According to one embodiment, a transmit/receive antenna module includes a radar circuit arranged at a substrate, a transmit antenna arranged at a first end portion of the substrate and connected to the radar circuit, a receive antenna arranged at a second end portion of the substrate and connected to the radar circuit. The transmit antenna is capable of transmitting an electromagnetic wave parallel to the substrate. The receive antenna is capable of receiving an electromagnetic wave parallel to the substrate.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2023-151902, filed Sep. 20, 2023, the entire contents of which are incorporated herein by reference.

FIELD

Embodiments described herein relate generally to a transmit/receive antenna module, a system, a method, and a storage medium.

BACKGROUND

An Integrated circuit having a radar function has been commercialized, and a radar device has become available at low cost. The radar device is expected to be applied to various fields such as automobiles, non-destructive inspection, medical, and security.

In the commercialized integrated circuit having the radar function, the number of antennas that can be mounted on is small. Therefore, increase of an aperture length of an antenna array is limited, and thus it is difficult to increase a spatial resolution.

In order to increase the number of applications of the radar device, it is desired that the aperture length of the antenna array can be adjusted and increased easily. As an example, it is proposed to provide a plurality of antenna modules. A plurality of integrated circuits and the antenna arrays are mounted on the antenna module.

When the number of the antennas increases in association with the increase of the aperture length of the antenna array, the required installation space becomes larger and the installation of a plurality of antenna modules becomes difficult.

DETAILED DESCRIPTION

Embodiments will be described below with reference to the drawings. In the following descriptions, a device and a method are illustrated to embody the technical concept of the embodiments. The technical concept is not limited to the configuration, shape, arrangement, material or the like of the structural elements described below. Modifications that could easily be conceived by a person with ordinary skill in the art are naturally included in the scope of the disclosure. To make the descriptions clearer, the drawings may schematically show the size, thickness, planer dimension, shape, and the like of each element differently from those in the actual aspect. The drawings may include elements that differ in dimension and ratio. Elements corresponding to each other are denoted by the same reference numeral and their overlapping descriptions may be omitted. Some elements may be denoted by different names, and these names are merely an example. It should not be denied that one element is denoted by different names. Note that “connection” means that one element is connected to another element via still another element as well as that one element is directly connected to another element. If the number of elements is not specified as plural, the elements may be singular or plural.

In general, according to one embodiment, a transmit/receive antenna module includes a radar circuit arranged at a substrate, a transmit antenna arranged at a first end portion of the substrate and connected to the radar circuit, a receive antenna arranged at a second end portion of the substrate and connected to the radar circuit. The transmit antenna is capable of transmitting an electromagnetic wave parallel to the substrate. The receive antenna is capable of receiving an electromagnetic wave parallel to the substrate.

First Embodiment

FIG.1is a block diagram illustrating an example of a radar device110according to a first embodiment. The radar device110includes at least one module. At least one integrated circuit having a radar function is mounted on the module. An example of the module is a transmit antenna module having a transmission function (hereinafter referred to as a transmitter module)10, a receive antenna module having a reception function (hereinafter referred to as a receiver module)20, and a signal generator module30generating a reference signal and a clock signal.FIG.1shows an example including one transmitter module10and one receiver module20. The first embodiment includes an example including transmitter modules10and receiver modules20. By connecting the transmitter modules10and the receiver modules20so as to be connected to the signal generator module30, the synchronous control of a plurality of integrated circuits and the adjustment or the increase of the aperture length of an antenna array can be easily achieved.

The radar device110further includes a processor90. The processor90is connected to the transmitter module10, the receiver module20, and the signal generator module30. The processor90includes a CPU92, a ROM96, and a RAM98. The ROM96is a non-transitory computer-readable storage medium. The ROM96stores a computer program which is executable by the CPU92for controlling the radar device110. The RAM98temporarily stores various data that are in operation. The CPU92executes program to have a function of a scheduler94. The scheduler94generates a trigger signal to control the transmission timing.

The signal generator module30generates a signal to control the transmission and reception of the radar signal according to a radar scheme. An example of the radar scheme is a linear frequency modulated continuous wave (L-FMCW) scheme in which the frequency increases linearly as time passes. The signal generator module30includes a distributor34and an integrated circuit (hereinafter referred to as an IC)32having the radar function of the L-FMCW scheme. Other examples of the radar scheme include a non-modulation CW scheme and a pulse scheme. Embodiments are not limited to these radar schemes and are applied to other radar schemes.

The IC32generates the clock signal and an L-FMCW signal (hereinafter referred to as a chirp signal) as the reference signal. The frequency of the chirp signal is in a frequency range. When it is unnecessary to distinguish the chirp signal and the clock signal from each other, these signals are simply referred to as “signal”.

The transmitter module10and the receiver module20operate according to the clock signal output by the signal generator module30. Therefore, the transmitter module10and the receiver module20operate in synchronization with each other.

An output signal of the IC32is input to the distributor34. The distributor34distributes the input signal to two output terminals. A first output signal of the distributor34is supplied to the transmitter module10. A second output signal of the distributor34is supplied to the receiver module20. Since the clock signal from the single signal generator module30is supplied to the transmitter module10and the receiver module20, a transmission and a reception are synchronized.

The transmitter module10includes transmit antennas16, at least two ICs12, and at least one distributor18. The IC12has a radar transmission function according to the L-FMCW scheme. The transmitter module10may comprise a substrate (not shown). The ICs12, the transmit antennas16, and the distributor18may be formed on the substrate. The number of the ICs12is, for example, four. The number of the transmit antennas16is, for example, sixteen. The number of the distributors18is, for example, three. The distributor18distributes the input signal to the two output terminals.

The signal from the distributor34is input to a distributor18c. The distributor18cdistributes the input signal to two output terminals. The first output signal of the distributor18cis input to a distributor18a. The second output signal of the distributor18cis input to a distributor18b.

The distributor18adistributes the input signal to two output terminals. The first output signal of the distributor18ais input to an IC12a. The second output signal of the distributor18ais input to an IC12b. The IC12ais connected to four transmit antennas16a,16b,16c, and16d. The IC12bis connected to four transmit antennas16e,16f,16g, and16h.

The distributor18bdistributes the input signal to two output terminals. The first output signal of the distributor18bis input to an IC12c. The second output signal of the distributor18bis input to the IC12d. The IC12cis connected to four transmit antennas16i,16j,16k, and16l. The IC12dis connected to four transmit antennas16m,16n,16o, and16p.

The clock signal from the signal generator module30is supplied to the ICs12ato12d. The transmissions of the ICs12ato12dare synchronized based on the clock signal. The IC12acauses the transmit antennas16ato16dto transmit electromagnetic waves corresponding to the chirp signal (hereinafter referred to as a radar signal) to an object. The IC12bcauses the transmit antennas16eto16hto transmit the electromagnetic waves corresponding to the radar signal to the object. The IC12ccauses the transmit antennas16ito16lto transmit the electromagnetic waves corresponding to the radar signal to the object. The IC12dcauses the transmit antennas16mto16pto transmit the electromagnetic waves corresponding to the radar signal to the object.

The number of the transmit antennas16connected to each of the ICs12ato12dis not limited to four, but may be two, six or more, or an odd number. The number of the transmit antennas16connected to each of the ICs12ato12dis not limited to the same but may be different for each of the ICs12. The intervals between all of adjacent antennas (for example,16aand16b) of the transmit antennas16ato16pmay be set to uniform intervals or may be set to a plurality of intervals relatively prime to each other. An example of the uniform interval is one wavelength or a half wavelength of one of electromagnetic wave frequencies in the frequency range of a transmission signal, e.g., the chirp signal.

The receiver module20includes receive antennas26, at least two ICs22, and at least one distributor28. The IC22has a radar reception function of the L-FMCW scheme. The receiver module20includes a substrate (not shown). The ICs22, receive antennas26, and distributor28may be formed on the substrate. The number of the ICs22is, for example, four. The number of the receive antennas26is, for example, sixteen. The number of the distributors28is, for example, three. The distributor28distributes the input signal to two output terminals.

The signal from the distributor34is input to a distributor28c. The distributor28cdistributes the input signal to two output terminals. The first output signal of the distributor28cis input to a distributor28a. The second output signal of the distributor28cis input to a distributor28b.

The distributor28adistributes the input signal to two output terminals. The first output signal of the distributor28ais input to an IC22a. The second output signal of the distributor28ais input to an IC22b. The IC22ais connected to four transmit antennas26a,26b,26c, and26d. The IC22bis connected to four receive antennas26e,26f,26g, and26h.

The distributor28bdistributes the input signal to two output terminals. The first output signal of the distributor28bis input to the IC22c. The second output signal of the distributor28bis input to the IC22d. The IC22cis connected to four receive antennas26i,26j,26k, and26l. The IC22dis connected to four receive antennas26m,26n,26o, and26p.

