JP2001044714A - Dielectric line and radio equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dielectric line where a dielectric strip and a conductor plate can be processed with usual processing precision so as to facilitate the assembly of them and a small transmission loss characteristic can be obtained and to provide a ratio unit using the dielectric line. SOLUTION: In this dielectric line, a groove width W1 of a groove g1 is decided so that the positioning of a dielectric strip with respect to a 1st conductor plate is attained with high precision through the insertion of the dielectric strip 3 into the groove g1 of a 1st conductor plate 1 and a relation between the width W1 and a groove width W2 of a groove g2 of a 2nd conductor plate 2 holds as W2>W1 so that the groove g2 of the 2nd conductor plate 2 can easily be fitted to the dielectric strip while the dielectric strip 3 is positioned.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a dielectric line in a millimeter wave module and the like and a radio device using the same.

[0002]

2. Description of the Related Art There are several types of dielectric lines in which a dielectric strip is disposed between two parallel conductive planes. Japanese Unexamined Utility Model Publication No. 59-183002 discloses a so-called grooved type dielectric line in which a groove is formed and a dielectric strip is fitted in the groove. FIG. 5 is a sectional view showing a configuration example of the dielectric waveguide. Here, reference numerals 1 and 2 denote conductor plates, respectively, in which grooves are formed on the surfaces facing each other and dielectric strips 3 are fitted.

Further, the cut-off frequency of the LSM01 mode propagating in the propagation region by the dielectric strip portion is LSE01.
A non-radiative dielectric line for single mode transmission (hereinafter, referred to as a single mode transmission) in which the distance between the conductor planes of the dielectric strip portion and the distance between the conductor planes in other non-propagation regions is determined so as to be lower than the mode cutoff frequency , "Hyper NRD Guide") is disclosed in Japanese Patent Application Laid-Open No. 9-102706. Such a dielectric line can also be formed by forming a groove on the opposing surfaces of two parallel conductor plates and fitting a dielectric strip into the groove.

[0004]

In the prior art for forming the above-mentioned grooved type dielectric line, as shown in FIG. 5, the width W of the dielectric strip 3 and the groove formed in the conductor plates 1 and 2 are set as shown in FIG. Were made almost equal in width. Therefore, even if the grooves of the dielectric strip 3 and the upper and lower conductor plates 1 and 2 are processed with high precision, in a dielectric line having a complicated structure, it may be difficult to fit the dielectric strip into the grooves of the conductor plate. Occurs. By making the groove width of the upper and lower conductor plates larger than the width of the dielectric strip, and providing a clearance in the dimensional relationship between the width of the dielectric strip 3 and the width of the groove of the conductor plate, at least the grooves of the upper and lower conductor plates are provided. The gap between the side surface of the dielectric strip and the inner surface of the groove, which is the propagation region of the electromagnetic wave, varies depending on the position on the dielectric line, and the variation increases. As the transmission loss increases, a problem arises.

SUMMARY OF THE INVENTION It is an object of the present invention to satisfy the two contradictory conditions of ease of assembly of a conductor plate and a dielectric strip and reduction of transmission loss, and to process the dielectric strip and the conductor plate with ordinary processing accuracy. It is an object of the present invention to provide a dielectric line and a wireless device using the dielectric line, which are capable of assembling them, facilitating their assembly, and obtaining low transmission loss characteristics.

[0006]

According to the present invention, there is provided a propagation region in which a dielectric strip is disposed between first and second conductor plates which are substantially parallel to each other, and an electromagnetic wave is propagated in the dielectric strip portion.
In a dielectric line provided with a non-propagation region that blocks electromagnetic waves at a portion other than the dielectric strip, a groove for fitting the dielectric strip is formed in the first conductor plate, and a groove is formed on the first conductor plate. A groove having a large width and covering the dielectric strip is formed in the second conductive plate.

Since the groove formed in the first conductor plate may be a groove into which a dielectric strip can be fitted, the width of the groove is made equal to the width of the dielectric strip, or processing accuracy and assembly accuracy are taken into consideration. Then, it may be formed slightly wider. On the other hand, the second conductor plate faces the first conductor plate in a state where the dielectric strip is already fitted in the groove of the first conductor plate. By making the width of the groove to be formed wider than the groove width of the first conductor plate, the assembly becomes easy. Further, since the relative positional accuracy between the groove of the first conductor plate and the dielectric strip is high, the variation in the gap between the side surface of the dielectric strip and the inner surface of the groove is small, and as a result, an increase in transmission loss is suppressed.

