JP2014127760A - Filter circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To absorb a plurality of frequency components and to reduce an insertion loss of a desired frequency component.SOLUTION: A filter for passing a first frequency component included in a signal branched by a signal branch unit 2 to an output port 4, and for reflecting second to N-th frequency components included in the signal is provided. The filter includes: a filter circuit 3 for making the second to the N-th frequency components open at the input side; and a filter circuit 5 for passing to a terminator 6 the second to the N-th frequency components included in the signal branched by the signal branch unit 2, and for reflecting the first frequency component included in the signal and for making the first frequency component open at the input side.

Description

  The present invention is mounted on, for example, a wireless communication device or a radar device, and can reduce the loss of the passing amount of signals in the microwave band, the millimeter wave band, and the like, and can increase the number of bands to be absorbed. The present invention relates to a simple filter circuit.

For example, in a high-frequency device that is installed in a wireless communication device or radar device and handles signals in the microwave band or millimeter wave band, the function of passing a signal in a desired frequency band and absorbing a signal in an unnecessary frequency band Is used.
For example, in the filter circuit disclosed in Patent Document 1, the position where the frequency component outside the passband of the bandpass filter (1) becomes open on the input side (output side) of the bandpass filter (input of the bandpass filter) A band pass filter (2) for passing a frequency component outside the pass band of the band pass filter (1) is disposed at a position where the impedance when the band pass filter is viewed from the side is opened, and the band pass filter (2) On the output side, the frequency component outside the pass band of the band pass filter (1) is absorbed by terminating with the characteristic impedance of the band pass filter (2).

Here, the position where the impedance is opened can be realized by arranging a line having a length that opens the impedance in general.
However, it is difficult to manage (control) the reflection phase of the frequency component outside the pass band of the band pass filter. Further, the length at which the impedance is open is a length that is double the wavelength with respect to the specific frequency component.
For this reason, in the position where the frequency component outside the pass band of the band pass filter is open on the input side, the frequency component whose impedance is open is usually one frequency component, and the impedance for any plurality of frequency components Cannot be released.

Usually, the frequency component (1) is passed through and a band pass filter that reflects the frequency components other than the frequency component (1) and the frequency component (2) is reflected and the frequency components (frequency) other than the frequency component (2) are reflected. When compared with the band rejection filter that passes the component (1)), the insertion loss of the frequency component (1) is larger in the band pass filter than in the band rejection filter.
Therefore, in the filter circuit disclosed in Patent Document 1, it is assumed that the insertion loss of the frequency component in the passband becomes large.

In the filter circuit disclosed in Patent Document 1, since the frequency component of the pass band is not open on the input side, the frequency component of the pass band enters the band pass filter and is arranged in the subsequent stage of the band pass filter. The frequency component outside the pass band is absorbed by the terminal portion that absorbs the frequency component outside the pass band.
Therefore, there is a limit to the signals in the unnecessary frequency band that can be absorbed, and the insertion loss of signals in the desired frequency band is increased.

Japanese Patent No. 4643845 (paragraph number [0005])

  Since the conventional filter circuit is configured as described above, it can absorb any one frequency component, but cannot absorb a plurality of frequency components. In addition, there is a problem that insertion loss of a desired frequency component increases.

  The present invention has been made to solve the above-described problems, and an object thereof is to obtain a filter circuit that can absorb a plurality of frequency components and reduce the insertion loss of a desired frequency component. And

  In the filter circuit according to the present invention, a signal branching unit that branches a signal input from an input port, and a first frequency component included in the signal branched by the signal branching unit are passed through an output port, A filter that reflects the Nth frequency component from the second frequency component contained in the signal, wherein the first filter from which the second frequency component to the Nth frequency component is open on the input side; A filter that passes the second to Nth frequency components included in the signal branched by the branching unit to the terminator and reflects the first frequency component included in the signal. The first frequency component is composed of a second filter that is open on the input side.

