JP2002232213A - Nonradiative dielectric line and millimeter-wave transmitter/receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonradiative dielectric line that is excellent in reliability with a small loss. SOLUTION: In this nonradiative dielectric line formed by inserting a dielectric line 2 between parallel planar conductors 1 and 3 arranged in an interval being equal to or less than 1/2 wavelength of a high frequency signal, the dielectric line 2 is made of ceramics whose open pore ratio is equal to or less than 5%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a nonradiative dielectric line used in a high frequency band such as a millimeter wave,
The present invention relates to a non-radiative dielectric line suitably used for a millimeter wave integrated circuit and the like, and also relates to a millimeter wave transceiver such as a non-radiative dielectric line type millimeter wave integrated circuit and a millimeter wave radar module.

[0002]

2. Description of the Related Art A conventional nonradiative dielectric line (Nonradiati
FIG. 1 shows the configuration of S1 (hereinafter, referred to as an NRD guide). NRD guide S in FIG.
Reference numeral 1 denotes a dielectric line 2 interposed between a pair of parallel plate conductors 1 and 3 having an interval d of λ / 2 or less with respect to a wavelength λ of an electromagnetic wave (high-frequency signal) propagating in the air at the operating frequency. By doing so, an electromagnetic wave can be propagated along the dielectric line 2, and the radiation wave is based on the operation principle of being suppressed by the blocking effect of the parallel plate conductors 1 and 3.

It is known that there are two types of electromagnetic wave propagation modes of the NRD guide S1, an LSM mode and an LSE mode, but an LSM mode with a small loss is generally used. As another type of the NRD guide, there is also an NRD guide S2 provided with a curved dielectric line 14 as shown in FIG. It has the advantage that it is possible to reduce the size and design circuits with a high degree of freedom.

In FIGS. 1 and 2, the upper parallel plate conductors 3, 13 are partially cut away or shown by broken lines so as to see through the inside. Reference numerals 1 and 11 are lower parallel plate conductors.

Conventionally, as materials for the dielectric lines 2 and 14 of the NRD guides S1 and S2, resins having a relative dielectric constant of 2 to 4 such as Teflon and polystyrene have been used in view of simplicity of easy processing and low loss. Materials have been used.

[0006]

However, the relative permittivity of the conventionally used Teflon, polystyrene and the like is 2 to 2.
NRD guides S1 and S
Constitution 2 has the disadvantage that bending loss at the curved portion and loss at the junction of the dielectric line are large. For this reason, a steep curved portion cannot be provided. Also,
Even in the case of a gentle curved portion, it is necessary to precisely determine the radius of curvature of the curved portion. Further, a frequency range usable with a small bending loss is, for example, 60 GHz.
In the vicinity, 1-2 GHz was not enough. This is because NRD guides S 1 and S
2, the dispersion curves of the LSM mode and the LSE mode are very close to each other.
This is because the part is converted to the LSE mode and the loss increases.

Also, as a material for the dielectric lines 2 and 14,
The relative dielectric constant of alumina (Al ₂ O ₃ ) ceramics etc. is 10
Some use ceramics of about 50 GHz
In order to use the above high frequency, the dielectric lines 2, 14
Must be very narrow, which is not practical in terms of workability and mounting.

Further, if the NRD guide is formed of a dielectric line made of a resin material such as Teflon, which has been conventionally used, it is difficult to bond the dielectric line and the parallel plate conductor, and the dielectric line is not positioned due to vibration or thermal expansion difference. There has been a problem that a shift has occurred and malfunctions have occurred.

Further, as described in Japanese Patent Application Laid-Open No. 57-166701, the cross-sectional shape of the dielectric waveguide is not limited to a rectangle, but is variously geometrically symmetric with respect to a parallel plate conductor. Although it is required in principle to have a shape, if the NRD guide is composed of a dielectric line made of a resin material such as Teflon, which has been conventionally used, the dielectric line will be deformed or misaligned due to vibration or a difference in thermal expansion. Then, there is a problem that the symmetrical shape is deformed and does not function normally.

When the relative density of the dielectric line is low, the dielectric constant becomes lower than the physical property value of the material, so that not only the desired transmission characteristics cannot be obtained, but also the open porosity becomes large, and when the line is processed, In addition, there is a problem that impurities generated in the processing step adhere to the surface of the line and deteriorate transmission characteristics, and also, moisture is adsorbed on the surface of the line due to atmospheric humidity to deteriorate transmission characteristics. Also, at the processing stage of the track, burr,
Chipping and the like occurred, and it was sometimes difficult to form a symmetrical shape. Furthermore, when the dielectric line is fixed with an adhesive, an adhesive having a large dielectric loss penetrates into an open pore portion or a chipped portion of the dielectric line, which causes a decrease in density, and attenuates a high-frequency signal to reduce transmission loss. There was a problem that it increased.

Accordingly, the present invention has been completed in view of the above circumstances, and an object of the present invention is to reduce the conversion of an LSM mode electromagnetic wave to an LSE mode, so that the dielectric line has a small radius of curvature and a usable frequency range. An object of the present invention is to provide a high-performance NRD guide capable of forming a wide steep curved portion, thereby reducing the size of a millimeter-wave integrated circuit and the like, having high reliability, and reducing loss of a high-frequency signal. Another object of the present invention is to provide a miniaturized millimeter-wave transmitter / receiver that uses such an NRD guide and has a small transmission loss of a high-frequency signal.

[0012]

A non-radiative dielectric line according to the present invention is a non-radiative dielectric line formed by interposing a dielectric line between parallel plate conductors arranged at intervals of not more than half the wavelength of a high-frequency signal. In the dielectric line, the dielectric line has an open porosity of 5%.
% Or less of ceramics.

