The present invention relates to a waveguide slot array antenna device having a slot at at least one wall surface of a waveguide.
In a waveguide slot array antenna device in which a plurality of slots are formed at a wall surface of a waveguide with a rectangular sectional shape, a waveguide slot array antenna device in which a slot length is approximately ½ the wavelength, and which the slots are arranged at an interval of approximately ½ the guide wavelength (wavelength in waveguide) in a guide axis direction of the waveguide is publicly known.
In
A guide axis direction of the waveguide 1 is defined as an x-direction, a direction orthogonal to a guide axis of the waveguide 1 on a wall surface at which a slot 100 is formed is defined as a y-direction, and a normal direction of the wall surface at which the slot 100 is formed is defined as a z-direction.
A waveguide inner wall 3 and a waveguide outer wall 4 respectively show the internal surface of a broad wall surface of the waveguide 1 and the external surface of the broad wall surface of the waveguide 1.
For convenience's sake, a dimension between the waveguide inner walls in the y-direction is denoted as b, and a dimension between the waveguide outer walls is denoted as B.
A narrow wall surface 5 is a wall surface at which the slot 100 is formed.
Respective slots 101 and 102 provided to the narrow wall surface 5 of the waveguide 1 are each inclined by an angle of +τ or −τ with respect to the y-direction orthogonal to the guide axis of the waveguide 1. Adjacent slots are each disposed to be symmetrical with respect to a center line 6 in a waveguide width direction between the adjacent slots.
On this occasion, a dimension of the slot 100 in the y-direction is smaller than the dimension b between the waveguide inner walls.
Impedance is matched by setting the whole length of the slot to be approximately ½ the wavelength to cause resonance for pure resistance and arranging the slot 100 with an inclination by the angle τ as the angle of arrangement for the slot 100 with respect to the y-direction orthogonal to the guide axis of the waveguide 1 to adjust the resistance of the slot 100.
In addition, since an electric field is generated in a width direction of the slot 100, linear polarization with polarization in the guide axis direction as the main polarization is radiated by disposing the respective adjacent slots to be symmetrical with respect to the center line 6 (see Non-Patent Document 1 below).
In the case where the frequency is constant and the dimension B between waveguide outer walls and the dimension b between waveguide inner walls in the y-direction of the waveguide 1 are reduced in the waveguide slot array antenna device of Conventional Example 1, the length of the slot 100 necessary to obtain resonance characteristics is unchanged at approximately ½ the wavelength, and only the dimension B between waveguide outer walls and the dimension b between waveguide inner walls in the y-direction of the waveguide 1 are reduced.
Therefore, in
Meanwhile, a method is proposed to ensure the resonance length of a slot such that the slot does not exceed the dimension b between waveguide inner walls by using a crank-shaped slot that is bent in the guide axis direction at both end sections of the slot when the waveguide width is smaller with respect to the slot length.
In
On this occasion, the configuration is such that a dimension of the crank-shaped slot 200 in the y-direction does not exceed a dimension b between waveguide inner walls (see Patent Document 1 below).
Although it is mentioned that the crank-shaped slot 200 is a configuration at the wall surface of the coaxial line 201 described above for resonating the slot 200 in a slot array antenna formed with the crank-shaped slot 200, a method of impedance adjustment for the slot 200 is neither disclosed nor implied.
Particularly, when the crank-shaped slot 200 is used in a waveguide slot array antenna, states of a current flowing in the wall surface of the coaxial line 201 and the waveguide wall surface are different, and an operation of the slots 200 is different accordingly.
Particularly in the case where the crank-shaped slot 200 is applied to a waveguide slot array antenna provided with the slot 100 at the narrow wall surface 5 of the waveguide 1 as shown in
Due to this, the bent end section largely blocks a current flowing in the direction y orthogonal to the guide axis of the waveguide 1, thus increasing conductance per single slot.
Thus, in the case where it is necessary to increase the number of slots provided per waveguide, impedance cannot be matched with a waveguide bonding section.
In addition, assuming that the polarization in the guide axis direction is the main polarization, the cross polarization component of a radiation pattern of a single slot increases due to an increase in the electric field component orthogonal to the main polarization generated from the bent end section.
