JPH11355009A - Strip line resonator, strip line filter, strip line duplexer and communication equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily obtain outer connection of a desired value even if outer connection by means of a tap feeding method is applied to a step impedance resonator. SOLUTION: In the strip line filter, resonance electrodes 13a, 13b, 13c and input/output lines 15a and 15b are formed on the upper face of a dielectric substrate 12 and a ground electrode 16 is formed on the whole rear face of the dielectric substrate 12. The line width of both end parts in the resonance electrodes 13a, 13b and 13c are larger than those of center parts. The line widths are made in forms that they stepwise change. The outer sides of resonance electrodes 13a and 13c becoming input/output stages are formed by straight lines and the input/output lines 15a and 15b are connected to the sides of the straight lines.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a stripline resonator, a stripline filter, a stripline duplexer, and a communication device.

[0002]

2. Description of the Related Art Conventionally, there has been a strip line resonator having a resonance electrode formed on a dielectric substrate as a resonator used for a microwave or millimeter wave band filter. In this strip line resonator, the line of the resonance electrode is used. By changing the characteristic impedance in the longitudinal direction of the resonator by changing the width in steps, the resonator length can be shortened to reduce the size, or the step impedance can be improved. Strip-line resonators of the type are known. The resonance electrode of a conventional step impedance type stripline resonator is formed in a substantially symmetric shape with respect to a central axis, and both sides of the resonance electrode are formed in a step shape.

Normally, coupling (external coupling) to an external circuit such as a stripline resonator of this type or a filter using the stripline resonator is performed by capacitive coupling using a gap capacitance between a resonance electrode and an input / output line. How to get the
Alternatively, a method of directly connecting an input / output line to the resonance electrode to obtain external coupling, a so-called tap feeding method, is used. In the former external coupling by capacitive coupling, the degree of external coupling (hereinafter, referred to as external coupling Q) is changed by changing the gap size, and the desired external coupling Q is obtained by adjusting the gap size. In the latter external coupling by the tap feeding method, the external coupling Q is changed by changing the connection position of the input / output line to the resonance electrode (hereinafter referred to as a tap position), and the tap position is adjusted to obtain a desired external coupling. The connection Q is obtained.

[0004]

In the external coupling by the capacitive coupling, the rate of change of the external coupling Q with respect to the gap dimension is large, and strict dimensional accuracy is required to obtain a desired external coupling Q. It has the disadvantage that it is difficult or that the desired external coupling Q cannot be obtained. On the other hand, in the external coupling by the tap feeding method, the rate of change of the external coupling Q with respect to the tap position is gentler than that of the capacitive coupling, and the desired external coupling Q
Can be easily obtained.

However, in the above-described conventional step-impedance stripline resonator, since the side of the resonance electrode to which the input / output line is connected is formed in a step-like manner, for example, as shown in FIG. When the tap position is at or near the step portion of the resonance electrode where the tap position changes, as shown by the broken line in FIG. 3, the external coupling Q sharply changes, and the setting of the external coupling Q There was a problem that adjustment was very difficult. That is, by continuously changing the tap position, a gentle and continuous change in the external coupling Q cannot be obtained.
There is a problem that a desired external coupling Q cannot be obtained.

Accordingly, an object of the present invention is to provide a strip line resonator and a strip line which can easily obtain a desired value of external coupling even when external coupling by a tap feed method is applied to a step impedance type resonator. A filter, a stripline duplexer, and a communication device are provided.

[0007]

In order to achieve the above object, a strip line resonator, strip line filter or strip line duplexer according to the present invention has a line width formed on a dielectric substrate which changes stepwise. The input / output line is connected to the resonance electrode of the strip line resonator composed of the resonance electrode of the shape, and the side of the resonance electrode to which the input / output line is connected is formed as a straight line or a gentle curve. It is characterized by having.

