JP2004120792A - Waveguide conversion structure, waveguide connection structure, primary radiator, oscillator and transmission apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide: a dielectric line waveguide converter which implements direct conversion with a circular waveguide without being enlarged and complicated; a dielectric line easy to be multilayered; a primary radiator of wide band characteristics; an oscillator easily outputting an oscillated signal through a dielectric line; and a transmission apparatus using these. <P>SOLUTION: The dielectric line is configured by arranging a dielectric strip 3 between two parallel conductor surfaces, and a terminal part of the dielectric strip 3 is inserted into a waveguide 4 just for a predetermined quantity approximately vertically to the electromagnetic wave propagation direction of the waveguide 4. Thus, mode conversion is performed between an LSM01 mode of the dielectric line and a circular TE11 mode of a circular cavity waveguide. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to a waveguide conversion structure for performing line conversion between waveguides, a connection structure between a plurality of waveguides, a primary radiator using a waveguide, an oscillator, and a transmission device using the same. It is.

A waveguide loaded with a dielectric, a dielectric line, or a hollow waveguide is used as a line of a high frequency circuit in a microwave band or a millimeter wave band, but a line converter is required when both lines are mixed. Become. Therefore, conventionally, as shown in Patent Document 1, for example, the tip of the dielectric strip of the dielectric line is tapered, and the end of the waveguide is spread in a horn shape, thereby connecting the dielectric line to the dielectric line. A line conversion section with the waveguide was configured.

In addition, when a circuit is formed using a large number of dielectric lines, a structure is required that not only arranges dielectric strips on the same plane but also propagates signals from one plane to another plane. Therefore, conventionally, as shown in Patent Document 2, a hole is formed in a conductor plate at an intersection where a plurality of dielectric lines are to be three-dimensionally cross-layered, and a dielectric strip is cut and opened at a position facing the hole. The radio wave reflector was arranged to face the open end.

In addition, as an antenna device for transmitting and receiving electromagnetic waves in the millimeter-wave band and the microwave band, a dielectric resonator is arranged near the end of the dielectric strip and on an extension of the dielectric strip, and the dielectric strip and the dielectric resonator are arranged. Patent Document 3 discloses an antenna device in which a primary radiator is formed by forming a slot in one conductor plate sandwiching the same, and a dielectric lens is arranged in the axial direction of the dielectric resonator.
Japanese Patent Application No. 6-205424 JP-A-8-181502 JP-A-8-316727

However, in the structure of the dielectric line waveguide converter disclosed in Patent Document 1, it is necessary to process the end face of the dielectric strip of the line conversion part and the metal parts of the dielectric line and the waveguide into special shapes. Was. In addition, since the propagation direction of the electromagnetic wave between the dielectric line and the waveguide is linear, the degree of freedom in circuit design is low, and the entire circuit may be large. In addition, a rectangular waveguide is used as the waveguide, and the line conversion cannot be directly performed on the circular waveguide.

多 In the multi-stage three-dimensional intersection structure of Patent Document 2, a radio wave reflector must be provided at the three-dimensional intersection, which is structurally complicated and difficult to manufacture.

Furthermore, the primary radiator using the dielectric line disclosed in Patent Document 3 has a problem that the frequency band that can be used as the primary radiator is narrow due to the characteristics of the dielectric resonator.

An object of the present invention is to provide a waveguide conversion structure, a waveguide connection structure, a primary radiator, an oscillator, and a transmission device using these, which have solved the above-mentioned various problems.

The waveguide conversion structure of the present invention is a conversion structure between a first waveguide and a second waveguide, wherein the first waveguide is a line in which a dielectric is loaded in a conductor, and The second waveguide is a hollow waveguide, and one of the dielectrics of the first waveguide is placed in the second waveguide in a direction substantially perpendicular to the electromagnetic wave propagation direction of the second waveguide. It is configured with parts inserted or close to each other.
Further, the waveguide conversion structure of the present invention is characterized in that a predetermined amount of the end of the dielectric of the first waveguide is inserted into the second waveguide.

The waveguide conversion structure of the present invention is characterized in that the cross-sectional shape of the second waveguide is partially different in the conversion section between the first and second waveguides.

The waveguide connection structure of the present invention is constructed by providing a plurality of first waveguides in the above-described waveguide conversion structure and inserting a part of each dielectric strip into the second waveguide. It is characterized by doing.

The primary radiator of the present invention is a primary radiator in which one end of the second waveguide in the waveguide conversion structure or the waveguide connection structure is opened and the end face is an opening surface. Constitute.