Since the conventional waveguide slot array antenna device is configured as described above, the conductance per single slot increases due to the bent end section of the crank-shaped slot 200 largely blocking the current flowing in the direction y orthogonal to the guide axis of the waveguide 1.
Thus, in the case where it is necessary to increase the number of slots provided per waveguide, there has been a problem that impedance cannot be matched with the waveguide bonding section.
In addition, assuming that the polarization in the guide axis direction is the main polarization, there has been a problem that the cross polarization component of the radiation pattern of the single slot increases due to the increase in the electric field component orthogonal to the main polarization generated from the bent end section.
The present invention has been made to solve the problems described above, and an object of the invention is to obtain a waveguide slot array antenna device with a small cross polarization component and capable of impedance matching even in the case where the number of slots provided per waveguide is increased while the waveguide width is restricted to be short with respect to the slot length.
In a waveguide slot array antenna device of the invention, when a direction orthogonal to a guide axis at a surface of a waveguide at which a slot is provided is denoted as a waveguide width direction, a middle section of the slot is placed in the waveguide width direction, and at least one of tip sections of the slot has a shape extending along a guide axis direction of the waveguide, and a part of the tip section of the slot extending along the guide axis direction is configured to overlap with an inner wall of the waveguide when seen from a normal direction of the surface of the waveguide at which the slot is provided.
According to the invention, the part of the tip section of the slot extending along the guide axis direction is configured to overlap with the inner wall of the waveguide.
Thus, the conductance of the single slot can be reduced by adjusting the joined amount of the tip section of the slot and the inner wall of the waveguide.
Thus, even in the case where the number of slots provided per waveguide is increased while the waveguide width is restricted to be short with respect to the slot length, impedance matching with a waveguide bonding section can be taken.
In addition, it can be necessarily configured such that the middle section of the slot is long and that the tip section extending along the guide axis direction is short.
Thus, regarding components forming a radiation pattern, there is an advantageous effect such that cross polarization component thereof can be reduced, because contribution of an electric field generated at the middle section of the slot is larger, while contribution of an electric field generated at the tip section of the slot is smaller.
In the following, in order to describe the present invention in more detail, embodiments for carrying out the invention will be described with reference to the accompanying drawings.
In
A guide axis direction of the waveguide 1 is defined as an x-direction, a direction orthogonal to a guide axis of the waveguide 1 on a wall surface at which a slot 10 is formed is defined as a y-direction, and a normal direction of the wall surface at which the slot 10 is formed is defined as a z-direction.
A waveguide inner wall 3 and a waveguide outer wall 4 respectively show an internal surface of a broad wall surface of the waveguide 1 and an external surface of the broad wall surface of the waveguide 1.
For convenience's sake, the dimension between waveguide inner walls in the y-direction is denoted as b, and the dimension between waveguide outer walls is denoted as B.
A narrow wall surface 5 is the wall surface at which the slot 10 is formed.
In
The slot 11 has a crank shape in which the angle between the middle section 13 and the bent end section 14 or 15 at a tip section thereof is a right angle.
The whole length of the slot 11 is approximately ½ a wavelength thereof.
When the inner side of the bent end sections 14 and 15 of the slot 11 is denoted as P1 and the outer side thereof is denoted as P2, the inner side P1 exists on the inner side in the waveguide 1 relative to the waveguide inner wall 3, and the outer side P2 exists on the outer side in the waveguide 1 relative to the waveguide inner wall 3.
Note that a shaded section is a portion of the bent end sections 14 and 15 that penetrates into the waveguide when the slot 11 is seen from above and is a joining section P3 between the slot 11 and the interior of the waveguide 1.
When the dimension of the slot 11 in the y-direction is denoted as Sb in
That is, the slot 11 is configured to overlap with the inner wall 3 of the waveguide 1 when the slot 11 is seen from above.
In
Next, an operation thereof will be described.
Since a high-frequency signal input to the waveguide 1 propagates in TE10 mode, a current flows in the y direction orthogonal to the guide axis in the narrow wall surface 5 of the waveguide 1.
The waveguide 1 is short-circuited, and the current becomes maximum at a location apart from the short-circuit surface 2 by approximately ¼ the guide wavelength. The slot 11 is arranged in that position.
