The present invention relates to a high frequency waveguide, an antenna device, and an electronic apparatus with the antenna device.
The high frequency waveguide is normally used as a path of radio waves. The high frequency waveguide is formed by combining first and second waveguide components.
Specifically, the high frequency waveguide is formed by integrating the first and second waveguide components under a condition that openings of grooves formed on the first and second waveguide components are matched. It should be noted that the following Patent Literature 1 describes a technology related to this.
In addition, a radar device has been recently installed in the automobiles for collision avoidance and inter-vehicle distance control. The radar device is configured to obtain a detection angular range for measurement even when the automobile rounds a curve. The detection angular range includes a right angle of 15 degrees and a left angle of 15 degrees (i.e., totally 30 degrees)
The following is one of the methods of obtaining the detection angular range. An antenna is disposed in front of a transceiver through a waveguide component while being configured to move right and left with respect to the waveguide component. It should be noted that the following Patent Literature 2 (Japan Laid-open Patent Application Publication No. JP-A-2002-223113) describes a technology related to this.
Patent Literature 1: Japan Laid-open Patent Application Publication No. JP-A-2004-048486
Patent Literature 2: Japan Laid-open Patent Application Publication No. JP-A-2002-223113
The aforementioned well-known examples have a drawback that radio waves leak out of the first and second waveguide components.
Specifically, each of the first and second waveguide components includes a flange disposed on the outer periphery of the opening of the groove thereof forming the waveguide. The first and second waveguide components are integrated by welding the flanges or fixing the flanges by means of screws. However, a clearance may be formed between the flanges by mistake in the integration operation. In this case, radio waves may leak out of the clearance.
In view of the above, the present invention addresses a need to effectively inhibit radio waves from leaking out of the waveguide.
On the other hand, the aforementioned well-known examples have a drawback that the antenna device is formed in a large size.
Specifically, it is inevitable for the antenna to be formed in a remarkably large size for obtaining a large detection angular range including right and left angles respectively having roughly 15 degrees. Further, a driving space is required for driving the large antenna right and left. The antenna device is consequently formed in a remarkably large size due to the configuration of the large antenna and the driving space.
The automobiles have been recently formed in compact sizes, for instance, for coping with energy saving. It is not preferable in this tide to form the antenna device in a large size even for safety reasons. In other words, the antenna device is required to be formed in a small size.
In view of the above, the present invention addresses a need to compactly form the antenna device with a simple structure.
A high frequency waveguide according to the present invention includes first and second waveguide components, an opened groove/grooves, and a plurality of protrusions. The first and second waveguide components are opposed each other at a predetermined interval of less than λ/4 (where λ is a wavelength of radio waves to be used). The opened groove is formed on at least either of opposed surfaces of the first and second waveguide components. The protrusions are formed on at least either of the opposed surfaces of the first and second waveguide components while being disposed in a surrounding of the groove formed on at least either of the first and second waveguide components. The protrusions respectively have a height of roughly λ/4.
In short, the protrusions, respectively having a height of roughly λ/4 (where λ is a wavelength of radio waves to be used), are disposed in the outer periphery of the groove. Even when a predetermined interval (of less than λ/4) is produced between the first and second waveguide components while the groove is opened to the interval, the protrusions disposed outside the opening allow an electric field to be generated in clearances among the protrusions in a direction parallel to a top plane formed by the protruded ends of the protrusions, but prevents an electric field from being generated in clearances among the protrusions in a direction perpendicular to the top plane of the protrusions. Especially, leakage of radio waves out of the waveguide is greatly inhibited by the condition that an electric field is prevented from being generated in the direction perpendicular to the top plane of the protrusions.
Next, a high frequency waveguide of another aspect of the present invention relates to the high frequency waveguide for thus greatly inhibiting leakage of radio waves. In the high frequency waveguide, the groove is formed on the first waveguide component, whereas the protrusions are disposed on the second waveguide component while being opposed to the groove and a surrounding of the groove. The protrusions respectively have a height of roughly λ/4 (where λ is a wavelength of radio waves to be used. The phase of the radio waves can be stabilized while propagating through the waveguide, even when the first and second waveguide components are moved in a direction perpendicular to the waveguide axis.