  According to the present invention, the first frequency component included in the signal branched by the signal branching unit is passed through the output port, while the second frequency component to the Nth frequency component included in the signal are passed. The second frequency component included in the signal branched by the signal branching unit and the first filter in which the Nth frequency component from the second frequency component is opened on the input side To the N-th frequency component through the terminator while reflecting the first frequency component included in the signal, the second filter having the first frequency component open on the input side Therefore, it is possible to absorb a plurality of frequency components and reduce the insertion loss of a desired frequency component.

It is a block diagram which shows the filter circuit by Embodiment 1 of this invention. It is a block diagram which shows the filter circuit by Embodiment 2 of this invention. It is a block diagram which shows the filter circuit by Embodiment 3 of this invention. It is a block diagram which shows the filter circuit by Embodiment 4 of this invention. It is a disassembled perspective view which shows the filter circuit 3 of the filter circuit by Embodiment 5 of this invention. FIG. 6 is a top view showing an upper surface 42 of the dielectric substrate 41 of FIG. 5. It is a bottom view which shows the lower surface 52 of the dielectric substrate 51 of FIG. It is sectional drawing of the filter circuit 3 in AA of FIG.

Embodiment 1 FIG.
FIG. 1 is a block diagram showing a filter circuit according to Embodiment 1 of the present invention.
In FIG. 1, an input port 1 is a port for inputting a signal.
The signal branching unit 2 is disposed on the input side of the filter circuits 3 and 5, and is a branching path that branches a signal input from the input port 1.
The filter circuit 3 passes the first frequency component included in the signal branched by the signal branching unit 2 to the output port 4, while the second to Nth (N is 3 or more) included in the signal. This is a filter that reflects (integer) frequency components, and the first to Nth frequency components are open on the input side.

The filter circuit 5 allows the second to Nth frequency components included in the signal branched by the signal branching unit 2 to pass through the terminator 6 and reflects the first frequency component included in the signal. It is a filter, and is a second filter whose first frequency component is open on the input side.
The terminator 6 is provided to absorb the second to Nth frequency components that have passed through the filter circuit 5.

Next, the operation will be described.
The signal input from the input port 1 is branched by the signal branching unit 2 and output to the input side of the filter circuits 3 and 5, but the filter circuit 5 opens the first frequency component on the input side. It is configured as follows.
For this reason, the first frequency component is equivalent to the fact that the load when the filter circuit 5 and the terminator 6 are viewed from the signal branching unit 2 is opened, and the filter circuit 5 and the terminator 6 are not electrically connected. become.
Therefore, the first frequency component included in the signal branched by the signal branching unit 2 is not input to the filter circuit 5 but is input only to the filter circuit 3.
Since the filter circuit 3 is a filter that passes the first frequency component to the output port 4, the first frequency component passes through the filter circuit 3 and is output from the output port 4.

On the other hand, the filter circuit 3 is configured such that the second to Nth frequency components are open on the input side.
Therefore, the second to Nth frequency components are opened when the filter circuit 3 and the output port 4 (load of the output port 4) are viewed from the signal branching unit 2, and the filter circuit 3 and the output port 4 are electrically connected. This is equivalent to not connecting.
Therefore, the second to Nth frequency components included in the signal branched by the signal branching unit 2 are not input to the filter circuit 3 but are input only to the filter circuit 5.
Since the filter circuit 5 is a filter that allows the second to Nth frequency components to pass through the terminator 6, the second to Nth frequency components pass through the filter circuit 5 and are output to the terminator 6. . As a result, the second to Nth frequency components are absorbed by the terminator 6.

  As apparent from the above, according to the first embodiment, the first frequency component included in the signal branched by the signal branching unit 2 is passed through the output port 4 while being included in the signal. The second to Nth frequency components are included in the signal branched by the signal branching unit 2 and the filter circuit 3 that is open on the input side. The second to Nth frequency components are passed through the terminator 6 while the first frequency component included in the signal is reflected, and the first frequency component is opened on the input side. Since the filter circuit 5 is provided, the second to Nth frequency components, which are unnecessary frequency components, can be absorbed, and the insertion loss of the first frequency component, which is a desired frequency component, can be absorbed. To reduce It achieves the effect can be.