In the NRD guide of the present invention, since the open porosity of the dielectric line is set to 5% or less, when processing the dielectric line, impurities generated in a processing step in processing the line adhere to the surface of the line. In addition, since moisture is not adsorbed on the line surface due to atmospheric humidity, transmission loss of a high-frequency signal can be reduced. In this way, a high-performance NRD guide with high reliability and small loss can be configured.

In the present invention, preferably, the dielectric line is made of a ceramic mainly composed of a composite oxide of Mg, Al, and Si, and has a Q value of 1000 or more at a measurement frequency of 60 GHz. I do.

According to the above configuration, the conversion of the LSM mode electromagnetic wave into the LSE mode is small, and therefore, a steep curved portion with a small radius of curvature and a wide frequency range can be formed on the dielectric line. NRD that can reduce the size of integrated circuits, is easy to process, and has a high degree of freedom in fabrication
Guides can be made. In addition, the transmission loss of the high-frequency signal is small, and a large number of dielectric lines with precise and stable shape accuracy can be easily manufactured from ceramics, so that the cost is low. In addition, since the relative permittivity of the dielectric line is higher than that of a resin material such as Teflon, for example, a jig for supporting the dielectric line, a circuit board, and the like are manufactured using these resin materials, and the vicinity of the dielectric line is manufactured. , It is less likely to be affected.

In the present invention, preferably, the molar ratio composition formula of the composite oxide is xMgO.yAl ₂ O ₃ .zS
iO ₂ (however, x = 10 to 40 mol%, y = 10 to 40
Mol%, z = 20-80 mol%, x + y + z = 100 mol%).

With the above configuration, the transmission loss can be further reduced, and the NR using the inexpensive and high-precision dielectric line can be reduced.
D guide can be manufactured.

In the millimeter-wave transceiver according to the present invention, a high-frequency diode oscillator is provided at one end between parallel plate conductors arranged at an interval equal to or less than half the wavelength of the millimeter-wave signal. A first dielectric line for transmitting the millimeter-wave signal, and a bias voltage application direction are arranged so as to match the direction of the electric field of the millimeter-wave signal;
A variable-capacitance diode that outputs the millimeter-wave signal as a transmission millimeter-wave signal obtained by frequency-modulating the millimeter-wave signal by periodically controlling the bias voltage; A second dielectric line, which is disposed or one end of which is joined and propagates a part of the millimeter wave signal to the mixer side, and a predetermined portion is provided on a peripheral portion of a ferrite plate disposed in parallel with the parallel plate conductor. A first connection unit, a second connection unit, and a third connection unit which are arranged at intervals and serve as input / output terminals of the millimeter wave signal, respectively, and the millimeter wave input from one of the connection units; A circulator for outputting a signal from another connection portion adjacent to the clockwise or counterclockwise direction in the plane of the ferrite plate, wherein the first connection is made to an output end of the millimeter wave signal of the first dielectric line. Department A circulator to be combined, a third dielectric line joined to the second connection part of the circulator and having the transmitting / receiving antenna at the tip while transmitting the millimeter wave signal, and the third dielectric line received by the transmitting / receiving antenna A fourth dielectric line for propagating the reception wave output from the third connection portion of the circulator to the mixer side through the third dielectric line, a midway of the second dielectric line and the fourth dielectric line. And a mixer unit that is formed by electromagnetically coupling or joining the dielectric lines in close proximity to each other and mixing a part of the millimeter wave signal and a received wave to generate an intermediate frequency signal. In the transceiver, at least one of the first to fourth dielectric lines is formed of the dielectric line of the present invention.

According to the present invention, a high-reliability, high-performance and small-sized millimeter-wave transceiver can be provided by the above configuration.

Further, in the millimeter wave transceiver according to the present invention, a high-frequency diode oscillator is provided at one end between parallel plate conductors arranged at an interval of one half or less of the wavelength of the millimeter wave signal,
A first dielectric line for transmitting a millimeter-wave signal output from the high-frequency diode oscillator, and a bias voltage application direction arranged so as to match an electric field direction of the millimeter-wave signal, and periodically controlling the bias voltage; By doing so, the variable capacitance diode that outputs the millimeter wave signal as a frequency-modulated transmission millimeter wave signal and the first dielectric line are disposed close to each other so that one end side is electromagnetically coupled or one end is joined. A second dielectric line for transmitting a part of the millimeter wave signal to the mixer side; and a ferrite plate arranged in parallel with the parallel plate conductor at a predetermined interval on a peripheral portion of the ferrite plate. A first connection portion, a second connection portion, and a third connection portion serving as signal input / output terminals, and the millimeter-wave signal input from one of the connection portions is provided on a surface of a ferrite plate; A circulator for outputting the clock signal from the other connecting portion adjacent in the clockwise or counterclockwise direction, wherein the first connecting portion is connected to the output end of the millimeter wave signal of the first dielectric line. A third dielectric line connected to the second connection portion of the circulator for transmitting the millimeter-wave signal and having a transmission antenna at the tip, a reception antenna at the tip, and a mixer at the other end. The fourth dielectric line provided is connected to the third connection part of the circulator, and the millimeter wave signal mixed and received by the transmission antenna is propagated, and the non-reflection termination part provided at the tip part is used as the fourth dielectric line. A fifth dielectric line for attenuating a millimeter wave signal, and a middle part of the second dielectric line and a middle part of the fourth dielectric line are brought close to each other and electromagnetically coupled or joined. And a mixer unit that mixes a part of the millimeter wave signal and the reception wave to generate an intermediate frequency signal, wherein at least one of the first to fifth dielectric lines is provided. It is characterized by comprising the dielectric line according to any one of Items 1 to 3.