In the oscillator according to the present invention, an oscillation element and a coupling conductor are provided in a second waveguide, and the coupling conductor derives an oscillation output signal of the oscillation element and couples the oscillation output signal to a resonance mode of the first waveguide. It is characterized by.

The transmitting apparatus according to the present invention includes an antenna apparatus provided with the primary radiator and an oscillator for generating a transmission signal for the antenna apparatus. The oscillator and the antenna device for transmitting the output signal of the oscillator are provided.

According to the present invention, since a radiation structure from the end of the dielectric portion of the first waveguide to the axial direction is not used, there is no unnecessary radiation, and the line conversion between the waveguides is performed with low loss. be able to. Also, since the electromagnetic wave propagation directions of the first waveguide and the second waveguide are orthogonal, the degree of freedom in designing the circuit configuration is increased, and the overall size can be reduced.

Further, according to the present invention, the end of the dielectric of the first waveguide is inserted into the second waveguide by a fixed amount, so that the first waveguide and the second waveguide are connected to each other. Can be easily adjusted.

According to the present invention, the first and second waveguides can be easily matched with each other.

Further, according to the present invention, since the plurality of first waveguides and the second waveguides constitute a waveguide connection structure, the plurality of first waveguides constitute the second waveguide. Will be connected via Therefore, by changing the insertion position (height) and the direction of the dielectric strip of the dielectric line with respect to the waveguide, the first waveguide can be easily multilayered and the propagation direction can be easily changed.

According to the present invention, a primary radiator using the first waveguide as a propagation path can be easily configured, and a wideband characteristic can be obtained.

According to the invention, the oscillation output signal of the oscillation element is converted into the propagation mode of the first waveguide through the resonance mode of the second waveguide. Therefore, the oscillation signal can be easily transmitted through the first waveguide.

According to the present invention, a small-sized, low-loss, and wide-band transmitting apparatus can be obtained.

A configuration of a dielectric line waveguide converter according to a first embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a perspective view of a main part of a dielectric waveguide waveguide converter, FIG. 2 is a diagram showing a configuration of the converter, FIG. 1A is a top view, and FIG. 1B is a BB portion in FIG. (C) is a cross-sectional view taken along the line CC in (A). In FIG. 2, reference numerals 1 and 2 denote conductor plates, respectively, and the dielectric strip 3 is arranged so as to be sandwiched between the upper and lower two conductor plates 1 and 2. The dielectric strip 3 and the conductor plates 1 and 2 constitute a non-radiative dielectric line (hereinafter, referred to as “NRD guide”). The conductor plate 1 is formed with a cylindrical hole having an inner diameter φa and a length L. The conductor plate 2 has a recess having an inner diameter of φa at the same depth as the height of the dielectric strip 3. A circular hollow waveguide 4 is formed by the holes of the conductor plate 1 and the recesses of the conductor plate 2 in a state where the conductor plates 1 and 2 are stacked.

FIG. 1 shows the positional relationship between the inner surface of the hollow waveguide 4 and the dielectric strip 3 of the NRD guide. With the above configuration, a structure in which a fixed amount of the end of the dielectric strip of the NRD guide is inserted into the inside of the circular hollow waveguide having the upper surface in the drawing as the opening surface.

内径 The inner diameter φa of the circular cavity waveguide uses a value standardized according to the frequency band. For example, in the 76 GHz band, φa = 2.8 mm. The insertion amount E of the dielectric strip 3 shown in FIG. 2B into the waveguide is 0.9 mm. The length L from the upper surface of the dielectric strip 3 to the opening surface of the waveguide 4 is 1.0 mm. The length L is (λg / 4) · n (n is an integer of 1 or more), where λg is the guide wavelength of the waveguide 4. As a result, the upper surface of the dielectric strip 3, which has returned by an amount corresponding to 1/4 wavelength from the opening surface of the waveguide 4, is equivalently a short-circuit surface, and the end of the upper conductor plate of the NRD guide is discontinuous in the waveguide. And the alignment between the NRD guide and the waveguide is facilitated.

に お い て In FIG. 1, the solid arrow indicates the electric field distribution, and the broken line perpendicular thereto indicates the magnetic field distribution. The basic mode of the NRD guide is the LSM01 mode, in which the magnetic field is directed in the direction of propagation of the electromagnetic wave of the dielectric strip in a direction perpendicular to the upper and lower conductor plates as shown in FIG. The fundamental mode of one circular hollow waveguide is a circular TE11 mode, and as shown in FIG. The electromagnetic field will be distributed. In this way, the LSM01 mode of the dielectric line and the TE11 mode of the circular cavity waveguide are electromagnetically coupled to perform line conversion.

