JP2002176302A - Directional coupler, high frequency module and communication equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To construct a small directional coupler composed of a slot line whose coupling is large. SOLUTION: Two lines 4a and 4b obtained by opening respectively a part of a ground electrode 2 formed on one surface of a dielectric board 1 in a slot shape are formed and arranged parallelly for a prescribed length by making the lines 4a and 4b partially adjacent at a prescribed interval. Two electrode removed parts 5a and 5b are formed in a prescribed width on the ground electrode 2 sandwiched by the parallelly arranged slots 4a and 4b with an interval about 1/4 of a signal wavelength in the propagation direction of a signal, and the ground electrode 2 separated by the two electrode removing parts 5a and 5b are electrically connected with two wires 6 that a re not in contact with the dielectric board 1b. Meanwhile, slots 4c and 4d and electrode removed parts 5c and 5d and a wire 6 are also provided on the other surface of the dielectric board 1 having a ground electrode 3 so as to face the surface having the ground electrode 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a directional coupler used in a microwave band and a millimeter wave band, a high-frequency module including the same, and a communication device.

[0002]

2. Description of the Related Art Conventionally, as a directional coupler formed on a dielectric substrate, one having two microstrip lines arranged close to each other and arranged in parallel over a predetermined length has been used. As described above, the directional coupler using the microstrip line is suitable for a high-frequency circuit using a microstrip line as a transmission line, but is applicable to a high-frequency circuit using a slot line or a slot-type line as a transmission line. It was difficult.

Therefore, it is conceivable to construct a slot-type directional coupler by replacing a microstrip line with a slot line as it is. An example will be described with reference to FIG.

FIG. 7A is an external perspective view of a slot line directional coupler, FIG. 7B is a plan view, and FIG. 7C is a side sectional view.

In FIG. 7, reference numeral 1 denotes a dielectric substrate, and a ground electrode 2 is formed on one surface of the dielectric substrate 1. The ground electrode is formed with two slots 4a and 4b, each of which is opened in a slot shape with a width W, and a part of the slots 4a and 4b is brought close to each other at an interval s to form a predetermined length. Are arranged in parallel by L.

As shown in FIG. 7A, the slot 4a
Are both PORT1 and PORT2, and correspondingly, both ends of the slot 4b are PORT4 and PORT3.
And When a signal is input from PORT1, PORT3 functions as a coupling port, and PORT4 functions as an isolation port.

[0007]

A directional coupler having such slots arranged in parallel with the slots close to each other has the following problems to be solved.

That is, in general, a slot-based line has a problem that the coupling amount cannot be increased because the electromagnetic field in the slot portion is highly confined. In order to increase the coupling amount, it is effective to reduce the distance between the two slots, but from the viewpoint of dimensional accuracy and the linear density of circuit fabrication,
There is a limit naturally. In addition, it is possible to increase the coupling amount by increasing the length L of the coupling portion, but the external shape of the high-frequency module is increased by increasing the external shape of the circuit. For example, if a 3 dB directional coupler is to be configured at 25 GHz, the length L of the coupling portion needs to be 10 mm or more.

An object of the present invention is to provide a small directional coupler having a desired coupling amount using a planar dielectric line, a high-frequency module including the same, and a communication device.

[0010]

SUMMARY OF THE INVENTION According to the present invention, two lines each having a part of a ground electrode opened in a slot shape are arranged in parallel on a dielectric substrate so that a part of each line is brought close to each other. A ground electrode sandwiched between the parallel arrangement portions of the two lines is provided with two electrode removing portions at an interval of approximately の wavelength of the signal wavelength in the signal propagation direction, and between the electrodes separated by the removing portion, A conductor bridge that does not contact the dielectric substrate is formed.

Further, according to the present invention, the slot openings are formed on both surfaces of the dielectric substrate at symmetrical positions sandwiching the dielectric substrate.

Also, the present invention provides the above-mentioned conductor bridge,
Consist of metal wire or metal ribbon.

Further, the present invention provides a dielectric layer provided on a surface of a dielectric substrate, a plurality of via holes provided in the dielectric layer, the plurality of via holes being electrically connected to the separated electrodes, and the via hole provided in the dielectric layer. The conductor bridge is constituted by a conductor pattern that conducts between them.

Further, according to the present invention, the positions of the electrode removal portions on both surfaces of the dielectric substrate are formed at plane-symmetric positions.

Further, according to the present invention, a high-frequency module is formed using the directional coupler.

Further, according to the present invention, a communication device is configured using the high-frequency module.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of a directional coupler using a planar dielectric line according to a first embodiment will be described with reference to FIGS. 1A is an external perspective view of the directional coupler, FIG. 1B is a plan view, and FIGS. 1C and 1D are side sectional views.