By arranging a plurality of slots 11 and 12 at an interval of approximately ½ the guide wavelength from the position of the slot 11, the respective slots 11 and 12 are provided to block the maximum current flowing in the narrow wall surface 5.
Since the length of the slot 10 is approximately ½ the wavelength, the high-frequency signal propagated through the waveguide 1 joins with each of the plurality of slots 10, whereby the slots 10 are resonated.
On this occasion, the waveguide slot array antenna device is represented by an equivalent circuit in which the loads of the slots 10 are constituted in a parallel circuit.
In this case, since each slot 10 has a resonance length, the susceptance component of an admittance 21 of the single slot is zero.
Therefore, assuming that the number of the slots 10 within the waveguide is N (N is an arbitrary natural number), the admittance where the short-circuit surface is seen from the feeding side is N times the real part of the admittance 21 of each slot, namely the conductance.
Thus, in order to match a characteristics admittance of the waveguide 1 with a load admittance where the short-circuit surface is seen from the feeding side, when the characteristics admittance of the waveguide 1 is normalized to 1, a desired conductance per slot becomes 1/N.
When each slot 10 satisfies this condition, a radio wave is radiated efficiently from each slot 10.
Next, an effect thereof will be described.
In
Regarding a method of arranging the slot, as a portion parallel to the guide axis direction of the slot is larger, the current is largely blocked, and thus the conductance of the slot is larger,
Therefore, with a configuration in which a part of the slot 11 is protruded from the waveguide inner wall 3, adjustment of the joined amount of the bent end sections 14 and 15 of the slot 11 and the interior of the waveguide 1 is carried out, whereby the conductance of the single slot can be reduced.
In this manner, the number of slots provided per waveguide can be increased.
Further, moving both end sections of the slot 11 toward the outer side in the waveguide 1 naturally enables a configuration in which the middle section 13 of the slot 11 is long and the bent end sections 14 and 15 are short.
Therefore, regarding components forming a radiation pattern, it is possible to reduce the cross polarization level, since contribution of an electric field generated at the middle section 13 of the slot 11 is large and contribution of an electric field generated at the bent end sections 14 and 15 of the slot 11 is small.
As one example of a low conductance effect according to Embodiment 1,
Note that the whole length of the slot is adjusted such that resonance characteristics are obtained at a center frequency (f/f0=1) for each slot.
In
In addition, A1 is the characteristics of the slot 200 of Conventional Example 2, and B1 is the characteristics of the slot 10 of Embodiment 1.
From
In
In this manner, since the reduction in conductance of the single slot is achieved with the use of Embodiment 1, it is possible to obtain the low reflection coefficient even in the case where the number N of slots is increased.
In a similar manner to the above,
In
In addition, broken lines of A3 and A4 are the characteristics of the slot 200 of Conventional Example 2, and solid lines of B3 and B4 are the characteristics of the slot 10 of Embodiment 1; A3 and B3 represent main polarizations, and A4 and B4 represent cross polarizations.
In
These are one example of the calculations. By changing the amount of the joining section P3 between the interior of the waveguide 1 and the bent end sections 14 and 15 of the slot 11 shown in
As described above, according to Embodiment 1, the middle section 13 of the slot 11 is configured to protrude from the inner wall 3, and the joining section P3 between the slot 11 and the interior of the waveguide 1 is provided in the bent end sections 14 and 15 of the slot 11.
Therefore, the conductance of the single slot can be reduced by adjusting the joined amount of the bent end sections 14 and 15 of the slot 11 and the interior of the waveguide 1.
Thus, even in the case where the number of slots provided per waveguide is increased while the waveguide width is restricted to be short with respect to the slot length, impedance matching with a waveguide bonding section can be taken.
Moreover, it can be necessarily configured such that the middle section 13 of the slot 11 is long and that the bent end sections 14 and 15 extending along the guide axis direction is short.
Thus, regarding the components forming the radiation pattern, the cross polarization component can be reduced, since the contribution of the electric field generated at the middle section 13 of the slot 11 is large and the contribution of the electric field generated at the bent end sections 14 and 15 of the slot 11 is small.
In the figure, a slot 30 is formed in a Z-shape at a narrow wall surface 5 of a waveguide 1.