FIG. 3 shows the reflection characteristics viewed from the NRD guide under this condition. As described above, by appropriately determining the insertion amount of the dielectric strip, the line conversion between the dielectric line and the waveguide can be performed in a predetermined frequency band with low reflection characteristics.

In the structure shown in FIGS. 1 and 2, the dielectric strip 3 is arranged so as to be in contact with one end face in the waveguide 4. However, depending on the design, the dielectric strip is moved from the end face of the waveguide. May float.

Next, an example of a dielectric line waveguide converter having a matching adjusting means will be described with reference to FIGS. In the example shown in FIG. 4A, a matching projection 5 is provided inside the waveguide near the upper part of the dielectric strip 3 of the NRD guide so that the inner diameter becomes narrower in the direction of the electric field of the circular TE11 mode. . Thereby, the impedance of the portion where the matching projection 5 is provided can be set to an intermediate value between the impedance of the NRD guide and the impedance of the waveguide, and matching between the impedance of the NRD guide and the impedance of the waveguide 4 can be achieved. It can be easily achieved.
In the example shown in FIG. 4B, a screw 6 whose amount of insertion into the waveguide can be adjusted is provided as the alignment protrusion. The adjustment of the screw 6 makes it possible to adjust the screw to an optimum alignment state.

In each of the examples described above, the tip of the dielectric strip inserted into the waveguide has a shape perpendicular to the electromagnetic wave propagation direction, but may have another shape. FIG. 5 is a plan view of the dielectric line waveguide converter. As shown in FIG. 5A, the tip of the dielectric strip 3 is tapered, or as shown in FIG. The shape may be a cylindrical surface. The matching with the waveguide can be adjusted by the tip shape of the dielectric strip 3.

Next, FIG. 6 shows the configuration of the dielectric waveguide converter according to the third embodiment. FIG. 6A is a perspective view showing the positional relationship between the inner wall surface of the waveguide and the dielectric strip of the NRD guide, and FIG. 6B is a plan view seen from the opening side of the waveguide. Unlike the dielectric waveguide converter shown in FIGS. 1 and 2, the waveguide 4 is a rectangular cavity waveguide. The electromagnetic wave propagation direction of the waveguide 4 is perpendicular to the electromagnetic wave propagation direction of the NRD guide (the upper surface direction in FIG. 6A). The dimensions a and b of the rectangular waveguide 4 may be designed to be standardized according to the frequency band to be used. In FIG. 6, a solid arrow indicates an electric field distribution, and a broken line perpendicular thereto indicates a magnetic field distribution. The fundamental mode of the NRD guide is the LSM01 mode, and the fundamental mode of the rectangular waveguide is the rectangular TE10 mode. In this example, the rectangular TE10 mode magnetic field is oriented along the direction of the LSM01 mode magnetic field of the NRD guide, and the electric field is oriented in the short side direction.

Even when a rectangular cavity waveguide is used in this manner, the insertion amount of the dielectric strip 3 into the waveguide 4 and the length from the upper surface of the dielectric strip 3 to the opening surface of the waveguide 4 (height) ) To achieve matching between the NRD guide and the waveguide. As in the case of the first embodiment, the alignment adjustment between the NRD guide and the waveguide is performed by providing a matching projection inside the waveguide 4 to reduce the width in the electric field direction. You may.

Next, a dielectric line connection structure according to a fourth embodiment will be described with reference to FIGS.
FIG. 7 is a cross-sectional view passing through the respective dielectric strip portions of the two dielectric lines. Reference numerals 3a and 3b denote dielectric strips arranged so as to be sandwiched between the conductor plates 1 and 2, respectively, thereby constituting two NRD guides. A cylindrical space is provided in a portion surrounded by the conductor plates 1 and 2, and the space is a circular hollow waveguide 4. End portions of the two dielectric strips 3a and 3b are inserted into the waveguide 4 by a predetermined amount. The relationship between this waveguide and the NRD guide is the same as that of the dielectric waveguide converter shown in FIG. 1, and two waveguide waveguide converters are combined by sharing the waveguide portion. Is equivalent to However, in this case, the distance L from one dielectric strip 3a to the other dielectric strip 3b is determined by equivalently setting the upper surface of the dielectric strip 3a in the figure and the lower surface of the dielectric strip 3b in the figure as a ground potential. It is provided that the two NRD guides are aligned through the tube. This structure connects the NRD guides between two different layers.

