JPH11239010A - Non-radiative dielectric line coupler - Google Patents

Abstract

(57) [Problem] To provide a non-radiative dielectric line capable of expanding a bandwidth at a used frequency. A linear or curved first and second dielectric lines (15, 16) are provided adjacent to each other between a pair of parallel flat conductors (14), and the first and second dielectric lines (15, 16) are provided. A high-frequency signal transmitted through the line 16 is output from the first dielectric line 15 and the second dielectric line 16, and
In the transmittance curves for the frequencies of the high-frequency signals output from the first and second dielectric lines 15 and 16, the transmittance at the operating frequency has an extreme value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-radiative dielectric line coupler, and more particularly, to a coupler (coupler) incorporated in a millimeter wave integrated circuit or the like for coupling a non-radiative dielectric line used as a guide for a high-frequency signal. .

[0002]

2. Description of the Related Art Non-radiative dielectric lines
As shown in FIG. 5, an ectric guide (also referred to as an NRD guide) is configured by arranging parallel plate conductors 2 and 3 above and below a dielectric line 1 having a rectangular cross section. In such a nonradiative dielectric line, the interval between the parallel plate conductors 2 and 3 is λ /
When it is less than 2, the high-frequency signal whose wavelength is larger than λ is cut off and cannot enter the space between the parallel plate conductors 2 and 3. When the dielectric line 1 is interposed between the parallel plate conductors 2 and 3, a high frequency signal can be propagated along the dielectric line 1, and a radiation wave from the high frequency signal is transmitted to the parallel plate conductors 2 and 3.
Is suppressed by the blocking effect. Note that λ is approximately equal to the wavelength of a high-frequency signal (electromagnetic wave) that propagates in a vacuum. In FIG. 5, a part of the upper parallel plate conductor 3 is cut away.

In this non-radiative dielectric line, as a coupler used to split and couple a high-frequency signal (electromagnetic wave), two dielectric lines 5 and 6 are arranged at a predetermined interval L as shown in FIG. The arrangement was used. FIG. 6 is a schematic diagram of a dielectric line, and upper and lower parallel plate conductors are omitted.

[0004] Part of the electromagnetic wave incident from the port a of the dielectric line 5 passes through the dielectric line 5 as it is and is output from the port b. Part of the electromagnetic wave is electromagnetically coupled to the dielectric line 6 and c.

[0005] The electromagnetic wave incident from the port d is
Similarly, the output is divided into ports b and c. When electromagnetic waves are incident on ports a and d at the same time, the separated electromagnetic waves are mixed and output to ports b and c.

By appropriately adjusting the distance L between the two dielectric lines, it is possible to obtain a transmittance having a desired division ratio. In non-radiative dielectric waveguides, a splitter or a coupler was configured using this coupler (for example, IEEE T
ransactions on Microwave Theory and Techniques, MT
T-31, No. 8, August 1983, P648-654, JP-A-8-862
No. 1, JP-A-6-174824).

The dielectric lines 5 and 6 do not need to be straight lines. Normally, in order to connect with other non-radiative dielectric line circuits, as shown in FIG. In this case, a combination of the curved dielectric lines 8 and a combination of two curved dielectric lines (not shown) are used.

Linear dielectric line 7 and curved dielectric line 8
Or an asymmetric coupler in which two curved dielectric lines having different radii of curvature are combined, compared with those using two linear dielectric lines 5, 6 or two dielectric lines having the same radius of curvature. It is known that the transmittance to the port c at the time of incidence from a is small. This is believed to be because the high frequency signals in the two dielectric lines are not symmetric.

[0009]

However, since the conventional non-radiative dielectric line coupler has a narrow bandwidth, it is insufficient for a device requiring a wide band such as communication.
In addition, since the band is narrow, it is necessary to finely adjust the distance between the dielectric lines so as to have a desired transmittance at a used frequency, which is difficult to manufacture.

That is, FIG. 8 shows calculation results of characteristics of the conventional non-radiative dielectric line coupler shown in FIG. This characteristic diagram is for a case where a high frequency signal incident from a port a is equally divided into a port b and a port c at an operating frequency of 60 GHz. S _ba represents the transmittance of the high-frequency signal output to port b, and S _ca represents the transmittance of the high-frequency signal output to port c. As shown in FIG. 8, the transmittance changes greatly depending on the frequency. When the frequency deviates from 60 GHz, the transmittance also changes greatly. For this reason, the bandwidth of the conventional coupler usually stays at about 1 GHz. Such a bandwidth of about 1 GHz is insufficient for devices that require a wide band such as communication.

