating the communication performance of a wireless terminal, it is desirable to perform performance evaluation in a multiwave propagation environment as well as static characteristics evaluation in an anechoic chamber. So far, for example, an antenna evaluation apparatus in which a plurality of metal partitions are arranged between a transmission antenna and a reception antenna has been proposed as an antenna evaluation apparatus that generates multiple waves (see, for example, Patent Document 1).

  In FIG. 12, the structural example of the conventional evaluation apparatus described in the said patent document 1 is shown.

FIG. 12A is a plan sectional view of a conventional antenna evaluation apparatus, and FIG. 12B is a front sectional view thereof. 12 (a) and 12 (b), a radio wave reflection box for an electromagnetic wave environment test, which is a conventional antenna evaluation apparatus, has a turntable 1202 and a reception inside a horizontally placed metal box 1201 having a rectangular parallelepiped sealed structure. The antenna 1203 is set apart. The turntable 1202 is configured to be supported by the rotation drive mechanism 1205, and is configured to continue to rotate at an arbitrarily set speed. On the turntable main body 1204, a device under test 1206 can be placed on the periphery thereof. The receiving antenna 1203 is a standard dipole antenna. A partition 1207 made of a metal magnetic material is provided between the turntable 1202 and the receiving antenna 1203. The partition 1207 attenuates the reception level by reflecting the electromagnetic wave directly directed from the device under test 1206 to the reception antenna 1203. In this case, while the turntable 1202 continues to rotate, the device under test 1206 is operated to emit radio waves, thereby agitating the electromagnetic field in the box 1201 and causing severe fading. Since the reception antenna 1203 receives the multiplexed wave reflected by each wall surface, the electromagnetic interference wave can be measured by setting the median of the cumulative probability of the received electric field strength as the reception level.
Japanese Patent Laid-Open No. 10-026645

  However, since the propagation environment varies greatly depending on the terrain and structures, antenna evaluation that can faithfully simulate various propagation environments is necessary to evaluate whether sufficient communication quality is maintained in the place where the wireless device is actually used. A device is required.

  On the other hand, although the conventional antenna evaluation apparatus can generate multiple waves such as a Rayleigh fading environment, it cannot control the multiple wave propagation environment itself because the phase cannot be controlled. As a result, there is a problem that various propagation environments cannot be simulated. Moreover, since the screen which shields a wave directly in a box is installed, the subject that evaluation including a human body cannot be performed occurred.

  In order to solve the above-described problem, the first aspect of the present invention provides a scatterer composed of a plurality of radiators, a scatterer support that holds the scatterers, and at least radio waves radiated into the space from the plurality of radiators. The antenna evaluation apparatus includes a circuit unit capable of controlling either the amplitude or the phase, and includes a device under measurement serving as at least one antenna component near the center of the scatterer.

  The second aspect of the present invention is the antenna evaluation apparatus according to the first aspect of the present invention, wherein the scatterers are arranged at equal intervals so that the plurality of radiators are apexes of a substantially regular polygon.

  The third aspect of the present invention is the antenna evaluation apparatus according to the first or second aspect of the present invention, wherein the scatterer support portion is assembled in a lattice shape so as to have a substantially regular polygonal column shape.

  The fourth aspect of the present invention is the antenna evaluation apparatus according to the first or second aspect of the present invention, wherein the number of radiators is an odd number.

  A fifth aspect of the present invention is the antenna evaluation apparatus according to any one of the first to fourth aspects of the present invention, wherein the radiator is a dipole antenna.

  The sixth aspect of the present invention is the antenna evaluation apparatus according to any one of the first to fifth aspects of the present invention, wherein the radiator includes at least a vertically polarized antenna and a horizontally polarized antenna as components.

  According to a seventh aspect of the present invention, the device under test includes a wireless device including at least one antenna as a component, and a human body or a pseudo human body in a talking posture in which the wireless device is held by hand in the vicinity of the ear. It is the antenna evaluation apparatus in any one of 6th this invention.

  According to an eighth aspect of the present invention, the device under test includes a wireless device including at least one antenna as a component, and a human body or a pseudo human body in a mail posture in which the wireless device is held by hand at a front position of the body. It is an antenna evaluation apparatus according to any one of the first to sixth aspects of the present invention.

  The ninth aspect of the present invention is the antenna evaluation apparatus according to any one of the first to eighth aspects of the present invention, wherein a device under test is placed on a turntable and the turntable continues to rotate during measurement.

  The tenth aspect of the present invention is the antenna evaluation apparatus according to any one of the first to ninth aspects of the present invention, wherein an antenna evaluation apparatus is installed inside an anechoic chamber.

  The eleventh aspect of the present invention includes a scatterer composed of a plurality of radiators, a scatterer support unit that holds the scatterers, and a circuit unit connected to the plurality of radiators, and radiates from the plurality of radiators. Multiple waves constructed by the scatterer by controlling at least either the amplitude or the phase of each radio wave to be measured by the circuit unit, placing a device under test having at least one antenna as a component near the center of the scatterer An antenna evaluation apparatus for performing an electromagnetic wave environment test of a device under measurement in a propagation environment and a measurement method using the antenna evaluation apparatus.

  The twelfth aspect of the present invention is the sixth or eleventh aspect of the present invention in which the ratio of the average transmission power of the vertically polarized antenna and the horizontally polarized antenna of the radiator is controlled to have a desired cross polarization discrimination degree. This is an antenna evaluation apparatus and a measurement method using the antenna evaluation apparatus.