In the strip line resonator, strip line filter or strip line duplexer having the above configuration, the side to which the input / output line of the step impedance type resonance electrode whose line width changes stepwise is connected is straight or gentle. Since it is formed by a curve,
By continuously changing the position (tap position) where the input / output line is connected, a gentle and continuous change in the external coupling Q can be obtained. Therefore, in the stripline resonator, the stripline filter, or the stripline duplexer according to the present invention, the external coupling Q having a desired value can be easily obtained by adjusting the tap position.

Further, since the communication apparatus according to the present invention includes the stripline resonator, the stripline filter or the stripline duplexer having the above-mentioned features, it can be easily connected to other circuit parts with an appropriate external coupling Q. Can be connected. Therefore, an inexpensive communication device having good characteristics can be obtained.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of a strip line filter according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a perspective view of a stripline filter,
FIG. 2 is a plan view showing the upper surface of FIG. The strip line filter of the present embodiment has a half wavelength (λ
/ 2) a filter composed of three step-impedance stripline resonators having a dielectric substrate 12 having a predetermined relative dielectric constant, and having resonance electrodes 13a, 13b, 13c and input electrodes on the upper surface of the dielectric substrate 12. Output line 15
a and 15b are formed, and a ground electrode 16 is formed on the entire lower surface of the dielectric substrate 12. Resonant electrodes 13a, 13
b and 13c are arranged in parallel so that their axes are parallel to each other, and the resonators formed for each of the resonance electrodes 13a, 13b and 13c are electromagnetically coupled to each other.

The resonance electrodes 13a, 13b, and 13c are formed such that the line width at both ends is larger than the line width at the center, and the line width is changed stepwise. A stripline resonator is formed. The resonance electrode 13b arranged at the center is formed in a step shape on both sides of the line length, but the resonance electrodes 13a and 13c serving as input / output stages are formed with straight sides on the outer side. The input / output lines 15a and 15b are connected to the side, respectively. That is, in the present embodiment, the side to which the input / output line of the step impedance type resonator of the input / output stage is connected is formed as a straight line.

FIG. 3 is a diagram showing an example of the relationship between the tap position (X in FIG. 2) and the external coupling Q in a step impedance type stripline resonator having a center frequency of about 60 GHz. As shown in FIG. 3, when the tap position is changed in the conventional resonator, the external coupling Q sharply changes in a step-like manner at a certain tap position, but in the resonator of the present embodiment, the tap position is changed. On the other hand, the outer bond Q is gentle and continuously changing.

That is, in the configuration of the stripline filter of the present embodiment, a gentle and continuous change of the external coupling Q can be obtained by continuously changing the tap position, and therefore the tap position is adjusted. This makes it possible to easily obtain the external coupling Q having a desired value.

Further, in this embodiment, since each of the resonance electrodes is a step impedance type resonator, the length of the resonance electrode is shortened to reduce the size. Also, by changing the step position and the line width of each resonance electrode, the harmonic frequency (2fo,
3fo ..) can be improved to improve spurious characteristics.

Next, the configuration of a strip line filter according to a second embodiment of the present invention will be described with reference to FIG.
In the examples shown in FIGS. 1 and 2 of the first embodiment, the respective resonators are arranged in parallel. However, the strip line filter shown in FIG. 4 has three resonance electrodes 13a, 13b and 13c are arranged in series to constitute a filter. Each resonator is capacitively coupled by a capacitance generated in a gap between adjacent resonance electrodes. One side of the resonance electrodes 13a and 13c serving as input / output stages is formed as a straight line, and the input / output lines 15a and 15b are connected to the sides of the straight line, respectively.

Also in this strip line filter, since the sides to which the input / output lines are connected are formed as straight lines, the same effects as those of the strip line filter of the first embodiment can be obtained.

The input / output lines 15a and 15 shown in FIG.
b is bent at a right angle on the way and drawn out to the left and right ends of the dielectric substrate 12, but is not limited thereto, and may be drawn out to the upper part of the dielectric substrate 12, or The pattern of one of the resonance electrodes may be formed in a reverse shape, and the input / output line may be drawn out to the lower side of the dielectric substrate 12. Further, the input / output line may be extended to the lower surface of the dielectric substrate via the end face so as to be surface-mounted.