According to the present invention, a high-reliability, high-performance and small-sized millimeter-wave transceiver can be provided by the above configuration. Also, the millimeter-wave signal for transmission does not enter the mixer via the circulator, and as a result, the noise of the received signal is reduced, and when applied to a millimeter-wave radar, the detection distance increases, and the transmission of the millimeter-wave signal is reduced. It has excellent characteristics.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The NRD guide of the present invention will be described in detail below. The NRD guide of the present invention has the same basic configuration as that of FIG. 1 and will be described below with reference to FIG. In the drawing, reference numerals 1 and 3 denote lower and upper parallel plate conductors arranged at an interval d equal to or less than half the wavelength λ of a high-frequency signal, and 2 denotes a parallel plate conductor interposed and sandwiched between the parallel plate conductors 1 and 3. It is a dielectric line, and the end faces of a plurality of dielectric line portions may be arranged facing each other at a predetermined interval. The wavelength λ corresponds to the wavelength of a high-frequency signal at the operating frequency in the air. Parallel plate conductor 1 for NRD guide S1,
No. 3 is Cu, A in terms of high electric conductivity and workability.
1, Fe, SUS (stainless steel), Ag, A
A metal plate made of u, Pt, or the like, processed by forging, casting, die casting, grinding, or the like, or an insulating plate made of ceramics, resin, or the like, on which the conductor layers are formed may be used.

In the present invention, the open porosity of the dielectric line 2 is limited to 5% or less. If the open porosity exceeds 5%, moisture absorption occurs due to the pores in the dielectric line 2 and the transmission characteristics deteriorate. In addition, the density distribution in the dielectric line 2 becomes non-uniform, and accordingly, the dielectric constant in the dielectric line 2 becomes non-uniform, thereby deteriorating the transmission characteristics. At the same time, the strength of the line itself deteriorates due to the decrease in density, and furthermore, a problem arises that the transmission characteristics deteriorate due to the deformation of the line shape.
The open porosity is preferably 3% or less, more preferably 2% or less.

The lower limit of the open porosity is not particularly limited, but is preferably as small as possible.

The open porosity (%) can be measured by the Archimedes method. Specifically, JISC2
According to 141, this can be done by calculating 100 × (saturated weight-dry weight) / (saturated weight-water weight).

The dielectric line 2 of the present invention has a working frequency of 60.
Mg, Al, S whose Q value at GHz is 1000 or more
It is preferable to use a ceramic mainly containing the composite oxide of i. The above ceramics have a relative dielectric constant of about 4.5 to 8. The relative permittivity is limited to this range because, when the relative permittivity is less than 4.5, the conversion of the LSM mode electromagnetic wave to the LSE mode increases as described above. When the relative dielectric constant exceeds 8, when used at a frequency of 50 GHz or more, the width of the dielectric line 2 must be extremely thin, and processing becomes difficult, shape accuracy is deteriorated, and strength is reduced. Problems also arise in terms of points. In addition, the operating frequency 60
Mg, Al, S whose Q value at GHz is 1000 or more
In the case of ceramics containing a composite oxide of i as a main component, this realizes sufficiently low loss as a dielectric line used at 60 GHz included in a microwave band and a millimeter wave band in recent years. .

The composition and composition ratio of the dielectric line 2 are represented by a molar ratio composition formula of xMgO.yAl ₂ O ₃ .zSiO ₂
X = 10 to 40 mol%, y = 10 to 40
The main component is a composite oxide of Mg, Al, and Si that satisfies mol%, z = 20 to 80 mol%, and x + y + z = 100 mol%.

The reason why the composition ratio of the main component of the ceramic (dielectric ceramic composition) as the material of the dielectric line 2 of the present invention is limited to the above range is as follows. That is, x is 10
The reason for setting it to 40 mol% is that if it is less than 10 mol%, a good sintered body cannot be obtained, and if it exceeds 40 mol%, the relative permittivity becomes large. In particular, x is desirably 15 to 35 mol% from the viewpoint that the Q value at 60 GHz is 2000 or more.

The reason why y is set to 10 to 40 mol% is as follows.
If y is less than 10 mol%, a good sintered body cannot be obtained, and if y exceeds 40 mol%, the relative dielectric constant increases. y is preferably 17 to 35 mol% from the viewpoint that the Q value at 60 GHz is 2000 or more.

The reason why z is set to 20 to 80 mol% is that z is 2
When it is less than 0 mol%, the relative permittivity becomes large,
If it exceeds 80 mol%, a good sintered body cannot be obtained, and the Q value decreases. z represents the Q value at 60 GHz of 200
From the viewpoint of 0 or more, 30 to 65 mol% is desirable.

The x, y, and z indicating the mol% of MgO, Al ₂ O ₃ and SiO ₂ are EPMA (Electron).
Probe Micro Analysis) method, XR
D (X-ray Diffraction)
It can be specified by an analytical method such as a method.

In the ceramics (dielectric ceramic composition) for the dielectric line 2 of the present invention, the main crystal phase is cordierite (2MgO.2Al ₂ O ₃ .5SiO ₂ ) and the other crystal phases are Mullite (3Al ₂ O ₃ .2SiO ₂ ),
Spinel (MgO.Al ₂ O ₃ ), protoenstatite {a type of steatite containing magnesium metasilicate (MgO.SiO ₂ ) as a main component}, clinoenstatite {magnesium metasilicate (MgO.SiO ₂ ) as a main component A type of steatite, forsterite (2M
gO · SiO ₂ ), cristobalite silicic acid (SiO ₂ )
A kind of tridymite {a kind of silicic acid (SiO ₂ )},
In some cases, safarin (a kind of silicate of Mg and Al) is precipitated, but the precipitated phase differs depending on the composition. In the dielectric porcelain composition of the present invention, a crystalline phase consisting of cordierite alone may be used.

