JP3676683B2 - Microwave passive circuit, high-pass filter and duplexer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a microwave passive circuit including a tip short-circuited stub made of a suspended line, a high-pass filter including the microwave passive circuit as a component, and a duplexer.
[0002]
[Prior art]
Conventionally, in forming a short-circuited short-circuit stub for a main line through which a signal propagates in a suspended line, the stub is disposed only on one side of the line.
[0003]
FIG. 8 is a configuration diagram of a conventional high-pass filter described in JOHM WILEY & SONS, “MICROWAVE PLANAR PASSIVE CIRCUIT AND FILTERS”, and shows a top view and a cross-sectional view.
In the figure, 100 is an outer conductor, 101 is a dielectric substrate, and 102 is a main line through which a signal propagates. Reference numeral 103 denotes a parallel plate capacitor, which is configured by disposing the main line 102 on both surfaces of the dielectric substrate 101. Further, the outer conductor 100 is provided with a metal post 105, and the post 105 is brought into contact with the tip of the stub 106 connected to the main line 102 to constitute a tip short-circuit stub.
[0004]
[Problems to be solved by the invention]
In the conventional high-pass filter, when forming a short-circuited short stub with respect to the main line 102 through which the signal propagates, the stub 106 is arranged only on one side with respect to the main line 102, and the tip and the outer conductor are in contact with each other. By doing so, a short-circuit point was formed. However, in the configuration as described above, when a displacement occurs between the metal post 105 and the circuit board including the main line 102, the contact position between the short-circuit point and the stub changes, and the electrical length of the stub changes. As a result, there is a problem that the reactance value is shifted and the characteristics of the entire circuit are deteriorated.
[0005]
The present invention has been made to solve the above-described problem, and suppresses fluctuations in reactance of the short-circuited short-circuit stub caused by misalignment between the circuit board of the suspended line and the metal post, and the characteristics of the microwave passive circuit including the stub Deterioration is suppressed.
[0006]
[Means for Solving the Problems]
In the microwave passive circuit according to the present invention, when a circuit is formed by a suspended line , a short-circuit point is formed at one point of a main line through which a signal propagates by bringing a tip into contact with a metal post with a metal screw. The tip short-circuit stubs of the book are connected so that the angle formed by them is 180 degrees, and the length of each stub is less than a quarter wavelength at the operating frequency.
[0008]
Further, the two tip short-circuited stubs are bent in the opposite directions in the middle thereof.
[0011]
The high-pass filter according to the present invention is characterized in that a high-pass element is connected to the microwave passive circuit.
[0012]
Furthermore, the duplexer according to the present invention is characterized in that a low-pass filter is connected to the high-pass filter and a common terminal is provided at the connection point.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1 FIG.
1 is a configuration diagram of a microwave passive circuit according to a first embodiment of the present invention, and shows a top view and a cross-sectional view. In the figure, 1 is an outer conductor, 2 is a dielectric substrate, and includes a main line 3 through which a signal propagates and two stubs 4, which constitute a suspended line. Further, 5 is a metal post, 6 is a metal screw, and these form a short-circuit point, which is brought into contact with the tip of the stub 4 to constitute a tip short-circuit stub. The tip short-circuit stubs 4 are connected so that the angle formed by them is 180 degrees.
[0014]
Next, the operation will be described. Each of the two stubs 4 has a length of less than a quarter wavelength at the operating frequency, and functions as a high-pass element having inductive reactance. Here, when the case where the position of the dielectric substrate 2 including the stub 4 is shifted in the direction parallel to the stub 4 with respect to the outer conductor 1 is considered, when the position of the short-circuit point of the stub 4 is shifted, the stub alone is viewed. The reactance value of fluctuates greatly. However, when considering two stubs together, one stub has a longer reactance value due to an increase in electrical length, while the other stub has a decrease in reactance value due to a decrease in electrical length. Accordingly, the reactance value viewed from a point on the main line 3 to which the two stubs 4 are connected can be maintained at a substantially constant value regardless of the positional deviation of the dielectric substrate 2.