The characteristics of the coupler are such that when the distance L between the two dielectric lines 5 and 6 changes, the transmittance greatly changes. Therefore, it is necessary to arrange the two dielectric lines 5 and 6 with high accuracy. This has hindered mass productivity of the non-radiative dielectric line.

Further, as described above, in an asymmetric coupler in which a linear dielectric line and a curved dielectric line are combined, or two curved dielectric lines having different radii of curvature are combined, the two dielectric lines have different shapes. Due to the asymmetry of the high frequency signal, there is a problem that the high frequency signal as designed is not output to the port c. Therefore, conventionally, it has been necessary to form a coupler by using a curved dielectric line having the same radius of curvature or combining a curved dielectric line with a sufficiently large radius of curvature and a linear dielectric line. Therefore, the degree of freedom in design is reduced, and at the same time, miniaturization of the nonradiative dielectric line circuit is prevented.

The present invention can be applied to a device having a wider bandwidth than conventional devices and requiring a wide band such as communication, and at the same time, can be easily mass-produced, has a high degree of freedom in design, and has a small size. An object of the present invention is to provide a radiative dielectric line coupler.

[0014]

According to the non-radiative dielectric line of the present invention, linear or curved first and second dielectric lines are provided adjacent to each other between a pair of parallel plate conductors. A high-frequency signal transmitted through the dielectric line and / or the second dielectric line is output to the first and second dielectric lines and a high-frequency signal output from the first and second dielectric lines. In the transmittance curve with respect to the frequency of the signal, the transmittance at the used frequency has an extreme value.

Here, it is preferable that the first dielectric line is linear or curved, and the second dielectric line is curved having a radius of curvature smaller than the radius of curvature of the first dielectric line. It is desirable that the first and second dielectric lines have the same extreme value of the transmittance at the used frequency.

It is preferable that the first and second dielectric lines are made of a dielectric material having a relative permittivity of 4 or more, and the second dielectric line is curved with a radius of curvature of 8 mm or less. Further, the first and second dielectric lines are made of a dielectric material having a relative permittivity of less than 4, and the second dielectric line has a radius of curvature of 1.
Desirably, it is a curved shape of 2 mm or less.

[0017]

In a conventional non-radiative dielectric line coupler, two linear dielectric lines are used, a curved dielectric line having the same radius of curvature is used, or a curved dielectric line having a sufficiently large radius of curvature and a straight line are used. It consisted of a combination of dielectric lines. This is due to the problem that a high-frequency signal as designed is not output from port a to port c, as described above.

The characteristics of an asymmetric coupler combining a linear dielectric line and a curved dielectric line are as shown in FIG. An asymmetric coupler has a higher transmittance to port b and a smaller transmittance to port c than a coupler using two linear dielectric lines.

Therefore, the point where the transmittances to the port b and the port c become equal moves to a lower frequency side as compared with the coupler using two linear dielectric lines (FIG. 8).

The present inventors have found that the above-mentioned problems can be solved all at once by positively utilizing such problems of the asymmetric coupler, and have reached the present invention. That is, conventionally, for example, when manufacturing a coupler in which a high-frequency signal is equally distributed to port b and port c at 60 GHz, as shown in FIG.
Although the curve of S _{ba and} the curve of S _ca intersect at 0 GHz, in the present invention, as shown in FIG. 10, the extreme value of the curve of S _ba and the extreme value of the curve of S _ca at an operating frequency of 60 GHz are shown in FIG. Was made to match.

That is, by reducing the radius of curvature of one curved dielectric line, the asymmetry of the two dielectric lines is further increased, and by adjusting the distance between the two dielectric lines, As shown in FIG. 10, the transmittance at the operating frequency becomes an extreme value. Therefore, in the non-radiative dielectric line coupler of the present invention, since the transmittance to the port b and the port c is an extreme value at the operating frequency, the slope of the transmittance curve near the operating frequency becomes very small, The bandwidth is widened, so that the present invention can be applied to devices requiring a wide band such as communication. FIG. 10 is a graph showing the calculation result of the relationship between the transmittance and the frequency of the non-radiative dielectric line coupler of the present invention.

Further, since the bandwidth is wide, even if the distance between the two dielectric lines constituting the coupler slightly changes, the transmittance hardly changes. Therefore, the adjustment is easy, mass production is easy, and the design is free. The degree increases.

Further, the non-radiative dielectric line coupler of the present invention can have a wider bandwidth by making the radius of curvature smaller than that of the conventional dielectric line, so that the coupler can be downsized. The non-radiative dielectric line coupler of the present invention has a 50 G
It is preferably used when used at a high frequency of not less than Hz.