A middle section 33 of a slot 31 provided to the narrow wall surface 5 of the waveguide 1 is placed to be inclined by an angle τ with respect to the y-direction orthogonal to a guide axis of the waveguide 1, and bent end sections 34 and 35 at both ends of the middle section 33 extend parallel to a guide axis direction of the waveguide 1.
The slot 31 has a Z-shape in which an angle between the middle section 33 and the bent end section 34 or 35 at a tip section thereof is an acute angle.
The whole length of the slot 31 is approximately ½ the wavelength.
A shaded section is a portion of the bent end sections 34 and 35 that penetrates into the waveguide when the slot 31 is seen from above and is a joining section P3 between the slot 31 and the interior of the waveguide 1.
An electric field E1 of the middle section 33 of the slot 31 is generated in a width direction of the slot 31 and is decomposed into an electric field E2 and an electric field E3 as components respectively in the x-direction and y-direction. Also, E4 is an electric field of the bent end sections 34 and 35 of the slot. Those similar to the above are denoted by the same reference numerals, and descriptions thereof will be omitted.
Next, an operation thereof will be described.
First, a conductance thereof will be described.
Since a degree of blockage of a current by the slot 31 can be also adjusted by changing the angle τ of the middle section 33 of the slot 31, it is possible to further adjust the conductance.
Thus, even in the case where the number of slots provided per waveguide is increased, impedance matching with a waveguide bonding section can be taken.
Next, a cross polarization thereof will be described.
Assuming that a polarization in the guide axis direction is a main polarization, the middle section 33 of the slot 31 is at the angle τ in order to achieve a desired conductance.
The electric field E1 generated from the middle section 33 of the slot 31 at this time is generated in the slot width direction.
Therefore, a cross polarization component is generated from the middle section 33 of the slot 31 depending on the angle τ of the middle section 33.
The electric field E1 generated at the middle section 33 of the slot 31 can be decomposed into and considered as the electric field E2 that is the guide axis component and the electric field E3 that is the component orthogonal to the guide axis.
On the other hand, from the bent end sections 34 and 35 of the slot 31, the electric field E4 is generated in a direction perpendicular to the guide axis.
Thus, by forming the slot 31 to be in a Z-shape, the electric field E3 that is the component in the waveguide width direction of the electric field E1 generated from the middle section 33 of the slot 31 and the electric field E4 generated from the bent end sections 34 and 35 of the slot 31 are synthesized to cancel out the cross polarization component. Therefore, it is possible to reduce the cross polarization component.
As described above, according to Embodiment 2, the middle section 33 of the slot 31 is placed to be inclined by the angle τ with respect to the y-direction orthogonal to the guide axis of the waveguide 1.
Therefore, in addition to the effect of Embodiment 1, it is possible to adjust further the conductance, since the degree of blockage of the current by the slot 31 can be also adjusted by changing the angle τ of the middle section 33 of the slot 31.
Thus, even in the case where the number of slots provided per waveguide is increased while the waveguide width is restricted to be short with respect to the slot length, impedance matching with a waveguide bonding section can be taken.
Moreover, by forming the slot 31 to be in a Z-shape, the electric field E3 that is the component in the waveguide width direction of the electric field E1 generated from the middle section 33 of the slot 31 and the electric field E4 generated from the bent end sections 34 and 35 of the slot 31 are synthesized to cancel out the cross polarization component. Therefore, the cross polarization component can be reduced.
In the figure, a slot 40 is formed in a crank shape at a narrow wall surface 5 of a waveguide 1.
Bent end sections at both ends of slots 41 and 42 are extended parallel to a guide axis direction of the waveguide 1.
An angle between the middle section of the slots 41 and 42 and the bent end section at a tip section thereof is formed to be an obtuse angle. Those similar to the above are denoted by the same reference numerals, and descriptions thereof will be omitted.
In the figure, a slot 50 is formed in an L-shape at a narrow wall surface 5 of a waveguide 1.
A bent end section at one end of slots 51 and 52 extends parallel to a guide axis direction of the waveguide 1.
An angle between the middle section of the slots 51 and 52 and the bent end section at a tip section thereof is formed to be a right angle. Those similar to the above are denoted by the same reference numerals, and descriptions thereof will be omitted.
In the figure, a slot 60 is formed in an L-shape at a narrow wall surface 5 of a waveguide 1.
