JP2010003935A - Antenna characteristics measuring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antenna characteristics measuring device capable of stably controlling the temperature of an antenna to be measured. <P>SOLUTION: This antenna characteristic measurement device is provided with: a thermostatic chamber 11, having a temperature control part 11t for controlling the inside temperature on a first inner wall; and a radio wave absorber 12 (12a<SB>1</SB>, 12a<SB>2</SB>, 12a<SB>5</SB>, 12b) covering inner walls in the thermostatic chamber. The radio wave absorber 12 includes an opening 12op formed between the measurement object antenna 100 and the temperature control part 11t; and an antireflection means 12b preventing radio waves which radiate from the measurement object antenna 100 from being reflected by the temperature control part 11t (first inner wall 11w). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an antenna characteristic measuring apparatus, and more particularly to an antenna characteristic measuring apparatus that can stably measure an antenna temperature characteristic.

  Patent Document 1 discloses a measuring device for temperature characteristics of electronic equipment. This measuring apparatus uses an anechoic chamber, and the object to be measured is placed in the anechoic chamber in a state of being covered with a cover. The inside of the cover is connected to the air conditioning equipment installed outside the anechoic chamber by piping, and the temperature of the object to be measured is controlled by this air conditioning equipment.

Patent Document 2 discloses a radio wave shielding plate configured using a metal mesh.
JP 2005-347524 A JP 2008-4901 A

  However, in the configuration of Patent Document 1, since the anechoic chamber is a very large object, the piping becomes long and it is difficult to stably control the temperature of the object to be measured. For this reason, there is a problem that it is difficult to use for measuring the temperature characteristic of an antenna that requires precise characteristic measurement.

  The present invention has been made to solve such problems, and an object of the present invention is to provide an antenna characteristic measuring apparatus that can stably control the temperature of the antenna under measurement.

  An antenna characteristic measurement apparatus according to the present invention includes a thermostatic bath having a temperature control unit for controlling an internal temperature on a first inner wall, and a radio wave absorber covering the inner wall of the thermostatic bath, An opening provided between the antenna to be measured and the temperature control unit, and antireflection means for preventing radio waves radiated from the antenna to be measured from being reflected by the temperature control unit are characterized.

  Since the temperature control inside the thermostatic chamber can be performed relatively accurately, according to the present invention, the temperature control of the antenna under measurement can be stably performed as compared with the example of Patent Document 1. In addition, since the radio wave absorber of the present invention includes an opening between the antenna to be measured and the temperature control unit, the radio wave absorber is prevented from interfering with temperature control in the thermostatic chamber by the temperature control unit. . Furthermore, since the radio wave absorber of the present invention includes antireflection means for preventing the radio wave radiated from the antenna under measurement from being reflected by the temperature control unit, the radio wave is reflected by the temperature control unit through the opening. Can prevent the measurement accuracy from being lowered.

  In the present invention, the radio wave absorber includes a temperature control unit so that a gap is formed between the first radio wave absorber and the first radio wave absorber that cover the inner wall of the thermostatic chamber excluding the first inner wall. And a second radio wave absorber disposed between the antenna to be measured, the gap is preferably an opening, and the second radio wave absorber is preferably an antireflection means. Thus, by dividing the radio wave absorber into the first and second radio wave absorbers, the antireflection means and the opening can be easily formed.

  In the present invention, it is preferable that the second radio wave absorber is in the form of a screen, and the opening is located at least above the second radio wave absorber. According to this, the opening can be easily formed by appropriately adjusting the height of the second radio wave absorber.

  In the present invention, the height of the second radio wave absorber is preferably higher than a straight line connecting the upper end portion of the first inner wall of the thermostatic chamber and the antenna to be measured. According to this, it is possible to prevent the radio wave emitted from the antenna under measurement to the temperature control unit side from reaching the first inner wall of the thermostatic chamber having the temperature control unit beyond the second radio wave absorption unit. Accordingly, it is possible to prevent the radio wave from being reflected by the first inner wall, thereby reducing the measurement accuracy.