The dielectric ceramic composition for the dielectric line 2 of the present invention is manufactured as follows. As a raw material powder, for example, MgCO ₃ powder, Al ₂ O ₃ powder, and SiO ₂ powder are weighed at a predetermined ratio, wet-mixed and dried, and the mixture is heated to 1100 ° C. to 1300 ° C. in the atmosphere.
And then pulverized to a powder. It is obtained by adding an appropriate amount of a resin binder to the obtained powder and molding, and firing this molded body at 1300 to 1450 ° C in the air.

The raw material powder composed of the elements Mg, Al and Si contained in the raw material powder may be any of inorganic compounds such as oxides, carbonates and acetates, or organic compounds such as organic metals. Any material can be used as long as it becomes an oxide by firing.

The main component of the dielectric porcelain composition of the present invention is mainly composed of a composite oxide of Mg, Al and Si.
As long as the Q value at GHz is not less than 1000, impurities other than the above-mentioned elements may be mixed with the pulverized ball or raw material powder, or the sintering temperature range may be controlled and mechanical properties may be improved. May be contained. For example,
Rare earth element compound, Ba, Sr, Ca, Ni, Co, I
Non-oxides such as oxides such as n, Ga, and Ti, and nitrides such as silicon nitride. These may include one or more kinds.

The high frequency band referred to in the present invention is expressed by the following equation.
A high frequency band corresponding to the microwave band and the millimeter wave band of the 00 GHz band, for example, 30 GHz or more, particularly 50 GHz or more, and more preferably 70 GHz or more is suitable.

Further, as other materials of the dielectric line made of ceramics, alumina ceramics, glass ceramics, forsterite ceramics and the like may be used. However, in view of dielectric properties, workability, strength, miniaturization, reliability, etc. Light ceramics are preferred.

The NRD guide S1 of the present invention is a wireless LA
N, used for millimeter wave radar of automobiles, etc.
For example, an obstacle around a car and other cars are irradiated with a millimeter wave, and the reflected wave is combined with the original millimeter wave to obtain an intermediate frequency signal. The distance to the car, their moving speed, etc. can be measured.

Thus, according to the present invention, a highly reliable, high-performance, small-sized NRD guide can be constructed. Further, since a dielectric line made of ceramics having a lower dielectric constant than conventional alumina ceramics or the like is used, L
Conversion of SM mode electromagnetic waves to LSE mode can be reduced, and loss of high frequency signals can be suppressed.

A millimeter-wave transceiver using the NRD guide of the present invention will be described below. 3 and 4 show a millimeter-wave radar as a millimeter-wave transceiver of the present invention. FIG. 3 is a plan view of an integrated transmission antenna and reception antenna. FIG. It is a top view of an independent thing.

In FIG. 3, reference numeral 51 denotes one parallel plate conductor of the present invention (the other is omitted); and 52, a voltage-controlled millimeter provided at one end of a first dielectric line 53 and having a high-frequency diode oscillator. Wave signal oscillator (voltage controlled oscillator)
The bias voltage of the variable capacitance diode arranged near the high-frequency diode of the first dielectric line 53 is periodically controlled so that the bias voltage application direction matches the direction of the electric field of the high-frequency signal. By using a sine wave or the like, the signal is output as a frequency-modulated millimeter wave signal for transmission.

Reference numeral 53 denotes a first dielectric line having a high-frequency diode oscillator attached to one end for transmitting a transmission millimeter-wave signal obtained by modulating a millimeter-wave signal output from the high-frequency diode oscillator. A circulator 55 made of a ferrite disk or the like having first, second, and third connection portions 54a, 54b, and 54c coupled to the first, third, and fourth dielectric lines 53, 55, and 57, respectively. , Connected to the second connection portion 54b of the circulator 54 to propagate the millimeter wave signal and to transmit and receive the
The third dielectric line 56 having 6 is a transmission / reception antenna configured by making the tip of the third dielectric line 55 tapered or the like.

The transmitting / receiving antenna 56 inputs and outputs a high-frequency signal through a through hole formed in the parallel plate conductor 51, and is installed on the outer surface of the parallel plate conductor 51 via a metal waveguide connected to the through hole. Horn antenna or the like may be used.

Reference numeral 57 denotes a circulator 54 which is received by the transmission / reception antenna 56, propagates through the third dielectric line 55, and
The received wave output from the third connection unit 54c of the
The fourth dielectric line 58 propagating to the 9th side is disposed close to the first dielectric line 53 so that one end side is electromagnetically coupled to the first dielectric line 53, and the second dielectric line 58 transmits a part of the millimeter wave signal to the mixer 59 side. The dielectric line 58a is a non-reflection terminator (terminator) provided at one end of the second dielectric line 58 opposite to the mixer 59. In the figure, M1 mixes a part of the millimeter wave signal and the received wave by bringing the middle part of the second dielectric line 58 and the middle part of the fourth dielectric line 57 close to each other and electromagnetically coupling them. This is a mixer section for generating an intermediate frequency signal.

The circulator 54 of the present invention is provided at a predetermined interval, for example, at an angle of 120 ° with respect to the center point of the ferrite disk, at a peripheral portion of a pair of ferrite disks disposed in parallel between the parallel plate conductors 51, 51. The first connection portions 54a, 54a,
A second connection portion 54b and a third connection portion 54c,
A millimeter wave signal input from one connection is output from another connection adjacent to the ferrite disk clockwise or counterclockwise in the plane of the ferrite disk. In addition, the parallel plate conductor 5
A magnet for rotating the wavefront of the electromagnetic wave propagating through the ferrite disk passes through a portion of the outer main surface corresponding to the ferrite disk in a direction substantially perpendicular to the ferrite disk. It is provided so that. The ferrite plate of the present invention is not limited to a disk-shaped one, but may be a polygonal one or the like.