FIG. 8 shows the reflection characteristic between φa = 2.8 mm, L = 1.1 mm, H = 1.8 mm, E = 0.4 mm in FIG. 7 and the two NRD guides as input / output ports. S11 and transmission characteristics S21 are obtained. In this example, a low insertion loss characteristic is obtained over a wide band of 70 to 75 GHz, and the reflection loss is the smallest in the 73 GHz band. In this manner, two NRD guides can be connected to each other with a low reflection and low insertion loss in a predetermined frequency band.

Next, a dielectric line connection structure according to a fifth embodiment will be described with reference to FIGS.
FIG. 9 is a cross-sectional view through each of the dielectric strip portions as in FIG. In this example, dielectric strips 3a, 3b, 3c of three NRD guides are inserted into a single waveguide 4 by a predetermined amount. With this structure, three layers are connected to each other by two layers. FIG. 10 shows φa = 2.8 mm, L = 1.1 mm, H = 1.8 mm, E = 0.4 mm in FIG. 9 and the characteristics of S11, S21, and S31 using the above three NRD guides as ports. Is shown. In this example, in the 78 GHz band, there is little reflection as viewed from port # 1 and low insertion loss characteristics to port # 2 and port # 3 are obtained.

FIGS. 11 and 12 are views showing the dielectric line connection structure and the characteristics thereof according to the sixth embodiment. FIG. 11 is a cross-sectional view passing through each of the dielectric strip portions as in FIG. In this example, dielectric strips 3a, 3b, 3c of three NRD guides are inserted into a single waveguide 4 by a predetermined amount. However, unlike FIG. 9, the positions (layers) of the three dielectric strips are different from each other. With this structure, a structure is obtained in which three NRD guides are connected to each other by three layers. FIG. 12 shows φa = 2.8 mm, L1 = 4.8 mm, L2 = 1.1 mm, H = 1.8 mm, and E = 0.4 mm in FIG. 10, and the above three NRD guides are used as ports, respectively, and S11 and S21 are used. , S31. In this example, in the 75 GHz band, the reflection seen from the port # 1 is small, and the insertion loss from the port # 1 to the port # 2 is the smallest. The insertion loss from the port # 1 to the port # 3 is slightly increased due to the mismatch, but can be used sufficiently depending on the purpose of use.

7, FIG. 9, FIG. 9, and FIG. 11 show the positional relationship of the respective dielectric strips as cross-sectional views, but they can be arranged as shown in FIG. 13 in plan view. In FIG. 13A, two dielectric strips 3a and 3b are arranged on the same line in a plan view. In the example of (B), the angle of intersection of the axes of the dielectric strips 3a and 3b is θ, and the electromagnetic wave propagation direction is changed by θ. Further, in the example of (C), three dielectric strips are arranged in a predetermined angular relationship with each other. The waveguide shown in (C) uses the TE01 mode instead of the circular TE11 mode. Since this circular TE01 mode has a rotationally symmetrical electromagnetic field distribution centered on the center of the waveguide, it can be connected with a constant characteristic regardless of the angle formed by the two dielectric strips.

FIG. 14 shows a dielectric line connection structure according to the seventh embodiment. In this example, the circular cavity waveguide 4 is divided into upper and lower portions, and a bearing is provided on the flange portion to form a rotary joint structure. According to such a structure, the intersection angle θ between the two NRD guides by the dielectric strips 3a and 3b can be freely changed by 360 °. In addition, if a polarizer in which the plane of polarization of the electromagnetic wave is rotated by the applied voltage is provided inside the waveguide 4 and the applied voltage to the polarizer is controlled in accordance with the crossing angle θ, the dielectric strip 3a, The LSM01 mode of the two NRD guides according to 3b and the circular TE11 mode of the waveguide can always be optimally coupled to always obtain low insertion loss characteristics.

Next, a configuration example of the primary radiator will be described with reference to FIGS. FIG. 15 is a sectional view passing through the dielectric strip 3 in the longitudinal direction. The configuration of the NRD guide and the waveguide 4 portion by the dielectric strip 3 is basically the same as that of the dielectric line waveguide converter shown in FIGS. Here, the waveguide 4 forms a horn antenna having an upper surface in the drawing as an opening surface. The circular pattern in the figure shows the schematic radiation pattern. FIG. 16 shows an actual measurement example of the radiation pattern. As described above, a beam having a relatively wide half-value angle is formed by the structure in which one end of the circular cavity waveguide is opened.