[0015]
As described above, according to the configuration of the first embodiment, the reactance fluctuation due to the misalignment of the short-circuit point when the tip short-circuit stub is configured by the suspended line can be canceled, and the characteristic deterioration of the entire circuit is suppressed. be able to. Although the angle formed between the main line 3 and the tip short-circuit stub 4 is a right angle here, the same effect can be obtained at an angle other than the right angle.
[0016]
Embodiment 2. FIG.
2 is a block diagram showing a microwave passive circuit according to Embodiment 2 of the present invention. In the figure, reference numeral 12 denotes a dielectric substrate, which includes two main lines 13 and two stubs 14 through which signals propagate. The stubs 14 are bent at right angles and in opposite directions. In addition, outside conductors are arranged outside them to form a suspended line as in the first embodiment. Reference numeral 15 denotes a metal post, which forms a short-circuit point, and constitutes a tip short-circuit stub by contacting the tip of the stub 14.
[0017]
Next, the operation will be described. The second embodiment is different from the first embodiment in that the two short-circuited tip stubs 14 are bent at right angles and in opposite directions. Therefore, in the first embodiment, the dielectric substrate 2 including the stub 4 suppresses the characteristic variation when the positional deviation occurs in the direction parallel to the stub 4, whereas in the second embodiment, the dielectric substrate 12 However, it is possible to suppress fluctuations in characteristics when a displacement occurs in a direction perpendicular to the stub 14.
[0018]
As described above, according to the configuration of the second embodiment, it is possible to cancel out the reactance fluctuation caused by the misalignment of the short-circuit point when the tip short-circuit stub is configured with the suspended line, and suppress the characteristic deterioration of the entire circuit. be able to. Here, the angle at which the tip short-circuit stub 14 is bent is a right angle, but the same effect can be obtained when the angle is not a right angle.
[0019]
Embodiment 3 FIG.
3 is a block diagram showing a microwave passive circuit according to Embodiment 3 of the present invention. In the figure, reference numeral 22 denotes a dielectric substrate, which includes a main line 23 and a stub 27 through which a signal propagates. The stub 27 includes a line 24 and a line 26 having a line width larger than that of the line. In addition, outside conductors are arranged outside them to form a suspended line as in the first embodiment. Reference numeral 25 denotes a metal post, which forms a short-circuit point and constitutes a tip short-circuit stub by contacting the tip of the stub 27.
[0020]
Next, the operation will be described. The reactance Z when the short-circuit point side is viewed from a point separated from the short-circuit point of the tip short-circuited stub 27 by the electrical length θ is Zo as the characteristic impedance of the stub and θ as the electrical length of the stub.
Z = jZotanθ
Given in. At this time, the reactance change amount when the electrical length θ changes due to the displacement of the short-circuit point of the stub is proportional to the differential coefficient of the reactance Z and becomes Zo / (cos θ) ² . Therefore, by increasing the line width in the vicinity of the short-circuit point and reducing the characteristic impedance Zo only in the same part, the desired reactance value can be realized with the tip short-circuited short-circuit stub and the reactance change amount can be reduced. Can be small.
[0021]
As described above, according to the third embodiment, it is possible to suppress the reactance fluctuation due to the positional deviation of the short-circuit point when the tip short-circuit stub is configured by the suspended line, and to suppress the characteristic deterioration of the entire circuit. it can.
[0022]
Embodiment 4 FIG.
4 is a block diagram showing a microwave passive circuit according to Embodiment 4 of the present invention. In the figure, reference numeral 32 denotes a dielectric substrate, which includes a main line 33 and a stub 37 through which a signal propagates. The stub 37 includes a line 34 and a line 36 having a line width larger than that of the line. In addition, outside conductors are arranged outside them to form a suspended line as in the first embodiment. Reference numeral 35 denotes a metal post, which forms a short-circuit point and makes a tip short-circuit stub by contacting the tip of the stub 37.
[0023]
Next, the operation will be described. In the fourth embodiment, the microwave passive circuit described in the third embodiment is applied to the microwave passive circuit described in the first embodiment. In both cases, the reactance when the short-circuit position of the tip short-circuited stub fluctuates is changed. Since the change can be suppressed, the reactance change can be further suppressed by using them together.
[0024]
As described above, according to the configuration of the fourth embodiment, it is possible to suppress the reactance fluctuation due to the misalignment of the short-circuit point when the tip short-circuit stub is configured by the suspended line, and to suppress the characteristic deterioration of the entire circuit. be able to.
[0025]
Embodiment 5 FIG.
5 is a block diagram showing a microwave passive circuit according to Embodiment 5 of the present invention. In the figure, reference numeral 42 denotes a dielectric substrate, which includes two main lines 43 and stubs 44 through which signals propagate. The stubs 44 are bent at right angles and in opposite directions, and the lines 45 and It consists of a line 46 having a larger line width than the line. In addition, outside conductors are arranged outside them to form a suspended line as in the first embodiment. Reference numeral 47 denotes a metal post, which forms a short-circuit point and constitutes a tip short-circuit stub by contacting the tip of the stub 44.
[0026]
Next, the operation will be described. In the fifth embodiment, the microwave passive circuit described in the third embodiment is applied to the microwave passive circuit described in the second embodiment. In both cases, the reactance when the short-circuit point position of the tip short-circuit stub varies is used. Since the change can be suppressed, the reactance change can be further suppressed by using them together.
[0027]
As described above, according to the configuration of the fifth embodiment, it is possible to suppress the reactance fluctuation due to the misalignment of the short-circuit point when the tip short-circuit stub is configured by the suspended line, and to suppress the deterioration of the characteristics of the entire circuit. be able to.
[0028]
Embodiment 6 FIG.
6 is a block diagram showing a high-pass filter according to Embodiment 6 of the present invention. In the figure, reference numeral 62 denotes a dielectric substrate, which includes a main line 63 and a stub 64 through which a signal propagates. In addition, outside conductors are arranged outside them to form a suspended line as in the first embodiment. Reference numeral 65 is a metal post that forms a short-circuit point and makes a short-circuited stub by contacting the tip of the stub 64. Reference numeral 66 denotes a capacitor, which is composed of a chip capacitor or a parallel plate capacitor.
[0029]
Next, the operation will be described. In the sixth embodiment, a capacitor 66, which is a high-pass element, is connected to the microwave passive circuit shown in the first embodiment, and these constitute a high-pass filter. As described in the first embodiment, the reactance fluctuation when the position of the short-circuit point of the short-circuited short-circuit stub fluctuates can be suppressed by using two stubs. It is possible to realize a high-pass filter with little characteristic deterioration at the time. Note that the high-pass filter can be configured by connecting the capacitor 66, which is a high-pass element, to the microwave passive circuits shown in the second to fifth embodiments.
[0030]
As described above, according to the configuration of the sixth embodiment, it is possible to suppress the reactance fluctuation due to the positional deviation of the short-circuit point when the tip short-circuit stub is configured by the suspended line, and the high-pass filter including the stub can be suppressed. It is possible to suppress the deterioration of characteristics.
[0031]
Embodiment 7 FIG.
FIG. 7 is a block diagram showing a duplexer in accordance with Embodiment 7 of the present invention. In the figure, reference numeral 72 denotes a dielectric substrate including a main line 73 and a stub 74 through which a signal propagates. In addition, outside conductors are arranged outside them to form a suspended line, as in the first embodiment. Reference numeral 75 is a metal post that forms a short-circuit point and is brought into contact with the tip of the stub 74 to constitute a tip short-circuit stub. A capacitor 76 is constituted by a chip capacitor or a parallel plate capacitor, and constitutes a high-pass filter together with the tip short-circuit stub. On the other hand, the dielectric substrate 72 includes a high-impedance line 77 and a low-impedance line 78, which are connected in cascade on the same substrate to form a low-pass filter, and are connected to the high-pass filter. A common terminal 79 is provided at the point, and a duplexer is constituted by the above components.