In the first embodiment, the frequency of the second to Nth frequency components absorbed by the terminator 6 is arbitrary, and a filter characteristic with a small insertion loss of the first frequency component can be obtained. For example, when each of the second to Nth frequency components is selected to be an integer multiple of 2 to N of the first frequency component, and the filter circuit of FIG. By passing the fundamental wave with low loss, it is possible to absorb 2 to N times higher harmonics (integer multiples of the fundamental wave) of the amplifier which becomes an unnecessary signal. In particular, when the filter circuit according to the first embodiment is provided in the subsequent stage of the amplifier that achieves high efficiency by matching not only the fundamental wave component but also the harmonic component, the load of 2 to N times higher harmonics Can be made constant.
For this reason, stable operation of the amplifier, unnecessary resonance in the communication device or radar device, and reduction of harmonic output can be achieved.

In the first embodiment, the terminator 6 absorbs the second to Nth frequency components. However, by connecting a circuit having a load equivalent to the terminator 6 to the subsequent stage of the filter circuit 5, The second to Nth frequency components may be absorbed. For example, a circuit having a load equivalent to that of the terminator 6 may be an output port or an antenna element.
Note that the filter circuit of FIG. 1 can be configured by a planar circuit.

Embodiment 2. FIG.
FIG. 2 is a block diagram showing a filter circuit according to Embodiment 2 of the present invention. In the figure, the same reference numerals as those in FIG. FIG. 2 shows the internal configuration of the filter circuit 3.
One end of the main line 11 of the filter circuit 3 is connected to the signal branching unit 2, and the other end is connected to the output port 4.

The resonator 12 passes the first frequency component included in the signal branched by the signal branching unit 2 to the output port 4 while reflecting the second frequency component included in the signal. It is comprised from the joint line of the one side short circuit one side open | release line couple | bonded with the main line 11.
The line length 13 of the coupled line constituting the resonator 12 is an odd multiple of approximately 0.25λ (λ is the wavelength) with respect to the second frequency component.
It should be noted that the resonator 12 is located at an open position when viewed from the signal branching unit 2, that is, a position where the distance 14 from the signal branching unit 2 is an odd multiple of approximately 0.25λ with respect to the second frequency component. Is arranged. However, the distance 14 varies depending on various conditions in mounting.

The resonator 15 passes the first frequency component included in the signal branched by the signal branching unit 2 to the output port 4 while reflecting the third frequency component included in the signal. It is comprised from the joint line of the one side short circuit one side open | release line couple | bonded with the main line 11.
The line length 16 of the coupled line constituting the resonator 15 is an odd multiple of approximately 0.25λ with respect to the third frequency component.
Note that the resonator 15 is open when viewed from the signal branching portion 2, that is, a position where the distance 17 from the signal branching portion 2 is an odd multiple of approximately 0.25λ with respect to the third frequency component. Is arranged. However, the distance 17 varies depending on various conditions in mounting.

Next, the operation will be described.
The signal input from the input port 1 is branched by the signal branching unit 2 and output to the input side of the filter circuits 3 and 5, but the filter circuit 5 opens the first frequency component on the input side. It is configured as follows.
For this reason, the first frequency component is equivalent to the fact that the load when the filter circuit 5 and the terminator 6 are viewed from the signal branching unit 2 is opened, and the filter circuit 5 and the terminator 6 are not electrically connected. become.
Therefore, the first frequency component included in the signal branched by the signal branching unit 2 is not input to the filter circuit 5 but is input only to the filter circuit 3.

The filter circuit 3 passes the first frequency component and reflects the second frequency component. The resonator 12 is a band rejection filter, and the first frequency component is allowed to pass and the third frequency component is reflected. Therefore, the first frequency component passes through the filter circuit 3 and is output from the output port 4.
Since the resonators 12 and 15 constituting the filter circuit 3 are band rejection filters that reflect the second and third frequency components, the first frequency is compared with the case of being constituted by a band pass filter. Component insertion loss can be reduced.