As another embodiment of the millimeter wave transceiver of the present invention, there is a type shown in FIG. 4 in which a transmitting antenna and a receiving antenna are independent. In the drawing, reference numeral 61 denotes one parallel plate conductor (the other is omitted), and 62 denotes a voltage-controlled millimeter-wave signal oscillating unit provided at one end of the first dielectric line 63 and having a high-frequency diode oscillator. The bias voltage of the variable capacitance diode disposed near the high frequency diode of the first dielectric line 63 is periodically controlled so that the bias voltage application direction coincides with the direction of the electric field of the high frequency signal, so that a triangular wave, a sine wave, etc. As a result, a frequency-modulated transmission millimeter wave signal is output.

Reference numeral 63 denotes a first dielectric line having a high-frequency diode oscillator attached to one end for transmitting a transmission millimeter-wave signal obtained by modulating a millimeter-wave signal output from the high-frequency diode oscillator. A ferrite disk or the like having first, second, and third connection portions (similar to FIG. 3 and not shown) connected to the first, third, and fifth dielectric lines 63, 65, and 67, respectively. Circulator consisting of 65
Is connected to a second connection portion of the circulator 64 to transmit a millimeter wave signal and to transmit a transmitting antenna 6
The third dielectric line 66 having a 6 is a transmission antenna formed by making the tip of the third dielectric line 65 a taper shape or the like, and the 67 is connected to a third connection portion of the circulator 64. The fifth dielectric line is provided with a non-reflection terminating portion 67a for attenuating a millimeter-wave signal for transmission at the tip.

Reference numeral 68 denotes a second dielectric line which is disposed close to the first dielectric line 63 so that one end thereof is electromagnetically coupled, and transmits a part of the millimeter wave signal to the mixer 71 side.
Reference numeral 68a denotes a non-reflection terminal provided at one end of the second dielectric line 68 opposite to the mixer 71, and reference numeral 69 denotes a fourth which transmits a reception wave received by the reception antenna 70 to the mixer 71 side. This is a dielectric line. In the figure, M2 mixes a part of the millimeter wave signal and the received wave by bringing the middle of the second dielectric line 68 and the middle of the fourth dielectric line 69 close to each other and electromagnetically coupling them. Is a mixer section for generating an intermediate frequency signal.

The transmitting antenna 66 and the receiving antenna 70 input or output a high-frequency signal through a through hole formed in the parallel plate conductor 61, and
The antenna may be a horn antenna or the like installed on the outer surface of the device via a metal waveguide connected to the through hole.

In the present invention, in FIG. 3, one end of the second dielectric line 58 is arranged close to the first dielectric line 53 or one end thereof is joined. The first dielectric line 53 has a linear shape, the second dielectric line 58 has an arc shape, and the radius of curvature r of the arc portion is
Is preferably equal to or longer than the wavelength λ of the high-frequency signal. As a result, the high-frequency signal can be branched with equal output while reducing the loss. Also, at the junction, the second dielectric line 58
May be linear, the first dielectric line 53 may be arc-shaped, and the radius of curvature r of the arc-shaped portion may be equal to or longer than the wavelength λ of the high-frequency signal. In this case, the same effect as described above can be obtained.

In the mixer 59, the second dielectric line 58 and the fourth dielectric line 57 can be joined together. In this case, as in the above case, these dielectric lines 58 and 57 are connected together. Preferably, one of the joints is formed in an arc shape, and the radius of curvature r of the arc portion is equal to or longer than the wavelength λ of the high-frequency signal. Further, when the second dielectric line 58 and the fourth dielectric line 57 are arranged close to each other so as to be electromagnetically coupled,
In the proximity portion, at least one of the proximity portions of the second dielectric line 58 and the fourth dielectric line 57 is formed in an arc shape, so that a close arrangement can be achieved.

Preferably, the radius of curvature r of the above-mentioned joint portion is 3λ or less, and if it exceeds 3λ, the joining structure becomes large, and the advantage of miniaturization cannot be obtained. When the radius of curvature r of the junction is set smaller than the wavelength λ, the branching strength to the dielectric line having the arc-shaped junction decreases.

The joining structure between the first dielectric line 53 and the second dielectric line 58, the joining structure between the second dielectric line 58 and the fourth dielectric line 57, and the second
The arrangement of the dielectric line 58 and the fourth dielectric line 57 close to each other is the same as described above in the case of FIG.

These various components are provided between parallel plate conductors arranged at an interval of one half or less of the wavelength λ of the millimeter wave signal.

In FIG. 3, the first dielectric line 5
A switch is provided in the middle of 3 and turned on and off (ON-
OFF), pulse modulation control can also be performed.
For example, as shown in FIG. 6, a second choke type bias supply line 112 is formed on one main surface of a wiring board 88, and a beam lead type PIN diode or a Schottky barrier diode mounted by soldering is provided in the middle thereof. Switch. In FIG. 6, E indicates the direction of the electric field of the high-frequency signal propagating in the dielectric line 77.