In FIG. 1A, reference numeral 1 denotes a dielectric substrate, and ground electrodes 2 and 3 are formed on both surfaces of the dielectric substrate 1. On one surface of the dielectric substrate 1, two slots 4a and 4b each formed by opening a part of the ground electrode 2 in a slot shape with a width W are formed.
Parts of a and 4b are arranged in parallel at a predetermined length L so as to be close to each other at an interval s. As shown in FIG. 1B, two electrode removing portions are provided on the ground electrode 2 sandwiched between the slots 4a and 4b arranged in parallel at an interval of approximately 1/4 of the signal wavelength in the signal propagation direction. 5a and 5b are formed with a predetermined width, and the ground electrode 2 separated by the two electrode removing portions 5a and 5b is electrically connected by two wires 6 not in contact with the dielectric substrate 1.

On the other hand, slots 4c and 4d and electrode removing portions 5c and 5d are formed in the ground electrode 3 so as to face the surface having the ground electrode 2 also on the other surface of the dielectric substrate 1, and are separated from each other. A wire 6 for electrically connecting the ground electrode 3 is provided.

At this time, both ends of the slot 4a and the slot 4c are PORT1 and PORT2, and both ends of the slot 4b and the slot 4d are opposed to the PORT1 and PORT2.
4, PORT3.

The signal incident from the PORT 1 propagates through the line composed of the slot 4a, the slot 4c and the dielectric substrate 1 and is output to the PORT 2. By using the above-described structure, the slot 4a , 4b are connected to each other via two electrode removing portions 5a, 5b,
On the other side, a part of the signal flows out to the line composed of the slot 4b, the slot 4d and the dielectric substrate 1 by the slot 4c, 4d being coupled to each other via the two electrode removing portions 5c, 5d. I do.

At this time, the signal passing through the electrode removing portions 5a and 5c to the PORT 4 and the signal passing through the electrode removing portions 5b and 5d to the PORT 4 are two signals formed on the same plane. Electrode removal parts (5a and 5b, 5
By setting the interval between c and 5d) to be approximately 1/4 of the signal wavelength λ, the phases of the signals are shifted by λ / 2 and become opposite phases, and thus cancel each other out, and no signal is output to the PORT4. On the other hand, since the signals traveling to PORT3 have the same phase, a signal is output to PORT3.
Therefore, it has a function as a directional coupler.

The form of the conductor for electrically connecting the ground electrode separated by the two electrode removing portions may be not only a wire but also a ribbon having a predetermined width.

Further, the slot is formed only on one surface,
The characteristics as a directional coupler can also be provided by providing an electrode removing section and electrically connecting the separated ground electrode with a wire. However, by using the above-described structure on both sides of the dielectric substrate, the energy of the transmission signal can be concentrated on the dielectric substrate portion sandwiched by the slots formed on both sides, thereby reducing transmission loss and improving Transmission characteristics can be obtained.

Next, differences in characteristics between the directional coupler according to the prior art shown in FIG. 7 and the directional coupler according to the first embodiment will be described with reference to FIGS.

FIG. 2A is a plan view of the directional coupler according to the first embodiment, and FIG. 2B is a directional coupler according to the first embodiment which uses no wires. FIG. 9 is a plan view of a directional coupler having a structure in which a part of the electrode removal portions 5a to 5d of the ground electrodes 2 and 3 is left without being removed as indicated by 6 '. In FIG. 2, La is the length of the lines arranged in parallel,
Lb indicates the distance between the centers of the electrode removing portions, W indicates the slot width, and s indicates the slot interval.

FIG. 3 shows the frequency characteristic of each characteristic value according to each specification, and FIG.
3A, that is, the characteristics of the directional coupler according to the first embodiment, FIG. 3B shows the characteristics of the directional coupler having the specifications shown in FIG. 2B, and FIG. (C) shows the characteristics of the directional coupler shown in FIG.

In calculating the characteristics shown in FIG. 3, La, Lb, W, and s shown in FIG.
Lb = 0.75 mm, W = 0.2 mm, s = 0.1 mm
Was set.

Further, as a frequency band, characteristics of 22 to 28 GHz were calculated centering on 25 GHz.

In FIG. 3, S11 is a reflection loss, S21
Indicates insertion loss characteristics, S31 indicates directionality, and S41 indicates isolation characteristics.

As can be seen from FIG.
In the vicinity of 5 GHz, S41 is greatly attenuated, and the coupling amount (= S31-S4
1 (dB)), and the characteristics as a directional coupler are improved. In addition, since S31 has a flat characteristic curve, stable directionality can be obtained in a wide frequency band.

