Test device and a test method
A test device 1 that measures the transmission properties or reception properties of the test object 100 having the test antenna 110 , and includes an anechoic box 50 , a plurality of test antennas 6 that transmit or receive radio signals to or from the antenna, under tests, a posture changeable mechanism 56 that changes the posture of the test object arranged in the quiet zone QZ, a measurement device 2 that measures the transmission properties or reception properties of the test object with respect to the test object whose posture is changed by the posture changeable mechanism using the test antenna, and the reflector 7 that radio signal is reflected. The plurality of test antennas include a reflection type test antenna 6 a and the plurality of direct-type test antennas 6 b, 6 c, 6 d.
1. A test device to measure transmission properties or reception properties of a test object having an antenna under test, the test device comprising:
an anechoic box having an internal space that is not affected by a radio environment;
a plurality of test antennas, accommodated in the internal space, to transmit or receive a radio signal to or from the antenna under test;
a posture changeable mechanism to change a posture of the test object arranged in a quiet zone (QZ) in the internal space;
a measurement device to measure the transmission properties or the reception properties of the test object, using the test antenna with respect to the test object whose posture is changed by the posture changeable mechanism; and
a reflector on which the radio signal is reflected, wherein
the plurality of test antennas include a reflection-type test antenna that transmits or receives the radio signal to or from the antenna under test through the reflector, and a plurality of direct-type test antennas that directly transmits or receives the radio signal to or from the antenna under test,
the plurality of direct-type test antennas are arranged on the same plane passing through an arrangement position (P DUT ) of the test object, and form predetermined arrival angles differing from each other with respect to a radio wave arrival direction from the reflection-type test antenna at the arrangement position of the test object, and at least one of the plurality of direct-type test antennas form an additional arrival angle different from the predetermined arrival angles with respect to a radio wave arrival direction from either one of other the direct-type test antennas at the arrangement position of the test object, and
the plurality of direct-type test antennas are arranged at least 2D 2 /λ away from the antenna under test where D is an antenna size of the test under test, λ is the wavelength of the radio wave transmitted from the plurality of direct-type test antennas.
2. The test device according to claim 1 , wherein
the plurality of direct-type test antennas are arranged on a plane (IP) inclined with respect to a horizontal plane.
3. The test device according to claim 2 , wherein
the anechoic box has a shape of a substantially rectangular parallelepiped or a substantially cube, and the inclined plane intersects with a boundary between one side plate and a top plate or a boundary between the one side plate and a bottom plate of the anechoic box.
4. The test device according to claim 2 , wherein
the plurality of direct-type test antennas include:
a direct-type first test antenna that forms an arrival angle of a predetermined angle (θ) in one rotation direction with respect to the radio wave arrival direction from the reflection-type test antenna at the arrangement position of the test object;
a direct-type second test antenna that forms an arrival angle of two times the predetermined angle (θ) in other rotation direction opposite to the one rotation direction with respect to the radio wave arrival direction at the arrangement position of the test object; and
a direct-type third test antenna that forms an arrival angle of four times the predetermined angle (θ) in the other rotation direction with respect to the radio wave arrival direction at the arrangement position of the test object.
5. The test device according to claim 1 , wherein
the predetermined arrival angle and the additional arrival angle are multiples of a specific angle.
6. The test device according to claim 1 , wherein
the predetermined arrival angle and the additional arrival angle include 30°, 60°, 90°, 120°, and 150°.
7. The test device according to claim 1 , wherein
the plurality of direct-type test antennas are arranged outside a path of the radio wave beam passing through the quiet zone by reflecting the reflector of the reflection-type test antenna.
8. A test device to measure transmission properties or reception properties of a test object having an antenna under test, the test device comprising:
an anechoic box having an internal space that is not affected by a radio environment;
a plurality of test antennas, accommodated in the internal space, to transmit or receive a radio signal to or from the antenna under test;
a posture changeable mechanism to change a posture of the test object arranged in a quiet zone (QZ) in the internal space;
a measurement device to measure the transmission properties or the reception properties of the test object, using the test antenna with respect to the test object whose posture is changed by the posture changeable mechanism; and
a reflector on which the radio signal is reflected, wherein
the plurality of test antennas include a reflection-type test antenna that transmits or receives the radio signal to or from the antenna under test through the reflector, and a plurality of direct-type test antennas that directly transmits or receives the radio signal to or from the antenna under test,
the measurement device includes:
a signal processing unit that converts a frequency of a signal transmitted as a radio wave by the plurality of the test antenna or a frequency of a radio signal received by the plurality of test antennas; and
a switching unit that switches a signal path between the signal processing unit and the plurality of direct-type test antenna to a signal path that one test antenna of the plurality of direct-type test antennas and the signal processing unit are connected, and
the plurality of direct-type test antennas are arranged at least 2D 2 /λ away from the antenna under test where D is an antenna size of the test under test, λ is the wavelength of the radio wave transmitted from the plurality of direct-type test antennas.