  In the thirteenth aspect of the present invention, at least either the amplitude or the phase is controlled by the circuit unit so that the superposition of the respective radio waves radiated from the plurality of radiators becomes a Rayleigh fading environment in the vicinity of the center of the scatterer. The antenna evaluation apparatus according to the eleventh or twelfth aspect of the present invention, which performs an electromagnetic wave environment test of a device under test in a multiwave propagation environment constructed by a scatterer, and a measurement method using the antenna evaluation apparatus.

  According to a fourteenth aspect of the present invention, at least one of the maximum Doppler frequency and the Doppler shift direction of the device under test is superimposed as phase information of radio waves radiated from a plurality of radiators by the circuit unit. The antenna evaluation apparatus according to any one of the thirteenth aspects of the present invention and a measurement method using the same.

  In the fifteenth aspect of the present invention, at least either the amplitude or the phase is controlled by the circuit unit so that the superposition of the radio waves radiated from the plurality of antennas becomes a rice fading environment in the vicinity of the center of the scatterer. The antenna evaluation apparatus according to the eleventh or twelfth aspect of the present invention for performing an electromagnetic wave environment test of a device under test in a multiwave propagation environment constructed by a scatterer and a measurement method using the antenna evaluation apparatus.

  The sixteenth aspect of the present invention is the antenna evaluation apparatus according to any one of the eleventh to fifteenth aspects of the present invention for performing an average effective gain evaluation of the device under test in a multiwave environment, and a measurement method using the antenna evaluation apparatus.

  In addition, the seventeenth aspect of the present invention includes a scatterer including a plurality of radiators, a scatterer support portion that holds the scatterers, and a circuit unit connected to the plurality of radiators, and radiates from the plurality of radiators. A multi-wave constructed by a scatterer, in which at least either the amplitude or the phase of each radio wave is controlled by a circuit unit, a device to be measured having at least two antennas as components is arranged near the center of the scatterer An antenna evaluation apparatus for evaluating diversity characteristics of a device under measurement in a propagation environment and a measurement method using the antenna evaluation apparatus.

  The eighteenth aspect of the present invention is the antenna evaluation apparatus according to the seventeenth aspect of the present invention, in which diversity characteristics are evaluated at least for diversity gain at the time of selective diversity reception, and a measurement method using the antenna evaluation apparatus.

  The nineteenth aspect of the present invention is the antenna evaluation apparatus according to the seventeenth aspect of the present invention, in which the diversity characteristic is evaluated by the diversity gain at the time of the maximum ratio combination, and the measurement method using the antenna evaluation apparatus.

  According to a twentieth aspect of the present invention, there is provided a scatterer comprising a plurality of radiators, a scatterer support unit for holding the scatterers, a circuit unit connected to the plurality of radiators, a digital signal generation unit, an error rate, A high-frequency modulation signal generated by the digital signal generator is input to a plurality of radiators via a circuit unit, and radio waves radiated from the plurality of radiators are superimposed and multiplexed near the center of the scatterer. An error rate characteristic of the device under test in a multi-wave propagation environment is evaluated by being received by at least one antenna of the device under test located near the center of the scatterer and being input to the error rate measurement unit. An antenna evaluation apparatus to be performed and a measurement method using the same.

  The twenty-first aspect of the present invention is the antenna evaluation apparatus according to the twentieth aspect of the present invention, in which the error rate characteristic is BER as an evaluation index, and the measurement method using the same.

  The twenty-second aspect of the present invention is the antenna evaluation apparatus according to the twentieth aspect of the present invention, in which the error rate characteristic is PER as an evaluation index, and the measurement method using the same.

  As described above, according to the antenna evaluation apparatus of the present invention, a plurality of scatterers, scatterer support units, measurement / evaluation units each including a phase circuit and an attenuation circuit are arranged at equal intervals on the circumference. By controlling the amplitude and phase of the scatterer consisting of the antenna, the properties of the multi-wave propagation environment constructed near the center of the circle can be controlled by the radio waves radiated from the scatterer. By placing a measured antenna such as a diversity antenna in the vicinity, performance evaluation in an actual use environment can be performed.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, this invention is not limited to the following embodiment.