As can be seen from FIG. 3B, when only a part of the electrode is left and replaced with a wire,
Effective isolation cannot be obtained, and sufficient characteristics as a directional coupler cannot be obtained.

This is because the slots 4a, 4c to the slots 4b, 4d
This is because the signal does not flow directly to the device. Therefore, it can be seen that a directional coupler having a large coupling amount can be formed by electrically connecting the electrode removing portion with a metal not in contact with the dielectric substrate 1.

Note that, on the two surfaces of the dielectric substrate 1,
The same effect as described above can be obtained even if the two electrode removing portions are not formed at the opposing positions, but the electrode removing portions (5a and 5b, 5c and 5d) on the respective surfaces are placed at the opposing positions. By forming (5c for 5a and 5d for 5b), the vertical symmetry of the dielectric substrate 1 is maintained, unnecessary spurious modes are not generated, and high isolation characteristics can be maintained.

Next, the configuration of a directional coupler using a planar dielectric line according to the second embodiment will be described with reference to FIG. FIG. 4A is an external perspective view of a directional coupler, and FIG.
Is a plan view, and (C) is a side sectional view.

In FIG. 4A, reference numeral 1 denotes a dielectric substrate, and ground electrodes 2 and 3 are formed on both surfaces of the dielectric substrate 1. On one surface of the dielectric substrate 1, two lines 4a and 4b each formed by opening a part of the ground electrode 2 in a slot shape are formed, and a part of the slots 4a and 4b is arranged at a predetermined interval. They are arranged close to each other by a predetermined length. As shown in FIG. 4B, two electrode removing portions are provided on the ground electrode 2 sandwiched between the slots 4a and 4b arranged in parallel at an interval of approximately 1/4 of the signal wavelength in the signal propagation direction. 5a and 5b are formed with a predetermined width.

Reference numerals 9a and 9b denote dielectric layers laminated on the dielectric substrate 1. The dielectric layer 9a includes an electrode removing portion 5
Via holes 7a, 7a ', 7b, 7b' are formed at positions separated by a predetermined distance from a, 5b, respectively. Via holes 7a-7 are formed on the outer surface of the dielectric layer 9a.
Strip lines 8a and 8b are formed so as to electrically connect between a 'and 7b-7b'.

Similarly, via holes 7c, 7c ', 7d, 7d' and strip lines 8c, 8d are formed in the dielectric layer 9b, and the separated ground electrodes 3 are electrically connected. ing.

With this structure, the same effect as that of the first embodiment can be obtained, and by using the layer structure, the strength of the electrical connection between the separated ground electrodes can be increased, and the reliability can be improved. Is improved. In addition, since the positional accuracy of the connection portion is higher than when a wire or a ribbon is used, reproducibility of characteristics is improved, and mass productivity is improved.

The via holes 7c, 7c ', 7d, 7
d 'and the strip lines 8c, 8d are connected to the via holes 7a, 7d.
If a ', 7b, 7b' and the strip lines 8a, 8b are formed in plane symmetry, the vertical symmetry of the dielectric substrate 1 is maintained, unnecessary spurious modes do not occur, and high isolation is achieved. Characteristics can be maintained.

Next, the configuration of the high-frequency module according to the third embodiment will be described with reference to FIG. FIG. 5 is a block diagram illustrating a configuration of the high-frequency module. In FIG. 5, VCO is a voltage controlled oscillator, ISO is an isolator, CPL is a directional coupler, and Cir. Is a circulator, MIX is a mixer, and AMP is an operational amplifier. The oscillation signal of the VCO includes an isolator ISO, a directional coupler CPL, and a circulator Cir. And transmitted from the antenna. The signal received from the antenna is transmitted to the circulator Cir. Is input to the mixer MIX. The mixer MIX mixes this signal with the signal from the directional coupler CPL to generate an intermediate frequency signal. The amplifier AMP amplifies this signal and outputs it as an intermediate frequency signal IF.

For the directional coupler CPL shown in FIG. 5, the directional coupler shown in FIG. 1 or 2 is used. In this manner, by using a directional coupler having excellent characteristics of the directionality and the amount of coupling, a small-sized high-frequency module having excellent characteristics can be configured.

Next, the configuration of a communication device according to the fourth embodiment will be described with reference to FIG. FIG. 6 is a block diagram illustrating a configuration of the communication device. This communication device includes the high-frequency module and the signal processing circuit shown in FIG. The signal processing circuit illustrated in FIG. 6 includes an encoding / decoding circuit,
The communication device is constituted by a synchronization control circuit, a modulator, a demodulator, a CPU, and the like. The signal processing circuit is further provided with a circuit for inputting and outputting a transmission / reception signal. As described above, by using the high-frequency module, a communication device that is small and has excellent communication performance is configured.