The clock signal from the signal generator module30is supplied to the ICs22ato22d. The ICs22ato22dperform the synchronized reception based on the clock signal. The IC22aprocesses the signals received by the receive antennas26ato26daccording to the chirp signal. The IC22bprocesses the signals received by the receive antennas26eto26haccording to the chirp signal. The IC22cprocesses the signals received by the receive antennas26ito26laccording to the chirp signal. The IC22dprocesses the signals received by the receive antennas26mto26paccording to the chirp signal.

The number of the receive antennas26connected to each of the ICs22ato22dis not limited to four, but may be two, six or more, or an odd number. The number of the receive antennas26connected to each of the ICs22ato22dis not limited to the same number, but may be different for each of the IC. The intervals between all of adjacent antennas26(for example,26aand26b) of the receive antennas26ato26pmay be set to uniform intervals or may be set to a plurality of intervals relatively prime to each other. An example of the uniform interval is the one wavelength or the half wavelength.

The transmitter module10, the receiver module20, and the signal generator module30are connected to the processor90. The processor90is an upper layer device of the radar device110. The processor90may perform beam-forming process of a transmission beam and a reception beam. The processor90performs an initial setting and a timing control of the transmitter module10. The processor90can perform an array signal processing of the received signal to detect the presence or absence of belongings, the direction of the belongings, the distance to the belongings, and the type of belongings and may display an image of the belongings. In that case, the CPU92has a function of an image generator module in addition to the function of the scheduler94.

The spatial resolution required for the direction estimation and the image display of the radar device110using the antenna array including a plurality of antennas is determined depending on the number of the antennas. Only a limited number of the antennas can be connected to the single IC12or22that has the radar function. Thus, the spatial resolution cannot be increased. In the embodiment, a plurality of ICs, for example, four ICs12ato12d, are cascaded to realize a transmit antenna array including sixteen antennas16ato16p. A plurality of ICs, for example, four ICs22ato22d, are cascaded to realize a transmit antenna array including sixteen antennas26ato26p. Thus, the spatial resolution of the radar device110can be quadruple of a spatial resolution of a case in which one IC12is used in the transmitter module10and one IC22is used in the receiver module20.

A dedicated IC may be used as each of the ICs12ato12d, the ICs22ato22d, and the IC32. However, the same IC may be used in common.

FIG.2is a block diagram illustrating an example of an IC38used in common as each of the ICs12ato12d, the ICs22ato22d, and the IC32according to the first embodiment. The IC38includes a transmitter circuit40, a receiver circuit50, and a signal generation circuit60.

The signal generation circuit60includes an oscillator62and a clock generator64. The oscillator62generates the chirp signal. The output signal of the signal generation circuit60is output to the outside of the IC38via an output terminal60a.

The transmitter circuit40includes transmission amplifiers42a,42b,42c, and42d, and distributors44a,44b, and44c, and a controller46. The chirp signal and the clock signal from the outside of the IC38are input to an input terminal40a. The trigger signal from the processor90is input to the controller46. The processor90supplies the trigger signal to the controller46of one the transmitter circuits40, which initiates transmission.

The clock signal is input to the controller46. The controller46controls the operation timing of each of the transmission amplifiers42based on the clock signal and the trigger signal. The chirp signal is input to the distributor44c. The distributor44csupplies the chirp signal to the distributor44aand the distributor44b. The distributor44asupplies the chirp signal from the distributor44cto the transmission amplifier42aand the transmission amplifier42b. The distributor44bsupplies the chirp signal from the distributor44cto the transmission amplifier42cand the transmission amplifier42d.

Each of the transmission amplifiers42ato42dis connected to each of the four transmit antennas16. As a result, the radar signal according to the chirp signal is irradiated from each of the four transmit antennas16.

An example of the electromagnetic wave used as the radar signal in the embodiment is an electromagnetic wave having a wavelength of 1 to 30 millimeters. An electromagnetic wave having a wavelength of 1 to 10 millimeters is referred to as a millimeter wave. An electromagnetic wave having a wavelength of 10 to 100 millimeters is referred to as a microwave. Another example of the electromagnetic wave is an electromagnetic wave having a wavelength of 100 micrometers to 1 millimeter, which is referred to as a terahertz wave.

The distributor44ais arranged at a position substantially equidistant from the transmission amplifier42aand the transmission amplifier42b. Therefore, the length of a signal line S11between the distributor44aand the transmission amplifier42acan easily be made equal to the length of a signal line S12between the distributor44aand the transmission amplifier42b. The distributor44bis arranged at a position substantially equidistant from the transmission amplifier42cand the transmission amplifier42d. Therefore, the length of a signal line S13between the distributor44band the transmission amplifier42ccan easily be made equal to the length of a signal line S14between the distributor44band the transmission amplifier42d. The distributor44cis arranged at a position substantially equidistant from the distributor44aand the distributor44b. Therefore, the length of a signal line S15between the distributor44cand the distributor44acan easily be made equal to the length of a signal line S16between the distributor44cand the distributor44b.

By dividing the signal from the input terminal40ainto two signals by the distributor44cand further dividing each of the two divided signals into two signals in this manner, the lengths of the signal lines between the input terminal40aand the four transmission amplifiers42ato42dcan easily be made equal. As a result, variation in the transmission delay of four chirp signals input to the four transmission amplifiers42ato42dcan be suppressed and the directivity of the transmit antenna array can be accurately controlled. If the signal from the input terminal40ais divided into four signals by one distributor, four signal lines need to be routed to make the lengths of the four signal lines equal, and thus the degree of integration of the IC38cannot be increased.

The receiver circuit50includes reception amplifiers52a,52b,52c, and52d, mixers54a,54b,54c, and54d, A/D converters (ADC)56a,56b,56c, and56d, distributors58a,58b, and58c, and a controller59. The chirp signal and the clock signal from the outside of the IC38are input to an input terminal50a.

The clock signal is input to the controller59. The controller59controls the operation timing of the receiver circuit50based on the clock signal. Thus, the operations of the transmitter circuit40and the receiver circuit50are synchronized. The controller59causes the reception amplifiers52connected to all of the receive antennas26ato26pto operate simultaneously.

The chirp signal is input to the distributor58c. Each of the four receive antennas26is connected to each of the reception amplifiers52ato52d.

The outputs of the reception amplifiers52ato52dare supplied to the ADCs56ato56dvia the mixers54ato54d, respectively.

The distributor58csupplies the chirp signal and the clock signal from the input terminal50ato the distributor58aand the distributor58b. The distributor58asupplies the chirp signal from the distributor58cto the mixers54aand54band supplies the clock signal from the distributor58cto the ADCs56aand56b. The distributor58bsupplies the chirp signal from the distributor58cto the mixers54cand54dand also supplies the clock signal from the distributor58cto the ADCs56cand56d.

The mixers54ato54duse the chirp signals to convert RF signals from the reception amplifiers52ato52dinto IF-band received signals. The ADCs56ato56dsynchronize the IF-band received signals with the clock signals and covert these synchronized signals to digital signals.

The digital signals from the ADCs56ato56dare supplied to the processor90via output terminals (not shown).

The distributor58ais arranged at a position substantially equidistant from the mixer54aand the mixer54band a position substantially equidistant from the ADC56aand the ADC56b. Therefore, the length of a signal line S21between the distributor58aand the mixer54acan easily be made equal to the length of a signal line S22between the distributor58aand the mixer54b. The length of a signal line S23between the distributor58aand the ADC56acan easily be made equal to the length of a signal line S24between the distributor58aand the ADC56b.

The distributor58bis arranged at a position substantially equidistant from the mixer54cand the mixer54dand a position substantially equidistant from the ADC56cand the ADC56d. Therefore, the length of a signal line S25between the distributor58band the mixer54ccan easily be made equal to the length of a signal line S26between the distributor58band the mixer54d. The length of a signal line S27between the distributor58band the ADC56ccan easily be made equal to the length of a signal line S28between the distributor58band the ADC56d.

The distributor58cis arranged at a position substantially equidistant from the distributor58aand the distributor58b. Therefore, the length of a signal line S29between the distributor58cand the distributor58acan easily be made equal to the length of a signal line S30between the distributor58cand the distributor58b.

Thus, by dividing the signal from the input terminal50ainto two signals by the distributor58cand further dividing each of the two divided signals into two signals, the lengths of the signal lines between the input terminal50aand the four mixers54ato54dcan easily be made equal and the length of the signal lines between the input terminal50aand the four ADCs56ato56dcan easily be made equal. As a result, variation in the transmission delay of four chirp signals respectively input to the four mixers54ato54dcan be suppressed and the RF signals can be converted into IF signals without the occurrence of the phase shift. Furthermore, variation in the timing deviations of four clock signals respectively input to the four ADCs56ato56dcan be suppressed, and the IF signals can be converted to the digital signals at correct timing. If the signal from the input terminal50ais divided into four signal lines, the four signal lines need to be routed in order to make the lengths of the four signal lines equal. Thus, the degree of integration of the IC38cannot be increased.

FIG.3is a block diagram illustrating another example of a radar device120according to the first embodiment.FIG.3includes a modified example of the antenna module.FIG.1shows an example in which the number of the antennas of the transmit/receive antenna array is sixteen.FIG.3shows an example in which the number of the antennas of the transmit/receive antenna array is sixty-four. The radar device120includes a transmitter unit122, a receiver unit124, the signal generator module30, and the processor90.

The signal generator module30is connected to the transmitter unit122and the receiver unit124. Since the clock signal from the single signal generator module30is supplied to the transmitter unit122and the receiver unit124, the transmission and the reception can be synchronized.

The transmitter unit122includes transmitter modules10a,10b,10c, and10dand distributors130a,130b, and130c. Each of the transmitter modules10a,10b,10c, and10dis equivalent to the transmitter module10shown inFIG.1. Each of the transmitter modules10a,10b,10c, and10dincludes sixteen transmit antennas16. The transmitter module122includes sixty-four transmit antennas16. The number of the transmitter modules10included in the transmitter unit122is not limited to four, but may be any number as long as the number is two or more.

The distributor130csupplies the signals (chirp signal and clock signal) from the signal generator module30to each of the distributor130aand the distributor130b. The distributor130asupplies the signals from the distributor130cto each of the transmitter module10aand the transmitter module10b. The distributor130bsupplies the signals from the distributor130cto each of the transmitter module10cand the transmitter module10d.

The distributor130cis arranged at a position substantially equidistant from the distributor130aand the distributor130b. The distributor130ais arranged at a position substantially equidistant from the transmitter module10aand the transmitter module10b. The distributor130bis arranged at a position substantially equidistant from the transmitter module10cand the transmitter module10d. Therefore, the chirp signal from the signal generator module30is supplied to each of the transmitter modules10ato10dvia the signal lines having the substantially equal lengths. The operations of the receiver modules10ato10dare synchronized based on the clock signal from the signal generator module30.

The receiver unit124includes receiver modules20a,20b,20c, and20dand distributors132a,132b, and132c. Each of the receiver modules20a,20b,20c, and20dis equivalent to the receiver module20shown inFIG.1. Each of the receiver modules20a,20b,20c, and20dincludes sixteen receive antennas. The receiver unit124includes sixty-four receive antennas26. The number of the receiver modules20included in the receiver unit124is not limited to four, but may be any number as long as the number is two or more.

The distributor132csupplies the signals (chirp signal and clock signal) from the signal generator module30to each of the distributor132aand the distributor132b. The distributor132asupplies the signals from the distributor132cto each of the receiver module20aand the receiver module20b. The distributor132bsupplies the signals from the distributor132cto each of the receiver module20cand the receiver module20d. The distributor132cis arranged at a position substantially equidistant from the distributor132aand the distributor132b. The distributor132ais arranged at a position substantially equidistant from the receiver module20aand the receiver module20b. The distributor132bis arranged at a position substantially equidistant from the receiver module20cand the receiver module20d. Therefore, the chirp signal and the clock signal from the signal generator module30are supplied to each of the receiver modules20ato20dvia the signal lines having the substantially equal lengths. The operations of the receiver modules20ato20dare synchronized based on the clock signal from the signal generator module30.

The transmitter modules10a,10b,10c, and10d, the receiver modules20a,20b,20c, and20d, and the signal generator module30are connected to the processor90.

The radar device120uses sixteen ICs12to operate the sixty-four transmit antennas16and uses sixteen ICs22to operate the sixty-four receive antennas26. Therefore, the spatial resolution of the radar device120can be quadruple of the spatial resolution of the radar device110in which the four ICs12are used to operate the sixteen transmit antenna16and the four ICs22are used to operate the sixteen receive antennas26.

One application example of the radar devices110and120according to the first embodiment is a security system for inspecting belongings of an object. For example, locations where this system is arranged are near entrance gates of areas where security is required to be maintained, such as train stations, amusement parks, concert halls, and buildings. This system inspects the object when the object passes through the entrance gate and prevents an object possessing a predetermined item from entering the area. It is not desirable to stop the object for the inspection. Therefore, a walk-through type inspection device that emits electromagnetic waves to the object passing through the gate is proposed.

FIG.4illustrates the principle of the walk-through type inspection device, which is one application example of the radar device according to the first embodiment.FIG.4shows an example of the walk-through type inspection device to which the radar device120shown inFIG.3is applied. The radar device110shown inFIG.1can also be applied to the walk-through type inspection device.

The inspection device inspects the belongings of an object140walking through a path142. The path142is also referred to as an inspection lane. A left enclosure144is arranged at the left portion of the path142. A right enclosure146is arranged at the right portion of the path142. In this specification, right and left refer to right and left viewed from the object140walking through the path142. The left enclosure144and the right enclosure146are formed of a material that does not absorb and reflect electromagnetic waves, for example, resin.

The transmitter unit122shown inFIG.3is divided into two portions. A first portion includes the transmitter modules10aand10b. A second portion includes the transmitter modules10cand10d. The transmitter modules10may not be divided equally in number. For example, the transmitter unit122may be divided into three transmitter modules and one transmitter module. The transmitter modules10aand10bof the first portion are arranged in the left enclosure144. The transmitter modules10cand10dof the second portion are arranged in the right enclosure146.

The receiver unit124shown inFIG.3is divided into two portions. A first portion includes the receiver modules20aand20b. A second portion includes the receiver modules20cand20d. The receiver modules20may not be divided equally in number. For example, the receiver unit124may be divided into three receiver modules and one receiver module. The receiver modules20aand20bof the first portion are arranged in the left enclosure144. The receiver modules20cand20dof the second portion are arranged in the right enclosure146.

FIG.4does not specifically show the installation location and direction of the transmitter modules10and the receiver modules20in the left enclosure144and the right enclosure146. The installation location and direction of the transmitter modules10and the receiver modules20in the left enclosure144and the right enclosure146may be arbitrary and can be determined according to specifications of the spatial resolution, the performance, and the like desired to be achieved.

FIG.5illustrates the transmission directions of the electromagnetic waves of the transmitter modules10(transmit antennas16) and the reception directions of the electromagnetic waves of the receiver modules20(receive antennas26) according to the first embodiment. The direction of the electromagnetic wave is represented by the direction of a main lobe in the radiation pattern of the antenna.

The transmission directions of the electromagnetic waves of the transmitter modules10(transmit antennas16) in the left enclosure144are to the right direction, such that the path142is the object inspection area. The reception directions of the electromagnetic waves of the receiver modules20(receive antennas26) in the left enclosure144are to the right direction, such that the path142is the object inspection area.

The transmission directions of the electromagnetic waves of the transmitter modules10(transmit antennas16) in the right enclosure146are to the left direction, such that the path142is the object inspection area. The reception directions of the electromagnetic waves of the receiver modules20(receive antennas26) in the right enclosure146are to the left direction, such that the path142is the object inspection area.

Each of the right direction and the left direction is not limited to one angle, but is set to a range of angles. For example, when the entire circumference is 360 degrees and 0 degrees is the travel direction of the object140, the right is +90 degrees and the left is +270 (−90) degrees. The right direction is an angle range of +90 degrees±less than 90 degrees. The left direction is an angle range of +270 degrees±less than 90 degrees.

FIG.6is a perspective view illustrating an example of the walk-through type inspection device which is the application example of the radar device120according to the first embodiment.

In the left enclosure144, the substrate of the transmitter module10aand the substrate of the transmitter module10bare arranged so as to be parallel to, in other words, horizontal to the surface of the path142. The substrate of the receiver module20aand the substrate of the receiver module20bare arranged so as to be orthogonal to, in other words, vertical to the surface of the path142. The transmitter modules10aand10b, and the receiver modules20aand20bare arranged to form a cuboid antenna module262.

In the transmitter modules10aand10b, sixteen transmit antennas16are arranged in a line at one end of each of the transmitter modules10aand10b(substrates). In the transmitter modules20aand20b, sixteen transmit antennas26are arranged in a line at one end of each of the transmitter modules20aand20b(substrates).

The transmitter modules10aand10bin the left enclosure144are arranged in a direction in which the transmit antennas16are opposed to the path142. The receiver modules20aand20bin the left enclosure144are arranged in a direction in which the receive antennas26are opposed to the path142.

The above arrangement of the transmitter modules10aand10band the arrangement of the receiver modules20aand20bare examples. These modules may be arranged in arrangements other than the above, for example, may be arranged linearly in one or two lines, or be arranged simply in four lines. The transmit antennas16and the receive antennas26in the antenna module262may also be arranged in arrangements other than the above, for example, may be arranged linearly in one or two lines, or be arranged simply in four lines. Furthermore, a plurality of antenna modules262may be arranged in the enclosure144.

The distributors130and132(not shown inFIG.6) are also arranged in the left enclosure144.

In the right enclosure146, the substrate of the transmitter module10cand the substrate of the transmitter module10dare arranged so as to be parallel to, in other words, horizontal to the surface of the path142. The substrate of the receiver module20cand the substrate of the receiver module20dare arranged so as to be orthogonal to, in other words, vertical to the surface of the path142. The transmitter modules10cand10dand the receiver module20cand20dare arranged to form a cuboid antenna module264.

In the transmitter modules10cand10d, sixteen transmit antennas16are arranged in a line at one end of each of the transmitter modules10cand10d(substrate). In the transmitter modules20cand20d, sixteen transmit antennas26are arranged in a line at one end of each of the transmitter modules20cand20d(substrate).

The transmitter modules10cand10din the right enclosure146are arranged in a direction in which the transmit antennas16are opposed to the path142. The transmitter modules20cand20din the right enclosure146are arranged in a direction in which the transmit antennas26are opposed to the path142.

The above arrangement of the transmitter modules10cand10dand the arrangement of the receiver modules20cand20dare examples. These modules may be arranged in arrangements other than the above, for example, may be arranged linearly in one or two lines, or be arranged simply in four lines. The transmit antennas16and the receive antennas26in the antenna module264may also be arranged in arrangements other than the above, for example, may be arranged linearly in one or two lines, or be arranged simply in four lines. Furthermore, a plurality of antenna modules264may be arranged in the enclosure146.

The distributors130and132are arranged in the right enclosure146.

The signal generator module30is connected to the distributors130cand132c. The clock signal output from the signal generator module30is supplied to the transmitter module122and the receiver unit124. Therefore, the ICs12and22operate in synchronization with each other.

The transmission antenna16can transmit the electromagnetic wave parallel to the substrate. The radar signal transmitted from one transmit antenna16in the transmitter modules10aand10bin the left enclosure144propagates toward the path142and is reflected in a left area of the object140on the path142. A reflected wave of the radar signal (hereinafter referred to as a reflected signal) propagates toward the left enclosure144. The receive antenna26can receive the electromagnetic wave parallel to the substrate. The reflected signal is received by all of the receive antennas26of the receiver modules20aand20bin the left enclosure144. The receiver modules20aand20bprocess the received signals and supply the processed received signals to the processor90. The processor90inspects the belongings in the left area of the object140based on the received signals. The processor90may generate an image of the object140based on the received signals and inspect the belongings based on the image.

The radar signal transmitted from one transmit antenna16in the transmitter modules10cand10din the right enclosure146propagates toward the path142and is reflected in a right area of the object140on the path142. The reflected signal propagates toward the right enclosure146. The reflected signal is received by all of the receive antennas26of the receiver modules20cand20din the right enclosure146. The receiver modules20cand20dprocess the received signals and supply the processed received signals to the processor90. The processor90inspects the belongings in the right area of the object140based on the received signals. The processor90may generate an image of the object140based on the received signals and inspect the belongings based on the image.

FIG.6shows an example in which the antennas16and26and the ICs12and22(including the distributors130and132) are formed integrally on the substrate of the module. The antennas16and26and the ICs12and22(including the distributors130and132) may be formed on respective substrates.

An example of the transmit antenna16and the receive antenna26according to the first embodiment includes a patch antenna, a dipole antenna including a reflection plate, or a substrate integrated waveguide (SIW) aperture antenna. When one of the transmit antenna array and the receive antenna array is arranged horizontally and the other of the transmit antenna array and the receive antenna array is arranged vertically, as shown inFIG.6, one antenna array is either the dipole antenna including the reflection plate or the SIW aperture antenna and the other antenna array is the other of the SIW aperture antenna or the dipole antenna including the reflection plate.

FIG.7is a schematic perspective view illustrating an example of the transmit antenna16or the receive antenna26including the SIW aperture antenna according to the first embodiment.FIG.8is a schematic plan view illustrating an example of the transmit antenna16or the receive antenna26according to the first embodiment.FIG.9is a schematic cross-sectional view illustrating an example of the transmit antenna16or the receive antenna26according to the first embodiment.FIG.9is a cross-sectional view along a line A1-A2inFIG.8.FIG.10is a schematic cross-sectional view illustrating an example of the transmit antenna16or the receive antenna26according to the first embodiment.FIG.10is a cross-sectional view along a line A3-A4inFIG.8.

A substrate318includes a plurality of antennas315. The antenna315includes a first structure310W. The first structure310W is the SIW. The antenna315is the SIW aperture antenna.

The first structure310W includes a first waveguide conductive layer316f, another first waveguide conductive layer316g, a plurality of first waveguide electrode portions316a, and a plurality of second waveguide electrode portions316b. The direction from the other first waveguide conductive layer316gto the first waveguide conductive layer316fis along the third direction D3. As shown inFIG.8, the direction from the waveguide conductive electrode portions316ato the waveguide conductive electrode portions316bis along the second direction D2.

The first waveguide conductive layer316fand the other first waveguide conductive layer316gare electrically connected to each other by the first waveguide conductive electrode portions316aand the second waveguide conductive electrode portions316b. The first direction D1, the second direction D2, and the third direction D3are orthogonal to one another. The third direction D3may be referred to as the X-axis direction. In that case, the second direction D2is referred to as the Y-axis direction and the first direction D1is referred to as the Z-axis direction.

The first structure310W may further include a third waveguide electrode portion316cand a fourth waveguide electrode portion316d. The third waveguide electrode portion316cis electrically connected to the first waveguide conductive layer316fand the other first wave guide conductive layer316g. The fourth waveguide conductive electrode portion316dis electrically connected to the first waveguide conductive layer316fand the other first waveguide conductive layer316g. The distance along the second direction D2between the third waveguide conductive electrode portion316cand the fourth waveguide conductive electrode portion316dis shorter than the distance along the second direction D2between the first waveguide conductive electrode portions316aand the second waveguide conductive electrode portions316b. The first structure310W may not include the third waveguide electrode portion316cand the fourth waveguide electrode portion316d.

A part of the substrate318is arranged between the first waveguide conductive layer316fand the other first waveguide conductive layer316gand between the first waveguide conductive electrode portions316aand the second waveguide conductive electrode portions316b.

The first structure310W includes an aperture310o. The aperture310ois arranged at an end of the first structure310W in the first direction D1. The aperture310ofunctions as an aperture antenna. The electromagnetic wave is irradiated from the aperture310o.

The antenna315may include waveguides315W. The waveguide315W includes a first conductive layer315c, another first conductive layer315d, a first electrode portion315a, and another first electrode portion315b. The direction from the other first conductive layer315dto the first conductive layer315cis along the third direction D3. The direction from the other first electrode portion315bto the first electrode portion315ais along the second direction D2. The first conductive layer315cand the other first conductive layer315dare electrically connected to each other by the first electrode portion315aand the other first electrode portion315b.

At least a part of the substrate318is arranged between the first conductive layer315cand the other first conductive layer315dand between the first electrode portion315aand the other first electrode portion315b.

The position of the third waveguide electrode portion316cin the first direction D1is between the position of the first conductive layer315cin the first direction D1and the position of the first waveguide electrode portions316ain the first direction D1. The position of the fourth waveguide electrode portion316din the first direction D1is between the position of the first conductive layer315cin the first direction D1and the position of the second waveguide electrode portions316bin the first direction D1. The first waveguide electrode portions316aand the second waveguide electrode portions316bthat form the aperture310omay be opposed to one of the waveguides315W. The third waveguide electrode portion316cand the fourth waveguide electrode portion316dthat form the aperture310omay be opposed to one of the waveguides315W.

The direction from the first waveguide conductive layer316fto the first waveguide conductive layer315cis along the first direction D1. The direction from the other first waveguide conductive layer316gto the other first conductive layer315dis along the first direction D1. For example, the other first conductive layer316gmay be a fixed potential (for example, a ground potential).

The substrate318has a first surface318fand another first surface318g. The direction from the other first surface318gto the first surface318fis along the third direction D3. The first conductive layer315cis arranged at the first surface318f. The other first conductive layer315dis arranged at the other first surface318g. One of the waveguides315W extending along the third direction D3in the substrate318can be coupled with one of the first structures310W.

FIG.11is a schematic perspective diagram illustrating an example of the receive antenna26or the transmit antenna16including the dipole antenna including the reflection plate according to the first embodiment.FIG.12is a schematic plan view illustrating an example of the receive antenna26or the transmit antenna16according to the first embodiment.

The substrate328includes a plurality of antennas325. The antenna325includes a second conductive layer325a. At least a part of the second conductive layer325aextends along the third direction D3. The antenna325may include another second conductive layer325b. At least a part of the other second conductive layer325bextends along the third direction D3. The direction from the other second conductive layer325bto the second conductive layer325ais along the third direction D3. The second conductive layer325aand the other second conductive layer325bconstitute the dipole antenna. The antenna325is the dipole antenna including the reflection plate.

The second conductive layer325aand the other second conductive layer325bare arranged at the second surface328fof the substrate328.

The substrate328may include a second waveguide conductive layer327aand another second waveguide conductive layer327b. The direction from the other second waveguide conductive layer327bto the second waveguide conductive layer327ais along the second direction D2. A part of the substrate328is arranged between the other second waveguide conductive layer327band the second waveguide conductive layer327a. The second waveguide conductive layer327acan be coupled with the second conductive layer325a(and the other second conductive layer325b). For example, the other second waveguide conductive layer327bmay be the fixed potential (for example, the ground potential). A plurality of second waveguide conductive layers327amay be arranged. One of the second waveguide conductive layers327acan be coupled with the second conductive layer325a(and the other second conductive layer325b).

The substrate328may include another second surface328g. The direction from the other second surface328gto the second surface328fis along the second direction D2. The second waveguide conductive layer327amay be arranged at the second surface328f. The other second waveguide conductive layer327bmay be arranged at the other second surface328g.

The configurations of the transmit antenna16and the receive antenna26shown inFIG.7toFIG.12are examples, and the configurations are not limited to these examples.

FIG.13is a block diagram illustrating an example of the electrical configuration of the radar device120shown inFIG.6. The radar device120includes the transmitter unit122, the receiver unit124, the signal generator module30, and the processor90. The transmitter unit122is divided into two transmitter subunits122aand122b. The receiver unit124is divided into two receiver subunits124aand124b.

The transmitter subunit122ais arranged in the left enclosure144. The transmitter subunit122aincludes the transmitter modules10aand10band the distributor130a. The transmitter subunit122bis arranged in the right enclosure146. The transmitter subunit122bincludes the transmitter modules10cand10dand the distributor130b. The distributor130cis not arranged in either the left enclosure144or the right enclosure146, but is arranged in the vicinity of the signal generator module30. A first output terminal of the distributor130cis connected to the transmitter subunit122a(distributor130a). A second output terminal of the distributor130cis connected to the transmitter subunit122b(distributor130b).

The receiver subunit124ais arranged in the left enclosure144. The receiver subunit124aincludes the receiver modules20aand20band the distributor132a. The receiver subunit124bis arranged in the right enclosure146. The receiver subunit124bincludes the receiver modules20cand20dand the distributor132b. The distributor132cis not arranged in either the left enclosure144or the right enclosure146, but is arranged in the vicinity of the signal generator module30. A first output terminal of the distributor132cis connected to the receiver subunit124a(distributor132a) and a second output terminal of the distributor132cis connected to the receiver subunit124b(distributor132b).

The antenna module262arranged in the left enclosure144includes the transmitter subunit122aand the receiver subunit124a. The antenna module264arranged in the right enclosure146includes the transmitter subunit122band the receiver subunit124b.

The radar devices110and120according to the first embodiment can inspect the belongings of the object140walking through the path142. Since the object140does not need to stop for the inspection, the inspection throughput of the radars110and120is improved.

In order to further improve the inspection throughput, it is proposed to provide a plurality of radar devices to simultaneously inspect a plurality of objects on a plurality of inspection lanes. In this case, the number of the radar devices to be arranged increases in accordance with the number of the inspection lanes, increasing the cost. In addition, the entire inspection lanes expand due to the size of the enclosure of the radar device and the margin area between the radar devices (between the inspection lanes) for installation and maintenance purposes. Furthermore, since the operations between the radar devices adjacent to each other are in asynchronous, interference may occur at unexpected timing points between the radar devices, affecting the inspection results. The interference can be avoided by introducing the electromagnetic wave absorption material or the electromagnetic wave reflection control material between the radar devices, but the introduction of these materials leads to increases in cost and margin space.

FIG.14is a perspective view illustrating an example of a walk-through type inspection device210, which is an application example of the radar device according to the first embodiment. The inspection device210includes a plurality of radar devices120(FIG.6) arranged along a plurality of paths. The inspection device210may include a plurality of radar devices100(FIG.1) arranged along a plurality of paths, instead of the radar devices120. For the sake of illustration,FIG.14shows the inspection device210including two lanes, but the inspection device210including three or more lanes is configured in the same manner. A first path1421and a second path1422are defined. The second path1422is arranged at the right of the first path1421.

The first left enclosure1441is arranged at the left portion of the first path1421. The first right enclosure1461is arranged at the right portion of the first path1421. The second left enclosure1442is arranged at the left portion of the second path1422. The second right enclosure1462is arranged at the right portion of the second path1422. The first right enclosure1461and the second left enclosure1442do not need to be spaced apart, but may be in close contact with each other. In other words, the first right enclosure1461and the second left enclosure1442may be a single enclosure.

The configurations of the first left enclosure1441and the second left enclosure1442are the same as that of the left enclosure144shown inFIG.6. The configurations of the first right enclosure1461and the second right enclosure1462are the same as that of the right enclosure146shown inFIG.6.

The signal generator module30is connected to the first left enclosure1441, the first right enclosure1461, the second left enclosure1442, and the second right enclosure1462.

FIG.15is a block diagram illustrating an example of the electrical configuration of the inspection device210according to the first embodiment. The inspection device210includes the transmitter unit122, the receiver unit124, the signal generator module30, and the processor90.

The transmitter unit122includes four transmitter subunit122a1,122b1,12222, and122b2. The configurations of the transmitter subunits122a1and12222are the same as that of the transmitter subunit122ain the left enclosure144shown inFIG.13. The configurations of the transmitter subunits122b1and122b2are the same as that of the transmitter subunit122bin the right enclosure146shown inFIG.13. The transmitter unit122further includes distributors130c1and130c2.

The receiver unit124includes four receiver subunits124a1,124b1,124a2, and124b2. The configurations of the receiver subunits124a1and124a2are the same as that of the receiver subunit124ain the left enclosure144shown inFIG.13. The configurations of the receiver subunits124b1and124b2are the same as that of the receiver subunit124bin the right enclosure146shown inFIG.13. The receiver unit124further includes distributors132c1and132c2.

A first output signal of the signal generator module30is supplied to a distributor212. A second output signal of the signal generator module30is supplied to a distributor214. The two output signals of the distributor212are supplied to the distributors130c1and130c2, respectively. The two output signals of the distributor214are supplied to the distributors132c1and132c2, respectively. The distributors130c1and130c2are not arranged in the inside of any of the first left enclosure1441, the first right enclosure1461, the second left enclosure1442, or the second right enclosure1462, but are arranged in the vicinity of the distributor212. The distributors132c1and132c2are not arranged in the inside of any of the first left enclosure1441, the first right enclosure1461, the second left enclosure1442, or the second right enclosure1462, but are arranged in the vicinity of the distributor214.

The transmitter subunit122a1and the receiver subunit124a1are arranged in the left enclosure1441of the first path1421. The transmitter subunit122b1and the receiver subunit124b1are arranged in the right enclosure1461of the first path1421. The transmitter subunit12222and the receiver subunit124a2are arranged in the left enclosure1442of the second path1422. The transmitter subunit122b2and the receiver subunit124b2are arranged in the right enclosure1462of the second path1422.

An antenna module2621arranged in the first left enclosure1441includes the transmitter subunit122a1and the receiver subunit124a1. An antenna module2641arranged in the first right enclosure1461includes the transmitter subunit122b1and the receiver subunit124b1. An antenna module2622arranged in the second left enclosure1442includes the transmitter subunit12222and the receiver subunit124a2. An antenna module2642arranged in the second right enclosure1462includes the transmitter subunit122b2and the receiver subunit124b2.

In the antenna modules2621,2641,2622, and2642, all of the transmitter modules10and the receiver modules20are controlled by the chirp signal and the clock signal supplied from the signal generator module30and the trigger signal supplied from the processor90. Thus, since the signal generator module30is used in common for a plurality of inspection lanes, the cost can be reduced, and since the inspection lanes are in synchronization, the effects of unexpected interference can be suppressed.

In order to avoid mutual interference due to the transmit antennas16transmitting the radar signals at the same timing, the processor90selectively supplies the trigger signal to parts of the transmitter modules10such that the transmit antennas16are separately driven for a certain part. An example of the parts includes time, frequency, and codes.

FIG.16is a diagram illustrating an example of transmission/reception sequence of the inspection device210according to the first embodiment.FIG.16shows an example of time division transmission of the radar signal. The processor90supplies the trigger signal to the transmitter module such that the antenna module2621arranged in the first left enclosure1441and the antenna module2641arranged in the first right enclosure1461are sequentially driven for the inspection of the second path1421. Next, the processor90supplies the trigger signal to the transmitter module such that the antenna module2622arranged in the second left enclosure1442and the antenna module2642arranged in the second right enclosure1462are sequentially driven for the inspection of the second path1422.

More specifically, for the inspection of the first path1421, the processor90supplies the trigger signal to the antenna module10ain the antenna module2621arranged in the first left enclosure1441. The transmitter module10acauses the transmit antennas16a,16b, to sequentially transmit the radar signals toward the first path1421. Next, the processor90supplies the trigger signal to the transmitter module10bin the antenna module2621. The transmitter module10bcauses the transmit antennas16a, to sequentially transmit the radar signals toward the first path1421. Next, the processor90supplies the trigger signal to the transmitter module10cin the antenna module2641arranged in the first right enclosure1461. The transmitter module10ccauses the transmit antennas16a,16b, to sequentially transmit the radar signals toward the first path1421. Next, the processor90supplies the trigger signal to the transmitter module10din the antenna module2641. The transmitter module10dcauses the transmit antennas16a, to sequentially transmit the radar signals toward the first corridor1421.

When the transmit antennas16in the antenna module2621transmit the radar signals, the processor90causes all of the receive antennas26ato26pin all of the receiver modules20a,20b,20c, and20din the antenna module2621to receive the reflected signals from the first path1421. Thus, the inspection of the first path1421finishes.

Thereafter, the processor90supplies the trigger signal to the transmitter module10ain the antenna module2622arranged in the second left enclosure1442, for the inspection of the second path1422. The transmitter module10acauses the transmit antennas16a,16b, to sequentially transmit the radar signals toward the second path1422. Next, the processor90supplies the trigger signal to the transmitter module10bin the antenna module2622. The transmitter module10bcauses the transmit antennas16a, to sequentially transmit the radar signals toward the second path1422. Next, the processor90supplies the trigger signal to the transmitter module10cin the antenna module2642arranged in the second right enclosure1462. The transmitter module10ccauses the transmit antennas16a,16b, to sequentially transmit the radar signals toward the second path1422. Next, the processor90supplies the trigger signal to the transmitter module10din the antenna module2642. The transmitter module10dcauses the transmit antennas16a, to sequentially transmit the radar signals toward the second path1422.

When the transmit antennas16in the antenna module2622transmit the radar signals, the processor90causes all of the receive antennas26ato26pin all of the receiver modules20a,20b,20c, and20din the antenna module2622to receive the reflected signals from the second path1422. Thus, the inspection of the second path1422finishes.

In such a time division driving, when the number of the inspection lanes (paths) is increased, the available time of the inspection of each lane is restricted, decreasing the inspection efficiency. The same applies in the cases of the frequency division transmission and the code division transmission.

For avoiding this, it is proposed to perform inspections of a plurality of lanes simultaneously.FIG.17illustrates another example of the transmission/reception sequence of the inspection device210according to the first embodiment.FIG.17shows an example of simultaneous transmission of the radar signals to a plurality of lanes. The processor90simultaneously drives the antenna module2621arranged in the first left enclosure1441and the antenna module2622arranged in the second left enclosure1442, and then simultaneously drives the antenna module2641arranged in the first right enclosure1461and the antenna module2642arranged in the second right enclosure1462.

In this specification, simultaneous is not limited to strict simultaneous, but includes a case where the timing of the start of driving the antenna module2641in the first right enclosure1461and the timing of the start of driving the antenna module2642in the second right enclosure1462are sifted by a few seconds.

More specifically, the processor90supplies the trigger signals to the transmitter modules10aand10bin the antenna module2621arranged in the first left enclosure1441and the transmitter modules10cand10din the antenna module2641arranged in the first right enclosure1461for the inspection of the first path1421. Simultaneously, the processor90supplies the trigger signals to the transmitter modules10aand10bin the antenna module2622arranged in the second left enclosure1442and the transmitter modules10cand10din the antenna module2642arranged in the second right enclosure1462for the inspection of the second path1422. Thus, the transmitter modules10aand10bin the antenna module2621cause the antenna modules16a,16b, . . . to sequentially transmit the radar signals toward the first path1421, and the transmitter modules10cand10din the antenna module2641cause the antenna modules16a,16b, . . . to sequentially transmit the radar signals toward the first path1421.

When the transmit antennas16in the antenna modules2621and2622transmit the radar signals, the processor90causes all of the receive antennas26in the antenna modules2621and2622to receive the reflected signals.

By transmitting the radar signals simultaneously for a plurality of lanes in this manner, a decrease in the inspection efficiency can be avoided even when the signal generator module30is used in common for the inspection of a plurality of lanes.

When a plurality of radar devices are arranged in lines, the radar signals of two adjacent radar devices may interference with each other.FIG.18illustrates an example of possible interference of the radar devices according to the first embodiment.FIG.18illustrates the conditions under which the radar signal transmitted from a transmit antenna x2of a transmitter module x1for the first path1421interferes with a reflected wave (reflected signal) of the radar signal transmitted from a transmit antenna y2of a transmitter module yl for the second path1422. In a case where a shortest path length U (2W+2L+D inFIG.18) in which the radar signal transmitted from the transmit antenna x2of the transmitter module x1for the first path1421propagates directly to a specific receive antenna for the second path1422is the same as the sum of a distance R1from the transmit antenna y2of the transmitter module y1for the second path1422to the object140and a distance R2from the object140to a specific receive antenna, the interference occurs. In other words, the interference occurs when the difference between 2W+2L+D and (R1+R2) is smaller than the distance resolution AR of the radar device, as shown in Formula 1.

W is a path width, L is a width of the enclosure144or146, and D is an interval (margin) between the first right enclosure1461and the second left enclosure1442.

R1and R2are variable depending on the position of the object140on the second path1422. The maximum value of the sum of R1and R2can be designed in advance by adjusting the viewing angles of the transmit antenna and the receive antenna. When the radar device is arranged such that the maximum value of the sum of R1and R2is smaller than 2W+2L+D, the received data at unnecessary distances can be ignored from the range data. Therefore, the interference between the paths can be avoided even when the transmission/reception sequence inFIG.17is used.

In order to avoid the interference, the path width W, the enclosure width L, and/or the margin D is set such that the condition of Formula 2 is satisfied.

In the above Formula 2, a is a value greater than ΔR.

According to the first embodiment, the cost of the radar device can be reduced by using the signal generator module30in common for the radar devices in a plurality of inspection lanes (paths). In addition, by appropriately setting the width of the inspection lanes, the width of the enclosure, and the margin between the lanes, the operation that does not decrease the inspection efficiency can be performed even without using complicated scheduling of the transmission timing for the transmission antennas in each of the inspection lanes.

Second Embodiment

FIG.19is a perspective view illustrating an example of a walk-through type inspection device230according to the second embodiment. The inspection device230includes a plurality of radar devices arranged along a plurality of paths. For the sake of illustration,FIG.19shows the inspection device230including two lanes, but the inspection device including three or more lanes is configured in the same manner.

The first left enclosure1441is arranged at the left portion of the first path1421. An enclosure240is arranged between the first path1421and the second path1422. The second right enclosure1462is arranged at the right portion of the second path1422.

The configuration of the first left enclosure1441is the same as that of the left enclosure144according to the first embodiment. The configuration of the second right enclosure1462is the same as that of the right enclosure146according to the first embodiment. The enclosure240includes both of the function of the first right enclosure1461and the function of the second left enclosure1442according to the first embodiment. While each of the first right enclosure1461and the second left enclosure1442according to the first embodiment includes antenna modules262and264including a transmitter module and a receiver module, the enclosure240according to the second embodiment includes an antenna module266including a transmitter/receiver module.

In the enclosure240, a substrate of a transmitter/receiver module250dand a substrate of a transmitter/receiver module250bare arranged so as to be parallel to, in other words, horizontal to the surfaces of the paths1421and1422. A substrate of a transmitter/receiver module250aand a substrate of a transmitter/receiver module250care arranged so as to be orthogonal to, in other words, vertical to the surfaces of the paths1421and1422. The transmitter/receiver modules250a,250b,250c, and250dare arranged to form a cuboid antenna module266.

In the transmitter/receiver modules250aand250c, thirty-two transmit antennas16are provided as a transmit antenna array in a line at one end of the transmitter/receiver modules250aand250c(substrate) and thirty-two receive antennas26are provided as a receive antenna array in a line at the other end of the transmitter/receiver modules250aand250c(substrate). In the transmitter/receiver modules250band250d, thirty-two receive antennas26are provided as a receive antenna array in a line at one end of the transmitter/receiver modules250band250d(substrate) and thirty-two transmit antennas16are provided as a transmit antenna array in a line at the other end of the transmitter/receiver modules250band250d(substrate).

The transmitter/receiver modules250aand250care arranged in a direction in which the transmit antenna16is opposed to the path1421and the receive antenna26is opposed to the path1422. The transmitter/receiver modules250band250dare arranged in a direction in which the transmit antenna16is opposed to the path1422and the receive antenna26is opposed to the path1421.

The above arrangements of the transmitter/receiver modules250a,250b,250c, and250dare examples. The transmitter/receiver modules250a,250b,250c, and250dmay be arranged other than the above, for example, in one or two straight lines, or simply in four lines. The transmit antennas16and the receive antennas26in the antenna modules262,264, and266may also be arranged other than the above, for example in one or two straight lines, or simply in four lines. A plurality of antenna modules262,264, and266may be arranged in the enclosure1441,1462, and240, respectively.

The signal generator module30is connected to the first left enclosure1441, the enclosure240, and the second right enclosure1462.

FIG.20is a block diagram illustrating an example of the electrical configuration of the inspection device230according to the second embodiment. The inspection device230includes the transmitter unit122, the receiver unit124, the transmitter/receiver unit260, the signal generator module30, and the processor90.

The configuration of the transmitter unit122is the same as that of the transmitter unit122shown inFIG.13. The configuration of the receiver unit124is the same as that of the receiver unit124shown inFIG.13.

A first output signal of the signal generator module30is supplied to the transmitter unit122(distributor130c). A second output signal of the signal generator module30is supplied to the receiver unit124(distributor132c). A third output signal of the signal generator module30is supplied to the transmitter/receiver unit260(distributor272c).

The first output signal of the distributor272cis supplied to the distributor272a. The first output signal of the distributor272ais supplied to the transmitter/receiver module250a. The second output signal of the distributor272ais supplied to the transmitter/receiver module250b. The second output signal of the distributor272cis supplied to the distributor272b. The first output signal of the distributor272bis supplied to the transmitter/receiver module250c. The second output signal of the distributor272bis supplied to the transmitter/receiver module250d.

The inspection device230includes the three antenna modules262,264, and266. The antenna module262inspects the first path1421. The antenna module264inspects the second path1422. The antenna module266includes the transmitter/receiver modules250a,250b,250c, and250d. The antenna module266inspects the first path1421and the second path1422and is arranged in the enclosure240.

The clock signal from the same signal generator module30is supplied to the antenna module262for the inspection of the first path1421, the antenna module264for the inspection of the second path1422, and the antenna module266for the inspection of the first path1421and the second path1422. Therefore, the transmissions of the radar signals for the inspection of the two paths are synchronized and the receptions of the reflected signals are synchronized.

FIG.21is a block diagram illustrating an example of the transmitter/receiver module250according to the second embodiment.FIG.21illustrates the transmitter/receiver module250a. The other transmitter/receiver modules250b,250c, and250dhave the same configuration.

The transmitter/receiver module250aincludes eight ICs12a,12b,12c,12d,12e,12f,12g, and12hfor transmission and eight ICs22a,22b,22c,22d,22e,22f,22g, and22hfor reception. The first output signal of the distributor272ais supplied to a distributor268. The first output signal of the distributor268is supplied to a distributor18g. The second output signal of the distributor268is supplied to a distributor28g.

The first output signal of the distributor18gis supplied to a distributor18c. The second output signal of the distributor18gis supplied to a distributor18f. The first output signal of the distributor18cis supplied to a distributor18a. The second output signal of the distributor18cis supplied to a distributor18b. The first output signal of the distributor18fis supplied to a distributor18d. The second output signal of the distributor18fis supplied to a distributor18e. The first output signal of the distributor18ais supplied to the IC12a. The second output signal of the distributor18ais supplied to the IC12b. The first output signal of the distributor18bis supplied to the IC12c. The second output signal of the distributor18bis supplied to the IC12d. The first output signal of the distributor18dis supplied to the IC12e. The second output signal of the distributor18dis supplied to the IC12f. The first output signal of the distributor18eis supplied to the IC12g. The second output signal of the distributor18eis supplied to the IC12h.

The first output signal of the distributor28gis supplied to a distributor28c. The second output signal of the distributor28gis supplied to a distributor28f. The first output signal of the distributor28cis supplied to a distributor28a. The second output signal of the distributor28cis supplied to a distributor28b. The first output signal of the distributor28fis supplied to a distributor28d. The second output signal of the distributor28fis supplied to a distributor28e. The first output signal of the distributor28ais supplied to the IC22a. The second output signal of the distributor28ais supplied to the IC22b. The first output signal of the distributor28bis supplied to the IC22c. The second output signal of the distributor28bis supplied to the IC22d. The first output signal of the distributor28dis supplied to the IC22e. The second output signal of the distributor28dis supplied to the IC22f. The first output signal of the distributor28eis supplied to the IC22g. The second output signal of the distributor28eis supplied to the IC22h. The clock signal from the signal generator module30is supplied to all of the ICs12for the transmission and the ICs22for the reception.

In the inspection device230, all of the transmitter modules10, the receiver modules20, and the transmitter/receiver modules250are controlled by the clock signal output by the signal generator module30. Therefore, the signal generator module30is used in common for a plurality of inspection lanes, reducing the cost.

FIG.22is a diagram illustrating an example of the connection between the IC12and the transmit antennas16according to the second embodiment. Each of the ICs12ato12his connected to four transmit antennas16.

FIG.23is a diagram illustrating an example of the connection between the IC22and the receive antennas26according to the second embodiment. Each of the ICs22ato22his connected to four transmit antennas16.

FIG.24illustrates an example of the transmit direction and the receive direction of the transmitter/receiver module250according to the second embodiment. The transmit antenna16and the receive antenna26are arranged at end portions opposed to each other of the substrate of the transmitter/receiver module250. The transmit antenna16transmits the radar signal in a viewing angle Ft around a direction Dt of the main lobe of the radiation pattern. The receive antenna26receives the reflected signal in a viewing angle Fr around a direction Dr of the main lobe of the radiation pattern. The transmit antenna16and the receive antenna26are arranged such that an example of the angle formed by the direction Dt of the main lobe of the transmit antenna16and the direction Dr of the main lobe of the receive antenna26is 90 degrees or more and 180 degrees or less. The angle may be 170 degrees or more and 180 degrees or less. When the direction Dt and the direction Dr have such a relationship, the viewing angle Ft and the viewing angle Fr do not overlap. Therefore, the reflected signal of the radar signal transmitted from the transmit antenna16of each of the transmitter/receiver modules250cannot be received by the receive antenna26of the transmitter/receiver modules250.

FIG.25illustrates a part of the transmission/reception sequence of the radar signal of the inspection device230according to the second embodiment.

During the inspection of the first path1421, the radar signal transmitted by the transmitter module10aor10barranged in the first left enclosure1441is reflected by the object1401. The reflected signal can be received by the receiver modules20aand20barranged in the first left enclosure1441. When the object1401is not present, the direct wave of the radar signal transmitted by the transmitter module10aor10barranged in the first left enclosure1441can be received by the transmitter/receiver modules250band250darranged in the enclosure240.

During the inspection of the first path1421, the radar signal transmitted by the transmitter/receiver module250aor250carranged in the enclosure240is reflected by the object1401. The reflected signal can be received by the other transmitter/receiver module250bor250darranged in the enclosure240. The radar signal transmitted by the transmitter/receiver module250aor250ccannot be received by the transmitter/receiver module250aor250citself. When the object1401is not present, the direct wave of the radar signal transmitted by the transmitter/receiver module250bor250darranged in the enclosure240can be received by the receiver modules20aand20barranged in the first left enclosure1441.

During the inspection of the second path1422, the radar signal transmitted by the transmitter/receiver module250bor250darranged in the enclosure240is reflected by the object1402. The reflected signal can be received by the transmitter/receiver modules250aand250carranged in the enclosure240. The radar signal transmitted by the transmitter/receiver module250bor250dcannot be received by the transmitter/receiver module250bor250ditself. When the object1402is not present, the radar signal transmitted by the transmitter/receiver module250bor250darranged in the enclosure240can be received by the receiver modules20cand20darranged in the second right enclosure1462.

During the inspection of the second path1422, the radar signal transmitted by the transmitter module10cor10darranged in the second right enclosure1462is reflected by the object1402. The reflected signal is received by the receiver modules20cand20darranged in the second right enclosure1462. When the object1402is not present, the radar signal transmitted by the transmitter module10cor10darranged in the second right enclosure1462can be received by the transmitter/receiver modules250aand250carranged in the enclosure240.

In the inspection device230according to the second embodiment, the transmission and reception of the first left enclosure1441and the second right enclosure1462that include the transmitter module10and the receiver module20as separate modules is different from the transmission and reception of the enclosure240that includes the transmitter/receiver module250. The receiver module20arranged in the first left enclosure1441or the second right enclosure1462can receive the reflected signal of the radar signal transmitted from the transmitter module10arranged in the same enclosure. However, the transmitter/receiver module205arranged in the enclosure240cannot receive the reflected signal of the radar signal transmitted from the transmitter/receiver module arranged in the same enclosure.

FIG.26shows an example of the transmission/reception sequence of the inspection device230according to the second embodiment. The processor90simultaneously drives the antenna module262arranged in the first left enclosure1441and the antenna module264arranged in the second right enclosure1462and then drives the antenna module266arranged in the enclosure240.

More specifically, the processor90supplies the trigger signals to the transmitter modules10aand10bin the antenna module262arranged in the first left enclosure1441and simultaneously supplies the trigger signals to the transmitter modules10cand10din the antenna module264arranged in the second right enclosure1462. Thus, the transmitter modules10aand10bin the antenna module262cause the transmit antennas16a,16b, . . . to sequentially transmit the radar signals toward the first path1421, and simultaneously the transmitter modules10cand10din the antenna module264cause the transmit antennas16a,16b, . . . to sequentially transmit the radar signals toward the second path1422.

Next, the processor90supplies the trigger signals to the transmitter/receiver modules250aand250cin the antenna module266arranged in the enclosure240, and simultaneously supplies the trigger signals to the transmitter/receiver modules250band250din the antenna module266. Thus, the transmitter/receiver modules250aand250cin the antenna module266cause the transmit antennas16a,16b, . . . to sequentially transmit the radar signals toward the first path1421, and simultaneously, the transmitter/receiver modules250band250din the antenna module266cause the transmit antennas16a,16b, . . . to sequentially transmit the radar signals toward the second path1422.

When the transmit antennas16in the antenna modules262,264, and266transmit the radar signals, the processor90causes all of the receive antennas26in the antenna modules262,264, and266to receive the reflected signals.

By transmitting the radar signals simultaneously for a plurality of lanes in this manner, a decrease in the inspection efficiency can be avoided even when the signal generator module30is used in common for the inspection of a plurality of lanes. As described above, simultaneous includes the case where the timing points of the start of the transmission for two adjacent lanes are shifted by a few seconds.

FIG.27is shows another example of the transmission/reception sequence of the inspection device230according to the second embodiment. The processor90simultaneously drives the antenna module262arranged in the first left enclosure1441and the antenna module266arranged in the enclosure240, and then simultaneously drives the antenna module264arranged in the second right enclosure1462and the antenna module266arranged in the enclosure240.

More specifically, the processor90causes the transmit antennas16a, . . . of the transmitter module10ain the antenna module262arranged in the first left enclosure1441and the transmit antennas16a, . . . of the transmitter module10bin the antenna module262to sequentially transmit the radar signals toward the first path1421, and simultaneously causes the transmit antennas16a, . . . of the transmitter module250bin the antenna module266arranged in the enclosure240and the transmit antennas16a, . . . of the transmitter/receiver module250din the antenna module266to sequentially transmit the radar signals toward the second path1422.

Next, the processor90causes the transmit antennas16a, . . . of the transmitter/receiver module250ain the antenna module266arranged in the enclosure240and the transmit antennas16a, . . . of the transmitter/receiver module250cin the antenna module266to sequentially transmit the radar signals toward the first path1421, and simultaneously causes the transmit antennas16a, . . . of the transmitter module10cin the antenna module264arranged in the second right enclosure1462and the transmit antennas16a, of the transmitter module10din the antenna module264to sequentially transmit the radar signals toward the second path1422.

When the transmitter modules10ato10dand the transmitter/receiver modules250ato250dtransmit the radar signals, the processor90causes all of the receive antennas26ato26pof all of the receiver modules20ato20dand all the receive antennas26ato26pof all of the transmitter/receiver modules250ato250dto receive the reflected signals from the first path1421and the second path1422. Thus, the inspection of the first path1421and the second path1422finishes.

The processor90inspects the first path1421and the second path1422based on the transmitted signals (chirp signals) used for the transmission of the electromagnetic waves to the first path1421and the second path1422by the transmit antennas16of the transmit/receive modules250aand250cand the received signals obtained by the received electromagnetic waves from the first path1421and the second path1422by the receive antennas26of the transmit/receive modules250band250d. More specifically, the processor90can obtain information such as a distance to a predetermined item, a direction, a position, a shape, a type, and the like by comparing the transmitted signal and the received signal. The radar device can perform the inspection by comparing the transmitted signal of the transmit antenna and the received signal of the receive antenna by using the transmit antenna and the receive antenna opposed to each other. According to the present embodiment, since the chirp signal from the signal generator module30is sequentially transmitted from all of the receive antennas16, the inspection can be performed by comparing the transmitted signals of the transmit antennas of the transmitter/receiver modules250and the received signals of the receive antennas of the transmitter/receiver modules250.

In the transmission/reception sequence inFIG.27as well, even when the signal generator module30is used in common for the inspection of a plurality of lanes, the reduction in the inspection efficiency can be avoided by simultaneously transmitting the radar signals for a plurality of lanes. As described above, simultaneous includes the case where the timing points of the start of the transmission for two adjacent lanes are shifted by a few seconds.

FIG.28illustrates a modified example of the inspection device230(FIG.19) according to the second embodiment. InFIG.19, the antenna modules of the first left enclosure1441and the antenna module of the second right enclosure1462have the same configurations. In the first left enclosure1441and the second right enclosure1462inFIG.19, the transmitter module10is arranged horizontally and the receiver module20is arranged vertically. In the enclosure240, the transmitter/receiver modules250band250dare arranged such that the receive antennas26are arranged to be opposed to the transmit antennas16of the transmitter modules10aand10bof the first left enclosure1441.

The configurations of the enclosure240and the second right enclosure1462in the modified example inFIG.28are the same as those inFIG.19. In the first left enclosure1441, the transmitter modules10aand10bare arranged vertically and the receiver modules20aand20bare arranged horizontally. Therefore, in the enclosure240, the transmitter/receiver modules250aand250care arranged such that the transmit antennas16are arranged to be opposed to the transmit antennas16of the transmitter modules10aand10bof the first left enclosure1441. The transmitter/receiver modules250dand250bare arranged such that the receive antennas26are arranged to be opposed to the receive antennas26of the receiver modules20aand20bof the first left enclosure1441. In this modified example as well, the performance same as that according to the second embodiment can be obtained.

In the enclosure240of the modified example inFIG.28, the transmitter/receiver modules250band250dmay be arranged such that the receive antennas26are arranged to be opposed to the transmit antennas16of the transmitter modules10aand10bof the first left enclosure1441.

In the second right enclosure1462in the modified example inFIG.28, the transmitter modules10cand10dmay be arranged vertically and the receiver modules20cand20dmay be arranged horizontally.

The arrangements of the transmitter module10and the receiver module20in each of the enclosures1441and1462described above are not limited to cuboid arrangements but are arbitrary. For example, these modules may be arranged linearly in one or two lines, or be arranged simply in four lines. The number of the modules is not limited to four, but may be arbitrary plural number. The arrangement of the transmitter modules250in the enclosure240is not limited to the cuboid arrangement but is arbitrary. For example, these modules may be arranged linearly in one or two lines, or be arranged simply in four lines. The number of the modules is not limited to four, but may be arbitrary plural number.

The radar device according to the second embodiment has a module configuration including the IC38having the radar function. A module includes the module10having the transmission function, the module20having the reception function, the module30having the signal generation function of the chirp signal and the clock signal, and the module250having the transmission/reception function. The signal generator module30is used in common for a plurality of inspection lanes, for example, for the first path1421and the second path1422. The module10having the transmission function is arranged in each of the first path1421and the second path1422. The module20having the reception function is arranged in each of the first path1421and the second path1422. The module250having the transmission/reception function is arranged in common for the first path1421and the second path1422. When the module250transmits the radar signal for the first path1421, the module250receives the radar signal for the second path1422but does not receive the radar signal for the first path1421. When the module250transmits the radar signal for the second path1422, the module250receives the radar signal for the first path1421but does not receive the radar signal for the second path1422. In the second embodiment, by providing the module30instead of separately providing the module10having the transmission function and the module20having the reception function in the first path1421and the second path1422, the number of the modules can be reduced and thus a low-cost and space-saving inspection device that can inspect plurality of lanes can be provided.

One application example of the inspection device is a security system. The security system is arranged in facilities where an indefinite number of people gather, such as airports, train stations, shopping malls, concert halls, exhibition halls, and the like. The security system detects whether or not the object (person or the like) is in possession of a predetermined item such as a dangerous material that is not authorized to be possessed and the like. Since the object may move and may not stay in the inspection area for a long period of time, it is desirable to accurately detect the belongings of the predetermined item in a short period of time.

The inspection device of the present embodiment can inspect the object arranged in or passing through the first area and the second area in short period of time.