Further, the present invention provides a dielectric line having a dielectric strip disposed between substantially parallel conductor plates, wherein a groove for disposing the dielectric strip is formed in the two conductor plates, and at least one of the grooves is provided. On the groove bottom of one conductor plate and the dielectric strip portion in contact with the groove bottom,
An engagement portion for engaging the one conductor plate and the dielectric strip is formed.

With this structure, even if the groove width of the first or second conductor plate does not match the width of the dielectric strip with high precision, positioning in the width direction within the groove can be performed, and the vicinity of the dielectric strip can be determined. The cross-sectional structure becomes uniform at each part of the dielectric waveguide. Therefore, the fluctuation of the propagation constant of the dielectric line is reduced, and the reflection loss is suppressed.

Further, according to the present invention, a wireless device is configured by using the dielectric line having the above structure as a transmission path of a transmission signal or a reception signal. For example, in a millimeter wave radar, a high gain millimeter wave radar is configured by using the transmission line for transmitting a signal transmitted to an antenna or a signal received from the antenna.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of a dielectric line according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view of a dielectric line in a plane perpendicular to the electromagnetic wave propagation direction. Here, 1 is a first conductor plate, 2 is a second conductor plate, and grooves g1 and g2 extending in a direction perpendicular to the paper surface are formed on opposing surfaces of both conductor plates. Numeral 3 denotes a dielectric strip arranged along the grooves g1 and g2. Width W of groove g1 provided in first conductive plate 1
1 is designed to be slightly larger than W in consideration of processing accuracy and assembly accuracy of the groove g1 and the dielectric strip 3. For example, in the case of a dielectric line transmitting an electromagnetic wave of 75 to 78 GHz, processing is performed with W = 1.15 mm and W1 = 1.2 mm as target values. The width W2 of the groove g2 provided in the second conductor plate 2 is such that when the conductor plate 2 is covered from above with the dielectric strip 3 fitted in the groove g1 of the conductor plate 1, The dielectric strip 3 is designed to fit into the groove. Therefore, the relationship W2> W1 is established.

That is, in the state where the dielectric strip 3 is fitted along the groove g1 of the conductor plate 1 by utilizing the elasticity of the dielectric strip 3, the distance between W and W1 can be reduced. Can be made small, but when the second conductor plate 2 is covered, the dielectric strip 3 is already positioned by the groove g1 of the first conductor plate 1 and its elasticity hardly acts ( (Cannot be used), so the clearance between W2 and W is largely determined. For example, in a dielectric line in the above frequency band, W
The groove g2 is machined with 2-W = 0.3 mm and W2 = 1.45 mm as a target value.

The grooves g1 and g2 are formed, for example, by cutting a flat metal plate using a milling machine. In addition, the dielectric strip, a method of cutting out a dielectric plate of a predetermined thickness by cutting using a milling machine,
Created by a resin molding method.

In FIG. 1, when the distance between the conductor plates in the propagation region (height of the dielectric strip 3) is h1 and the distance between the conductor plates in the non-propagation region is h2, the LSM01 mode of propagation in the propagation region is assumed. The cutoff frequency is lower than the cutoff frequency of the LSE01 mode, and L
The dielectric constants of h1, h2 and the dielectric strip 3 are determined so as to satisfy the conditions for blocking the electromagnetic waves in the SM01 mode and the LSE01 mode. This enables transmission in a single mode of the LSM01 mode, regardless of the bend angle.
There is no loss associated with the mode conversion from the LSM mode to the LSE mode, and the degree of freedom in designing the dielectric line can be increased without increasing the transmission loss.

FIG. 2 shows the relationship between the gap between W2 and W and the resulting transmission loss of the dielectric line. As described above, when W2-W is 0.3 mm, the increase in transmission loss is suppressed to about 0.1 dB / cm, and it can be seen that there is no practical problem.

Next, the configuration of a dielectric line according to a second embodiment will be described with reference to FIG. FIG. 3 is a cross-sectional view of the dielectric line in a plane perpendicular to the direction of propagation of electromagnetic waves. Here, 1 is a first conductor plate, 2 is a second conductor plate, and grooves g extending in a direction perpendicular to the plane of the drawing are formed on opposing surfaces of both conductor plates.
1 and g2. 3 is the groove g1, g
2 are dielectric strips arranged along the line 2. At the center of the groove g1 of the first conductor plate 1, an engaging projection 4 is formed continuously along the direction in which the groove extends. On the other hand, an engagement recess 5 is formed on the lower surface of the dielectric strip 3 in the drawing in the longitudinal direction. The engaging protrusion 4 on the conductor plate side and the engaging recess 5 on the dielectric strip side are engaged with each other so as to position the dielectric strip 3 in the width direction. The configuration on the second conductor plate 2 side is the same as that in the first embodiment.