The wiring substrate 88 is connected to the first dielectric line 5
3, the bias voltage application direction of the pulse modulation diode such as the PIN diode or the Schottky barrier diode coincides with the direction of the electric field of the LSM mode high-frequency signal between the circulator 54 and the signal branch portion with the second dielectric line 58. And is interposed in the first dielectric line 53. Further, another circulator is interposed in the first dielectric line 53, the first dielectric line 53 is connected to the first and third connection portions, and another dielectric line is connected to the second connection portion. And a switch provided with a Schottky barrier diode in a configuration as shown in FIG. 6 may be provided on the end face of the tip of the dielectric line.

In FIG. 4, the circulator 64
, And the transmission antenna 66 may be connected to the tip of the first dielectric line 63. in this case,
Although the size is reduced, a part of the received wave is easily mixed into the voltage controlled oscillator (millimeter wave signal oscillator) 62 to cause noise or the like, and therefore the type shown in FIG. 4 is preferable.

In the type shown in FIG. 4, the second dielectric line 68 is disposed close to the third dielectric line 65 such that one end is electromagnetically coupled to the third dielectric line 65, or one end is connected to the third dielectric line 65. It may be arranged so as to be joined and propagate a part of the millimeter wave signal to the mixer 71 side. This configuration also has the same functions, functions and effects as those of FIG.

In FIG. 4, a switch having the same configuration as that shown in FIG. 6 is provided in the middle of the first dielectric line 63, and pulse modulation can be controlled by turning it on and off. it can. For example, as shown in FIG. 6, a second choke type bias supply line 1
12 is a switch provided with a beam lead type PIN diode or a Schottky barrier diode which is solder-mounted halfway. The wiring substrate 88 is connected between the signal branching part of the first dielectric line 63 and the second dielectric line 68 and the circulator 64 by applying a bias voltage of a PIN diode or a Schottky barrier diode in the LSM mode. Are arranged so as to match the direction of the electric field of the high-frequency signal, and are interposed in the first dielectric line 63.

Further, another circulator is interposed in the first dielectric line 63, the first dielectric line 63 is connected to the first and third connection parts, and another circulator is connected to the second connection part. Connect the dielectric line, and on the end face of the tip of the dielectric line,
A switch provided with a Schottky barrier diode having a configuration as shown in FIG. 6 may be provided.

Also, in these millimeter wave transceivers,
The interval between the parallel plate conductors is the wavelength of the millimeter wave signal in the air, and is equal to or less than half the wavelength λ at the operating frequency.

Further, the millimeter wave transceiver shown in FIGS.
This is a CW (Frequency Modulation Cotinuous Waves) system, and the operation principle of the FMCW system is as follows. MODIN for inputting the modulation signal of the voltage controlled oscillator
An input signal whose voltage amplitude changes with time in the form of a triangular wave or the like is input to the terminal, the output signal is frequency-modulated, and the output frequency shift of the voltage controlled oscillator is shifted so as to become a triangular wave or the like. When an output signal (transmission wave) is radiated from the transmission / reception antenna 56 and the transmission antenna 66 and a target is present in front of the transmission / reception antenna 56 and the transmission antenna 66, a time difference corresponding to a reciprocation of the propagation speed of the radio wave is obtained.
The reflected wave (received wave) returns. At this time, mixer 5
The frequency difference between the transmission wave and the reception wave is output to the IFOUT terminal on the output side of 9, 71.

By analyzing frequency components such as the output frequency of the IFOUT terminal, Fif = 4R · fm · Δf / c
｛Fif: IF (Intermediate Frequency) output frequency,
R: distance, fm: modulation frequency, Δf: frequency shift width,
c: The distance can be obtained from the relational expression of light speed｝.

As described above, when the present invention is applied to a millimeter wave radar of an automobile, an obstacle around the automobile and other automobiles are irradiated with the millimeter wave, and the reflected wave is combined with the original millimeter wave to produce an intermediate frequency signal. By analyzing this intermediate frequency signal, the distance to obstacles and other vehicles, their moving speed, and the like can be measured.

The voltage controlled oscillators 52 and 62 using the high-frequency diode oscillator of the present invention will be described below. 5 and 6 show an NRD guide type high-frequency diode oscillator according to the present invention. In these figures, reference numeral 71 denotes a pair of parallel plate conductors, and 72 denotes a substantially rectangular parallelepiped metal for mounting (mounting) a Gunn diode 73. A metal member such as a block, 73 is a gun diode which is a kind of high-frequency diode that oscillates microwaves and millimeter waves, and 74 is a metal member 72.
A choke-type bias supply line 7 that is provided on one side of the circuit and supplies a bias voltage to the Gunn diode 73 and functions as a low-pass filter that prevents leakage of high-frequency signals.
A wiring board 4a is formed, 75 is a band-shaped conductor such as a metal foil ribbon for connecting the choke-type bias supply line 74a and the upper conductor of the Gunn diode 73, and 77 is arranged near the Gunn diode 73 to receive a high-frequency signal and receive an external signal. A dielectric line (corresponding to the first dielectric lines 53 and 63).

In FIG. 5, the choke-type bias supply line 74a has a wide line and a narrow line each having a length of approximately λ / 4, and a band-like conductor 75 has a length of approximately ｛(3/3). 4) + m｝ λ (m is an integer of 0 or more). The length of the strip-shaped conductor 75 is approximately 3λ / 4 to approximately ｛(3 /
4) +3｝ λ is good, and if it exceeds approximately ｛(3/4) +3｝ λ, the band-shaped conductor 75 becomes longer, and bending, twisting, and the like are likely to occur. As the variation increases, various resonance modes are generated, which causes a problem that a signal having a frequency different from a desired oscillation frequency is generated. More preferably, it is approximately 3λ / 4, approximately {(3/4) +1} λ.