On the other hand, the resonators 12 and 15 constituting the filter circuit 3 are configured such that the second and third frequency components are open on the input side.
Therefore, the second and third frequency components are opened when the filter circuit 3 and the output port 4 (load of the output port 4) are viewed from the signal branching unit 2, and the filter circuit 3 and the output port 4 are electrically connected. Is equivalent to not being connected to.
Therefore, the second and third frequency components included in the signal branched by the signal branching unit 2 are not input to the filter circuit 3 but are input only to the filter circuit 5.
Since the filter circuit 5 is a filter that passes the second and third frequency components to the terminator 6, the second and third frequency components pass through the filter circuit 5 and are output to the terminator 6. As a result, the second and third frequency components are absorbed by the terminator 6.

  As apparent from the above, according to the second embodiment, the filter circuit 3 includes the main line 11 having one end connected to the signal branching unit 2 and the other end connected to the output port 4, and the main line. 11, and resonators 12 and 15 of one short-circuited and one-sided open line coupled to the lengths 11 and 16 of the resonators 12 and 15 and the short-circuit position (distance from the signal branching section 2 to the resonators 12 and 15. 14 and 17) are determined according to the second and third frequency components to be reflected, and in addition to the same effects as those of the first embodiment, the insertion loss of the first frequency component is further reduced. There is an effect that can be.

  Further, since the distances 14 and 17 from the signal branching unit 2 to the resonators 12 and 15 can be set independently of the first frequency component, which is a desired frequency component, and other resonators, When the resonators 12 and 15 are viewed from the unit 2, a configuration in which the second and third frequency components are open can be easily constructed.

In the second embodiment, the frequency of the second and third frequency components absorbed by the terminator 6 is arbitrary, and a filter characteristic with a small insertion loss of the first frequency component can be obtained. When each of the second to third frequency components is selected to be an integer multiple of 2-3 of the first frequency component, and the filter circuit of FIG. By passing the wave with low loss, it is possible to absorb the second harmonic (twice the fundamental wave) and the third harmonic (three times the fundamental wave) of the amplifier as an unnecessary signal. In particular, when the filter circuit according to the second embodiment is provided in the subsequent stage of the amplifier that achieves high efficiency by matching not only the fundamental wave component but also the harmonic component, a load of 2 to 3 times higher harmonics Can be made constant.
For this reason, stable operation of the amplifier, unnecessary resonance in the communication device or radar device, and reduction of harmonic output can be achieved.

In the second embodiment, the terminator 6 absorbs the second and third frequency components. However, by connecting a circuit having a load equivalent to the terminator 6 to the subsequent stage of the filter circuit 5, A few frequency components may be absorbed. For example, a circuit having a load equivalent to that of the terminator 6 may be an output port or an antenna element.
In the second embodiment, the filter circuit 3 includes the resonators 12 and 15 that are the band rejection filters that reflect the second and third frequency components. By adding a resonator that reflects the frequency component, a resonator that reflects the fifth frequency component, and a resonator that reflects the Nth frequency component, the frequency component absorbed by the terminator 6 may be increased. Good.

The filter circuit of FIG. 2 can be configured as a planar circuit, but a resonator (resonator including a hole) is added by providing a hole in the back surface ground of the main line 11 or the like. It may be.
Further, the filter circuit of FIG. 2 may be configured by a multilayer substrate, and a resonator may be added to a different layer opposite to the back surface ground of the main line 11.