A bent end section at one end of slots 61 and 62 extends parallel to a guide axis direction of the waveguide 1.
The angle between the middle section of the slots 61 and 62 and the bent end section at a tip section thereof is formed to be an acute angle. Those similar to the above are denoted by the same reference numerals, and descriptions thereof will be omitted.
In the figure, a slot 70 is formed in an L-shape at a narrow wall surface 5 of a waveguide 1.
A bent end section at one end of slots 71 and 72 extends parallel to a guide axis direction of the waveguide 1.
An angle between the middle section of the slots 71 and 72 and the bent end section at a tip section thereof is formed to be an obtuse angle. Those similar to the above are denoted by the same reference numerals, and descriptions thereof will be omitted.
In the figure, a slot 80 is formed in an S shape at a narrow wall surface 5 of a waveguide 1.
A middle section of slots 81 and 82 is curved, and bent end sections at both ends extend parallel to a guide axis direction of the waveguide 1. Those similar to the above are denoted by the same reference numerals, and descriptions thereof will be omitted.
The shapes of the slots have been shown in Embodiment 1 and Embodiment 2, not limited to these, and the shapes shown in
In addition, the slots shown in
Further, although the bent end sections at both ends of the slot are extended to only either of a plus x-direction and a minus x-direction in
In
For convenience′ sake, a dimension between waveguide inner walls in a z-direction is denoted as c, and a dimension between waveguide outer walls is denoted as C.
A broad wall surface 9 is a wall surface at which slots 90 and 91 are formed.
The slots 90 and 91 are formed in a crank shape at the broad wall surface 9 of the waveguide 1.
Bent end sections at both ends of the slots 90 and 91 are extended parallel to a guide axis direction of the waveguide 1.
An angle between the middle section of the slots 90 and 91 and the bent end section at a tip section thereof is formed to be an obtuse angle.
The whole length of the slots 90 and 91 is approximately ½ the wavelength.
Note that the bent end section at one end of the slots 90 and 91 is configured to overlap with the inner wall 7 of the waveguide 1 when the slots 90 and 91 are seen from above. Those similar to the above are denoted by the same reference numerals, and descriptions thereof will be omitted.
Although the slot is placed at the narrow wall surface 5 of the waveguide 1 in Embodiment 1 and Embodiment 2, the slots 90 and 91 may be placed at the broad wall surface 9 of the waveguide 1, as shown in
Moreover, the slot may be placed at both the narrow wall surface 5 and the broad wall surface 9 of the waveguide 1.
In the figure, a waveguide slot array antenna shown in Embodiment 2 is used as one sub-array, and an array antenna is configured by arranging a plurality of the sub-arrays.
Those similar to the above are denoted by the same reference numerals, and descriptions thereof will be omitted.
Additionally, an array antenna may be configured by arranging a plurality of waveguide slot array antennas shown in Embodiment 1 and Embodiment 3 other than Embodiment 2.
Further, the following may be available: the waveguide 1 is a ridge waveguide provided with a ridge; the waveguide 1 is a coaxial waveguide that is a coaxial line; or the waveguide 1 is a dielectric-filled waveguide filled with dielectric in at least a part of the waveguide interior.
As described above, according to Embodiment 3, a degree of freedom in the design can be further provided through the modified examples of a variety of configurations, in addition to the configurations shown in Embodiment 1 and Embodiment 2.
In
In the waveguide slot array antenna device according to this embodiment in
In
In addition, the slot 10 is provided to a bottom surface 331 of the rectangular groove 303.
Note that the waveguide 300 constituted of the two recessed conductive members 301 and 302 divided by the dividing plane 330 is fabricated by applying metal plating to a member molded through resin injection molding.
Next, an operation thereof will be described.
The dividing plane 330 of the waveguide 300 in this embodiment is at the middle section of the broad wall surface 9, and a high-frequency signal input to the waveguide is propagated in TE10 mode as shown in Embodiment 1.
On this occasion, no current occurs in the middle section of the broad wall surface 9 where there is the dividing plane 330.
Thus, in this embodiment, a current flowing in the waveguide inner wall 3 is not disrupted or separated at the dividing plane 330 of the waveguide 300.