Further, the reason why (｛(3/4) + m｝ λ) is set is that resonance is possible even if it is slightly different from (｛(3/4) + m｝ λ). For example, the band-shaped conductor 5 is changed to ｛(3/4)
+ M｝ λ may be formed about 10 to 20% longer than
In that case, it is considered that part of the length λ / 4 of the first pattern of the choke-type bias supply line 74a in contact with the strip conductor 75 contributes to resonance. Therefore, the length of the strip-shaped conductor 5 can be changed within a range of about {(3/4) + m} λ ± 20%.

These choke type bias supply lines 74a
And the material of the strip-shaped conductor 75 is Cu, Al, Au, A
g, W, Ti, Ni, Cr, Pd, Pt, etc., and Cu and Ag are particularly preferable in that they have good electric conductivity, small loss, and large oscillation output.

The strip conductor 75 is electromagnetically coupled to the metal member 72 at a predetermined distance from the surface of the metal member 72, and is bridged between the choke type bias supply line 74 a and the Gunn diode 73. That is, one end of the strip-shaped conductor 75 is connected to one end of the choke-type bias supply line 74a by soldering or the like, and the other end of the strip-shaped conductor 75 is connected to the upper conductor of the gun diode 73 by soldering or the like. The middle part except for the connection part is floating in the air.

The metal member 72 may be a metal conductor because it also serves as an electrical ground (earth) for the Gunn diode 73, and the material is not particularly limited as long as it is a metal (including alloy) conductor. Instead of brass (brass: Cu-
(Zn alloy), Al, Cu, SUS (stainless steel), Ag, Au, Pt, etc. The metal member 72
Is a metal block made entirely of metal, an insulated substrate such as ceramics or plastic, which is entirely or partially metal-plated, or an insulated substrate entirely or partially coated with a conductive resin material or the like. Is also good.

The dielectric line 77 is the same as that shown in FIGS.
1 and is made of cordierite (2MgO.2Al) as described above.
₂ O ₃ .5 SiO ₂ ) ceramics (relative permittivity 4 to 5) and the like are preferable, and these have low loss in a high frequency band. The distance between the Gunn diode 73 and the dielectric line 77 is preferably about 1.0 mm or less, and if it exceeds 1.0 mm, the loss is reduced to exceed the maximum separation width at which electromagnetic coupling is possible.

Further, the high-frequency diode of the present invention includes an impatt (impact ionization avalan).
che transit time, diode, trap
att: trapped plasma avalanche triggered transi
t) Microwave diodes such as diodes and Gunn diodes and millimeter-wave diodes are preferably used.

[0073]

Embodiments of the present invention will be described below.

(Example) The NRD guide S1 of FIG. 1 was constructed as follows. As the material of the dielectric line 2, ceramics containing a composite oxide of Mg, Al, and Si of the present invention as a main component and having various composition ratios were produced.
Table 1 shows their relative dielectric constants and Q values at a frequency of 60 GHz.

[0075]

[Table 1]

A pair of parallel flat conductors 1 and 3 are made of aluminum and are 80 mm long × 80 mm wide × 2 mm thick.
Are arranged at an interval d of 1.8 mm.
24 dielectric lines 2 made of cordierite ceramics were interposed. The cross-sectional shape of the dielectric line 2 is a rectangle having a height of about 1.8 mm and a width of 0.8 mm, and an open porosity of 0.5%. The surface roughness of the inner surface of the metal plate was measured by a stylus type surface roughness measuring instrument, and was 0.3 μm. The metal plate and the dielectric line 2 were bonded with one-liquid type epoxy resin. When the transmission loss of the high-frequency signal was evaluated at 76.5 GHz with a network analyzer, it was 0.18 GHz.
dB / cm, and the loss was sufficiently low for practical use.

(Comparative Example) An NRD guide S1 of FIG. 1 was constructed in the same manner as in the example except that the open porosity of the dielectric line 2 made of cordierite ceramics was 10%. The transmission loss of the high-frequency signal was as large as 0.4 dB / cm.

The present invention is not limited to the above-described embodiment, and various changes may be made without departing from the scope of the present invention.

[0079]

According to the present invention, in the NRD guide, since the dielectric line is made of ceramics having an open porosity of 5% or less, it is possible to obtain a high-performance one which achieves both high reliability and low loss.

Preferably, the dielectric line is made of Mg, A
It is made of a ceramic mainly composed of a complex oxide of l and Si and has a Q value of 1000 at a measurement frequency of 60 GHz.
As described above, the conversion of the LSM mode electromagnetic wave to the LSE mode can be reduced and the loss of the high frequency signal can be suppressed by using the dielectric line made of ceramics having a lower dielectric constant than the conventional alumina ceramics or the like. .

Preferably, the molar ratio composition of the composite oxide is xMgO.yAl ₂ O ₃ .zSiO ₂ (where x = 1
0-40 mol%, y = 10-40 mol%, z = 20-8
0 mol%, x + y + z = 100 mol%), it is possible to produce an NRD guide using a dielectric line with further reduced transmission loss, inexpensive and high shape accuracy.

The millimeter wave transmitter / receiver of the present invention includes a type having a transmitting / receiving antenna and a type in which a transmitting antenna and a receiving antenna are independent, and at least one of the dielectric lines is formed of the dielectric line of the present invention. Thus, the LS of the LSM mode electromagnetic wave propagating through the dielectric line is
The conversion into the E mode is small, and therefore, a steep curved portion with a small radius of curvature and a wide operating frequency range can be manufactured on the dielectric line. As a result, the millimeter wave transceiver can be used in a wide operating frequency range and can be downsized. In addition, it is easy to process and can be manufactured with a high degree of freedom. Furthermore, in the type in which the transmitting antenna and the receiving antenna are independent, the millimeter wave signal for transmission does not enter the mixer via the circulator, and as a result, the noise of the received signal is reduced, the detection distance is increased, and the millimeter wave is further increased. Wave signal transmission characteristics are excellent.