In other words, the top plane of the protrusions respectively having a height of roughly λ/4 (where λ is a wavelength of radio waves to be used) functions as a magnetic wall for allowing an electric field to be generated in the clearances among the protrusions in a direction parallel to the top plane of the protrusions but preventing an electric field from being generated in the clearances among the protrusions in a direction perpendicular to the top plane of the protrusions. Therefore, the waveguide can be formed only by the groove formed on either of the first and second waveguide components. Further, the protrusions, respectively having a height of roughly λ/4, are uniformly expanded on a plane arranged along a direction perpendicular to a direction parallel to the waveguide axis. Therefore, a condition is achieved that a stable magnetic wall is constantly generated in front of the opening even when the first and second waveguide components are relatively displaced in a direction perpendicular to the waveguide axis. In other words, it is possible to stabilize the phase of the radio waves propagating through the waveguide. This results in formation of a high frequency waveguide less influenced by accuracy of a position of the groove.
An antenna device according to the present invention includes an antenna, a waveguide structure, and a transceiver. The antenna includes a first transceiver port and a second transceiver port. The waveguide structure is disposed behind the antenna. The waveguide structure forms a waveguide having a variable waveguide length between the first transceiver port and the second transceiver port. The transceiver is disposed behind the antenna through the waveguide structure. The transceiver is configured to emit and receive radio waves outputted from or inputted into the first and second transceiver ports of the antenna.
The waveguide structure is thus formed for changing the waveguide length. To change the waveguide length, the antenna is herein configured to be immovable whereas the waveguide structure, disposed behind the antenna, is configured to be movable. A wide detection angular range can be thereby obtained. Consequently, the antenna device can be formed in a smaller size than the well-known antennas configured to be entirely movable.
An exemplary embodiment of the present invention will be hereinafter explained. In the exemplary embodiment, an automobile is used as an electronic apparatus that an antenna device 6, including a high frequency waveguide structure, is installed.
In
The wheels 2 are configured to be driven/rotated by an engine (not illustrated in the figure) housed below a hood 3 of the main vehicle body 1.
Further, the main vehicle body 1 includes a handle (not illustrated in the figure) in an in-vehicle space 4 thereof. The handle allows a driver of the automobile to operate the wheels 2. Yet further, the main vehicle body 1 includes an antenna device 6 (see
Although explained later in detail, as illustrated in
For example, the controls include: a control of maintaining a predetermined inter-vehicle distance between the automobile and another automobile travelling ahead through a speed control of the automobile based on measurement of a distance between the automobile and another automobile travelling ahead; and a control of alarming within the in-vehicle space 4 based on a detection of a fallen object existing ahead.
The antenna device 6, illustrated in
Specifically, as illustrated in
First, the antenna 7 is formed in a flat plate shape as illustrated in
Explanation of the antenna device 6 will be continued with reference back to
Firstly, amongst the elements, the movable waveguide component 10 is formed by, for instance, a metal/resin magnetic component having a metal film plated on the surface thereof. As illustrated in
Explanation of the movable waveguide component 10 will be hereinafter further continued. As described above, the movable waveguide component 10 is formed in a fan shape. The movable waveguide component 10 includes a through hole 15 in a so-called rivet portion (i.e., a base portion) thereof. The through hole 15 allows a shaft element to penetrate therethrough for allowing the movable waveguide component 10 to be supported about the shaft element. Specifically, a small diameter portion 17 is inserted into the through hole 15. The small diameter portion 17 is formed on the front side of a cylindrical shaft 16. Prior to the insertion, the small diameter portion 17 is inserted into a through hole 19 formed in a driving component 18 illustrated in
It should be noted that
Further, a bearing 21 is disposed in the front inner part of the cylindrical shaft 16, whereas a bearing 22 is disposed in the rear inner part of the cylindrical shaft 16. A support shaft 23 is fixed to the through holes of the bearings 21, 22 while penetrating therethrough. In other words, the movable waveguide component 10 and the driving component 18 are configured to rotate about the support shaft 23.
As illustrated above, the movable waveguide component 10 and the driving component 18 are configured to rotate about the support shaft 23 while being integrally attached. The center of mass of the integrated movable parts is herein set to be in the support axle part of the support shaft 23. Therefore, the movable parts can keep a good weight balance. Consequently, it is possible to inhibit driving energy for pivoting the movable parts. This results in an advantageous effect of inhibiting power consumption.
Further, the well-balanced state of the movable parts can inhibit impact of disturbances (e.g., vibration and shock) on the antenna device 6. When installed in an automobile, the antenna device 6 receives less impact of vibration and shock. Therefore, the antenna device 6 has an advantageous effect of enhancement in reliability.
It should be noted that the support shaft 23 is fixed to a through hole 25 of a plate component 24 disposed as a front component of the transceiver 9 disposed behind the waveguide structure 8 as illustrated in
Explanation of the movable waveguide component 10 will be continued with reference back to
As illustrated in the magnetic circuit of
As described above, pivot of the driving component 18 is transferred to the movable waveguide component 10 integrated with the driving component 18. Accordingly, the movable waveguide component 10 is also configured to pivot right and left.
As described above, the immovable waveguide component 12 is disposed behind the movable waveguide component 10 thus configured to pivot right and left, while being opposed to the movable waveguide component 10 at a predetermined interval in a noncontact state.
As illustrated in
Each groove 29 includes a through hole 30 formed closer to the center part transversely separating the groove sets.
As illustrated in
A power supply port 35 of the plate component 24 is opposed to the power supply port 34. On the other hand, the immovable waveguide component 36 is integrated with the back surface of the antenna 7 disposed in front of the movable waveguide component 10, as illustrated in
As illustrated in
As illustrated in
Explanation of the antenna device 6 will be continued with reference back to
It should be noted that a casing 42, disposed in the rearmost position in
In the automobile illustrated in
First, the control unit 41 illustrated in
The radio waves W penetrate through the power supply port 35 of the plate component 24 and subsequently propagate into the power supply port 34 (see
The radio waves W are subsequently supplied from the power supply port 34 to the power supply port 32 of the immovable waveguide component 12 illustrated in
The grooves 13 of the movable waveguide component 10, illustrated in
Therefore, a waveguide of the emitted radio waves W of 76.5 GHz is formed on the back side of the movable waveguide component 10 by the opposed grooves, that is, the grooves 13 and the grooves 29 of the immovable waveguide component 12. The radio waves W propagate through the waveguide and subsequently get to the front surface of the movable waveguide component 10 through the through holes 14.
It should be noted that the movable waveguide component 10 is configured to reciprocally pivot right and left in conjunction with electrification of the electromagnetic coil 26 as described above. The waveguide length accordingly changes. The phase of the radio waves W thereby periodically changes in conjunction with pivot of the movable waveguide component 10 when the radio waves W get to the front surface of the movable waveguide component 10 through the through holes 14.
Under the condition that the phase of the radio waves W periodically changes, the radio waves W subsequently propagate into the grooves 37 (see
In other words, the circular-arc shaped grooves 13 and the transversely divided circular-arc shaped grooves 37 of the immovable waveguide component 36 illustrated in
It should be herein noted that the front surface of the movable waveguide component 10 is herein configured to reciprocally pivot right and left in conjunction with electrification of the electromagnetic coil 26, similarly to the back surface of the movable waveguide component 10 as described above. The waveguide length accordingly changes on the front surface of the movable waveguide component 10 as well. The phase of the radio waves W thereby periodically changes in conjunction with pivot of the movable waveguide component 10 when the radio waves W propagate through the waveguide.
The radio waves W subsequently get to the front surface of the immovable waveguide component 36 through the through holes 38 illustrated in
As illustrated in
Under the condition, a set of plural transceiver ports 11a and a set of plural transceiver ports 11b are transversely separated at a predetermined interval as illustrated in
As described above, it is herein important that the phase of the radio waves W supplied to the transceiver ports 11a, 11b is configured to periodically change in conjunction with pivot of the movable waveguide component 10. This is similar to the following exemplary case. Eight speaker units are separated at predetermined intervals and the phase of sounds to be outputted therefrom periodically changes in a sequential manner. A group of listeners is herein seated in front of the speaker units while being away therefrom. Further, the listeners are entirely aligned in eight columns, each of which includes plural listeners. The eight columns are transversely aligned while being opposed to the speaker units, respectively. Under the condition, a transverse position where listeners feel a strong sound is sequentially moved from center to right, then moved back to center again, further moved from center to left, and then moved back to center again. Thus, the phase of the radio waves W periodically changes similarly to the aforementioned transverse position where listeners feel a strong sound.
In other words, even when the antenna 7 is configured to be immovable, the radio waves W can be continuously forwardly emitted from the transceiver ports 11a, 11b formed on the left and right parts of the antenna 7 at the angular range including the right and left angles respectively having 15 degrees (totally 30 degrees) as described above. The radio waves W are herein emitted while a high-intensity wave portion thereof is configured to sequentially pivot within the angular range including the right and left angles respectively having 15 degrees (totally 30 degrees). When returning from a position ahead in the direction that the high-intensity wave portion is emitted, reflected waves are allowed to reversely propagate through the aforementioned path of the emitted radio waves W and get to the RF circuit unit 40.
The control unit 41 herein has information of an emission direction/angle of the radio waves W. Based on the information, the control unit 41 instantly determines whether or not an automobile travels ahead or an obstruction exists at the angle. The control unit 41 then transmits a result of the determination to the central controller installed in the main vehicle body 1 as described above.
It should be noted that direct detection of the pivot angle of the movable waveguide component 10 is preferable for enhancing accuracy in detection of the emission angle. In response, the present exemplary embodiment desirably adopts a structure and a configuration illustrated in
First, the immovable waveguide component 36 is specifically disposed in front of the movable waveguide component 10 at a predetermined interval in a noncontact state, whereas the immovable waveguide component 12 is disposed behind the movable waveguide component 10 at a predetermined interval in a noncontact state, as described above. Next, grooves formed on the components (i.e., a pair of the grooves 28 and the grooves 13, and a pair of the grooves 13 and the grooves 37, from back to front) are opposed to each other. The structure forms paths allowing the radio waves W to propagate therethrough.
The movable waveguide component 10 is herein configured to move. Therefore, it is required to produce a predetermined interval between the movable waveguide component 10 and the immovable waveguide components 36 and between the movable waveguide component 10 and the immovable waveguide component 12.
However, leakage of the radio waves may be caused when a predetermined interval is thus produced between the movable waveguide component 10 and the immovable waveguide component 36 and between the movable waveguide component 10 and the immovable waveguide component 12.
In view of the drawback, the present exemplary embodiment has a structure that a plurality of protrusions 44 are disposed on the fan-shaped movable waveguide component 10 while being arranged on the radial inner side of the respective grooves 13 (i.e., below the respective grooves 13 in
A further detailed explanation of the protrusions 44 will be continued. The protrusions 44 are protruded from the movable waveguide component 10 towards both the immovable waveguide component 36 disposed in front of the movable waveguide component 10 and the immovable waveguide component 12 disposed behind the movable waveguide component 10. The height of each protrusion 44 is set to be λ/4, which is equal to one-forth of a wavelength λ of the radio waves W propagating through the grooves 13.
Further, an interval between any adjacent two protrusions 44 is set to be less than λ/2, which is half of the wavelength λ of the radio waves W propagating through the grooves 13.
Even when the radio waves W have chances to leak to the radial inner side and the radial outer side of the grooves 13 while propagating through the grooves 13, the protrusions 44 produce an open state for the radio waves W (i.e., a state that no leakage path is left for the radio waves W). As a result, occurrence of leakage of the radio waves W to the radial inner and outer sides can be prevented.
The radio waves W consequently propagate within the waveguide formed by the grooves 13, 37. The radio waves W are then emitted ahead of the main vehicle body 1 through the transceiver ports 11a, 11b while being pivoted right and left at a predetermined angular range.
In the present exemplary embodiment, a magnetic sensor 45 is disposed closer to the protrusions 44 disposed on the radial outermost part of the movable waveguide component 10 for enhancing accuracy of the emission direction, as illustrated in
The magnetic sensor 45 includes four magnetic resistance elements 46, 47, 48, 49 and a bias magnet (not illustrated in the figure). As illustrated in
Further, ¼ pitch, i.e., one-fourth of the pitch (interval) between any adjacent two protrusions 44, is set as a distance between the center of the magnetic resistance element 46 and the center of the magnetic resistance element 49 and a distance between the center of the magnetic resistance element 47 and the center of the magnetic resistance element 48.
Under the condition, the magnetic sensor 45 is disposed in any suitable positions excluding the center of the movable waveguide component 10 (e.g., an upper right position) in a front view as illustrated in
As described above, the radio waves W are required to pivot at the angular range including the right and left angles respectively having 15 degrees (totally 30 degrees) when being emitted from the main vehicle body 1. Therefore, the magnetic sensor 45 is configured not to exceed imaginary lines extended from the protrusions 44 aligned in the transversely outermost columns even when the movable waveguide component 10 illustrated in
For example, when the movable waveguide component 10 is pivoted in the counterclockwise direction in
Based on this, the control unit 41 determines that the movable waveguide component 10 is pivoted in the counterclockwise direction. The control unit 41 counts frequency of outputs in the output point A thereafter. The control unit 41 recognizes frequency of the counterclockwise pivots of the movable waveguide component 10 based on the frequency.