(Embodiment 1)
FIG. 1 is a diagram illustrating an example of an antenna evaluation apparatus according to Embodiment 1 of the present invention, and FIG. 2 is a diagram illustrating a detailed configuration example of an attenuation circuit and a phase circuit in the antenna evaluation apparatus of FIG. . In FIG. 1, the fading-emulator 101 includes a scatterer 102, a scatterer support unit 103, a cable 109, and a measurement / measurement unit 114. The scatterer support portion 103 is made of a resin material such as polypropylene or vinyl chloride, and is assembled so as to have a regular hexagonal prism shape in a lattice shape. The scatterers 102 as transmitting antennas are arranged at equal intervals on the circumference at a position of about 1.5 m from the floor surface by the scatterer support portion 103, and become the vertices of a regular heptagon. Seven antennas 102a, 102b, 102c, 102d, 102e, 102f, and 102g, which are seven half-wave dipole antennas, are arranged at positions. In this case, the seven half-wave dipole antennas are arranged vertically so as to be vertically polarized, and are connected to one end of each of the cables 109a, 109b, 109c, 109d, 109e, 109f, and 109g. Yes. Further, the cable 109a is disposed inside each of the support columns 106a, the four-piece connection portion 104a, and the support columns 107a that are hollow in the scatterer support portion 103, and passes through a hole provided in the lower portion of the support column 107a to the terminal 201b of the attenuation circuit 115. The other end is connected. Similarly, the other ends of the other cables 109b, 109c, 109d, 109e, 109f, and 109g are connected to the terminals 202b, 203b, 204b, 205b, 206b, and 207b of the attenuation circuit 115. The terminals 201c, 202c, 203c, 204c, 205c, 206c and 207c of the attenuation circuit 115 are connected to the terminals 208b, 209b, 210b, 211b, 212b, 213b and 214b of the phase circuit 116, respectively, and the terminals 208c, 209c, 210c, 211c, 212c, 213c and 214c are connected to seven output terminals of the distribution circuit 117, respectively. In this case, the attenuators 201a, 202a, 203a, 204a, 205a, 206a and 207a are respectively connected to the D / A converter 119, and voltage is applied by the D / A converter 119 so that each has a desired attenuation. Being controlled. The phase shifters 208a, 209a, 210a, 211a, 212a, 213a, and 214a are connected to the D / A converter 119, respectively, and voltage is applied by the D / A converter 119 so that each has a desired phase amount. Is controlled. The input terminal of distribution circuit 117 is connected to the output terminal of network analyzer 118, and network analyzer 118 and D / A converter 119 are each connected to computer 120. On the other hand, an antenna 110 which is a receiving antenna and is a half-wave dipole antenna is fixed to the upper end of the column 111, and the lower end of the column 111 is fixed to the upper end of the pole 112. In this case, the antenna 110 is connected to one end of the cable 113, and the cable 113 is disposed inside the hollow column 111 made of a resin material such as polypropylene or vinyl chloride, and is provided below the column 111. The other end is connected to the input terminal of the network analyzer 118 through the hole.

  The antenna evaluation apparatus configured as described above will be described below. As an example, a case where a Rayleigh fading environment is constructed as a multiwave propagation environment will be described.

  For example, the network analyzer 118 is set to a single frequency mode with a frequency of 2.14 GHz, the number of measurement points is 1601 points, the sweep time is 16 seconds, the transmission output level is +5 dBm, the display screen is the station coordinate display of S21. Each is set to be. In this case, the output terminal of the network analyzer 118 corresponds to the port 1 and the input terminal corresponds to the port 2. A signal having a frequency of 2.14 GHz output from the network analyzer 118 is distributed into seven in the distribution circuit 117 and input to the phase circuit 116 from seven output terminals of the distribution circuit 117. The phase of each signal in the phase circuit 116 is controlled by applying a voltage from the D / A converter 119 based on the control of the computer 120, and each signal output from the phase circuit 116 is input to the attenuation circuit 115. Is done. The amplitude of each signal in the attenuation circuit 115 is controlled by applying a voltage from the D / A converter 119 based on the control of the computer 120, and is respectively input to the scatterer 102 via the cable 109. The antennas 102a, 102b, 102c, 102d, 102e, 102f and 102g, which are half-wave dipole antennas, are radiated into the air, respectively. The seven radio waves radiated into the air are superposed in the space near the center of the regular heptagon to be multiplexed waves and received by the antenna 110. In this case, the multiple waves formed near the center of the regular heptagon by the radio wave radiated from the scatterer 102 are passed through the D / A converter 119 based on the control signal from the computer 120 so as to have a desired property. It is important that the voltage is applied to the attenuation circuit 115 and the phase circuit 116 as a voltage. For example, when the maximum Doppler shift is 1 Hz and the fading direction of the antenna 110 is directed from the antenna 110 to the antenna 102b, the phase shifter 202b is controlled so that the phase rotation amount of 1 Hz is superimposed on the antenna 102b. The phase shifters 201 and 203b are controlled so that the phase rotation amount of cos (2π / 7) Hz is superimposed on the antennas 102a and 102c, and the phase rotation amount of cos (4π / 7) Hz is applied to the antennas 102g and 102d. The phase shifters 207b and 205b are controlled so as to be superimposed, and the phase shifter 206b may be controlled so that the phase rotation amount of cos (6π / 7) Hz is superimposed on the antenna 102e. By superimposing such a phase rotation amount on the scatterer side, it is possible to accurately realize a fading environment without moving the device under measurement. The multiplexed wave having such properties is received by the antenna 110, input to the network analyzer 118 via the cable 113, and displayed on the display of the network analyzer 118.

  In this state, it is expected that a better Rayleigh fading environment can be constructed by calibrating the fading emulator 101 first. Specifically, the attenuation amount of each of the seven attenuators of the attenuation circuit 115 is changed from the D / A converter 119 based on the control signal from the computer 120 so that the radio wave is radiated from only one antenna, for example, the antenna 102a. The average reception level in the network analyzer 118 at that time is measured by the computer 120. After measuring the average reception level in the same manner for the remaining six antennas of the scatterer 102, the seven attenuations in the attenuation circuit 115 are set so that the honor reception level of the remaining antenna matches the antenna having the lowest average reception level. Adjust the attenuation of each unit. Thereby, since the output level radiated | emitted from each half wavelength dipole antenna can be made equal, it can be anticipated that the fall by fading is implement | achieved accurately.

  Next, when the fading emulator 101 evaluates the performance of the antenna 110 in a multiwave propagation environment, the measurement start signal is input from the computer 120 and the amplitude and phase of the received signal displayed on the display of the network analyzer 118 are calculated. Get 1601 points for 16 seconds. This corresponds to acquiring 1 point data in 0.01 seconds. By repeating this operation 10 times, for example, it is possible to acquire data of amplitude and phase of 16010 points, and the reliability of data by statistical processing is improved.