Embodiment 3 FIG.
3 is a block diagram showing a filter circuit according to Embodiment 3 of the present invention. In the figure, the same reference numerals as those in FIG. FIG. 3 shows the internal configuration of the filter circuit 3.
The resonator 18 passes the first frequency component included in the signal branched by the signal branching unit 2 to the output port 4, while reflecting the second frequency component included in the signal. It is comprised from the joint line of the one side short circuit one side open | release line couple | bonded with the main line 11.
The line length 19 of the coupled line constituting the resonator 18 is an odd multiple of approximately 0.25λ with respect to the second frequency component.
Since the resonator 18 forms a two-stage filter together with the resonator 12, the distance between the short-circuit position of the resonator 12 and the short-circuit position of the resonator 18 is a distance 20. It is arranged at a position where the two-stage to two-stage filters are opened (position where the distance from the signal branching section 2 is the distance 14).

The resonator 21 passes the first frequency component included in the signal branched by the signal branching unit 2 to the output port 4 while reflecting the fourth frequency component included in the signal. It is comprised from the joint line of the one side short circuit one side open | release line couple | bonded with the main line 11.
The line length 22 of the coupled line constituting the resonator 21 is an odd multiple of approximately 0.25λ with respect to the fourth frequency component.
Note that the resonator 21 is open when viewed from the signal branching section 2, that is, a position where the distance 23 from the signal branching section 2 is an odd multiple of approximately 0.25λ with respect to the fourth frequency component. Is arranged. However, the distance 23 varies depending on various conditions in mounting.

Next, the operation will be described.
The second embodiment is the same as the second embodiment except that a resonator 18 that constitutes a two-stage filter and a resonator 21 that is a band rejection filter that reflects the fourth frequency component are added.
The amount of absorption of the second frequency component can be increased by adding the resonator 18, and the fourth frequency component can be absorbed by adding the resonator 21.

The filter circuit of FIG. 3 can be configured as a planar circuit, but a resonator (resonator including a hole) is added by providing a hole in the back surface ground of the main line 11 or the like. It may be.
Further, the filter circuit of FIG. 3 may be configured by a multilayer substrate, and a resonator may be added to a different layer opposite to the back surface ground of the main line 11.

Embodiment 4 FIG.
In the fourth embodiment, a filter circuit that is applied when the first frequency component is not a frequency between the second to Nth frequency components will be described.
4 is a block diagram showing a filter circuit according to Embodiment 4 of the present invention. In the figure, the same reference numerals as those in FIG. FIG. 4 shows the internal configuration of the filter circuit 5.

The transmission line 31 is a phase adjustment transmission line in which the first frequency component included in the signal branched by the signal branching unit 2 is adjusted to a phase that is open on the input side.
The line length 32 of the transmission line 31 is such that the load of the multi-stage tip short-circuit stub 33 and the terminator 3 is open with respect to the first frequency component, that is, the electrical short-circuit of the multi-stage tip short-circuit stub 33. The length is such that the distance between the point and the signal branching section 2 is approximately 0.25λ. However, the line length 32 varies depending on various conditions in mounting.

The multi-stage tip short-circuit stub 33 has one end connected to the other end of the transmission line 31 and the other end connected to the terminator 6, and is included in the signals branched by the signal branching unit 2. This is a broadband bandpass filter that allows N frequency components to pass through the terminator 6 and reflects the first frequency component contained in the signal.
The length of each short-circuited short-circuit stub 33 is approximately 0.25λ with respect to the center frequency of the second to Nth frequency components.
Further, the arrangement positions of the respective short-circuited short stubs 33 are arranged at an interval of about 0.25λ with respect to the center frequency of the second to Nth frequency components.

Next, the operation will be described.
The signal input from the input port 1 is branched by the signal branching unit 2 and output to the input side of the filter circuits 3 and 5, and the transmission line 31 constituting the filter circuit 5 has a line length 32 of With respect to the first frequency component, the length is set such that the loads of the multi-stage tip short-circuit stub 33 and the terminator 3 are opened.
For this reason, the first frequency component is equivalent to the fact that the load when the filter circuit 5 and the terminator 6 are viewed from the signal branching unit 2 is opened, and the filter circuit 5 and the terminator 6 are not electrically connected. become.
Therefore, the first frequency component included in the signal branched by the signal branching unit 2 is not input to the filter circuit 5 but is input only to the filter circuit 3.
Since the filter circuit 3 is a filter that passes the first frequency component to the output port 4, the first frequency component passes through the filter circuit 3 and is output from the output port 4.