  In the present invention, it is preferable that a metal thin film is provided on at least one of the surface on the inner wall side of the thermostatic chamber of the first radio wave absorber or the surface facing the temperature control unit of the second radio wave absorber. . According to this, even if the first radio wave absorber or the second radio wave absorber is deformed due to a temperature change in the thermostat, the metal thin film that is a surface that reflects the radio wave is also deformed at the same time. Changes in input impedance can be reduced, and stable antenna characteristics can be measured.

  In the present invention, the radio wave absorber includes a first radio wave absorber that covers the inner wall of the thermostatic chamber excluding the first inner wall, and a second radio wave absorber that is disposed between the temperature controller and the antenna to be measured. The second wave absorber includes a plurality of plate-shaped wave absorbers, the plurality of wave absorbers are arranged obliquely with respect to the first inner wall, and the temperature control unit cannot be seen from the antenna under measurement. As described above, it is preferable that a plurality of gaps formed between the plurality of radio wave absorbing plates are arranged at predetermined intervals and the openings are openings, and the plurality of radio wave absorbing plates are antireflection means. According to this, since the plurality of gaps are provided, it is possible to prevent the air flow in the thermostat from being hindered by the radio wave absorber, and it is possible to suitably control the temperature. Furthermore, since each radio wave absorbing plate constituting the second radio wave absorber is directed obliquely, the reflected radio wave is difficult to return to the antenna under measurement. Therefore, unnecessary radio waves can be attenuated efficiently.

  In this invention, it is preferable that a 1st electromagnetic wave absorption part equips the surface by the side of the inner wall of a thermostat with a metal thin film. According to this, even if the first radio wave absorber is deformed due to a temperature change in the thermostatic chamber, the metal thin film that is a surface that reflects the radio wave is also deformed at the same time, so that the input impedance change of the first radio wave absorber is changed. Therefore, stable antenna characteristics can be measured.

  In the present invention, it is preferable that each of the plurality of plate-shaped wave absorbing plates includes a metal thin film on the surface facing the temperature control unit. According to this, even if the second radio wave absorber is deformed due to a temperature change in the thermostatic chamber, the metal thin film that is a surface that reflects the radio wave is also deformed at the same time, so that the input impedance change of the second radio wave absorber is changed. And more stable antenna characteristics can be measured.

  According to the present invention, the temperature control of the antenna to be measured can be stably performed because the thermostatic chamber capable of relatively accurately controlling the internal temperature is provided and the radio wave absorber covering the inner wall of the thermostatic chamber is provided. It becomes possible. In addition, although the temperature control unit is provided on the inner wall of the thermostat, according to the present invention, the radio wave absorber has an opening between the antireflection means and the antenna to be measured and the temperature control unit. The temperature can be controlled well, and the antenna characteristics can be measured with high accuracy.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[First Embodiment]

  1-3 is a figure for demonstrating the structure of the antenna characteristic measuring apparatus 10 by preferable 1st Embodiment of this invention, FIG. 1 is a schematic perspective view of the antenna characteristic measuring apparatus 10, FIG. FIG. 3 is a schematic cross-sectional view of the antenna characteristic measuring apparatus 10 taken along the line AA in FIG. 1 (however, a door 11d described later is closed), and FIG. 3 is a front view of the antenna characteristic measuring apparatus 10 inside.

As shown in FIG. 1, an antenna characteristic measuring apparatus 10 according to a preferred first embodiment of the present invention includes a thermostatic chamber 11 and radio wave absorbers 12a _{1 to} 12a ₅ , 12b (hereinafter, referred to as the thermostatic chamber 11). Collectively referred to as “radio wave absorber 12”) and a mounting table 13 on which the antenna 100 to be measured is mounted.

  The thermostat 11 has a temperature controller 11t including a storage 11s and a fan 11f in which piping for controlling the temperature in the thermostat 11 is housed on one surface of the inner wall (the back in FIG. 1). I have. Moreover, the thermostat 11 has the door part 11d which can be opened and closed in the front surface.

  The mounting table 13 is made of a material that is substantially transparent to radio waves such as foamed polystyrene or resin. The antenna under measurement 100 is, for example, a surface mount antenna for a mobile phone. Specifically, it is made of a substantially rectangular parallelepiped dielectric, has external terminals, and is arranged on the mounting table 13 in a state of being mounted on a mounting board (not shown). Then, the network analyzer NA outside the thermostat 11 and the external terminal of the antenna 100 to be measured are connected, and the temperature characteristics of the antenna 100 to be measured are measured. More specifically, the network analyzer NA outputs a measurement signal to the antenna under measurement 100, and as a result, the temperature characteristics of the signal input from the antenna under measurement 100 are converted into the temperature characteristics of the antenna under measurement 100. Get as.

The radio wave absorber 12 includes first radio wave absorbers 12a ₁ , 12a ₂ , 12a ₃ , 12a ₄ , and 12a ₅ that cover the inner wall of the thermostatic chamber excluding the inner wall 11w having the temperature controller 11t (hereinafter collectively referred to as “first 1) and a second radio wave absorber 12b provided in a partition shape between the temperature control unit 11t and the antenna 100 to be measured. Of the first radio wave absorber 12a, the first radio wave absorbers 12a ₁ , 12a ₂ , 12a ₃ , and 12a ₄ cover the upper, lower, left, and right sides of the inner wall of the thermostatic chamber 11, respectively. The first radio wave absorber 12a ₅ covers the surface (front surface) of the inner wall of the thermostatic chamber 11 when the door portion 11d of the constant temperature bath 11 is closed.

As shown in FIG. 2, the second radio wave absorber 12 b is disposed so as to have a predetermined distance from the inner wall (inner side surface of the temperature control unit 11 t) 11 w and partially penetrate the mounting table 13. As shown in FIGS. 2 and 3, the second radio wave absorber 12b has a gap between the second radio wave absorber 12a and the first radio wave absorber 12a. That is, the radio wave absorber 12 is connected to the antenna 100 to be measured. It arrange | positions so that it may have opening part 12op between the temperature control parts 11t. Then, the second radio wave absorber 12b, as shown by the dotted line X ₁ in FIG. 2, which is higher than the straight line connecting the upper end and the measured antenna 100 of the inner wall 11 w, also shown in dotted lines X ₂ Thus, it is embedded to a position lower than a straight line connecting the lower end portion of the inner wall 11w and the antenna 100 to be measured. Similarly, although not shown, the width of the second radio wave absorber 12b is wider than between the straight lines connecting the left and right ends of the inner wall 11w and the antenna 100 to be measured.

Due to the above-described configuration of the radio wave absorber 12, radio waves radiated from the antenna under measurement 100 to the top, bottom, left, and right and the front (the door portion 11d side is the front) are respectively the first radio wave absorbers 12a ₁ and 12a _2. , 12a ₃ , 12a ₄ , and 12a ₅ . Further, due to the configuration of the second radio wave absorber 12b, the radio wave emitted from the antenna under measurement 100 to the temperature control unit 11t side (rear) is absorbed by the second radio wave absorber 12b, and the radio wave is transmitted to the second radio wave absorber 12b. It can prevent reaching the inner wall 11w of the thermostat 11 which has the temperature control part 11t beyond the absorption part 12b. In other words, the second radio wave absorber 12b functions as an antireflection means for preventing radio waves radiated from the antenna under measurement 100 from being reflected by the temperature controller 11t (inner wall 11w). Therefore, high measurement accuracy can be obtained. Furthermore, since the air flow in the thermostat 11 is prevented from stagnation by the upper portion 12b of the second radio wave absorber and the openings 12op on both sides, the temperature control in the thermostat 11 can be appropriately performed. .

  The position and size of the second radio wave absorber 12b are basically determined as described above. However, since radio waves are actually diffracted, it is as good as possible while ensuring appropriate temperature control. It is preferable to appropriately adjust the position and size of the actual second radio wave absorber 12b based on the experimental results and the like so that the measurement result can be obtained.

  FIG. 4 is a schematic perspective view for explaining the structure of the back surface of the radio wave absorber 12.

  As shown in FIG. 4A, the radio wave absorber 12 includes a radio wave absorption layer 12r and a metal thin film 12m attached to a surface (back surface) located on the inner wall side of the thermostatic chamber 11 of the radio wave absorption layer 12r. I have. The radio wave absorption layer 12r is made of, for example, a mixture of styrene foam and ferrite. In addition to the above, the radio wave absorption layer 12r includes ISF (material based on carbon and foamed polyethylene), IR (material based on magnetic material and synthetic rubber), ITB (basic material including PET and ITO film). Material), IP or IP-BX (material based on carbon and styrene foam), ICM (material based on ferrite and inorganic material), IB (material based on ferrite sintered body), Various materials such as IS or IS-SM (materials based on carbon and foamed polyethylene) and ICT (materials based on carbon and incombustible material) can be used. As the metal thin film 12m, a foil-like one is preferably used. By pasting the foil-shaped metal thin film 12m on the back surface of the radio wave absorption layer 12r, even if the radio wave absorption layer 12r is deformed by a temperature change in the thermostat 11, the metal thin film 12m that is a surface that reflects radio waves is also deformed at the same time. Therefore, a change in input impedance of the radio wave absorber 12 can be reduced. Therefore, it is possible to stably measure the characteristics of the antenna.

  As the metal thin film, a net-like metal thin film 12n can be suitably used as shown in FIG. 4 (b) instead of the foil-shaped one in FIG. 4 (a). According to such a configuration, it is possible to efficiently reflect and attenuate radio waves by appropriately setting the mesh size of the net-like metal thin film 12n according to the measurement frequency. In particular, radio waves can be efficiently reflected and attenuated by setting the mesh size of the net-like metal thin film 12n to 1/10 or less of the wavelength of the measurement frequency. In addition, the net-like metal thin film 12n is flexible because it is net-like even if it is thicker than the foil-like metal thin film 12m, so that it can be reliably deformed simultaneously with the deformation of the radio wave absorption layer 12r, and is stable. Antenna characteristics can be measured.

  5 and 6 show graphs for explaining the effects of the first embodiment. FIG. 5 shows an input frequency (Frequency) of a measurement signal input from the network analyzer NA to the antenna under measurement 100, a reflected signal for the measurement signal (a signal reflected by the antenna under measurement 100 itself, a signal reflected from the outside, It is a graph which shows the relationship with the power ratio (reflection loss: Return Loss) of the synthetic | combination signal of the signal which returns to the measurement antenna 100. FIG. FIG. 6 is a graph obtained by performing inverse Fourier transform on the data of FIG. 5, and is a graph showing the relationship between time (Time) and reflection loss. 5 and 6, the dotted line represents a case where the radio wave absorber 12 is not provided at all in the thermostatic chamber 11, and the thin solid line represents the first radio wave absorber 12 a of the radio wave absorber 12 in the thermostatic chamber 11. The thick solid line represents the case where the radio wave absorber 12 (both the first and second radio wave absorbers 12a and 12b) is provided in the thermostatic chamber 11.

  From FIG. 5, when both the first and second radio wave absorbers 12a and 12b are present (thick solid line), the ripple is smaller than in the other cases (thin solid line and dotted line), and a correct waveform is observed. You can see that it is made. As shown in FIG. 6, when both the first and second radio wave absorbers 12a and 12b are present (thick solid line), the reflected wave is smaller than in the other cases (thin solid line and dotted line). It reflects that.

Next, as a second embodiment, an example in which the second radio wave absorber 12b in the first embodiment is configured differently will be described below.
[Second Embodiment]

  FIG. 7 is a schematic perspective view for explaining the configuration of the antenna characteristic measuring apparatus 20 according to the preferred second embodiment of the present invention. In addition, the same number is attached | subjected to the structure same as the said 1st Embodiment, and the description is abbreviate | omitted.

As shown in FIG. 7, in the antenna characteristic measuring apparatus 20 according to the second preferred embodiment of the present invention, the radio wave absorber 12 provided in the thermostatic chamber 11 includes a first radio wave absorber 12a (12a _{1 to} 12a). ₅ ) and a second radio wave absorber 22b. Although not shown in FIG. 7, as in the first embodiment, each of the first radio wave absorbers 12a has a foil-like metal thin film 12m or a net-like metal thin film 12n on the back side. .

  Details of the second radio wave absorber 22b will be described with reference to FIGS. 8A is a left front perspective view of the second radio wave absorber 22b, FIG. 8B is a right front perspective view, FIG. 9A is a front view, and FIG. 9B is a rear view. FIG.

  As shown in FIGS. 8 and 9, the second radio wave absorber 22b includes a plurality of radio wave absorber plates 22bp and two upper and lower plates made of resin for fixing the radio wave absorber plates 22bp in an upright state. The fixing plate 23 is provided.

  Each of the plurality of radio wave absorbing plates 22bp is obliquely aligned with a predetermined angle with respect to the inner wall of the thermostatic chamber 11 having the temperature control unit 11t, and is fixed by a fixing plate 23, which is a so-called blind shape. ing. Therefore, in FIG. 8A, FIG. 9A, and FIG. 9B, no gap is seen between the plurality of radio wave absorbing plates 22bp arranged side by side, but as shown in FIG. 8B. When viewed from the right front, a gap (opening) 22op is formed between adjacent radio wave absorbing plates 22bp. Further, as can be seen from FIG. 9A, the antenna 100 to be measured is blocked by the second radio wave absorber 22b so that the temperature controller 11t cannot be seen.

  Further, as shown in FIGS. 8B and 9B, each radio wave absorbing plate 22bp is a foil-like or net-like metal thin film on the back side of the radio wave absorbing layer 22br, as in the first radio wave absorbing unit 12a. 22bm is affixed.

  Such a second radio wave absorber 22b is arranged so as to cover the entire inner wall having the temperature controller 11t between the temperature controller 11t and the antenna 100 to be measured, as shown in FIG. Although not shown in the drawing, the lower part (including the fixed plate 23) of the second radio wave absorber 22b is arranged so as to partially penetrate the mounting table 13 as in the first embodiment, and the temperature controller It is embedded to a position lower than the straight line connecting the lower end of the inner wall with 11t and the antenna 100 to be measured. Moreover, it is preferable to leave a predetermined distance between the inner wall 11w and the second radio wave absorber 22b.

  In this embodiment, it is not necessary to provide the opening 12op around the second radio wave absorber 12b in the first embodiment, and the second radio wave absorber 22b covers the entire inner wall having the temperature control unit 11t. It can be arranged to cover. That is, since the second radio wave absorber 22b includes the opening 22op, the opening 22op can prevent the air flow in the thermostat 11 from being hindered. Therefore, temperature control in the thermostat 11 can be appropriately performed.

  Thus, according to the present embodiment, the plurality of radio wave absorbing plates 22bp function as antireflection means. Since the plurality of radio wave absorbing plates 22bp are directed obliquely, the effect that the reflected radio wave is difficult to return to the antenna 100 to be measured is also obtained. Therefore, unnecessary radio waves can be attenuated efficiently, and measurement with high accuracy is possible.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. Needless to say, it is included in the range.

  In the said embodiment, although the electromagnetic wave absorber 12 was provided with the metal thin film 12m in the surface (back surface) located in the inner wall side of the thermostat 11 of the electromagnetic wave absorption layer 12r and the electromagnetic wave absorption layer 12r, Of course, other materials can be used for the radio wave absorbing layer 12r. Note that when the radio wave absorbing layer 12r is made of a material that hardly deforms with respect to a temperature change, such as a sintered ferrite body, the metal thin film 12m can be omitted.

  In the above embodiment, an example in which a surface having a flat surface is used as the wave absorber is not limited to this, but a wave absorber having a plurality of pyramidal protrusions on the surface may be used. Absent.