As described above, the positioning is performed by the engagement between the engaging projection 4 on the conductor plate side and the engagement recess 5 on the dielectric strip side, so that the width of the groove g1 of the first conductor plate 1 is increased. W1 can be made wider than in the case of the first embodiment shown in FIG. For example, W1 = W2.

With such a structure, the gap between the left and right inner side surfaces of the groove g1 and the left and right side surfaces of the dielectric strip 3 can be made uniform at each part of the dielectric strip.
As a result, in each part of the dielectric line, the propagation constant becomes uniform, and the reflection loss is suppressed.

Next, the configuration of a millimeter wave radar module according to a third embodiment of the present invention will be described with reference to FIG. FIG. 4 is a block diagram of the millimeter wave radar module. Here, the VCO is a voltage controlled oscillator including a Gunn diode oscillator and a variable reactance element such as a varactor diode, and oscillates a millimeter wave signal according to a modulation signal.
The circulator A and the terminator A transmit the output signal of the VCO in the coupler direction, and absorb the reflected wave returning in the VCO direction in the terminator A. This circulator A and terminator A
This constitutes an isolator. The coupler propagates a signal from the circulator A as a transmission signal Tx toward the circulator B, and extracts a part of the signal as a local signal Lo. The terminator B absorbs the reflected wave returning from the circulator B toward the coupler. The coupler and the terminator B constitute a directional coupler. Circulator B propagates transmission signal Tx to the antenna and propagates reception signal Rx from the antenna to the mixer. The mixer mixes the received signal Rx with the local signal Lo and outputs the beat signal as an intermediate frequency signal IF. The first transmission line for each signal shown in FIG.
-The dielectric line shown in the second embodiment is used.

[0020]

According to the first aspect of the present invention, by inserting the dielectric strip into the groove of the first conductor plate,
The positioning of the dielectric strip is performed with high precision, and the groove of the second conductor plate is easily fitted into the positioned dielectric strip. In addition, since the relative positional accuracy between the groove of the first conductor plate and the dielectric strip is high, the variation in the gap between the side surface of the dielectric strip and the inner surface of the groove is small, and a dielectric line with low reflection and low transmission loss is obtained. can get.

According to the second aspect of the present invention, even if the groove width of the first or second conductor plate does not match the width of the dielectric strip with high accuracy, positioning in the width direction in the groove can be achieved. Since the cross-sectional structure in the vicinity of the dielectric strip is uniform at each part of the dielectric line, the variation in the propagation constant of the dielectric line is reduced, and the reflection loss is suppressed.

According to the third aspect of the present invention, a high-gain radio apparatus can be easily obtained by using a low-loss dielectric line. Also, when a long dielectric strip is disposed between the first and second conductor plates, the assembly is easy, so that a relatively large-scale circuit can be formed between the two conductor plates. The degree of integration can be easily increased. For example, in a millimeter wave radar module, by applying to a transmission line that transmits a signal transmitted to an antenna or a signal received from an antenna,
A high-gain and small millimeter-wave radar can be configured.

[Brief description of the drawings]

FIG. 1 is a sectional view of a dielectric line according to a first embodiment.

FIG. 2 is a diagram showing a relationship between a gap between a groove width W2 and a dielectric strip width W in the same dielectric line and transmission loss.

FIG. 3 is a sectional view of a dielectric line according to a second embodiment.

FIG. 4 is a block diagram showing a configuration of a millimeter wave radar module according to a third embodiment.

FIG. 5 is a sectional view showing a configuration of a conventional dielectric line.

[Explanation of symbols]

 1-first conductor plate 2-second conductor plate 3-dielectric strip 4-engaging protrusion 5-engaging recess

Claims (3)

[Claims] 1. A dielectric strip is disposed between substantially parallel first and second conductor plates, and a propagation region for transmitting an electromagnetic wave at the dielectric strip portion and an electromagnetic wave is blocked at a portion other than the dielectric strip. A groove for fitting the dielectric strip is formed in the first conductor plate, the groove being wider than the groove of the first conductor plate and covering the dielectric strip. Formed on the second conductor plate. 2. A dielectric strip is disposed between substantially parallel conductor plates, and a propagation region in which electromagnetic waves are propagated in the dielectric strip portion and a non-propagation region in which electromagnetic waves are blocked in portions other than the dielectric strip. In the provided dielectric line, a groove for disposing the dielectric strip is formed in the two conductor plates, and a groove bottom surface of at least one of the conductor plates and the dielectric strip portion in contact with the groove bottom surface are provided,
A dielectric line, wherein an engagement portion for engaging the one conductor plate and the dielectric strip is formed. 3. A wireless device using the dielectric line according to claim 1 as a transmission line for a transmission signal or a reception signal.