[0044]

According to the present invention, two lines, each having a part of the ground electrode opened in a slot shape, are arranged in parallel on the dielectric substrate so that the parts of the respective lines are close to each other. The two electrode removing portions are formed at intervals of approximately 1/4 wavelength of the signal wavelength in the signal propagation direction on the ground electrode formed and sandwiched between the parallel arrangement portions of the two lines, and between the electrodes separated by the removing portion. By forming a conductor bridge not in contact with the dielectric substrate, a small directional coupler having a large coupling amount and coupling in a wide frequency band can be configured.

Further, according to the present invention, by forming the slot openings on both sides of the dielectric substrate at symmetrical positions with respect to the dielectric substrate, the dielectric openings sandwiched between the slots formed on both sides are formed. The energy of the transmission signal can be concentrated on the body substrate, and a small directional coupler with small transmission loss can be configured.

According to the present invention, the directional coupler can be easily formed by forming the conductor bridge with a metal wire or a metal ribbon.

Further, according to the present invention, a conductor bridge is constituted by a plurality of via holes provided in a dielectric layer on the surface of a dielectric substrate and electrically connected to spaced electrodes, and a conductor pattern for conducting between the via holes. Thereby, a highly reliable directional coupler can be configured. In addition, since the position accuracy of the connection portion is increased, the reproducibility of the characteristics is improved,
Mass production is enhanced.

Further, according to the present invention, by forming the electrode removal portions on both surfaces of the dielectric substrate in plane symmetry, unnecessary small spurious modes do not occur and a small directional coupler having high isolation characteristics is provided. Can be configured.

Further, according to the present invention, by using the directional coupler, a compact high-frequency module having excellent electric characteristics can be configured.

Further, according to the present invention, by using the high-frequency module, a compact communication device having excellent communication characteristics can be configured.

[Brief description of the drawings]

FIG. 1 is an external perspective view, a plan view, and a side sectional view of a directional coupler according to a first embodiment.

FIG. 2 is a plan view of the directional coupler according to the first embodiment.

FIG. 3 is a diagram illustrating frequency characteristics of the directional coupler according to the first embodiment;

FIG. 4 is an external perspective view and a side view of a directional coupler according to a second embodiment.

FIG. 5 is a block diagram of a high-frequency module according to a third embodiment.

FIG. 6 is a block diagram of a communication device according to a fourth embodiment;

FIG. 7 is an external perspective view, a plan view, and a side sectional view of a conventional directional coupler.

[Explanation of symbols]

 1-dielectric substrate 2,3-ground electrode 4a-4d-slot 5a-5d-electrode removal part 6-wire 7a-7d'-via hole 8a-8d-strip line 9a, 9b-dielectric layer La-slot close to parallel Arrangement length Lb-Pitch for forming electrode removal portion s-Slot interval (electrode width) W-Slot width

Claims (7)

[Claims] 1. A dielectric substrate and two lines formed on the dielectric substrate with a part of a ground electrode opened in a slot shape, wherein a part of each line is arranged in parallel with each other close to each other. Providing two electrode removal portions by removing the ground electrode sandwiched between the parallel arrangement portions of the two lines at an interval of approximately 波長 wavelength of the signal wavelength in the signal propagation direction of the two lines; A directional coupler formed by electrically connecting the electrodes separated by the removing portion with a conductor bridge not in contact with the dielectric substrate. 2. The slot-shaped opening is formed on both surfaces of the dielectric substrate at symmetrical positions sandwiching the dielectric substrate, and a transmission signal is formed on a portion of the dielectric substrate sandwiched by the slot-shaped opening. 2. The directional coupler according to claim 1, wherein the directional coupler is a planar dielectric line on which energy is concentrated. 3. The directional coupler according to claim 1, wherein the conductor bridge is formed of a metal wire or a metal ribbon. 4. A dielectric layer provided on a surface of the dielectric substrate, a plurality of via holes provided in the dielectric layer, each of which is electrically connected to the separated electrode, and a via hole provided on the dielectric layer. 3. The directional coupler according to claim 1, wherein the conductor bridge is formed by a conductor pattern that conducts. 5. The directional coupler according to claim 2, wherein the positions of the electrode removing portions on both surfaces of the dielectric substrate are plane-symmetric with respect to the dielectric substrate. 6. A high-frequency module comprising the directional coupler according to claim 1. 7. A communication device comprising the directional coupler according to claim 1 or the high-frequency module according to claim 6.