1 is a schematic perspective view for explaining an antenna characteristic measuring apparatus 10 according to a preferred first embodiment of the present invention. FIG. 2 is a schematic cross-sectional view taken along the line AA in FIG. 1 for explaining the antenna characteristic measuring apparatus 10 according to the first preferred embodiment of the present invention. 1 is a front view of an inside of an antenna characteristic measuring apparatus 10 according to a preferred first embodiment of the present invention. It is a schematic perspective view for demonstrating the structure of the back surface of the electromagnetic wave absorber 12 in the antenna characteristic measuring apparatus 10 by preferable 1st Embodiment of this invention. It is a graph for demonstrating the effect by preferable 1st Embodiment of this invention. It is a graph for demonstrating the effect by preferable 1st Embodiment of this invention. It is a schematic perspective view for demonstrating the antenna characteristic measuring apparatus 20 by preferable 2nd Embodiment of this invention. It is a figure for demonstrating the 2nd electromagnetic wave absorption part 22b in the antenna characteristic measuring apparatus 20 by preferable 2nd Embodiment of this invention, (a) is a left front perspective view, (b) is a right front perspective view. It is. It is a figure for demonstrating the 2nd electromagnetic wave absorption part 22b in the antenna characteristic measuring apparatus 20 by preferable 2nd Embodiment of this invention, (a) is a front view, (b) is a rear view.

Explanation of symbols

10, 20 the antenna characteristic measuring apparatus 11 thermostatic chamber 11d thermostat of the door portion 11t temperature controller 11f temperature control of the fan 11s of the temperature control unit repository 11w thermostatic chamber inner wall 12 wave absorber _12a of (12a 1, _12a 2, 12a ₃ , 12a ₄ , 12a ₅ ) 1st radio wave absorber 12b, 22b 2nd radio wave absorber 12r, 22br, 22bm radio wave absorber layer 12m, 12n metal thin film 12op, 22op opening 13 mounting table 22bp radio wave absorber 23 Fixed plate 100 Antenna to be measured NA Network analyzer

Claims (8)

A thermostat having a temperature control unit for controlling the internal temperature on the first inner wall;
A radio wave absorber covering the inner wall of the thermostatic chamber,
The radio wave absorber is
An opening provided between the antenna to be measured and the temperature control unit;
An antenna characteristic measuring apparatus comprising: an antireflection means for preventing radio waves radiated from the antenna under measurement from being reflected by the temperature control unit. The radio wave absorber is
A first radio wave absorber that covers the inner wall of the thermostatic chamber excluding the first inner wall;
A second radio wave absorber disposed between the temperature control unit and the antenna to be measured so that a gap is formed between the first radio wave absorber and
The antenna characteristic measuring apparatus according to claim 1, wherein the gap is the opening, and the second radio wave absorber is the antireflection means.   3. The antenna characteristic measuring apparatus according to claim 2, wherein the second radio wave absorber has a screen-like shape, and the opening is located at least above the second radio wave absorber.   5. The height of the second radio wave absorber is higher than a straight line connecting the upper end of the first inner wall of the thermostatic chamber and the antenna to be measured. 6. Ante characteristic measuring device as described in 1.   The metal thin film is provided on at least one of the surface on the inner wall side of the thermostatic chamber of the first radio wave absorber or the surface facing the temperature control unit of the second radio wave absorber. The antenna characteristic measuring device according to any one of 2 to 4. The radio wave absorber is
A first radio wave absorber that covers the inner wall of the thermostatic chamber excluding the first inner wall;
Including a second radio wave absorber disposed between the temperature control unit and the antenna to be measured,
The second radio wave absorber includes a plurality of plate-like radio wave absorbers,
The plurality of radio wave absorbing plates are arranged obliquely with respect to the first inner wall and arranged at a predetermined interval so that the temperature control unit cannot be seen from the antenna to be measured,
2. The antenna characteristic measuring apparatus according to claim 1, wherein a plurality of gaps formed between the plurality of radio wave absorbing plates are the openings, and the plurality of radio wave absorbing plates are the antireflection means. .   The antenna characteristic measuring apparatus according to claim 6, wherein the first radio wave absorber includes a metal thin film on an inner wall side surface of the thermostatic chamber.   8. The antenna characteristic measuring apparatus according to claim 6, wherein each of the plurality of plate-shaped radio wave absorbing plates includes a metal thin film on a surface facing the temperature control unit. 9.

Images