[0024]

FIG. 1 is a perspective view of a non-radiative dielectric line coupler according to the present invention. In FIG. 1, reference numeral 14 denotes a pair of parallel plate conductors, 15 denotes a linear first dielectric line,
Reference numeral 6 denotes a curved second dielectric line. Also, symbols a, b
Are input / output ports of the first dielectric line 15, and are hereinafter referred to as port a and port b, respectively. Symbols c and d are input / output ports of the second dielectric line 16, and are hereinafter referred to as port c and port d, respectively. In FIG. 1, the upper parallel plate conductor 1 is shown.
4 is partially omitted.

In such a non-radiative dielectric line coupler, the high-frequency signal transmitted through the first dielectric line 15 is transmitted by the first dielectric line 15.
The signal is output in the high-frequency signal transmission direction of the dielectric line 15 and is output from the second dielectric line 16.

The high-frequency signal transmitted through the second dielectric line 16 is output in the high-frequency signal transmission direction of the second dielectric line 16 and is also output from the first dielectric line 15. good. Further, a high-frequency signal input from the first dielectric line 15 and the second dielectric line 16 is divided in the high-frequency signal transmission direction of the first dielectric line 15 and the second dielectric line 16 and output. There may be.

The parallel plate conductor 14 is made of a conductor plate of Cu, Al, Fe, SUS (stainless steel), Ag, Au, Pt, or the like, or a conductor layer made of such a conductor, in view of high electric conductivity and workability. A formed insulating plate may be used.

The dielectric lines 15, 16 are desirably made of a low-loss resin material such as Teflon or a low dielectric constant ceramic material such as cordierite. These are low-loss, easy to process, and suitable for mass production.

Although FIG. 1 shows a non-radiative dielectric line coupler in which a linear first dielectric line 15 and a curved second dielectric line 16 are combined, it goes without saying that the present invention deviates from the scope of the present invention. If not, for example, the first dielectric line and the second dielectric line may be curved.

When a high-frequency signal is input from port a,
The decrease in the transmittance to the port c depends on the radius of curvature of the curved second dielectric line 16. Therefore, the minimum value of the transmittance to the port b and the maximum value of the transmittance to the port c increase and decrease as the radius of curvature of the curved second dielectric line 16 decreases. The location of this extremum is
It changes depending on the distance between the two dielectric lines 15 and 16. For this reason, the nonradiative dielectric line coupler of the present invention is realized by intentionally using the curved second dielectric line 16 having a smaller radius of curvature than the conventional one. By setting the radius of curvature of the second dielectric line 16 and the interval between the two dielectric lines 15 and 16 to a predetermined value, a non-radiative dielectric line coupler having an extreme value of a desired transmittance at a desired frequency is formed. You can do it.

The extreme value and frequency of the transmittance are determined by the radius of curvature of the curved second dielectric line 16 and the two dielectric lines 15,
The distance varies depending on the interval of 16 and the width, height, and relative permittivity of the dielectric lines 15 and 16 to be used. For this reason, the optimal second
The radius of curvature of the dielectric line 16 and the two dielectric lines 15, 1
The interval of 6 needs to be determined experimentally or by calculation for a desired transmittance, a desired frequency, and a dielectric line to be used.

In the non-radiative dielectric line coupler of the present invention, the first and second dielectric lines are made of a dielectric material having a dielectric constant of 4 or more, and the second dielectric line has a curved shape with a radius of curvature of 8 mm or less. It is desirable. In particular, it is desirable that the first dielectric line is linear. The first and second dielectric lines preferably have a dielectric constant of 4 to 10 from a practical viewpoint.

When the first and second dielectric lines are made of a dielectric material having a dielectric constant smaller than 4, it is preferable that the second dielectric line has a curved shape with a radius of curvature of 12 mm or less. In particular, it is desirable that the first dielectric line is linear. Preferably, the first and second dielectric lines are dielectrics having a dielectric constant of 2-3. Note that the radius of curvature refers to, for example, R in FIG.

If the above range is satisfied, the larger the difference between the radii of curvature of the two dielectric lines becomes, the smaller the extreme value of the transmittance to the port b becomes. For example, the height is 2.25 mm and the width is 1. 0 GHz, 60 GHz using a dielectric line having a dielectric constant of 5
The 3 dB coupler having the same transmittance to the ports b and c can be realized by using a linear dielectric line and a curved dielectric line having a radius of curvature of about 4 mm.