  FIGS. 3A to 3C show the measurement results when the antenna 110 receives multiple waves generated near the center of a regular heptagon by the radio waves radiated from the scatterer. FIG. 3A shows the reception level of a 1601 point received signal in time series, and the average reception level is normalized to 0 dB. From this figure, it can be seen that when the drop from the average reception level is the largest, it reaches about 35 dB, and an instantaneous fluctuation of the reception signal level due to fading occurs. FIG. 3B shows the reception level of the received signal of 16010 points as a cumulative probability distribution, and it can be seen that the measurement results are in good agreement with the Rayleigh distribution which is a theoretical curve. Further, FIG. 3C shows the probability distribution of the phase of the received signal, and it can be seen that the phase is in good agreement with the theoretical curve.

  From the above, it is possible to construct a Rayleigh fading environment in the space near the center of the scatterer by the fading emulator 101, and further, by controlling the maximum Doppler shift and the direction of the Doppler shift, the desired multiple wave propagation It turns out that it becomes possible to construct an environment. As a result, the performance of the radio equipment corresponding to the actual usage environment can be evaluated by evaluating the antenna, which is the device under test, in a multi-wave propagation environment that accurately simulates the propagation environment in the area where it is actually used. Is possible.

  By constructing the fading emulator 101 described in the present embodiment in the anechoic chamber 401 as shown in FIG. 4, it becomes possible to eliminate the influence of disturbance such as unnecessary radio waves, and more accurate multiplexing. It can be expected to construct a wave propagation environment. In this case, of course, by connecting the pole 112 to the rotary table 402 in the anechoic chamber, it is possible to continue to rotate the antenna 110 as the receiving antenna during the measurement. Thereby, since the position of the scatterer with respect to the antenna 110 changes every moment, an effect almost equivalent to the case where the number of antennas is increased can be expected.

  In this embodiment, the case where a Rayleigh fading environment is constructed is described as an example, but the present invention is not limited to this. For example, if a voltage is applied from a D / A converter based on a control signal from a computer so that the attenuation amount of each attenuator in the attenuation circuit becomes a desired value in accordance with a rice factor or the like so as to become a rice fading environment. Good. Also in this case, it goes without saying that a rice fading environment having a desired rice factor can be constructed.

  In the following embodiment, the case where the number of antennas constituting the scatterer is seven is described, but the present invention is not limited to this. For example, by setting the number of antennas to 15, it is possible to make the scatterers have a more uniform distribution, and it can be expected to construct a multiwave propagation environment with higher accuracy. The number of antennas is preferably an odd number, but may be an even number. In this case, for example, the scatterers may be arranged at unequal intervals so that the reception antenna and the front and rear antennas of the scatterer do not line up in a straight line.

  In the following embodiment, the case where the antennas constituting the scatterer are arranged at equal intervals on the circumference is described, but it is needless to say that the present invention is not limited to this.

  The configuration of the control / measurement unit described in the following embodiments is not limited to this. In the following embodiments, a case where a network analyzer is used has been described. However, when only the amplitude information of a received signal needs to be measured, for example, measurement is performed using a spectrum analyzer, or a receiver and an A / D converter are used. Of course, it is possible to measure in combination.

  In this embodiment, the case where a half-wave dipole antenna is used as a receiving antenna is described, but the present invention is not limited to this.

  In the following embodiment, a case where a half-wave dipole antenna is used as a scatterer is described, but the present invention is not limited to this. In this case, the number of antennas may not be one. For example, as shown in FIG. 5, it is a matter of course that two antennas may be used. FIG. 5A is a diagram showing a configuration example of an antenna used as a scatterer, and FIG. 5B is a front view of two antennas. In FIG. 5A, the scatterer radiator 601 includes a sleeve antenna 602, a super-top dipole antenna 603, a distributor 604, an attenuator 605, and a terminal 606. In this case, the sleeve antenna 602 is used as the vertically polarized antenna, and the super-top dipole antenna 603 is used as the horizontally polarized antenna. For example, the terminal 606 connects the cable 109 a and the distributor 605 in FIG. 1. One end of the distributor 605 that is divided is connected to the sleeve antenna 602, and the shunt is connected via the other end attenuator 605. A peltop dipole antenna 603 is connected. In this case, as shown in FIG. 5B, the sleeve antenna 602 and the super-top dipole antenna 603 are disposed so as to be orthogonal to each other. By using such a scatterer radiator, it is possible to simultaneously radiate vertically polarized waves and horizontally polarized waves, so that it is possible to construct a multiple wave propagation environment closer to the actual environment. Further, the cross polarization discrimination degree can be changed by changing the attenuation amount of the attenuator 605. In FIG. 5, the configuration example in which the attenuator is inserted on the horizontal polarization side has been described. However, the present invention is not limited to this, and it is natural that the attenuator can be inserted on the vertical polarization side. . 5 describes the case where the cross polarization discrimination is controlled by the attenuator. However, the present invention is not limited to this. For example, if two control / measurement units are prepared, the circuit scale increases, but the vertical scale is increased. Of course, the polarization component and the horizontal polarization component can be controlled independently. In this case, the configuration example using two antennas has been described. However, the present invention is not limited to this. For example, a plurality of antennas having different frequencies may be provided.

  In the following embodiments, the case of 2.14 GHz is described as an example of the measurement frequency, but the present invention is not limited to this. Of course, by using an antenna capable of covering a wide frequency range as a scatterer, it is possible to cope with different applications. Of course, it is possible to cover a plurality of frequencies by using a plurality of dipole antennas having different resonance frequencies.

  In addition, although the cable demonstrated by the following embodiment is preferably a coaxial cable, it is not limited to this. For example, by using an optical cable, it is natural that the influence of the cable on the measurement result can be expected to be lowered. In this case, however, an electrical / optical converter is required at the end of the optical cable on the antenna side, and an optical / electrical converter is required at the end of the control / measurement unit. In addition, it is conceivable to perform wireless communication as a wireless signal having a frequency different from the measurement frequency instead of the cable. In this case, the same effect can be expected.

  It goes without saying that performance evaluation in the elevation angle direction can be performed by changing the height of the device to be measured arranged near the center of the scatterer. In this case, since a plurality of antennas surround the device under test, the average effective gain (MEG: Mean Effective Gain) of the device under test is controlled by controlling, for example, dispersion of radio waves radiated from each antenna. ) Can be measured.

  In the following embodiments, a case where a network analyzer is used as a signal source of radio waves radiated from a scatterer is described, but the present invention is not limited to this. For example, it is a matter of course that a signal generator can be used as a wave source. In this case, a modulated signal such as QPSK may be used.

(Embodiment 2)
6A is a diagram illustrating a configuration example of the antenna evaluation apparatus according to the second embodiment of the present invention, and FIG. 6B is a top view of the scatterer and the receiving antenna in FIG. 6A. is there. Note that the same parts as those in FIG. 6 (a) and 6 (b) is different from FIG. 1 in that two antennas 602 and 603 are used, and it is expected that, for example, the performance evaluation of the diversity antenna in a multi-wave propagation environment is performed. it can. For this purpose, two network analyzers 117 and 608 are used in the control / measurement unit 607, and the two network analyzers are synchronized by the reference unit 609. Antennas 602 and 603, which are half-wavelength dipole antennas, are disposed on a support base 604 disposed on the pole 112, and the antenna 602 is connected to an input terminal of the network analyzer 608 via a cable 605. The antenna 603 is connected to the input terminal of the network analyzer 118 via the cable 606. As shown in FIG. 6B, the antenna 602 is arranged at a position 1λ (λ: wavelength) away from the center of the scatterer, and the antenna 603 is arranged at a distance D from the antenna 602.

  FIG. 7 shows the complex correlation coefficient between the antennas when the distance D between the antennas 602 and 603 is changed from 0 to 2λ. The measurement result is indicated by a solid line, and the calculation result is indicated by a dotted line. In this case, it can be seen that the correlation coefficient exceeds 0.5 when D is in the range of about 1.1 to 1.6λ. This is due to the fact that the number of scatterers is limited to seven, which means that a multi-wave propagation environment can be constructed in a range where D is within about 1λ. In the case of 2.14 GHz, 1λ is about 15 cm. Therefore, an actual use environment can be constructed with high accuracy for a portable wireless device having an antenna interval smaller than 15 cm. It is possible to evaluate the performance of the diversity antenna with a simple measuring device.

  In this embodiment, the case where there are two antennas of the device to be measured has been described. However, the present invention is not limited to this, and even when three or more antennas are provided, the number of measuring devices such as a network analyzer can be increased. Of course, similar measurements are possible.

  In the present embodiment, the case where a half-wave dipole antenna is used as the device to be measured has been described. However, the present invention is not limited to this. As an example, the configuration shown in FIG. 8 can be considered. FIG. 8 is a diagram illustrating another configuration example of the antenna evaluation device according to the second embodiment of the present invention, and includes a portable wireless device 801 at the center of the scatterer. The same parts as those in FIG. 1 and FIG. In FIG. 8, the portable wireless device 801 includes a whip antenna 801a and a plate-like inverted F antenna 801b as diversity antennas, and the antenna interval in this case is sufficiently smaller than 1λ. By evaluating the portable wireless device 801 in a desired multi-wave propagation environment, it can be expected that performance evaluation of the portable wireless device in an actual use environment is performed with a simple measuring device.

  The reception level at each of the two reception antennas of the portable wireless device is measured, and the computer performs arithmetic processing so as to select the higher level of the two signals received at the same timing based on the measurement result. Of course, it becomes possible to perform the characteristic evaluation at the time of selection diversity. Furthermore, it goes without saying that the diversity gain at the time of maximum ratio combining can be obtained by performing arithmetic processing by a computer so that the S / N of signals received at the same timing is maximized. Also in these cases, the number of antennas is not limited to two, and it is needless to say that the same evaluation is possible with three or more antennas.

  In addition, by constructing the fading emulator 601 described in this embodiment in an anechoic chamber, it is possible to eliminate the influence of disturbance such as unnecessary radio waves, and it is possible to construct a more accurate multi-wave propagation environment. Of course you can expect. Of course, by connecting the pole 112 to the rotary table in the anechoic chamber, the antennas 602 and 603 as the receiving antennas can be continuously rotated during the measurement. Thereby, since the position of the scatterer with respect to the receiving antenna changes every moment, an effect almost equivalent to the case where the number of antennas is increased can be expected.

  It goes without saying that performance evaluation in the elevation angle direction can be performed by changing the height of the device to be measured arranged near the center of the scatterer. In this case, since a plurality of antennas surround the device under test, the average effective gain (MEG: Mean Effective Gain) of the device under test is controlled by controlling, for example, dispersion of radio waves radiated from each antenna. ) Can be measured.

