WO2006054762A1

WO2006054762A1 - Wideband low loss coupler, test jig employing it, and method for testing radio signal

Info

Publication number: WO2006054762A1
Application number: PCT/JP2005/021401
Authority: WO
Inventors: Eiji Suzuki
Original assignee: Agilent Technologies, Inc.
Priority date: 2004-11-17
Filing date: 2005-11-16
Publication date: 2006-05-26
Also published as: JP2006148355A

Abstract

A coupler for detecting a radio signal radiated from the antenna of an electronic device comprising a conductive case, and two or more resonance conductors provided in the case while being coupled electromagnetically to act as a filter. The resonance conductor comprises a first resonance conductor and a second resonance conductor connected electrically with a coaxial connector, the case has an opening for inserting the electronic device or the antenna into the case, and when the electronic device or the antenna is inserted into the case, the first resonance conductor couples electromagnetically with that antenna stronger than any other resonance conductors.

Description

Description Broadband low loss force bra and test jig using the turnip, and radio signal test method Technical Field

The present invention relates to a force bra, and more particularly, to a force bra having a wide band, low loss, and high stability. Background art

Conventionally, an electronic device having a wireless communication function has been tested for wireless function and wireless performance by wired connection with a test device. In recent years, however, many electronic devices that do not have a terminal for wired connection have been on the market. Such an electronic device can only be tested by detecting a radio signal radiated from an antenna under test included in the electronic device. Conventionally, there are an antenna type force bra and a cavity resonator type force bra as means for detecting a radio signal from an antenna under test.

The antenna-type force bra is a test antenna provided facing the antenna under test. The test antenna is electromagnetically coupled to the antenna under test in the near field, and a radio signal radiated from the antenna under test is detected (see, for example, Patent Document 1). Examples of test antennas include dipole antennas and planar antennas. This type of force bra has a low degree of electromagnetic coupling to the antenna under test (high loss). In addition, the degree of electromagnetic coupling is easily affected by the angle facing the antenna under test (low stability). In addition, this type of coupler needs to shield the test environment including the antenna under test from the outside in order to suppress external noise. · ·

On the other hand, the cavity resonator type force bra is a cavity resonator that resonates at a predetermined frequency with a minimum hole into which the antenna under test can be inserted. The antenna under test is inserted into the cavity resonator, and the radio signal radiated from the antenna under test is detected by the cavity resonator. This type of force bra has a high degree of electromagnetic coupling to the antenna under test (low loss). In addition, the degree of electromagnetic coupling is not easily affected by the facing angle of the antenna under test (high stability). In addition, this type of force bra is less susceptible to external noise and does not need to shield the test environment. As described above, the cavity resonator type coupler has many advantages over the antenna type coupler and is suitable for testing the wireless function and performance of electronic devices. (For example, see FIG. 1 on pages 1 and 2 of Japanese Patent Application Laid-Open No. 10-2 8 2 1 74). Disclosure of the invention

By the way, the band occupied by recent electronic devices for wireless communication has become much wider than before. For example, wireless LAN, which is one of the mainstream communication methods, employs a spectrum spreading method and has a wider occupied bandwidth than conventional FM modulation methods. Here, one problem arises. The cavity resonator type force bra does not have a sufficient passband to detect such a broadband wireless signal with high accuracy. Therefore, for example, when a modulation accuracy of such a broadband wireless signal is tested using a cavity resonator type force bra, a problem such as a large measurement error occurs. In addition, when testing conventional radio signals simultaneously on multiple channels, the frequency band to be tested is wide. In the past, for multichannel testing, a cavity resonator-type force bra had to be prepared for each channel. Therefore, the present invention is a power bra for detecting a radio signal emitted from an antenna provided in an electronic device, and provides a coupler with a low loss, a high stability, and a broadband as compared with the prior art. Objective.

The first invention is a force bra for detecting a radio signal radiated from an antenna provided in an electronic device, and includes a filter having a first end having a coaxial output and an open second end. The antenna or the electronic device can be arranged so that the radio signal can be electromagnetically coupled to the second end stronger than the first end.