In this manner, the high-frequency signal within the waveguide is propagated without leakage from the dividing plane 330, and the high-frequency signal joins with each of the plurality of slots 10. Therefore, an efficient waveguide slot array antenna device can be achieved.
By maintaining the predetermined gap 310 at the dividing plane 330 of the waveguide 300, contact friction that occurs at a contact section of the conductive members 301 and 302 can be prevented.
In this embodiment, the two recessed conductive members 301 and 302 are fabricated by applying metal plating to the member molded by resin injection molding.
Thus, by preventing the contact friction that occurs at the contact section of the two recessed conductive members 301 and 302, peeling of the metal plating can be prevented.
When the metal plating of the waveguide 300 is peeled, propagation characteristics thereof are deteriorated, which leads to deterioration in the antenna characteristics. Therefore, preventing this in advance enables a longer durability for the antenna.
In
In this manner, when stacking the two recessed conductive members 301 and 302, the protruding section 340 for mutual contact is provided in a position sufficiently apart from the waveguide inner wall 3, whereby the predetermined gap 310 can be maintained and fixed.
Note that in
In
The spacer 341 may be sandwiched in place of the protruding section 340 in this manner, and thus the predetermined gap 310 can be maintained and fixed in a similar manner.
It should be noted that no metal plating is applied to the protruding section 340 and the spacer 341 of the conductive members 301 and 302 serving as the contact sections. This is to prevent enlargement of a peeling place of the metal plating originating from a peeling portion of the metal plating due to friction.
Incidentally, in this embodiment, the description of the manufacturing method for the conductive members 301 and 302 forming the waveguide slot array antenna device has been limited to only the resin molding, not limited to this, and a manufacturing method such as cutting, die casting, or diffusion bonding of metal may be used for the waveguide, or any free combination of these is acceptable.
As described above, according to Embodiment 4, the recessed conductive member 301 provided with the rectangular groove 303 and the recessed conductive member 302 provided with the rectangular groove 304 are opposed with the gap 310 therebetween to thus form the waveguide 300 with an approximately rectangular cross section.
Therefore, the high-frequency signal within the waveguide is propagated without leakage from the dividing plane 330, and an efficient waveguide slot array antenna device can be achieved.
Moreover, even in the case where the conductive members 301 and 302 are formed of the resin on the surface of which the metal plating is applied, the peeling of the metal plating due to the contact friction can be prevented to thus prevent the deterioration in the antenna characteristics.
In
Next, an operation thereof will be described.
In the case of the rectangular waveguide of which the waveguide cross section is ideal in Embodiment 4 described above, division is made at approximately the middle section of the broad wall surface 9 where the current flowing within the waveguide becomes zero, and thus a waveguide slot array antenna device with good efficiency can be obtained without leakage of a high-frequency signal flowing within the waveguide from the dividing plane.
However, in the case where there is an asymmetric structure such as the slot 10 at the narrow wall surface 5 of the waveguide 300, there are cases where the middle section of the broad wall surface 9 of the waveguide 300 is not necessarily ideal for the dividing plane, in the case where the waveguide cross section has become an asymmetric structure with respect to the dividing plane 330 due to a draft angle, rounding (R), or the like at the time of the resin injection molding.
In addition, when a manufacturing error occurs in the depths of the grooves 303 and 304 of the recessed conductive members 301 and 302 forming the waveguide 300, there are cases where the waveguide 300 is not divided at the middle section of the broad wall surface 9.
In
Due to the groove 350 being provided in a position O apart from a starting point S on the gap 310 side of the waveguide inner wall 3 by an odd number multiple of approximately ¼ the free space wavelength, the operation is of a choke structure that is open (with infinite impedance) at the end section O of the groove 350 at both ends of the waveguide and short-circuited at the starting point S on the gap 310 side of the guide wavelength inner wall 3.
Thus, it becomes possible to reduce leakage of a high-frequency signal from the gap 310 at the dividing plane 330 of the waveguide 300 to a minimum.
Incidentally, the adjacent groove 350 may be an adjacent sub-array or waveguide line.
It is also possible that the groove 350 provided to the conductive member 301 is provided to both the conductive members 301 and 302 or provided to only the conductive member 302. A similar operation is performed also in this case.
In
A flat conductor 360 is provided in place of the conductive member 302 and arranged to oppose the conductive member 305 while maintaining the predetermined gap 310.