It should be noted that the present invention is not limited to the above embodiment, and various changes may be made without departing from the scope of the present invention.

[0036]

[Example] Cu 100 × 100 × 8m
m and two parallel plate conductors having a relative permittivity of 4.8 and a linear first dielectric line having a height of 2.25 mm and a width of 1 mm are provided between the parallel plate conductors. A non-radiative dielectric line coupler shown in FIG. 1 was manufactured as follows by disposing a curved second dielectric line.

This embodiment shows a case where a coupler in which high frequency signals are equally distributed to port b and port c at 60 GHz.

A linear first dielectric line having a length of 80 mm was used, and both ends were connected to a waveguide for measurement via a converter. The curved second dielectric line uses a 180 ° bend (semicircular shape) having a radius of curvature of 3.9 mm.
A linear dielectric line was connected to both ends, and connected to a waveguide for measurement via a converter.

The distance between the linear first dielectric line and the curved second dielectric line was experimentally determined to be 1.4 mm so that the transmittance had an extreme value at 60 GHz. For comparison, a conventional coupler having a radius of curvature of 12.7 mm having a radius of 12.7 mm was used.
Symmetric couplers using two 0 ° bends were also made.

With respect to the present invention and the conventional non-radiative dielectric line, the transmission characteristics of the millimeter wave (several tens to several hundreds of GHz band) were measured by a network analyzer [8577C] manufactured by Hewlett-Packard Company. 2 and 3 show the results of the coupler, and FIG. 4 shows the results of the conventional non-radiative dielectric line coupler. Since the transmittance of the vertical axis in the figure includes the loss of the above-described converter, the transmittance of the actual coupler alone becomes about 1 dB larger than this value.

2 and 3, the nonradiative dielectric line coupler of the present invention distributes high-frequency signals substantially equal to ports b and c over a wide frequency range of about 59 to 61.5 GHz, and has a wide band. I understand. On the other hand, in the conventional coupler, it can be seen that the transmittances of the port b and the port c are equal in a very narrow frequency range of about 60 to 60.5 GHz.

[0042]

According to the non-radiative dielectric line coupler of the present invention, the bandwidth can be very wide, and even if the distance between the two dielectric lines slightly changes, the transmittance hardly changes. It can be applied to devices that require a wide band, and at the same time, can be easily mass-produced and has a high degree of design freedom.

Further, in the nonradiative dielectric line coupler of the present invention, the bandwidth can be widened by making the radius of curvature smaller than that of the conventional dielectric line, so that downsizing can be achieved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a non-radiative dielectric line coupler of the present invention.

FIG. 2 is a graph showing the relationship between the transmittance and the frequency of the non-radiative dielectric line coupler of FIG.

FIG. 3 is a graph showing a part of FIG. 2 in an enlarged manner.

FIG. 4 is a graph showing the relationship between the transmittance and the frequency of a conventional non-radiative dielectric line coupler.

FIG. 5 is a perspective view of a non-radiative dielectric waveguide.

FIG. 6 is a schematic view of a conventional non-radiative dielectric line coupler using two linear dielectric lines.

FIG. 7 is a schematic view of a conventional non-radiative dielectric line coupler using a linear dielectric line and a curved dielectric line.

8 is a graph showing a calculation result of a relationship between a transmittance and a frequency of the non-radiative dielectric line coupler of FIG.

9 is a graph showing a calculation result of a relationship between a transmittance and a frequency of the non-radiative dielectric line coupler of FIG. 7;

FIG. 10 is a graph showing a calculation result of a relationship between the transmittance and the frequency of the non-radiative dielectric line coupler of the present invention.

[Explanation of symbols]

 14: Parallel plate conductor 15: First dielectric line 16: Second dielectric line

Claims (3)

[Claims] 1. A linear or curved first and second dielectric line is provided adjacent to a pair of parallel flat conductors to transmit the first and / or second dielectric line. A high-frequency signal is output to the first dielectric line and the second dielectric line, and in a transmittance curve with respect to the frequency of the high-frequency signal output from the first and second dielectric lines, at each of the used frequencies A non-radiative dielectric line coupler characterized by having an extreme value of transmittance. 2. The method according to claim 1, wherein the first dielectric line is straight or curved, and the second dielectric line is curved having a radius of curvature smaller than the radius of curvature of the first dielectric line. The non-radiative dielectric line coupler according to claim 1. 3. The non-radiative dielectric line coupler according to claim 1, wherein the first and second dielectric lines have the same extreme value of transmittance at a used frequency.