That is, the positions and shapes of the lead-out lines of the input / output lines are not limited to those of the first and second embodiments, but are set in consideration of the connection conditions with the external circuit. is there.

In each of the above embodiments, a strip line filter using a plurality of step impedance type strip line resonators has been described as an example. However, one step impedance type strip line resonator may be replaced with a trap filter or an oscillation element. It is needless to say that the present invention can be applied to the case of using as well.

Further, in each of the above embodiments, all the strip line resonators have been described as being of the step impedance type. However, the present invention is not limited to this, and a strip line resonator comprising a resonance electrode having a uniform line width may be used. May be included.

Next, a strip line resonator according to a third embodiment of the present invention will be described with reference to FIG. FIG. 5 shows an electrode pattern of a resonance electrode to which input / output lines are connected.
In the strip line resonators of the first and second embodiments, the sides of the resonance electrode to which the input / output lines are connected are formed linearly. However, the strip line resonator shown in FIG. One side to which the line 15 is connected is formed by a smooth curve. As this curve, a partial curve such as a circle or an ellipse is used.

Also in this configuration, since the side of the resonance electrode to which the input / output line is connected does not have a stepwise changing portion, by continuously changing the tap position, the external coupling Q can be smoothly and continuously changed. Can be obtained. Further, by changing the shape of the curve (for example, the radius of the arc), the rate of change of the external coupling Q with respect to the tap position can be adjusted. Therefore, by adjusting the tap position, an external coupling Q having a desired value can be easily obtained.

Next, the configuration of a strip line duplexer according to a fourth embodiment of the present invention will be described with reference to FIG. The strip line duplexer according to the present embodiment includes six step impedance type resonance electrodes 13 a to 13 f on the upper surface of one dielectric substrate 12, and a transmission input line 15.
a, reception output line 15b and antenna shared line 15c
Are formed. The three resonance electrodes 13a to 13c arranged in a substantially left half area of the dielectric substrate 12 are electromagnetically coupled to each other to form a transmission filter TX. Similarly, the third substrate disposed in the substantially right half area of the dielectric substrate 12
The three resonance electrodes 13d to 13f are electromagnetically coupled to each other to form a reception filter RX.

The outer sides of the resonance electrodes 13a and 13c disposed on both sides of the input / output stage of the transmission filter TX are formed as straight lines, and the transmission input line 15a and the antenna are formed on the sides of the straight lines. The shared lines 15c are respectively connected. Similarly, the outer sides of the resonance electrodes 13d and 13f disposed on both sides serving as the input / output stages of the reception filter RX are formed as straight lines, and the reception input line 15a and the antenna are formed on the sides of the straight lines. The shared lines 15c are respectively connected.

The antenna shared line 15c shares one of the input / output lines of the transmission filter TX and the reception filter RX. The resonance electrode 13c of the transmission filter TX and the resonance electrode 13d of the reception filter RX are connected to the antenna. They are connected by a shared line 15c.

Also in this configuration, the side of the resonance electrode to which the transmission input line, the reception output line, and the antenna shared line connected to the external circuit are formed is a straight line, and there is no portion that changes stepwise. Therefore, by continuously changing the tap position, a gentle and continuous change of the external coupling Q can be obtained.

In the strip line duplexer of the present embodiment, the sides of the resonance electrode connected to the external circuit may be formed with smooth curves. Also,
In the present embodiment, the transmission filter and the reception filter are formed on one dielectric substrate. However, two filters shown in the first embodiment or the second embodiment are used, and one of them is transmitted. A duplexer may be configured as a trust filter and the other as a receiving filter.