The second invention is the force bra according to the first invention, wherein the conductive case and two or more resonant conductors electromagnetically coupled to each other so as to act as a filter provided in the case. The resonance conductor includes a first resonance conductor and a second resonance conductor electrically connected to a coaxial connector, and the case inserts the electronic device or the antenna into the case. The first resonant conductor is electromagnetically coupled to the antenna stronger than any other resonant conductor when the electronic device or the antenna is inserted into the case. It is what. Furthermore, the third invention is a jig for testing a radio signal radiated from an antenna included in an electronic device, and includes the power bra of the first invention or the second invention, When the wireless signal is electromagnetically coupled to the force bra, the antenna or the electronic device and positioning means for bringing the force bra into a predetermined positional relationship are provided.

Still further, the fourth invention is a method of testing a radio signal emitted from an antenna provided in an electronic device, wherein the antenna or the electronic device has a coaxial output at a first end and a second end at a second end. The open band-pass filter is brought into a predetermined positional relationship, the radio signal is electromagnetically coupled to the second end stronger than the first end, and the signal of the coaxial output is tested. Is.

Since the power bra of the present invention couples a radio signal to a filter, the radio signal can be detected with a wider band and lower loss than in the past. Further, the force bra of the present invention can stably detect a radio signal because the force bra surrounds the periphery of the antenna under test. Furthermore, since the coupler of the present invention surrounds the antenna under test with a conductor, it is not easily affected by external noise, and a shield box or the like is almost unnecessary. Furthermore, the force bra of the present invention can block unwanted frequency components by the filter action. Brief Description of Drawings

FIG. 1 is a perspective view showing a test jig 10 according to the first embodiment of the present invention. FIG. 2A is a front view of the DUT 100.

FIG. 2B is a front view of the DUT 100.

FIG. 3 is a perspective view showing the coupler 400.

4 is a cross-sectional view taken along line J-J in FIG.

FIG. 5 is a perspective view showing the test jig 20 according to the first embodiment of the present invention. FIG. 6 is a perspective view showing the coupler 700.

FIG. 7 is a sectional view taken along line K-1K in FIG.

FIG. 8A is a diagram illustrating an example of frequency characteristics of a force bra.

FIG. 8B is a diagram showing an example of frequency characteristics of a force bra. BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments of the present invention will be described below with appropriate reference to the accompanying drawings. The first embodiment of the present invention is a test jig 10. See Figure 1 below. Figure 1 shows the trial 2 is a perspective view showing a test jig 10. FIG. The test jig 10 is a device that tests the object to be measured 100 using a force bra 400. In the description of the present invention, the term “test” can be read as a synonym such as measurement, evaluation, judgment or inspection.

Reference is now made to FIGS. 2A and 2B. 2A and 2B are front views of the DUT 100. In FIG. 2A, the device under test 100 has a built-in antenna 110 for radiating a radio signal. Therefore, the antenna 1 1 0 cannot be accessed from the outside. On the contrary, as shown in FIG. 2B, the device under test 100 includes an antenna 120 for radiating a radio signal so as to be exposed to the outside of the device under test 100. You can also. In this case, access to the antenna 120 from the outside is easy.

Now refer to Figure 1 again. The test jig 10 includes a base 2 200, a positioning device 3 0 0, and a coupler 4 0 0.

The positioning device 3 0 0 has a rail 3 1 0 and a stage that moves along the rail 3 1 0

3 2 0 and installed on the base 2 200. The stage 3 2 0 can hold the device to be measured 10 detachably and can position the device to be measured 100 in the arrow A direction. This positioning direction may be a direction perpendicular to the arrow A. Further, when a part of the positioning device 300 enters the coupler 400, a part of the positioning device 300 needs to be formed of an electromagnetically negligible material such as Teflon (trademark).

The coupler 4 00 is installed on the base 2 0 0 via the support member 5 0 0. Refer to Fig. 3 and Fig. 4 below. FIG. 3 is a perspective view showing only the coupler 400. 4 is a cross-sectional view taken along line J-1 in FIG. Coupler 4 0 0 includes case 4 1 0, 3 resonance bars 4 2 1 and 4 2 2 and 4 2 3 and 3 frequency adjustment screws 4 3 1 and

4 3 2 and 4 3 3, two coupling adjusting screws 4 4 1 and 4 4 2, and a coaxial connector 4 5 0. Case 4 1 0 and resonant bar 4 2 1 and 4 2 2 and 4 2 3 function as a comb-line semi-coaxial cavity filter.