[0032]
Next, the operation will be described. In the seventh embodiment, a duplexer is configured by connecting a low-pass filter to the high-pass filter described in the sixth embodiment and providing a common terminal at the connection point. Since the high-pass filter can suppress the characteristic fluctuation when the position of the short-circuit point of the tip short-circuit stub fluctuates, as shown in the sixth embodiment, a low-pass filter is connected to the filter. Thus, it is possible to realize a duplexer having a small characteristic variation.
[0033]
As described above, according to the configuration of the seventh embodiment, it is possible to suppress the reactance fluctuation due to the misalignment of the short-circuit point when the tip short-circuit stub is configured with the suspended line, and the high-pass filter including the stub can be suppressed. It is possible to suppress the deterioration of the characteristics of the entire duplexer having the component.
[0034]
【The invention's effect】
As described above, according to the present invention, it is possible to cancel the reactance fluctuation caused by the positional deviation of the short-circuit point when the tip short-circuit stub is configured by the suspended line, and to suppress the characteristic deterioration of the entire circuit.
[0035]
In addition, it is possible to suppress reactance fluctuations due to misalignment of a short-circuit point when a tip short-circuit stub is configured with a suspended line, and to suppress characteristic deterioration of a high-pass filter including the stub.
[0036]
Furthermore, it is possible to suppress reactance fluctuations due to misalignment of the short-circuit point when the tip short-circuit stub is configured with the suspended line, and to reduce the characteristics of the entire duplexer including the high-pass filter composed of the stub as a component. Can be suppressed.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing a microwave passive circuit according to a first embodiment of the present invention.
FIG. 2 is a configuration diagram showing a microwave passive circuit according to a second embodiment of the present invention.
FIG. 3 is a configuration diagram showing a microwave passive circuit according to a third embodiment of the present invention.
FIG. 4 is a configuration diagram showing a microwave passive circuit according to a fourth embodiment of the present invention.
FIG. 5 is a configuration diagram showing a microwave passive circuit according to a fifth embodiment of the present invention.
FIG. 6 is a block diagram showing a high-pass filter according to Embodiment 6 of the present invention.
FIG. 7 is a configuration diagram illustrating a duplexer according to a seventh embodiment of the present invention.
FIG. 8 is a configuration diagram showing a microwave passive circuit using a conventional suspended line.
[Explanation of symbols]
1, 100, outer conductor, 2, 12, 22, 32, 42, 62, 72, 101 Dielectric substrate 3, 13, 23, 33, 43, 63, 73, 102 Main line 4, 14, 27, 37, 44, 64, 74, 106 Stub 5, 15, 25, 35, 47, 65, 75, 105 Metal post, 6 Metal screw, 24, 26, 34, 36, 45, 46 Track, 66, 76 capacitor, 77 high impedance line, 78 low impedance line, 79 branching filter common terminal, 103 parallel plate capacitor, 104 tip short circuit stub.

Claims (4)

In constructing a circuit with a suspended line, the angle formed by two short-circuited stubs with a short- circuit point formed by bringing the tip into contact with a metal post with a metal screw at one point of the main line through which the signal propagates A microwave passive circuit which is connected so as to be 180 degrees and the length of each stub is less than a quarter wavelength at a use frequency. The microwave passive circuit according to claim 1,
The microwave passive circuit, wherein the two short-circuited short stubs are bent in opposite directions in the middle. High pass filter, characterized in that constructed by connecting a high pass element in microwave passive circuit according to claim 1 or 2. A duplexer comprising: a low-pass filter connected to the high-pass filter according to claim 3; and a common terminal provided at the connection point.

Images