FIG. 17 is a cross-sectional view showing the configuration of another primary radiator. In this example, a tapered portion is provided on the opening surface of the waveguide portion. With this structure, the radiation pattern is generally longer in the axial direction and shorter in the direction perpendicular to the axis. The radiation pattern can be controlled by the inclination and length of the tapered portion. Thus, a high-gain antenna device having a relatively narrow half-value angle can be configured.

FIG. 18 is a cross-sectional view showing the configuration of yet another primary radiator. In this example, a dielectric rod 7 is provided near the opening of the waveguide. According to this configuration, the antenna functions as a dielectric rod antenna, and the radiation pattern is determined by the length of the dielectric rod 7 and the tapered shape of the distal end. According to this structure, the directivity can be further sharpened as compared with the structure shown in FIG.

In each of the examples described above, a small primary radiator can be configured with a simple structure. In addition, since the antenna is not radiated from the slot by being coupled to a dielectric resonator as in the related art, broadband characteristics can be obtained.

FIG. 19 is a cross-sectional view showing the configuration of an antenna device using the above-mentioned various primary radiators. In FIG. 19, 10 is a primary radiator, and 11 is a dielectric lens. The dielectric lens 11 is provided coaxially with the primary radiator 10. With this structure, it is possible to further increase the directivity and obtain a high gain.

Next, FIG. 20 shows an example of a primary radiator that performs polarization control. 20A is a top view as viewed from the opening surface, and FIG. 20B is a front view. The relationship between the circular cavity waveguide and the NRD guide is the same as that shown in FIG. 1, FIG. 2 or FIG. 15, but in this example, the intersection angle in the plan view with respect to the axial direction of the dielectric strip 3 is approximately The inside of the waveguide is projected in the direction of 45 °, and this is provided as a degenerate separation element 8. The degenerate element 8 generates two modes that are in a degenerate relationship, and gives a difference between the phases of the electric field and the magnetic field. This emits electromagnetic waves of circular polarization (including elliptical polarization). Therefore, when a transmission signal in the LSM01 mode is propagated from the NRD guide, a circularly polarized electromagnetic wave is emitted. When a circularly polarized electromagnetic wave is incident, the received signal propagates through the NRD guide in the LSM01 mode according to the reversibility theorem of the antenna.

FIG. 21 is a diagram showing the configuration of another primary radiator that performs polarization control. In this example, a polarizer 12 is provided inside the waveguide 4. The polarizer 12 rotates the polarization plane by a predetermined angle, and the polarization plane of the circular TE11 mode of the circular cavity waveguide determined by the direction of the dielectric strip 3 is rotated by the polarizer 12 and emitted. The incident wave is swirled by the polarizer 12 and is coupled to the LSM01 mode of the NRD guide.

FIG. 22 is a diagram showing a configuration of a primary radiator that performs another polarization control. FIG. 22A is a top view as viewed from the radiation surface, and FIG. 22B is a cross-sectional view. In this example, a slot plate 13 is provided on the opening surface of the waveguide 4. The slot plate 13 has a slot 14 formed therein. Since an electromagnetic wave is emitted from the slot 14 with the direction of the electric field in the short axis direction of the slot 14, the direction of the polarization plane can be determined by determining the direction (inclination) of the slot 14.

Next, FIG. 23 shows an example of an oscillator using a dielectric line waveguide converter. In FIG. 23, reference numerals 1 and 2 denote conductor plates, which constitute upper and lower parallel conductor surfaces of the NRD guide and the waveguide 4. Here, the waveguide 4 is used as a circular cavity resonator. The upper and lower surfaces of the dielectric strip 3 are arranged so as to be sandwiched between the parallel conductor surfaces. Since this figure is a cross-sectional view of the upper and lower conductor plates 1 and 2 and the dielectric strip 3 in a plane passing in the axial direction, no electromagnetic wave non-propagation region of the NRD guide does not appear, but both sides of the dielectric strip 3. A space is provided in the portion, the dielectric strip 3 is an electromagnetic wave propagation region, and both side portions are electromagnetic wave non-propagation regions. A gun diode 16 is attached to the conductor plate 2, one terminal is grounded to the conductor plate 2, and the other terminal is made to protrude. Reference numeral 17 denotes a disc-shaped coupling conductor, which is attached to a protruding terminal of the gun diode 16. Reference numeral 18 denotes a bias voltage supply path for the Gunn diode 16, which is attached through a hole provided in the conductor plate 1 via a dielectric having a low dielectric constant. A hollow portion whose radius is an odd multiple of 1/4 of the guide wavelength is provided in the middle of the hole, and this is used as a trap 19.