Case 4 10 is a conductive hollow rectangular parallelepiped formed by combining main portion 4 1 1 and lid portion 4 1 2. Each of the main part 4 1 1 and the cover part 4 1 2 is obtained by applying a plating to a copper alloy and further performing gold plating. The case 4 10 may be a hollow body having good conductivity at a desired frequency at least near the surface. Therefore, the case 4 10 may not be composed of a plurality of parts as described above, and the metal may be another kind of metal or may not be plated. In addition, the shape of case 4 10 is A hollow cylinder may be used. For example, the case 400 can be replaced with a drawn tube or the like. Note that the dimensions of the case 4 10 are determined according to various characteristics expected for the force bra 40 0 (for example, frequency characteristics, loss, impedance, etc.). Hereinafter, these characteristics expected for the coupler 400 are referred to as “force bra specifications”.

Case 4 10 has an opening 4 1 0 a so that device under test 1 0 0 can be inserted into case 4 1 0. As a result, the antenna 1 10 shown in FIG. 2A or the antenna 1 2 0 shown in FIG. 2B can be arranged in the case 4 10. The surrounding area of the opening 4 1 0 a is a protective member made of Teflon (trademark) 4 6 1 so that the measured object 1 0 0 does not damage the measured object 1 0 0 when it comes into contact with the case 4 1 0. And 4 6 2 and 4 6 3 are installed. The protective members 4 6 1 and 4 6 2 and 4 6 3 can be freely deformed as long as the object to be measured 100 can be protected. Also, the protective members 4 6 1 and 4 6 2 and 4 6 3 may be manufactured from other materials that can be ignored electromagnetically. The protective members 4 6 1 and 4 6 2 and 4 6 3 are attached by means of electromagnetically negligible means such as adhesives or resin screws. The opening 4 10 a can be freely deformed, but it is desirable to surround the device under test 1 100 or the antenna 1 2 0 as much as possible. For example, the opening 4 1 0 a may be small enough to allow only the antenna 1 2 0 shown in FIG. 2B to be inserted into the case 4 1 0.

In the case 4 10, the resonance bars 4 2 1, 4 2 2, and 4 2 3 are provided on the inner surface 4 1 1 a. In addition, the case 4 1 0 has a frequency adjustment screw 4 3 1 and 4 3 2 and 4 3 3 and a coupling adjustment screw 4 4 1 and 4 4 on the surface 4 1 1 c facing the surface 4 1 1 a on the inside. .2 is provided.

Resonant rods 4 2 1 and 4 2 2 and 4 2 3 are cylindrical rods made of a copper alloy. Resonant rods 4 2 1 and 4 2 2 and 4 2 3 each have one end open and the other end attached to surface 4 1 1 a of case 4 0 0 and aligned at a predetermined interval. Yes. Resonant rods 4 2 1 and 4 2 2 and 4 2 3 are attached to case 4 1 0 by screws 4 7 1 and 4 7 2 and 4 7 3, respectively. The resonance rod 4 2 3 is electrically connected to the coaxial connector 4 5 0 via the loop 4 8 0. Resonant rods 4 2 1 and 4 2 2 and 4 2 3 may be rod-shaped members having good conductivity at a desired frequency at least near the surface. Therefore, the shape of the resonance bars 4 2 1 and 4 2 2 and 4 2 3 is not limited to the cylindrical shape, and can be deformed according to the force bra specification. Also these The number of resonance rods is not limited to three, but increases or decreases depending on the coupler specifications. For example, these resonant bars can be four prismatic metal bars.

The frequency adjusting screws 4 3 1 and 4 3 2 and 4 3 3 are screws made of a copper alloy. The frequency adjusting screw 4 3 1 can adjust the capacitance between the resonant rod 4 2 1 and the case 4 1 0 by changing the distance from the corresponding resonant rod 4 2 1. The frequency adjustment screw 4 3 2 can adjust the capacitance between the resonance rod 4 2 2 and the case 4 1 0 by changing the distance from the corresponding resonance rod 4 2 2. The frequency adjusting screw 4 3 3 can adjust the capacitance between the resonant bar 4 2 3 and the case 4 10 by changing the distance from the corresponding resonant bar 4 2 3. These changes in capacitance result in a change in tuning frequency for the corresponding resonant rod. The frequency adjusting screws 4 3 1 and 4 3 2 and 4 3 3 may be provided with an electrode plate at the tip thereof in order to change the capacity adjustment range. The coupling adjustment screws 4 4 1 and 4 4 2 are conductive metal screws. The coupling adjusting screw 4 4 1 can adjust the degree of coupling between the resonant rod 4 2 1 and the resonant rod 4 2 2 by changing the distance from the case 4 10. The coupling adjustment screw 4 4 2 can adjust the degree of coupling between the resonance rod 4 2 2 and the resonance rod 4 2 3 by changing the distance from the case 4 10. The coupling adjusting screws 4 4 1 and 4 4 2 can be modified in any way as long as they can adjust or define the degree of coupling between the resonance bars. Therefore, the coupling adjusting screws 4 4 1 and 4 4 2 may be fixed-length bars as long as the machining accuracy of the coupler 400 is sufficiently high. Further, the shape of the coupling adjusting screws 4 4 1 and 4 4 2 is not limited to the screw, but can be deformed according to the force bra specification. Further, the material of the coupling adjusting screws 4 4 1 and 4 4 2 is not limited to metal, and may be non-metal such as dielectric. For example, the coupling adjusting screws 4 4 1 and 4 4 2 can be changed to fixed-length prismatic rods made of a dielectric.

The coaxial connector 4 5 0 is a female SMA connector. The coaxial connector 45 0 may be a coaxial output, and may be a coaxial cable or another type of coaxial connector. For example, the coaxial connector 45O can be changed to an APC-3.5 connector. Next, the operation of the test jig 10 will be described with reference to FIGS. First, the DUT 100 or the antenna 1 2 0 is inserted into the force bra 4 0 0 and positioned at a predetermined position as close as possible to the resonance rod 4 2 1. Electromagnetic wave radiated from device under test 1 0 0 (actually antenna 1 1 0 or antenna 1 2 0) after insertion into coupler 4 0 0 Are coupled to the resonant bars 4 2 1 and 4 2 2 and 4 2 3. At this time, the electromagnetic wave radiated from the measured object 100 0 is most strongly coupled to the resonance rod 4 2 1 and is most weakly coupled to the resonance rod 4 2 3. The resonant bars 4 2 1 and 4 2 2 and 4 2 3 resonate with the case 4 10 in response to an electromagnetic wave having a specific frequency. The electromagnetic waves that resonate with these resonant bars are output as electrical signals from the coaxial connector 45 0 through the rape 4 80. As a result of the above operation, an electromagnetic wave radiated from the device under test 100, that is, a radio signal is output from the coaxial connector 4550. The tester can test the radio signal radiated from the device under test 100 by testing the output signal of the coaxial connector 45 0.

Case 4 1 0 and resonant rod 4 2 1 and 4 2 2 and 4 2 3 function as a comb-line semi-coaxial cavity filter, so the radio signal radiated from the measured object 1 0 0 is a com-line semi-coaxial In the pass band of the cavity filter, low loss is detected by force bra 400. As a result, the force bra 400 can detect the radio signal radiated from the device under test 100 with a wider band and lower loss than in the past. Note that the passband and stopband of the combline semi-coaxial cavity filter can be flexibly changed using conventional design techniques.

In addition, when the DUT 1 00 is inserted into the coupler 4 0 0, the antenna 1 1 0 or the antenna 1 2 0 is surrounded by the coupler 4 0 0, so that the DUT 1 0 0 radiates. Many of the generated radio signals are coupled to the coupler 4 0 0 (in particular, the resonance rod 4 2 1). As a result, the degree of electromagnetic coupling between the antenna 1 1 0 or the antenna 1 2 0 and the coupler 4 0 0 is less affected by the opposing angle of the antennas. As a result, the force bra 400 can stably detect the radio signal emitted from the device under test 100.

Further, positioning device 3 0 0 arranges antenna 1 1 0 or antenna 1 2 0 and coupler 4 0 0 in a predetermined positional relationship. As a result, the test jig 10 is highly accurate in tests that require reproducibility of the electromagnetic coupling between the antenna 1 1 0 or the antenna 1 2 0 and the force bra 4 0 0. Note that tests that require reproducibility of electromagnetic coupling include, for example, tests for transmission power and minimum reception sensitivity.

As described above, the opening 4 1 0 a of the coupler 4 0 0 can be appropriately modified. Thus, the test jig 20 according to the second embodiment of the present invention, which is a modified form of the opening 4 10 a, will be described below. Refer to Figure 5 below. FIG. 5 is a perspective view showing the test jig 20. The test jig 10 is a device that tests the object to be measured 100 using a coupler 700. In FIG. 5, the same components as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted. Further, the measured object 10 ° is as described with reference to FIGS. 2A and 2B. Now, in FIG. 5, the test jig 20 includes a base 2 200, a positioning device 6 0 0, and a coupler 7 0 0.

The positioning device 6 00 includes a rail 6 1 0 and a stage 6 2 0 that moves along the rail 6 1 0, and is installed on the base 2 200. The stage 6 20 can hold the device to be measured 10 detachably and can position the device to be measured 100 in the arrow B direction. The DUT 100 may be reciprocated along the arrow B, or may be moved in one direction along the arrow B so as to pass through the coupler 70 0. Further, when a part of the positioning device 600 enters the coupler 700, a part of the positioning device 600 needs to be formed of an electromagnetically negligible material such as Teflon (trademark).

The coupler 70 0 is installed on the base 2 0 0 via the support member 5 0 0. Refer to Fig. 6 and Fig. 7 below. FIG. 6 is a perspective view showing only the coupler 400. FIG. 7 is a cross-sectional view taken along the line KK in FIG. In FIG. 6, the same components as those in FIG. 3 are denoted by the same reference numerals, and detailed description thereof is omitted. In FIG. 7, the same components as those in FIG. 4 are denoted by the same reference numerals, and detailed description thereof is omitted. Coupler 7 0 0 is connected to case 7 1 0, 3 resonant rods 4 2 1 and 4 2 2 and 4 2 3 and 3 frequency adjustment screws 4 3 1 and 4 3 2 and 4 3 3 Adjusting screws 4 4 1 and 4 4 2 and coaxial connectors 4 5 0 are provided. Case 7 1 0 and resonant rods 4 2 1 and 4 2 2 and 4 2 3 function as combline semi-coaxial cavity filters.

Case 7 10 is obtained by changing the shape of the opening in case 4 10. Case 7 10 is a conductive hollow rectangular parallelepiped formed by combining main part 7 1 1. and lid part 7 1 2. Each of the main portion 7 1 1 and the lid portion 7 1 2 is obtained by applying copper plating to a copper alloy and further performing gold plating. In addition, since the case 7 10 may be a hollow body having good conductivity at a desired frequency at least near the surface, the main part 7 11 and the cover part 7 1 2 The same deformation as the lid portion 4 1 2 is possible. Case 7 1 0 is opened so that DUT 1 0 0 can be inserted into Case 7 1 0. It has a mouth 7 1 0 a. As a result, the antenna 1 10 shown in FIG. 2A or the antenna 1 2 0 shown in FIG. 2B can be arranged in the case 7 10. The surrounding area of the opening 7 1 0 a is a protective member made of Teflon (trademark) 7 6 1 so that the measured object 1 0 0 does not damage the measured object 1 0 0 when it comes into contact with the case 7 1 0 And 7 6 2 and 7 6 3 and 7 6 4 are installed. The protective members 7 6 1 to 7 6 4 can be freely deformed as long as the object to be measured 100 can be protected. Further, the protective members 7 6 1 to 7 6 4 may be manufactured from other materials that can be ignored electromagnetically. For the attachment of the protective members 7 6 1 to 7 6 4, electromagnetically negligible means such as adhesives or resin screws are used. Further, the opening 7 1 0 a may be small enough to allow only the antenna 1 2 0 shown in FIG. 2B to be inserted into the case 7 1 0.