With a normal operation of the choke structure as shown in
For example, as shown in
In this case, the configuration can be achieved with the single conductive member 305 forming the waveguide. Therefore, the cost for manufacturing the waveguide slot array antenna device can be reduced by about half.
As described above, according to Embodiment 5, the groove 350 is provided in the position apart from the inner wall 3 of the waveguide by an odd number multiple of approximately ¼ the free space wavelength at the usable frequency.
Therefore, even if there is a manufacturing error in the waveguide 300, the leakage of the high-frequency signal from the gap can be reduced to a minimum.
Moreover, the flat conductor 360 is arranged to oppose the conductive member 305 while maintaining the predetermined gap 310.
Therefore, the configuration can be achieved with the single conductive member 305, and the manufacturing cost can be reduced.
In the waveguide slot array antenna device according to this embodiment in
In the dielectric substrate 370, a copper foil 372 is formed on a surface of a dielectric 371 opposing the conductive member 305 except for the surface opposing a groove 306, and a copper foil 373 is formed on a back surface of the dielectric 371.
In addition, a plurality of through holes 374 that penetrate the dielectric 371 for conduction between the copper foil 372 and 373 are provided.
Thus, with the dielectric 371, the copper foil 372 and 373, and the through holes 374, a rectangular groove partially filled with the dielectric 371 is formed. Those similar to the above are denoted by the same reference numerals, and descriptions thereof will be omitted.
Next, an operation thereof will be described.
In this Embodiment 6, an operation as a waveguide is performed such that the recessed dielectric substrate 370 is opposed to the recessed conductive member 305.
In this case, the dividing plane 330 of the waveguide is determined by the thickness of the dielectric substrate 370.
Therefore, a cross sectional structure of the waveguide is a structure asymmetric with respect to the dividing plane 330 of the waveguide.
In
In this manner, a waveguide in which the loss due to leakage of a high-frequency signal from the gap 310 is suppressed and the dielectric 371 is partially filled can be obtained.
Moreover, the waveguide is easily configurable such that the dielectric 371 is partially filled within the waveguide, and the waveguide can be configured to be compact by a wavelength shortening effect in the guide wavelength of the waveguide.
As described above, according to Embodiment 6, the recessed conductive member is configured to be formed of the dielectric substrate 370 in which the rectangular groove partially filled with the dielectric 371 is formed by the dielectric 371, the copper foil 372 and 373, and the through holes 374.
Therefore, the waveguide can be downsized by the shortening effect in the guide wavelength of the waveguide due to the dielectric 371.
In the waveguide slot array antenna device according to Embodiment 7 in
At a waveguide inner wall 411 immediately under the formed slot 10, each conductor member 400 is arranged.
One side of the conductor member 400 formed in a quadrangular prism is arranged at the waveguide inner wall 411 such that an interval of the waveguide inner walls 410 and 411 immediately under the formed slot 10 is narrowed.
In
Next, an operation thereof will be described.
In
Therefore, the inductivity of a slot section is larger as the dimension d between waveguide inner walls immediately under the slot 10 is narrower.
Accordingly, it is possible to adjust the reactance component of the slot section at will.
In
One side of the conductor member 401 formed in a quadrangular prism is arranged at the waveguide inner wall 412 such that the interval of the waveguide inner walls 412 immediately under the formed slot 10 is narrowed.
In
Next, an operation thereof will be described.
When the dimension f between waveguide inner walls immediately under the slot 10 is narrowed with respect to the dimension b between waveguide inner walls not immediately under the slot 10 in
Therefore, the capacity of a slot section is larger as the dimension f between waveguide inner walls immediately under the slot 10 is narrower.
Accordingly, it is possible to adjust the reactance component of the slot section at will.
In
The bottom surface of the conductor member 402 formed in a quadrangular prism is arranged at a part of the waveguide inner wall 411 such that the interval of the waveguide inner walls 410 and 411 immediately under the formed slot 10 is narrowed. Here, those similar to the above are denoted by the same reference numerals, and descriptions thereof will be omitted.
In
The bottom surface of the conductor member 403 formed in a cylinder is arranged at a part of the waveguide inner wall 411 such that the interval of the waveguide inner walls 410 and 411 immediately under the formed slot 10 is narrowed. Here, those similar to the above are denoted by the same reference numerals, and descriptions thereof will be omitted.