(Embodiment 3)
FIG. 9 is a diagram illustrating a configuration example of the antenna evaluation device according to the third embodiment of the present invention.

  In addition, the same code | symbol is attached | subjected to FIG. 1, FIG. 6, and the same part as FIG. 8, and description is abbreviate | omitted. 9 differs from FIG. 8 in that a human body 901 that is stationary in a standing posture near the center of the scatterer holds the portable wireless device 801 close to the ear. This state is called a call posture because it simulates the posture in which the user holds the portable wireless device during a call. By evaluating the performance of the portable wireless device 801 in a multi-wave propagation environment constructed by the fading emulator 601 in this call posture, it is possible to evaluate the performance of the portable wireless device in a state close to the actual use state. Become.

  In addition, although this Embodiment demonstrated the telephone call attitude | position, it is not limited to this. It goes without saying that the same evaluation can be performed if the mobile radio device is used. For example, when sending / receiving emails or watching digital terrestrial television, the mobile wireless device is held in the front position of the body, and this is called the mail posture. Of course, it is possible to evaluate the performance of the portable wireless device in a state close to the usage state.

  The computer measures the reception levels at the two receiving antennas of the portable wireless device held by the human body, and selects the higher one of the two signals received at the same timing based on the measurement result. It goes without saying that it is possible to perform characteristic evaluation at the time of selection diversity by performing arithmetic processing according to. Furthermore, it goes without saying that the diversity gain at the time of maximum ratio combining can be obtained by performing arithmetic processing by a computer so that the S / N of signals received at the same timing is maximized. Also in these cases, the number of antennas is not limited to two, and it is needless to say that the same evaluation is possible with three or more antennas.

  When performing measurements in an anechoic chamber, the human body sits on the rotary table and keeps rotating the rotary table during the measurement so that the position of the scatterer viewed from the human body as the device under test can be determined. Since it changes from moment to moment, almost the same effect as increasing the number of antennas can be expected.

  It goes without saying that performance evaluation in the elevation angle direction can be performed by changing the height of the device to be measured arranged near the center of the scatterer. In this case, since a plurality of antennas surround the device under test, the average effective gain (MEG: Mean Effective Gain) of the device under test is controlled by controlling, for example, dispersion of radio waves radiated from each antenna. ) Can be measured.

(Embodiment 4)
FIG. 10 is a diagram illustrating a configuration example of an antenna evaluation apparatus according to Embodiment 4 of the present invention.

  In addition, the same code | symbol is attached | subjected to FIG. 1, FIG. 6, and the same part as FIG. 8, and description is abbreviate | omitted. 10 differs from FIG. 8 in that a table 1002 is installed at the upper end of the pole 112, and a simulated human body 1001 simulating a mail posture is holding the portable wireless device 801 on the front of the body on the upper surface of the table 1002. It is. By evaluating the performance of the portable wireless device 801 in a multi-wave propagation environment constructed by the fading emulator 601 in this mail attitude, it is possible to evaluate the performance of the portable wireless device in a state close to the actual use state. Needless to say, the use of a pseudo human body can improve the accuracy of measurement and can be expected to increase reproducibility.

  In the present embodiment, the mail attitude has been described, but the present invention is not limited to this. Any posture that uses a portable wireless device may be used. For example, even in the case of a talking posture, it is possible to evaluate the performance of the portable wireless device in a state close to the actual usage state.

  The reception levels at the two reception antennas of the portable wireless device held by the pseudo human body are measured, and the higher one of the two signals received at the same timing is selected based on the measurement result. Of course, it is possible to perform characteristic evaluation at the time of selection diversity by performing arithmetic processing by a computer. Furthermore, it goes without saying that the diversity gain at the time of maximum ratio combining can be obtained by performing arithmetic processing by a computer so that the S / N of signals received at the same timing is maximized. Also in these cases, the number of antennas is not limited to two, and it is needless to say that the same evaluation is possible with three or more antennas.

  When performing measurements in an anechoic chamber, place the simulated human body on a rotating table, and keep rotating the rotating table during the measurement so that the scatterer viewed from the simulated human body as the device under test. Since the position of the antenna changes every moment, it is possible to expect the same effect as when the number of antennas is increased.

  It goes without saying that performance evaluation in the elevation angle direction can be performed by changing the height of the device to be measured arranged near the center of the scatterer. In this case, since a plurality of antennas surround the device under test, the average effective gain (MEG: Mean Effective Gain) of the device under test is controlled by controlling, for example, dispersion of radio waves radiated from each antenna. ) Can be measured.

(Embodiment 5)
FIG. 11 is a diagram illustrating a configuration example of the antenna evaluation apparatus according to the fifth embodiment of the present invention. The same parts as those in FIG. 1 and FIG. 11 differs from FIG. 6A in the configuration of the control / measurement unit 1101. In FIG. 11, a digital signal such as QPSK generated by a digital signal generator is input to a modulator 1103 and converted into a CDMA (Code Division Multiple Access) modulated wave having a frequency of 2.14 GHz, for example, and distributed circuit 116. Is input. A signal received by the antenna 602 is input to one of the two input terminals of the synthesis circuit 1105 via the phase shifter 1104. On the other hand, a signal received by the antenna 603 is input to the other input terminal of the combining circuit 1105, and the two signals are combined in the combining circuit 1105 and input to the error rate detection circuit 1107. In this case, the phase change amount in the phase shifter 1104 is controlled by the control circuit 1106 so that the phase difference between the two signals input to the synthesis circuit 1105 becomes a desired value. For example, it is conceivable to control the amount of phase change so that two signals have the same phase, or to control the amount of phase change so that the S / N of the synthesized signal is maximized. The signal input to the error rate detection circuit 1107 is demodulated and compared with, for example, a digital signal generated by the digital signal generator 1102 and evaluated as BER (Bit Error Rate) or PER (Packet Error Rate).