With this configuration, the oscillation output signal of the Gunn diode 16 is guided to the coupling conductor 17, and the coupling conductor 17 excites the resonance mode of the cavity resonator formed by the waveguide 4. The resonance mode of the cavity resonator is coupled to the LSM01 mode of the NRD guide, and an oscillation signal is propagated in that mode.

FIG. 24 is a sectional view showing the configuration of another oscillator. Unlike FIG. 23, this figure is a cross-sectional view in a direction in which the end face of the dielectric strip 3 can be seen. A dielectric 20 for temperature compensation is provided inside the waveguide 4 as a cavity resonator. Since the effective permittivity of the waveguide 4 in the cavity resonator is determined by the permittivity of the dielectric body 20, the resonance frequency of the cavity resonator changes according to a change in the permittivity of the temperature compensation dielectric body 20. Therefore, the dielectric constant temperature characteristic of the temperature compensating dielectric 20 may be determined so that the temperature characteristic of the oscillation frequency of the Gunn diode 16 is stabilized.

FIG. 25 is a view showing the configuration of still another oscillator, in which (A) is a sectional view and (B) is a top view of the inside of the waveguide. In this example, the circuit board 21 is arranged inside the waveguide 4 as a cavity resonator. The circuit board 21 has an electrode 23, a variable reactance element 22, and a control voltage supply path 24 for supplying a control voltage to the variable reactance element 22. A stub is provided in the control voltage supply path 24 so as to prevent the oscillation signal from sneaking into the control voltage supply unit. Since the electrode 23 is electromagnetically coupled to the coupling conductor 17, the reactance component of the variable reactance element is loaded on the gun diode 16. Therefore, the oscillation frequency of the Gunn diode 16 can be controlled by the control voltage for the variable reactance element 22.

Next, FIG. 26 shows an example of a transmission / reception module used for a millimeter-wave radar. In FIG. 26, VCO is the oscillator with variable oscillation frequency shown in FIG. The antenna is constituted by any one of the above-mentioned various primary radiators and a dielectric lens. In FIG. 26, the output signal of the VCO is transmitted from the antenna via the path of the isolator → coupler → circulator, and the signal received by the antenna is supplied to the mixer via the circulator. The mixer mixes the received signal RX with the local signal Lo distributed by the coupler, and outputs a frequency difference between the transmitted signal and the received signal as an intermediate frequency signal IF. A control circuit (not shown) modulates the oscillation signal of the VCO and obtains the distance from the IF signal to the target and the relative speed.

Next, an example of another dielectric line waveguide converter will be described with reference to FIG.
FIG. 27 is a perspective view of a main part of the dielectric waveguide converter. The portion indicated by DWG is a dielectric line (DWG) in which a dielectric is loaded (filled) in a conductive tube. 4 is a circular hollow waveguide.

に お い て In FIG. 27, the solid arrow indicates the electric field distribution, and the broken line perpendicular thereto indicates the magnetic field distribution. The basic mode of the DWG is a TE01 mode, and as shown in FIG. 27, a mode in which a magnetic field is directed in the direction of propagation of electromagnetic waves of the dielectric line in a direction perpendicular to upper and lower conductor surfaces. The fundamental mode of one circular cavity waveguide is a circular TE11 mode. Will be distributed. In this way, the TE01 mode of the dielectric line and the TE11 mode of the circular cavity waveguide are electromagnetically coupled to perform line conversion.

FIG. 28 is a comparison between the dispersion curve of the DWG used in the dielectric waveguide converter shown in FIG. 27 and the dispersion curve of the NRD guide used in the dielectric waveguide converter shown in FIG. This is an example. As shown in (B) of this figure, in the NRD guide, the parallel plate mode is not cut off in the used frequency band of 60 GHz, and the LSM01 mode used as the main propagation mode near the converter with the waveguide is The mode is converted to the parallel plate mode which is a spurious mode, and the parallel plate mode is easily generated. On the other hand, as shown in (A) of the figure, in the DWG, the cutoff frequency at which the phase constant β of the parallel plate mode becomes 0 in the used frequency band of 60 GHz is higher than that of the used frequency band of 60 GHz. Due to the high frequency, the parallel plate mode is cut off in the operating frequency band, and is not affected by the parallel plate mode.