9. The test device according to claim 8 , wherein
the signal processing unit includes:
a first frequency conversion unit that converts a frequency of a signal to be transmitted as a radio signal by the reflection-type test antenna or a frequency of a radio signal received by the reflection-type test antenna; and
a second frequency conversion unit that converts a frequency of a signal to be transmitted as a radio signal by the direct-type one test antenna switched by the switching unit or a frequency of a radio signal received by the direct-type one test antenna.
10. The test device according to claim 9 , wherein
the first frequency conversion unit includes a first transmission converter that up-converts a signal to be transmitted as a radio signal from the reflection-type test antenna, and a first reception converter that down-converts a radio signal received by the reflection-type test antenna,
the second frequency conversion unit includes a second transmission converter that up-converts a signal to be transmitted as a radio signal from the plurality of the direct-type test antennas and a second reception converter that down-converts a radio signal received by the plurality of the direct-type test antennas,
the first transmission converter includes a first up-converter that up-converts a signal to be transmitted as a horizontally polarized radio signal from the reflection-type test antenna and a second up-converter that up-converts a signal to be transmitted as a vertically polarized radio signal from the reflection-type test antenna,
the first reception converter includes a first down converter that down-converts a horizontally polarized radio signal received by the reflection-type test antenna and a second down-converter that down-converts a vertically polarized radio wave received from the reflection-type test antenna,
the second transmission converter includes a third up-converter that up-converts a signal to be transmitted as a horizontally polarized radio signal from the plurality of the direct-type test antennas and a fourth up-converter that up-converts a signal to be transmitted as a vertically polarized radio signal from the plurality of the direct-type test antennas,
the second reception converter includes a third down-converter that down-converts a horizontally polarized radio signal received by the plurality of direct-type test antennas and a fourth down-converter that down-converts a vertically polarized radio signal received by the plurality of direct-type test antennas.
11. The test device according to claim 8 , wherein
the plurality of direct-type test antennas form mutually different arrival angles with respect to an arrival direction of a radio wave from the reflection-type test antenna at the arrangement position (P DUT ) of the test object.
12. The test device according to claim 8 , wherein
the plurality of direct-type test antennas are arranged outside a path of the radio wave beam passing through the quiet zone by reflecting the reflector of the reflection-type test antenna.
13. A test method to use a test device to measure transmission properties or reception properties of a test object having an antenna under test, the test device comprising:
an anechoic box having an internal space that is not affected by a radio environment;
a plurality of test antennas, accommodated in the internal space, to transmit or receive a radio signal to or from the antenna under test;
a posture changeable mechanism to change a posture of the test object arranged in a quiet zone (QZ) in the internal space; and
a measurement device to measure the transmission properties or the reception properties of the test object, using the test antenna with respect to the test object whose posture is changed by the posture changeable mechanism, wherein
the plurality of test antennas include a reflection-type test antenna that transmits or receives the radio signal to or from the antenna under test through a reflector, and a plurality of direct-type test antennas that directly transmits or receives the radio signal to or from the antenna under test,
the plurality of direct-type test antennas are arranged on the same plane passing through an arrangement position (P DUT ) of the test object, and form predetermined arrival angles differing from each other with respect to a radio wave arrival direction from the reflection-type test antenna at the arrangement position of the test object, and at least one of the plurality of direct-type test antennas form an additional arrival angle different from the predetermined arrival angles with respect to a radio wave arrival direction from either one of other the direct-type test antennas at the arrangement position of the test object, and
the plurality of direct-type test antennas are arranged at least 2D 2 /λ away from the antenna under test, where D is an antenna size of the test under test, λ is the wavelength of the radio wave transmitted from the plurality of direct-type test antennas, the test method including
a step to change the posture of the test object arranged in the quite zone by the posture changeable mechanism,
a step to select a test antenna to be used from among the plurality of test antennas, and
a measurement step to measure the transmission properties or the reception properties of the test object by using the selected test antennas by the measurement device with respect to the test object whose posture has been changed by the posture changeable mechanism.