  From the above, it becomes possible to perform BER evaluation or PER evaluation of a device under test in a multi-wave propagation environment constructed by scatterers.

  In this embodiment, the case where two antennas are used as the device to be measured has been described. However, the present invention is not limited to this, and the portable wireless device or the portable wireless device is held in a posture that is actually used by the human body. Of course, it may be the case. In this case, it goes without saying that the performance evaluation in the elevation angle direction can be performed by changing the height of the pole 112 and moving the position of the device under measurement up and down. Further, the pole 112 may be installed on the rotary table in the anechoic chamber and kept rotating during the measurement.

  Note that although a configuration example in the case where received signals from two antennas are combined by a combining circuit has been described in this embodiment, the present invention is not limited to this. For example, it is of course possible to perform BER evaluation or PER evaluation even when there is one antenna. In addition, as an example, it may be possible to perform selection diversity in which the higher level of the received signals at the two antennas is selected. In this case as well, BER evaluation or PER evaluation can be performed in the same manner. Of course.

  In the present embodiment, the configuration example in which the BER or PER is measured by the error rate detection circuit has been described. However, the present invention is not limited to this. For example, in the configuration shown in FIG. 6, it is a matter of course that the reception signal of each antenna of the device under test can be taken into a computer and the BER or PER can be calculated on the computer. In this case, it is a matter of course that selection diversity, maximum ratio combining, etc. may be processed on the computer.

  The antenna measurement apparatus according to the present invention is useful for performance evaluation of a mobile terminal antenna or the like in a multiwave propagation environment.

The figure which shows the structural example of the antenna evaluation apparatus of Embodiment 1. The figure which shows the detailed structural example of a part in the antenna evaluation apparatus shown in FIG. (A) It is a figure which shows an example of the measurement result of the antenna by the antenna evaluation apparatus of Embodiment 1, Comprising: The figure which displayed the reception level in time series (b) The figure which similarly displayed the reception level by cumulative probability distribution (c) ) Similarly, the phase of the received signal is displayed as a probability distribution The figure which shows an example which installed the antenna evaluation apparatus of Embodiment 1 in the anechoic chamber (A) The figure which shows the structural example of the radiator for scatterers of Embodiment 1 (b) The front view of the antenna which similarly comprises the radiator for scatterers The figure which shows the structural example of the antenna evaluation apparatus of Embodiment 2. It is a figure which shows an example of the measurement result by the antenna evaluation apparatus of Embodiment 2, Comprising: The figure which shows the relationship between an antenna space | interval and a complex correlation coefficient It is a figure which shows another structural example of the antenna evaluation apparatus of Embodiment 2, Comprising: The figure which shows the structural example provided with the portable radio | wireless apparatus near the center of a scatterer The figure which shows the structural example of the antenna evaluation apparatus of Embodiment 3. The figure which shows the structural example of the antenna evaluation apparatus of Embodiment 4. The figure which shows the structural example of the antenna evaluation apparatus of Embodiment 5. (A) Top view showing a configuration example of a conventional antenna evaluation apparatus (b) Side view of the same

Explanation of symbols

101, 601 fading emulator 102 scatterer 102a, 102b, 102c, 102d, 102e, 102f, 102g, 110, 602, 603 antenna 103 scatterer support 104a, 104b, 104c, 104d, 104e, 104f, 104g 4 or connection 105a, 105b, 105c, 105d, 105e, 105f, 105g 3 or connecting portions 106a, 106b, 106c, 106d, 106e, 106f, 106g, 107a, 107b, 107c, 107d, 107e, 107f, 107g, 108a, 108b, 108c , 108d, 108e, 108f, 108g, 111 Post 109, 109a, 109b, 109c, 109d, 109e, 109f, 109g, 113, 605, 606 Cable 11 2 poles 114, 607, 1101 control / measurement unit 115 attenuation circuit 116 phase circuit 117 distribution circuit 118,608 network analyzer 119 D / A converter 120 computer 201a, 202a, 203a, 204a, 205a, 206a, 207a, 505 attenuator 201b 202b, 203b, 204b, 205b, 206b, 207b, 208b, 209b, 210b, 211b, 212b, 213b, 214b, 201c, 202c, 203c, 204c, 205c, 206c, 207c, 208c, 209c, 210c, 211c, 212c , 213c, 214c, 506 terminals 208a, 209a, 210a, 211a, 212a, 213a, 214a, 1104 phaser 401 anechoic chamber 402 rotary table 501 Scatterer radiator 502 Sleeve antenna 503 Super top dipole antenna 504 Distributor 604 Support base 609 Reference device 801 Portable wireless device 802 Whip antenna 803 Plate-like inverted F antenna 901 Human body 1001 Pseudo human body 1002 Table 1201 Box body 1202 Turntable 1203 Reception antenna 1204 Table main body 1205 Rotation drive mechanism 1206 Device under test 1207 Partition 1208 Antenna angle variable mechanism 1102 Digital signal generator 1103 Modulator 1105 Synthesis circuit 1106 Control circuit 1107 Error rate detection circuit