Next, a configuration example of the millimeter wave radar module will be described with reference to FIGS. FIG. 29 is a top view with the upper conductor plate removed. This millimeter wave radar module is roughly composed of units of an oscillator, an isolator, a directional coupler, a circulator, a mixer, and a primary radiator. The oscillator generates a millimeter wave signal by means of a Gunn diode. The isolator is constructed by connecting a terminator to one port of a circulator having three dielectric strips as ports as shown in the figure. That is, the millimeter wave signal from the oscillator is propagated to the directional coupler side, and the reflected signal from the directional coupler is guided to the terminator. The directional coupler has four ports based on the NRD guide, and distributes an input signal from port # 1 to port # 3 and port # 4 at a predetermined power distribution ratio. The signal from port # 3 is output to the 0 dB coupler via the circulator.

In this 0 dB coupler, even when the movable part is displaced in the direction of the arrow shown in the figure, the dielectric strip provided on the movable part side and the dielectric strip on the fixed part side are always coupled with an insertion loss of approximately 0 dB. It is a combiner. The dielectric strips on the fixed part side and the movable part side of the 0 dB coupler are sandwiched between upper and lower conductor plates to form an NRD guide. In addition, the NRD guide on the movable part side converts the line into a DWG, and the DWG and the circular hollow waveguide constitute a dielectric waveguide converter similar to that shown in FIG.
In front of the circular cavity waveguide, a dielectric lens is provided at a position separated by a predetermined distance in the axial direction. Therefore, the directional direction of the antenna changes due to the displacement of the movable part in the direction of the arrow shown in the figure.

A transmission signal from the circulator is transmitted from an antenna to a target in a predetermined directional direction. The reflected signal from the target received by the antenna is input to the mixer via the circulator as a received signal. On the other hand, the signal from port # 4 of the directional coupler is input to the mixer as a local signal, and the mixer mixes the received signal with the local signal. For example, when the signal of the oscillator takes a binary frequency f1 or f2 in time, an IF signal having a frequency component of f1-f2 corresponding to a time difference generated by a path difference between two paths is obtained. By performing signal processing on the IF signal, distance measurement to the target is performed.
The block diagram of the millimeter wave radar module shown in FIG. 29 is the same as that shown in FIG.

FIG. 30 shows the structure of the line converter between the NRD guide and the DWG. (A) is a perspective view of the entire main part, and (B) is a perspective view in a state where an upper conductive plate of (A) is removed. In FIG. 30, reference numerals 1 and 2 denote conductor plates and reference numeral 3 denotes a dielectric strip. As shown in the figure, the NRD guide, the DWG, and the line converter indicated by TR therebetween are configured by disposing the dielectric strip 3 between the upper and lower conductor plates 1 and 2.

寸 法 The height and width dimensions of the dielectric strip 3 are constant in any of the NRD guide, DWG and line converter TR. In the NRD guide portion, the distance between the opposing surfaces (conductor surfaces) of the upper and lower conductor plates is formed to a predetermined dimension smaller than the height dimension of the dielectric strip 3. This constitutes an NRD guide that propagates a single mode of the LSM01 mode. In the DWG portion, the upper and lower conductor plates 1 and 2 are overlapped, that is, the interval between the opposing surfaces is substantially zero. This constitutes a dielectric loaded line.

In the line conversion part TR, the intervals between the conductor plates are sequentially changed so that the intervals between the opposing surfaces of the upper and lower conductor plates 1 and 2 are tapered from the NRD guide portion to the DWG portion. With this structure, reflection at the input / output part of the line conversion part TR and at the middle thereof is reduced, and the reflection characteristics as the line converter are maintained well.

FIG. 31 is a diagram showing the reflection characteristics of the primary radiator of the millimeter wave radar module, FIG. 32 is a diagram showing the gain characteristics of the antenna using the primary radiator and the dielectric lens, and FIG. (B) shows the characteristics when the dielectric line of the movable portion shown in FIG. 29 is configured by an NRD guide, respectively. As described above, if the primary radiator that converts the DWG into the waveguide mode is used, there is no adverse effect due to the parallel plate mode, so that there is no periodic attenuation of the antenna gain, and good antenna characteristics can be obtained. .

In each of the embodiments, the waveguide portion is configured as a hollow waveguide, but this portion may be a waveguide filled with a dielectric material other than air.