In the case 7 10, the resonance rods 4 2 1, 4 2 2, and 4 2 3 are provided on the inner surface 7 1 1 a. In addition, the case 4 1 0 has a frequency adjustment screw 4 3 1 and 4 3 2 and 4 3 3 and a coupling adjustment screw 4 4 1 and 4 4 on the surface 7 1 1 c facing the surface 7 1 1 a on the inside. 2 is provided.

In this embodiment, the frequency adjusting screws 4 3 1 and 4 3 2 and 4 3 3 adjust the capacity between the corresponding resonant bar and the case 7 1 0 by changing the distance from the corresponding resonant bar. can do. Further, the coupling adjusting screws 4 4 1 and 4 4 2 can adjust the degree of coupling between two adjacent resonance bars by changing the distance from the case 7 10. These screws can be deformed similarly to the first embodiment.

Next, the operation of the test jig 20 will be described with reference to FIGS. First, the DUT 100 or the antenna 1 2 0 is inserted into the force bra 7 0 0 and positioned at a predetermined position as close to the resonance rod 4 2 1 as possible. After insertion into the force bra 70 0 0, the electromagnetic wave radiated from the f-law constant 1 0 0 (actually antenna 1 1 0 or antenna 1 2 0) Join to 3. At this time, the electromagnetic wave radiated from the measured object 100 0 is most strongly coupled to the resonance rod 4 2 1 and is most weakly coupled to the resonance rod 4 2 3. The resonant bars 4 2 1 and 4 2 2 and 4 2 3 resonate with the case 7 1 0 in response to an electromagnetic wave having a specific frequency. The electromagnetic wave that resonates with these resonance bars is output as an electrical signal from the coaxial connector 45 0 through the loop 4 80. As a result of the above operation, the electromagnetic wave radiated from the object to be measured 100, that is, the radio signal Output from axis connector 4 5 0. The tester can test the radio signal radiated from the device under test 100 by testing the output signal of the coaxial connector 45 0.

Case 7 1 0 and resonant rod 4 2 1 and 4 2 2 and 4 2 3 function as a comb-line semi-coaxial cavity filter, so the radio signal radiated from the device under test 1 0 0 is a com-line semi-coaxial Low loss is detected by coupler 70 0 in the pass band of the cavity filter. As a result, the force bra 700 can detect the radio signal radiated from the device under test 100 with a wider band and lower loss than in the past. Note that the passband and stopband of the combline semi-coaxial cavity filter can be flexibly changed using conventional design techniques.

Also, when the DUT 1 0 0 is inserted into the coupler 7 0 0, the antenna 1 1 0 or the antenna 1 2 0 is surrounded by the coupler 7 0 0, so that the DUT 1 0 0 radiates. Many of the generated radio signals are coupled to the force bra 70 0 (in particular, the resonant bar 4 2 1). As a result, the degree of electromagnetic coupling between the antenna 1 1 0 or the antenna 1 2 0 and the coupler 7 0 0 is less affected by the opposing angle of the antennas. As a result, the force bra 70 0 can stably detect the no-haze signal emitted from the device under test 100.

Further, positioning device 6 0 0 arranges antenna 1 1 0 or antenna 1 2 0 and coupler 7 0 0 in a predetermined positional relationship. As a result, the test jig 20 has high accuracy in tests that require reproducibility of the electromagnetic coupling between the antenna 1 1 0 or the antenna 1 2 0 and the coupler 7 0 0. Note that tests that require reproducibility of electromagnetic coupling include, for example, tests for transmission power and minimum reception sensitivity.

In the above two embodiments, the layout of the semi-coaxial cavity filter mainly composed of the case and the resonator rod can be changed not only to the above-mentioned combline type but also to an interdigital type. it can. In the above two embodiments, the frequency adjusting screw may be removed and both ends of the resonance rod may be attached to the case. In this case, the cavity filter is a coaxial cavity filter.