Claims (22)

A scatterer comprising a plurality of radiators;
A scatterer support for holding the scatterer;
A circuit unit capable of controlling at least either the amplitude or the phase of radio waves radiated into the space from the plurality of radiators,
An antenna evaluation apparatus, comprising a device under test having at least one antenna as a component in the vicinity of the center of the scatterer. The antenna evaluation apparatus according to claim 1, wherein the scatterers are arranged at equal intervals so that the plurality of radiators become apexes of a substantially regular polygon. The antenna evaluation apparatus according to claim 1, wherein the scatterer support portion is assembled in a lattice shape so as to have an approximately regular polygonal column shape. The antenna evaluation apparatus according to claim 1, wherein the number of radiators is an odd number. The antenna evaluation apparatus according to claim 1, wherein the radiator includes a dipole antenna as a constituent element. The antenna evaluation apparatus according to claim 1, wherein the radiator includes at least a vertically polarized antenna and a horizontally polarized antenna as constituent elements. The device under test is
A wireless device comprising at least one antenna as a component;
The antenna evaluation apparatus according to claim 1, comprising a human body or a pseudo human body in a talking posture in which the wireless device is held by hand in the vicinity of an ear. The device under test is
A wireless device comprising at least one antenna as a component;
The antenna evaluation apparatus according to any one of claims 1 to 6, further comprising a human body or a pseudo human body in a mail posture in which the wireless device is held by hand at a front position of the body. 9. The antenna evaluation apparatus according to claim 1, wherein the device under test is placed on a turntable, and the turntable continues to rotate during measurement. An antenna evaluation apparatus according to claim 1, wherein the antenna evaluation apparatus according to claim 1 is installed inside an anechoic chamber. A scatterer comprising a plurality of radiators;
A scatterer support for holding the scatterer;
A circuit unit connected to the plurality of radiators,
Controlling at least one of amplitude and phase of each radio wave radiated from the plurality of radiators by the circuit unit;
A device to be measured having at least one antenna as a component is disposed near the center of the scatterer, and an electromagnetic wave environment test of the device to be measured in a multiwave propagation environment constructed by the scatterer is performed. Antenna evaluation apparatus and measurement method using the same. 7. The radiator according to claim 6, wherein the ratio of the average transmission power of the vertical polarization antenna and the horizontal polarization antenna is controlled to have a desired cross polarization discrimination. Or the antenna evaluation apparatus according to 11 and a measurement method using the antenna evaluation apparatus. At least one of the amplitude and the phase is controlled by the circuit unit so that the superposition of the respective radio waves radiated from the plurality of radiators becomes a Rayleigh fading environment near the center of the scatterer, and the scattering 13. The antenna evaluation apparatus according to claim 11 or 12, and a measurement method using the antenna evaluation test for the device under test in a multiwave propagation environment constructed by a body. 12. At least one of a maximum Doppler frequency and a Doppler shift direction of the device under test is superimposed as phase information of each of radio waves radiated from the plurality of radiators by the circuit unit. 14. The antenna evaluation apparatus according to any one of 13, and a measurement method using the same. At least one of amplitude or phase is controlled by the circuit unit so that the superposition of the respective radio waves radiated from the plurality of antennas becomes a rice fading environment in the vicinity of the center of the scatterer, and the scatterer 13. The antenna evaluation apparatus according to claim 11 or 12, and a measurement method using the antenna evaluation test, wherein an electromagnetic wave environment test of the device under test is performed in a multiwave propagation environment constructed by: An antenna evaluation apparatus characterized by performing mean effective gain (MEG) evaluation of the device under test in a multiwave environment by the measurement method according to any one of claims 11 to 15. Measurement method. A scatterer comprising a plurality of radiators;
A scatterer support for holding the scatterer;
A circuit unit connected to the plurality of radiators,
Controlling at least one of amplitude and phase of each radio wave radiated from the plurality of radiators by the circuit unit;
A device to be measured having at least two antennas as constituent elements is arranged near the center of the scatterer, and diversity characteristics of the device to be measured in a multi-wave propagation environment constructed by the scatterer are evaluated. Antenna evaluation apparatus and measurement method using the same. 18. The antenna evaluation device according to claim 17, and a measurement method using the antenna evaluation device, wherein the evaluation of the diversity characteristic is at least a diversity gain at the time of selective diversity reception. 18. The antenna evaluation apparatus according to claim 17, and the measurement method using the antenna evaluation apparatus, wherein the evaluation of the diversity characteristic is at least a diversity gain at the time of maximum ratio combining. A scatterer comprising a plurality of radiators;
A scatterer support for holding the scatterer;
A circuit unit connected to the plurality of radiators;
A digital signal generator;
It has an error rate measurement unit,
The high frequency modulation signals generated by the digital signal generation unit are input to the plurality of radiators via the circuit unit, and radio waves radiated from the plurality of radiators are superimposed and multiplexed near the center of the scatterer. An error rate characteristic of the device under test in a multi-wave propagation environment by being received by at least one antenna of the device under test arranged near the center of the scatterer and input to the error rate measurement unit An antenna evaluation apparatus and a measurement method using the same. The antenna evaluation apparatus according to claim 20 and a measurement method using the antenna evaluation apparatus, wherein the error rate characteristic uses BER (Bit Error Rate) as an evaluation index. 21. The antenna evaluation apparatus according to claim 20, and a measurement method using the same, wherein the error rate characteristic uses PER (Packet Error Rate) as an evaluation index.

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