Further, in each embodiment, an example is shown in which a predetermined amount of the dielectric portion of the dielectric line is inserted into the waveguide, but it is not always necessary to be in the “inserted” state, and the NRD guide is inserted inside the waveguide. Or a dielectric line of a dielectric line such as DWG may be arranged close to the dielectric line.

Perspective view showing the configuration of the main part of a dielectric line waveguide converter Diagram showing the configuration of the dielectric line waveguide converter Characteristic diagram of the dielectric waveguide converter The figure which shows the structure of the dielectric-waveguide waveguide converter provided with the matching adjustment means. Diagram showing the configuration of a dielectric line waveguide converter with matching adjustment A perspective view showing a configuration of a main part of a dielectric waveguide converter using a rectangular waveguide. Sectional view showing an example of a dielectric line connection structure Characteristic diagram of the same dielectric line connection structure Sectional view showing an example of a three-port dielectric line connection structure Characteristic diagram of the same dielectric line connection structure Sectional view showing another example of a three-port dielectric line connection structure. Characteristic diagram of the same dielectric line connection structure Plan view of dielectric line connection structure Sectional view showing an example of a dielectric line connection structure in which the angle relationship between input and output ports is variable Sectional view showing the configuration of the primary radiator The figure which shows the radiation pattern of the primary radiator shown in FIG. Sectional view showing the configuration of another primary radiator Sectional drawing which shows the structure of another primary radiator. Sectional view showing the configuration of an antenna device using a primary radiator The figure which shows the structure of the primary radiator provided with the polarization control means The figure which shows the structure of the primary radiator provided with the polarization control means The figure which shows the structure of the primary radiator provided with the polarization control means Sectional view showing configuration of oscillator Sectional view showing configuration of oscillator Sectional and top views showing the configuration of the oscillator Block diagram showing the configuration of the transmitting and receiving module Perspective view showing the configuration of the main part of a dielectric line waveguide converter The figure which shows the dispersion curve of the dielectric loading line DWG used by this converter, and the NRD guide as a comparative example. Diagram showing the configuration of the millimeter wave radar module Perspective view showing the structure of the line converter used in the millimeter wave radar module The figure which shows the reflection characteristic of the primary radiator of the same millimeter wave radar module, and the comparative example Diagram showing antenna gain characteristics of the same millimeter wave radar module and its comparative example

Explanation of reference numerals

1, 2-conductor plate 3-dielectric strip 4-waveguide 5-matching protrusion 6-screw 7-dielectric rod 8-degenerate separation element 10-primary radiator 11-dielectric lens 12-polarizer 13 -Slot plate 14-Slot 16-Gunn diode 17-Coupling conductor 18-Bias voltage supply path 19-Trap 20-Dielectric 21-Circuit board 22-Variable reactance element 23-Electrode 24-Control voltage supply path NRD-Non-radiative dielectric Body line DWG-dielectric loaded line

Claims (8)

A conversion structure between a first waveguide and a second waveguide,
The first waveguide is a line loaded with a dielectric in a conductor, the second waveguide is a hollow waveguide, and is substantially perpendicular to the electromagnetic wave propagation direction of the second waveguide. A waveguide conversion structure, wherein a part of the dielectric of the first waveguide is inserted into or close to the second waveguide. 2. The waveguide conversion structure according to claim 1, wherein a predetermined amount of an end of said dielectric of said first waveguide is inserted into said second waveguide. Construction. (3) The waveguide conversion structure according to (1) or (2), wherein the first waveguide and the second waveguide are matched by partially changing the cross-sectional shape of the side wall of the second waveguide. A plurality of first waveguides in the waveguide conversion structure according to any one of claims 1 to 3 are provided, and a dielectric of the first waveguide is inserted into the second waveguide. A waveguide connection structure for connecting the first and second waveguides to each other. A primary radiator in which one end of the second waveguide in the waveguide conversion structure according to any one of claims 1 to 3 or the waveguide connection structure according to claim 4 is opened. An oscillation element and a coupling conductor are provided in the second waveguide in the waveguide conversion structure according to any one of claims 1 to 3 or the waveguide connection structure according to claim 4, wherein the coupling conductor is An oscillator for deriving an oscillation output signal of the oscillation element and coupling the oscillation output signal to a resonance mode of a first waveguide. A transmission device comprising: an antenna device provided with the primary radiator according to claim 5; and an oscillator that generates a transmission signal for the antenna device. A transmission device comprising the oscillator according to claim 6, and an antenna device for transmitting an output signal of the oscillator.

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