On the other hand, when an output is obtained in the output point B earlier than in the output point A (a right part of the chart in
An output from the magnetic sensor 45 is supplied to the central controller of the main vehicle body 1 through the control unit 1. Based on the output, the central controller executes controls for enhancing safety during driving of the automobile by decelerating the automobile for keeping a predetermined inter-vehicle distance between the automobile and another automobile traveling ahead and by decelerating the automobile in response to detection of an obstruction existing ahead.
It should be noted that the magnetic sensor 45 is used as a positional detector unit in the aforementioned exemplary embodiment. However, a photo-detector may be used as the positional detector unit. In this case, the photo-detector is configured to emit light, and the emitted light is reflected by the protrusions 44. Therefore, the pivot angle can be detected by detecting the periodicity of the signal of the reflected light.
To detect an obstruction and the like existing in the pivot direction, a plurality of photo-detectors may be herein required or another element configured to detect the pivot direction may be herein required in addition to the aforementioned photo-detector.
Main features of the present exemplary embodiment will be hereinafter explained.
As described above, the movable waveguide component 10 is configured to relatively move with respect to the immovable waveguide components 12, 36 for changing the waveguide length. Accordingly, clearances are produced between the movable waveguide component 10 and the immovable waveguide component 12 and between the movable waveguide component 10 and the immovable waveguide component 36. The main feature of the present exemplary embodiment is to prevent radio waves from leaking through the clearances in the aforementioned condition.
In the present exemplary embodiment, the movable waveguide component 10 includes the plural protrusions 44, respectively having a predetermined size and a predetermined pitch, on the both surfaces thereof opposed to the immovable waveguide components 12, 36.
As illustrated in
The reasons for the aforementioned size-related settings are as follows. First, the sizes of the bottom surface and the opening of each groove 13, 29 are set to be less than λ/2 and the interval between the bottom surface of each groove 13 and the bottom surface of each groove 29 is set to be less than λ for stably propagating the radio waves W to be used.
Next, the height of each protrusion 44 is set to be roughly λ/4 for producing a condition that an electric field is allowed to be generated in clearances among the protrusions 44 along a direction parallel to a plane formed by the protruded ends of the protrusions 44 (hereinafter referred to as a top plane of the protrusions 44) but an electric field is prevented from being generated in the clearances among the protrusions 44 along a direction perpendicular to the top plane of the protrusions 44. Especially, the radio waves W can be prevented from leaking out of the openings of the grooves 13, 29 by producing a condition (i.e., a magnetic wall state) that an electric field is prevented from being generated along a direction perpendicular to the top plane of the protrusions 44.
Further, the distance between any adjacent protrusions 44 is set to be less than λ/2 for stabilizing the magnetic wall state.
Yet further, the interval between the movable waveguide component 10 and the immovable waveguide component 12 is set to be less than λ/4 for stabilizing an effect of preventing leakage of the radio waves W.
Although herein explained again,
Further in the present exemplary embodiment, as illustrated in
Further, each of the through holes 30 as the first input/output ports includes a first short-circuited surface 30A. The first short-circuited surface 30A is arranged on the opposite side to a corresponding one of the through holes 14 as the second input/output ports in the longitudinal direction of the groove 29. Yet further, each of the through holes 14 as the second input-output ports includes a plurality of plate-shaped protrusions 14A as a second short-circuited surface. The protrusions 14A are arranged on the opposite side to a corresponding one of the through holes 30 as the first input-output ports in the longitudinal direction of the groove 13.
Similar to the other protrusions 44, each of the plate-shaped protrusions 14A is set to have a height of roughly λ/4 (where λ is a wavelength of the radio waves W to be used).
Each of the plate-shaped protrusions 14A is set to have a height of roughly λ/4 for forming the following condition. An electric field is allowed to be generated in clearances among the plate-shaped protrusions 14A along the longitudinal direction (a transverse direction in
The radio waves W can be thereby prevented from leaking out of the through holes 14 as the second input/output ports along the longitudinal directions of the grooves 13, 29 (i.e., the transverse direction in
On the other hand, the first short-circuited surface 30A is, as described above, formed for producing the following condition. An electric field is prevented from being generated in a direction perpendicular to the top plane of the protrusions 44 respectively having a height of roughly λ/4. Further, an electric field is prevented from being generated in a direction parallel to the top plane of the protrusions 44. In other words, the radio waves W can be prevented from leaking out of the through holes 30 as the first input/output ports in the longitudinal direction of the grooves 13, 29 (i.e., along the transverse direction in
As described above,
Although herein explained again,
Next, other features of the present exemplary embodiment will be explained.
In the present exemplary embodiment, the driving component 18 is configured to reciprocate right and left in conjunction with electrification of the electromagnetic coil 26 while being integrated with the movable waveguide component 10. The radio waves W are thereby emitted ahead of the main vehicle body 1 at the angular range including the right and left angles respectively having 15 degrees (totally 30 degrees). Subsequently, the radio waves W, returning as reflected waves, are received. As a result, information of another automobile traveling ahead or an obstruction existing ahead (e.g., a fallen object) is obtained.
In this case, the information in the forward direction is vital to the main vehicle body 1. Therefore, at least the information in the forward direction is required to be obtained, for instance, even when the electromagnetic coil 26 is interrupted from being electrified due to some troubles. In other words, at least the information in the forward direction is preferably configured to be obtained in any situations because the information in the forward direction is the main information for the main vehicle body 1.
In view of the above, the present exemplary embodiment adopts the configuration illustrated in
As illustrated in
In the present exemplary embodiment, a magnet 18A is fixed to a lower left part of the driving component 18 as illustrated in
When the movable waveguide component 10 is pivoted about the support shaft 23 in the clockwise direction in the front view of
On the other hand, when the movable waveguide component 10 is pivoted about the support shaft 23 in the counterclockwise direction, the driving component 18 is also pivoted in the counterclockwise direction. In this case, the magnet 18A is moved to a position “b” illustrated on the right of the magnet 18A in
In conjunction with electrification of the electromagnetic coil 26, the movable waveguide component 10 is thus configured to pivot right and left. For example, when the electromagnetic coil 26 is interrupted from being electrified due to some troubles, the movable waveguide component 10 may stop pivoting in an intermediate position between fully pivoted positions.
In the present exemplary embodiment, however, attraction force of the magnet attraction portion 28A is applied to the magnet 18A fixed to the driving component 18 currently not receiving driving force of the electromagnetic coil 26. Therefore, the magnet 18A is forcibly attracted and pivoted to the position illustrated in
As illustrated in the front view of
At least information vital to the automobile (i.e., information in the forward direction) can be thus obtained. This is quite useful for enhancing functions of the automobile.
An antenna device 206 according to another exemplary embodiment of the present invention will be hereinafter explained with reference to
It should be noted that the main elements of the antenna device 206 of the present exemplary embodiment are similar to those of the antenna device 6 of the aforementioned exemplary embodiment 1. Therefore, the antenna device 206 will be hereinafter explained only by focusing differences from the antenna device 6. Further, an identical reference numeral is assigned to a member of the present exemplary embodiment and a member of the aforementioned exemplary embodiment when these members have an identical function. In this case, explanation of such member of the present exemplary embodiment will be hereinafter omitted for the sake of brevity of explanation.
Similarly to the antenna device 6 of the aforementioned exemplary embodiment 1, the antenna device 206 of the present exemplary embodiment is installed in the vicinity of the front center part of the main vehicle body 1 illustrated in
As illustrated in
Specifically, the antenna device 206 is formed by a variety of elements illustrated in
A waveguide structure 208 includes the disc-shaped movable waveguide component 210, the immovable waveguide component 36, and the immovable waveguide component 12. The immovable waveguide component 36 is disposed in front of the movable waveguide component 210, whereas the immovable waveguide component 12 is disposed behind the movable waveguide component 210 (see
Amongst the elements, the movable waveguide component 210 will be firstly explained. The movable waveguide component 210 is formed by, for instance, a magnet. The magnet is made of a metal or a resin, and includes a metal film plated on the surface thereof. Further as illustrated in
Explanation of the movable waveguide component 210 will be further continued. As described above, the movable waveguide component 210 is formed in a disc shape. The movable waveguide component 210 includes a through hole 215 (see
The clamper plate 219 is herein fixed to the movable waveguide component 210 while the outer periphery thereof covers the peripheral edge of the through hole 215 of the movable waveguide component 210.
As illustrated in
Further, the shaft 222 is rotatably supported by a bush 225 through bearings 223, 224 disposed back and forth.
Further, a coil 226 and a stator 227 are attached to the bush 225. Yet further, a yoke 228A and a magnet 228B are attached to the inner surface of the hub 217 opposed to the stator 227.
It should be noted that a fixation protrusion 225A is formed on the rear end of the bush 225. As illustrated in
In other words, the movable waveguide component 210 is configured to rotate in a direction depicted by the arrow A in
Explanation of the movable waveguide component 210 will be continued with reference back to
The positional detector plate 210A includes a plurality of openings 210B as a positional detector section. The openings 210B are circumferentially separated at predetermined intervals. As illustrated in
It should be noted that the rotational position of the movable waveguide component 210 may be configured to be detected by the positional detector section formed by a plurality of positional detector protrusions and a magnetic resistance element. The positional detector protrusions are herein disposed on the outer periphery of the disc-shaped movable waveguide component 210 while being separated at predetermined intervals. The magnetic resistance element is opposed to the positional detector protrusions.
Further, the main feature of the present exemplary embodiment is to prevent reduction in accuracy of detecting the rotational position to be caused by dust left attached to the positional detector section.
As specifically illustrated in
When the movable waveguide component 210 is rotated under the condition, the protrusions 244 aligned on the radial outer side circulate faster than the protrusions 244 aligned on the radial inner side. In other words, pressure gradually gets lower than the standard atmosphere towards radial outward of the movable waveguide component 210. This results in generation of wind flowing from the radial inner side to the radial outer side on the movable waveguide component 210. As a result, dust and the like are prevented from being easily accumulated in the openings 210B formed in the radial outer part of the movable waveguide component 210. In other words, it is possible to prevent reduction in accuracy of detecting the rotational position to be caused by existence of dust and the like.
As described above, the immovable waveguide component 12 illustrated in
Explanation of the antenna device 206 will be continued with reference back to
It should be noted that the casing 42, disposed in the rearmost position in
In the automobile illustrated in
In this case, the control unit 41, illustrated in
The radio waves W pass through the power supply port 35 of the plate component 9A, and subsequently propagate into the power supply port 34 (see
Accordingly, the radio waves W are supplied from the power supply port 34 to the power supply port 32 of the immovable waveguide component 12 (see
The grooves 213 of the movable waveguide component 210, explained with reference to
Therefore, the opposed grooves, that is, the grooves 213 of the movable waveguide 210 and the grooves 29 of the immovable waveguide component 12, form a waveguide for the emitted radio waves W of 76.5 GHz on the back surface of the movable waveguide component 210. The radio waves W subsequently propagating through the waveguide and propagate into the front surface of the movable waveguide component 210 through the through holes 214.
It should be noted that the movable waveguide component 210 is rotated by the motor 216 as described above. The waveguide length is accordingly changes. The phase of the radio waves W thereby periodically changes in response to rotation of the movable waveguide component 210 when the radio waves W get to the front surface of the movable waveguide component 21 through the through holes 214.
The radio waves W, thus periodically changing the phase thereof, subsequently propagate into the grooves 37 of the immovable waveguide component 36 (see
Similarly to the back surface of the movable waveguide component, the circular-arc shaped grooves 213 are formed on the front surface of the movable waveguide component 10 while being opposed to the circular-arc shaped grooves 37 transversely divided on the immovable waveguide component 36 illustrated in
The front surface of the movable waveguide component 210 is also rotated similarly to the back surface of the movable waveguide component 210. Accordingly, the waveguide length also changes on the front surface of the movable waveguide component 210. The phase of the radio waves W thereby periodically changes in response to rotation of the movable waveguide component 210 when the radio waves W propagate through the grooves 37.
The radio waves W subsequently pass through the through hole 38 illustrated in
As illustrated in
It should be noted that oblique line segments in
Obviously from
It should be noted that periods “a” and periods “b” are shown in
It should be noted that the rotation angle of the movable waveguide component 210 is preferably directly detected for enhancing accuracy in detection of the emission angle of the radio waves W to be emitted from the transceiver ports 11a, 11b. In view of the above, the present exemplary embodiment adopts an angle detector mechanism illustrated in
It should be noted that settings of the protrusions 244 according to the present exemplary embodiment illustrated in
The aforementioned movable waveguide component 10 includes the grooves 13. In the present exemplary embodiment, however, the movable waveguide component 110 includes protrusions 144, respectively having a height of roughly λ/4, in the positions where the aforementioned grooves 13 are formed in the aforementioned exemplary embodiment.
In the aforementioned exemplary embodiment 1, the grooves 13, 29 form the waveguide. On the other hand, only the grooves 29 are formed in the present exemplary embodiment. However, only the grooves 29 sufficiently achieve propagation of the radio waves W.
In the movable waveguide component 10 including uniformly arranged protrusions respectively having a height of roughly λ/4, an electric field is allowed to be generated in the clearances among the protrusions 144 along a direction parallel to the top plane of the protrusions 144. On the other hand, an electric field is prevented from being generated along a direction perpendicular to the top plane of the protrusions 144. In other words, the top plane of the protrusions 144 respectively having a height of roughly λ/4 functions as a magnetic wall. Therefore, only the grooves 29 can form a high frequency waveguide.
Further, the protrusions 144, respectively having a height of roughly λ/4, are uniformly expanded on a plane arranged along a direction perpendicular to a direction parallel to the waveguide axis. Therefore, the protrusions 144 have a function of inhibiting the radio waves W from leaking out of the waveguide. Further, the protrusions 144 can produce the following condition. A stable magnetic wall is constantly generated in front of the openings of the grooves even when the first and second waveguide components (i.e., the movable waveguide component 110 and the immovable waveguide component 12) are relatively displaced not only in a direction parallel to the waveguide axis but also in a direction perpendicular to the waveguide axis. Therefore, it is possible to achieve an advantageous effect of stabilizing the phase of the radio waves W propagating through the waveguide. In other words, it is possible to form high frequency waveguide less influenced by accuracy of groove positions.
Although not illustrated in
In the present exemplary embodiment, the movable waveguide component 110 includes the protrusions 144 in the waveguide section thereof instead of the grooves 13 formed in the aforementioned exemplary embodiment.
In the aforementioned exemplary embodiment 1, the grooves 13, 29 form the waveguide. On the other hand, only the grooves 29 are formed in the present exemplary embodiment. However, only the grooves 29 can form a waveguide and sufficiently achieve propagation of the radio waves. The waveguide length also herein changes. The phase of the radio waves also thereby changes.
In the movable waveguide component 110 including the uniformly arranged protrusions 144 respectively having a height of roughly λ/4, an electric field is allowed to be generated in the clearances among the protrusions 144 along a direction parallel to the top plane of the protrusions 144. However, an electric field is prevented from being generated along a direction perpendicular to the top plane of the protrusions 144. In other words, the top plane of the protrusions 144 respectively having a height of roughly λ/4 functions as a magnetic wall. Therefore, only the grooves 29 can form the high frequency waveguide.
Further, the protrusions 144, respectively having a height of roughly λ/4, are uniformly expanded on a plane arranged along a direction perpendicular to a direction parallel to the waveguide axis. Therefore, the protrusions 144 have a function of inhibiting the radio waves W from leaking out of the waveguide along a direction perpendicular to the waveguide axis. Simultaneously, the protrusions 144 can produce the following condition. A stable magnetic wall is constantly generated in front of the opening even when the first and second waveguide components (i.e., the movable waveguide component 110 and the immovable waveguide component 12) are displaced in a direction perpendicular to the waveguide axis. In other words, it is possible to achieve an advantageous effect of obtaining a phase shifter less influenced by accuracies in positions of the center axis of the movable members of the movable waveguide component 110 (i.e., the through hole 15, the cylindrical shaft 16, and the support shaft 23) and the like.
Although not illustrated in the figure, the relation between the movable waveguide component 110 and the immovable waveguide component 12, explained with reference to
As illustrated in
It should be noted that the movable waveguide component 210 of the aforementioned exemplary embodiment 2 may similarly include the aforementioned protrusions 244 in the groove 213. The aforementioned advantageous effects can be thereby achieved.
The present invention relates to a high frequency waveguide for inhibiting leakage of radio waves. Therefore, the present invention is highly expected to be applied to various electronic apparatuses.
Further, the present invention is designed to compactly form the antenna device without configuring the antenna component to move. Simultaneously, the present invention is designed to form the antenna device in a simple structure. Therefore, the present invention is highly expected to be further applied to, for instance, the automobiles that size and weight reductions are promoted in terms of energy saving.
Number | Date | Country | Kind |
---|---|---|---|
2008-156173 | Jun 2008 | JP | national |
2008-156175 | Jun 2008 | JP | national |
2008-156176 | Jun 2008 | JP | national |
2008-162915 | Jun 2008 | JP | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
---|---|---|---|---|
PCT/JP2009/001620 | 4/7/2009 | WO | 00 | 10/22/2010 |