Furthermore, in the above two embodiments, another filter may be provided instead of the cavity filter. For example, another type of filter having a coaxial output at the first end and an open second end is provided inside the conductive case, and the object to be measured 1 0 0 or the antenna 1 1 0 or the antenna 1 2 0 The case is processed so that it can be placed, and the object to be measured 1 0 0 A radio signal radiated from a force may be stronger than the first end and electromagnetically coupled to the second end. In addition to this, a coupler in which a waveguide filter having one end opened and a waveguide coaxial converter are connected in series may be used as a coupler, and the device under test 100 may be inserted into the open portion to test a radio signal. . However, in this case, since a slit or the like cannot be provided, there is a disadvantage that the shape of the DUT 100 is limited as compared with the semi-coaxial force bra or the coaxial force bra.

Here, an embodiment of the present invention will be described below with reference to FIG. In this example, a specific example of the coupler 400 of the test jig 10 according to the first embodiment will be described. Now, it is assumed that the coupler 400 detects a modulation signal defined by I EEE 802.12.1b, which is one standard of wireless LAN. In this case, the band to be detected by the force bra 400 is 2.4 G to 2.5 GHz. At this time, the dimensions of the case 410 are 109.7 mm in the horizontal (longitudinal direction), 33.7 mm in the vertical, and 29.8 mm in thickness (not shown). Resonant bars 421, 422, and 423 each have a diameter of 9.8 mm, a length of 30.6 mm, and a characteristic impedance of 75 ohms. These resonance bars are arranged at intervals of 30.6 mm. The characteristic impedance of the coaxial connector 450 is 50 ohms.

Reference is now made to FIGS. 8A and 8B. FIG. 8A is a graph showing the frequency characteristics of the coupler 400. Figure 8B is a graph showing the frequency characteristics of a conventional cavity resonator type force bra. In both figures, the vertical axis represents amplitude and the horizontal axis represents frequency. In both figures, the range of the vertical axis is [-50 dB: 0 dB], and the range of the horizontal axis is [2. 30 GHz: 2. 60 GHz]. In Figure 8A, Marker 1 (—3. 7430 dB @ 2. 40 GHz), Marker 2 (−3.5920 dB @ 2. 45 GHz), Marker 3 (—3.1. 160 dB B @ 2. 50 GHz). On the other hand, in Figure 8B, Marker 1 (—26. 504 @ 2.4 GHz), Marker 2 (-1 7. 078 dB B @ 2.45 GHz), Marker 3 (—23. 272 @ 2.5 GHz ) It is shown. Comparing the above data, it can be seen that the coupler 400 has a small loss as a whole and a small fluctuation range of the loss in a desired band (2.4 G to 2.5 GHz).

Claims

The scope of the claims

1. A power bra for detecting a radio signal radiated from an antenna provided in an electronic device,

Comprising a filter with a first end having a coaxial output and an open second end;

A force bra, wherein the antenna or the electronic device can be arranged so that the wireless signal can be electromagnetically coupled to the second end stronger than the first end.

2. a conductive case, and two or more resonant conductors electromagnetically coupled to each other so as to function as a filter provided in the case,

The resonant conductor includes a first resonant conductor and a second resonant conductor electrically connected to the coaxial connector;

The case has an opening for inserting the electronic device or the antenna into the case,

The first resonant conductor is electromagnetically coupled to the antenna stronger than any other resonant conductor when the electronic device or the antenna is inserted into the case. Power bra.

3. A jig for testing a radio signal radiated from an antenna provided in an electronic device,

A force bra according to claim 1 or claim 2;

Positioning means for bringing the antenna or the electronic device and the force bra into a predetermined positional relationship when electromagnetically coupling the radio signal to the force bra;

A test jig comprising:

4. A method of testing a radio signal emitted from an antenna provided in an electronic device,

A predetermined positional relationship between the antenna or the electronic device and a band pass filter having a coaxial output at the first end and an open second end;

Electromagnetically coupling the wireless signal to the second end stronger than the first end;

Testing the coaxial output signal.