[Brief description of the drawings]

FIG. 1 is a perspective view showing the inside of an NRD guide according to the present invention.

FIG. 2 is a perspective view showing the inside of another conventional NRD guide.

FIG. 3 is a plan view of one embodiment of a millimeter wave radar including an NRD guide according to the present invention.

FIG. 4 is a plan view of another embodiment of the millimeter-wave radar including the NRD guide of the present invention.

FIG. 5 is a perspective view of a millimeter wave oscillator for a millimeter wave radar according to the present invention.

FIG. 6 is a perspective view of a wiring board provided with a variable capacitance diode incorporated in the millimeter wave oscillation section of FIG.

[Explanation of symbols]

 1: Lower parallel plate conductor 2: Dielectric line 3: Upper parallel plate conductor

Claims (5)

[Claims] 1. A non-radiative dielectric line in which a dielectric line is interposed between parallel plate conductors arranged at an interval of one half or less of a wavelength of a high-frequency signal, wherein the dielectric line has an open porosity. A non-radiative dielectric line, comprising 5% or less of ceramics. 2. The dielectric line according to claim 1, wherein the dielectric line is made of a ceramic mainly composed of a composite oxide of Mg, Al, and Si, and has a Q value of 1,000 or more at a measurement frequency of 60 GHz. Non-radiative dielectric line. 3. The composite oxide has a molar ratio composition formula of xMg.
_{O · yAl 2 O 3 · zSiO} 2 ( where, x = 10 to 40 mol%, y = 10 to 40 mol%, z = 20 to 80 mol%,
3. The nonradiative dielectric line according to claim 2, wherein (x + y + z = 100 mol% is satisfied). 4. A high-frequency diode oscillator is provided at one end between parallel plate conductors arranged at an interval equal to or less than half the wavelength of the millimeter-wave signal, and propagates a millimeter-wave signal output from the high-frequency diode oscillator. A first dielectric line to be transmitted, wherein the bias voltage application direction is arranged so as to coincide with the electric field direction of the millimeter wave signal, and the millimeter wave signal is frequency-modulated by periodically controlling the bias voltage. A variable-capacitance diode that outputs a millimeter-wave signal as described above, and one end of the variable-capacitance diode is disposed close to or joined to the first dielectric line so that one end is electromagnetically coupled, and a part of the millimeter-wave signal is A second dielectric line for propagating the millimeter wave signal and a second ferrite plate disposed in parallel with the parallel plate conductor and arranged at predetermined intervals on the periphery of the ferrite plate. It has a first connection portion, a second connection portion, and a third connection portion which are ends, and the millimeter wave signal input from one of the connection portions is clockwise or counterclockwise in the plane of the ferrite plate. A circulator that is output from another peripherally adjacent connection part, wherein the first connection part is joined to an output end of the millimeter wave signal of the first dielectric line; A third dielectric line that is joined to the connection portion of the second and that transmits the millimeter wave signal and has a transmission / reception antenna at a tip end; and a circulator that is received by the transmission / reception antenna and propagates through the third dielectric line. A fourth dielectric line for transmitting a reception wave output from the third connection portion to the mixer side, and a middle of the second dielectric line and a middle of the fourth dielectric line. Electromagnetic coupling And a mixer unit that mixes a part of the millimeter wave signal and the received wave to generate an intermediate frequency signal, wherein the first to fourth dielectrics are provided. A millimeter wave transceiver, wherein at least one of the lines comprises the dielectric line according to any one of claims 1 to 3. 5. A high-frequency diode oscillator is provided at one end between parallel plate conductors arranged at an interval equal to or less than half the wavelength of the millimeter-wave signal, and propagates the millimeter-wave signal output from the high-frequency diode oscillator. A first dielectric line to be transmitted, wherein the bias voltage application direction is arranged so as to coincide with the electric field direction of the millimeter wave signal, and the millimeter wave signal is frequency-modulated by periodically controlling the bias voltage. A variable-capacitance diode that outputs as a millimeter-wave signal, and one end of the variable-capacitance diode is disposed close to or coupled to one end of the first dielectric line so that one end of the millimeter-wave signal is electromagnetically coupled, and a part of the millimeter-wave signal is transmitted to the mixer. A second dielectric line to be propagated, and input / output terminals of the millimeter wave signal, which are arranged at predetermined intervals on a peripheral portion of a ferrite plate disposed in parallel with the parallel plate conductor, and The first millimeter-wave signal input from one of the first connecting portions, the second connecting portion, and the third connecting portion in the clockwise or counterclockwise direction within the plane of the ferrite plate. A circulator for outputting from another adjacent connection part, wherein the first connection part is connected to an output end of the millimeter wave signal of the first dielectric line; and a second circulator of the circulator. A third dielectric line that is connected to the connection portion, propagates the millimeter wave signal, and has a transmitting antenna at the distal end; a fourth dielectric line having a receiving antenna at the distal end and a mixer at the other end; A line, connected to the third connection part of the circulator, for propagating the millimeter-wave signal received and mixed by the transmission antenna, and for attenuating the millimeter-wave signal at a non-reflection termination provided at the tip end. A fifth dielectric line, and a middle part of the second dielectric line and a middle part of the fourth dielectric line, which are electromagnetically coupled or joined to each other in close proximity to each other, and a part of the millimeter wave signal A millimeter wave transmitter / receiver provided with a mixer unit for generating an intermediate frequency signal by mixing the received wave with at least one of the first to fifth dielectric lines. A millimeter wave transmitter / receiver comprising: