FIELD

The present application relates to the field of antenna measurement, in particular to a terahertz leaky-wave antenna measuring system.

BACKGROUND

The terahertz two-dimensional periodic leaky-wave antenna can have a high directivity under a low profile condition due to the absence of a complicated feeding network and thus has been widely applied in the fields such as terahertz security check, spectrum analysis, and radar. The terahertz two-dimensional periodic leaky-wave antenna has a radiation cavity, i.e., a Fabry-Perot cavity and a feed. Periodic units are attached to a top of the radiation cavity. As on that of the reflector antenna, the location of the feed has a great influence on the performance of the two-dimensional leaky-wave antenna. Generally, in the theoretical design, the whole leaky-wave antenna is optimized after the phase center of the feed is fixed, which is considered as the best feed matching scheme.

However, the phase center of the feed may offset from the optimized location due to the errors caused by the deformation, the assembly, and the like of the antenna occurred under the actual working conditions. Therefore, it is important to determine the optimal location of the feed of the leaky-wave antenna through a measurement in order to obtain a high quality and high efficiency terahertz leaky-wave antenna. In the conventional leaky-wave antenna measuring system, since the feed is integrated into the radiation cavity and is not easy to move, an integrative measurement for the antenna cannot be achieved. Therefore, the conventional leaky-wave antenna measuring system cannot effectively solve the problem of correcting the actual phase center location of the feed of the two-dimension leaky-wave antenna while performing the integrative measurement for the terahertz antenna.

SUMMARY

A terahertz leaky-wave antenna measuring system includes an arched beam, a transmitting device, a radiation cavity, and a probe. The transmitting device is disposed on the arched beam. The radiation cavity is disposed at a center point of an arc defined by the arched beam. A groove is defined in the radiation cavity. The probe is disposed in the groove.

In an embodiment, the groove comprises a first sub-groove extended along a first direction, a second sub-groove extended along a second direction, and a third sub-groove extended along a third direction. The first sub-groove, the second sub-groove, and the third sub-groove are perpendicular to and intersected with each other.

In an embodiment, the transmitting device includes a rotating structure sleeved outside the arched beam and movable along the arched beam.

In an embodiment, the transmitting device includes a transmitting platform fixedly connected to an end of the rotating structure proximate to the radiation cavity.

In an embodiment, the transmitting device includes an adjustable support frame. The adjustable support frame is fixedly connected to the transmitting platform and located between the transmitting platform and the radiation cavity to form an accommodating space surrounded by the adjustable support frame and the transmitting platform.

In an embodiment, the transmitting device further includes a feed disposed on the transmitting platform and located in the accommodating space.

In an embodiment, the transmitting device includes a lens collimator connected to the adjustable support frame and disposed opposite to the feed. The adjustable support frame is configured to adjust a location of the lens collimator with respect to the feed.

In an embodiment, a plurality of metal sheets are disposed and spaced from each other on a surface of the radiation cavity proximate to the transmitting device.

In an embodiment, the terahertz leaky-wave antenna measuring system further includes supporting legs disposed at bottom ends of the arched beam to support the arched beam.

In an embodiment, the terahertz leaky-wave antenna measuring system further includes a wave-absorbing material layer. The wave-absorbing material layer is disposed about the arched beam and the radiation cavity to reduce the noise effect around the terahertz leaky-wave antenna measuring system.

In an embodiment, the terahertz leaky-wave antenna measuring system further includes a test platform disposed adjacent to the center point of the arch to support the radiation cavity thereon.

In an embodiment, the terahertz leaky-wave antenna measuring system further includes a vector network analyzer. A port of the vector network analyzer is connected to the feed, and another port of the vector network analyzer is connected to the probe.

In an embodiment, the terahertz leaky-wave antenna measuring system further includes a controller connected to the vector network analyzer.

In an embodiment, the terahertz leaky-wave antenna measuring system further includes a driving device. An output end of the driving device is connected to the transmitting device, and an input end of the driving device is connected to the computer controller. The driving device is configured to drive the transmitting device to move along the arched beam.

In an embodiment, the probe has a size of 2 mm×1 mm.

In an embodiment, the radiation cavity is a solid member made of a dielectric material.

In an embodiment, the radiation cavity is made of a silicon dielectric material.

In an embodiment, the feed is moved in a range of 0° to 180°.

In an embodiment, the driving device is a stepper motor.

In the terahertz leaky-wave antenna measuring system provided in the present application, the probe is placed in the groove and moved in the groove. The amplitude and phase distribution information of electromagnetic response signals at the locations where the probe arrives during the movement can be acquired by the probe, so that the feed is separated from the radiation cavity. The antenna far-field measurement is realized by extrapolating according to the reciprocity theorem. By directly changing the location of the feed in the transmitting device, the destruction to the original two-dimensional leaky-wave antenna is significantly reduced and the measurement accuracy is increased. Moreover, the system is simple and practicable, and a comprehensive reference can be provided for the feed installation and adjustment.

During the integrative measurement performed by using the terahertz leaky-wave antenna measuring system, the probe can be moved to find the location where a far-field gain of the two-dimensional leaky-wave antenna is maximum to determine the actual phase center location of the feed, thereby effectively solve the problem of correcting the actual phase center location of the feed of the two-dimensional leaky-wave antenna. The terahertz leaky-wave antenna measuring system can be used to measure a radiation property of a two-dimensional leaky-wave antenna at a terahertz wave band or a millimeter wave band and/or measure a transmission property of a frequency-selecting surface without the need of manufacturing a large number of antenna samples to be tested, thereby significantly decreasing the cost.