Next, the configuration of a communication device according to a fifth embodiment of the present invention is shown in FIG. In FIG. 7, ANT is an antenna, DPX is a duplexer (antenna duplexer), TX
Is a transmission filter, and RX is a reception filter. The output end of the transmission filter TX is connected to the antenna ANT, the input end is connected to the transmission circuit, the input end of the reception filter RX is connected to the antenna ANT, and the output end is connected to the reception circuit to constitute a communication device. .

Here, the duplexer DPX is the fourth
The stripline duplexer of the embodiment can be used. Further, the stripline filter of the first or second embodiment can be used as the transmission filter TX or the reception filter RX. By using the stripline filter and the stripline duplexer according to the present invention, it is possible to easily connect to other circuit sections with an appropriate external coupling Q, and to realize a low-cost communication device with good characteristics. .

The present invention is not limited to the above embodiments, but can be variously modified within the scope of the invention. For example, λ / 4 where one end of the resonance electrode is grounded
The present invention can also be applied to the step impedance type strip line resonator described above. The present invention is also applicable to a stripline resonator having a triplate configuration in which ground conductors are formed above and below a resonance electrode.

[0031]

As described above, according to the present invention,
The side where the input / output line of the step impedance type resonance electrode where the line width changes stepwise is connected is formed as a straight line or a gentle curve, so that the position (tap position) where the input / output line is connected is continuous. By changing to
A gentle and continuous change of the outer coupling Q can be obtained. Therefore, in the stripline resonator, the stripline filter, or the stripline duplexer according to the present invention, the external coupling Q having a desired value can be easily obtained by adjusting the tap position.

Further, by using the stripline resonator, stripline filter or stripline duplexer according to the present invention, it is possible to obtain an inexpensive communication device having good characteristics.

[Brief description of the drawings]

FIG. 1 is a perspective view of a strip line filter according to a first embodiment.

FIG. 2 is a plan view showing the upper surface of FIG.

FIG. 3 is a diagram showing a relationship between a tap position and an external coupling Q of the stripline resonator according to the present invention.

FIG. 4 is a plan view of a strip line filter according to a second embodiment.

FIG. 5 is a diagram showing a pattern of a resonance electrode to which input / output lines according to a third embodiment are connected.

FIG. 6 is a plan view of a strip line duplexer according to a fourth embodiment.

FIG. 7 is a block diagram of a communication device according to a fifth embodiment.

FIG. 8 is a diagram showing a pattern in which input / output lines are connected to a conventional step impedance type resonance electrode.

[Explanation of symbols]

 REFERENCE SIGNS LIST 12 dielectric substrate 13 a to 13 f resonance electrode 15 a to 15 c input / output line 16 ground electrode TX transmission filter RX reception filter DPX duplexer

Claims (5)

[Claims] 1. A strip line resonator comprising a resonance electrode having a shape in which a line width changes stepwise is formed on a dielectric substrate, and an input / output line is connected to the resonance electrode. A stripline resonator, wherein sides of the connected resonance electrode are formed as straight lines or gentle curves. 2. A dielectric substrate comprising a plurality of stripline resonators formed of resonance electrodes, wherein at least one of the resonance electrodes is formed of a resonance electrode having a line width that changes stepwise, and the line width has a step width. An input / output line is connected to at least one of the resonance electrodes having a changed shape, and a side of the resonance electrode to which the input / output line is connected is formed as a straight line or a gentle curve. And a stripline filter. 3. A stripline duplexer comprising at least one of the stripline resonator according to claim 1 or the stripline filter according to claim 2. 4. A plurality of stripline resonators each comprising a resonance electrode constituting a transmission filter and a reception filter are formed on a dielectric substrate, and at least one of the resonance electrodes has a shape in which the line width changes stepwise. An input / output line is connected to at least one of the resonance electrodes having a shape in which the line width is changed in a step-like manner, and the side of the resonance electrode to which the input / output line is connected is straight or gentle. A strip line duplexer characterized by being formed with a simple curve. 5. A strip line resonator according to claim 1, a strip line filter according to claim 2, or a strip line duplexer according to claim 3 or 4. Communication equipment.