In
One side of the conductor member 404 formed in a quadrangular prism is arranged at the waveguide inner wall 412 such that the interval of the waveguide inner walls 412 immediately under the formed slot 10 is narrowed. Here, those similar to the above are denoted by the same reference numerals, and descriptions thereof will be omitted.
In
One side of the conductor member 405 formed in a quadrangular prism is arranged at the waveguide inner walls 411 and 412 such that the interval of the waveguide inner walls 410 and 411 and the interval of the waveguide inner walls 412 immediately under the formed slot 10 are narrowed. Here, those similar to the above are denoted by the same reference numerals, and descriptions thereof will be omitted.
In
The recessed section 406 is a cutout in the waveguide inner wall 412 such that the interval of the waveguide inner walls 412 immediately under the formed slot 10 is broadened.
In
Incidentally, the recessed section 406 is a cutout in the waveguide inner wall 412 such that the interval of the waveguide inner walls 412 immediately under the formed slot 10 is broadened in
In
Both bottom surfaces of the conductor member 407 formed in a quadrangular prism are arranged at the waveguide inner wall 412 such that the interval of the waveguide inner walls 410 and 411 immediately under the formed slot 10 is narrowed.
In
Since the dimension d1+d2 between waveguide inner walls is smaller than the dimension d between waveguide inner walls, the interval of the waveguide inner walls 410 and 411 immediately under the formed slot 10 can be narrowed. Here, those similar to the above are denoted by the same reference numerals, and descriptions thereof will be omitted.
The examples of the shape of the conductor member for changing the dimension between waveguide inner walls are shown in
In addition, as shown in
Further, the structure for changing the dimension between waveguide inner walls may be a structure in which the waveguide inner wall is recessed to broaden the dimension between waveguide inner walls immediately under the slot as shown in
In this case also, it is possible to adjust the reactance component of the slot section at will.
As described above, according to Embodiment 7, the dimension between waveguide inner walls between the broad wall surfaces or between the narrow wall surfaces immediately under the formed slot 10 is configured to be different from the dimension between waveguide inner walls not immediately under the slot 10.
Therefore, by adjusting the dimension between waveguide inner walls between the broad wall surfaces or between the narrow wall surfaces immediately under the slot 10, the reactance component of the slot section can be adjusted at will.
It is noted that in the present invention, a free combination in the embodiments, a modification of arbitrary components in the embodiments, or an omission of arbitrary components in the embodiments is possible within a range of the invention.
In the present invention, when the direction orthogonal to the guide axis at the surface of the waveguide at which the slot is provided is denoted as the waveguide width direction, the middle section of the slot is placed in the waveguide width direction, and at least one of the tip sections of the slot has the shape extending along the guide axis direction of the waveguide, and part of the tip section of the slot extending along the guide axis direction is configured to overlap with the inner wall of the waveguide when seen from the normal direction of the surface of the waveguide at which the slot is provided, and thus the invention is suitable for a waveguide slot array antenna device formed with a slot at at least one wall surface of a waveguide.
1, 300: Waveguides, 2: Short-circuit surface, 3, 7, 410 to 412: Waveguide inner walls, 4, 8: Waveguide outer walls, 5: Narrow wall surface, 6: Center line, 9: Broad wall surface, 10 to 12, 30 to 32, 40 to 42, 50 to 52, 60 to 62, 70 to 72, 80 to 82, 90, 91: Slots, 13, 33: Middle sections, 14, 15, 34, 35: Bent end sections, 21: Admittance, 301, 302, 305: Conductive members, 303, 304, 306, 350: Grooves, 310: Gap, 330: Dividing plane, 331: Bottom surface, 340: Protruding section, 341: Spacer, 360: Flat conductor, 370: Dielectric substrate, 371: Dielectrics, 372, 373; Copper foils, 374: Through hole, 400 to 405, 407: Conductor members, 406: Recessed section.
Number | Date | Country | Kind |
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2012-077186 | Mar 2012 | JP | national |
2012-222157 | Oct 2012 | JP | national |
Filing Document | Filing Date | Country | Kind |
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PCT/JP2013/052064 | 1/30/2013 | WO | 00 |