On the other hand, the filter circuit 3 is configured such that the second to Nth frequency components are open on the input side.
Therefore, the second to Nth frequency components are opened when the filter circuit 3 and the output port 4 (load of the output port 4) are viewed from the signal branching unit 2, and the filter circuit 3 and the output port 4 are electrically connected. This is equivalent to not connecting.
Therefore, the second to Nth frequency components included in the signal branched by the signal branching unit 2 are not input to the filter circuit 3 but are input only to the filter circuit 5.
The multistage tip short-circuit stub 33 constituting the filter circuit 5 is a band-pass filter that passes the second to Nth frequency components to the terminator 6, and therefore the second to Nth frequency components are the filter circuit. 5 is output to the terminator 6. As a result, the second to Nth frequency components are absorbed by the terminator 6.

  As is apparent from the above, according to the fourth embodiment, the filter circuit 5 has one end connected to the signal branching unit 2 and is included in the signal branched by the signal branching unit 2. A transmission line 32 for phase adjustment whose frequency component is adjusted to an open phase on the input side, and a multi-stage where one end is connected to the other end of the transmission line 32 and the other end is connected to the terminator 6. Since the tip short-circuit stub 33 is configured, and the length of each tip short-circuit stub 33 and the arrangement interval of the tip short-circuit stubs 33 are determined according to the second to Nth frequency components to be reflected. As in the first embodiment, the second to Nth frequency components that are unnecessary plural frequency components can be absorbed, and the insertion loss of the first frequency component that is a desired frequency component can be reduced. There is an effect that can.

Since the line length 32 of the transmission line 31 can be set regardless of the second to Nth frequency components, when the filter circuit 5 is viewed from the signal branching unit 2, the second to Nth. It is possible to easily construct a configuration in which the frequency component is open.
In addition, since the filter circuit 5 that allows the second to Nth frequency components to pass through the terminator 6 is configured by using the multi-stage tip short-circuit stub 33, a wide band pass characteristic can be easily obtained.

According to the fourth embodiment, the frequency of the second to Nth frequency components absorbed by the terminator 6 is arbitrary, and a filter characteristic with a small insertion loss of the first frequency component can be obtained. For example, when each of the second to Nth frequency components is selected to be an integer multiple of 2 to N of the first frequency component, and the filter circuit of FIG. By passing the fundamental wave with low loss, it is possible to absorb 2 to N times higher harmonics (integer multiples of the fundamental wave) of the amplifier which becomes an unnecessary signal. In particular, when the filter circuit according to the fourth embodiment is provided in the subsequent stage of the amplifier that achieves high efficiency by matching not only the fundamental wave component but also the harmonic component, a load of 2 to N times higher harmonics Can be made constant.
For this reason, stable operation of the amplifier, unnecessary resonance in the communication device or radar device, and reduction of harmonic output can be achieved.
The filter circuit of FIG. 4 can be configured by a planar circuit.

In the fourth embodiment, the terminator 6 absorbs the second to Nth frequency components. However, by connecting a circuit having a load equivalent to the terminator 6 to the subsequent stage of the filter circuit 5, The second to Nth frequency components may be absorbed. For example, a circuit having a load equivalent to that of the terminator 6 may be an output port or an antenna element.
In the fourth embodiment, the multi-stage tip short-circuit stub 33 is used to form the filter circuit 5. However, the first frequency component is allowed to pass through the second to Nth frequencies. Any element that reflects the component may be used. For example, a band-pass filter including a multistage open-ended coupled line may be used.

In the fourth embodiment, the multi-stage tip short-circuited stub 33 is shown as a band pass filter. However, when the first frequency component is lower than the second to Nth frequency components, the first frequency component is used. The filter circuit 5 may be configured using a high-pass filter that transmits the second to Nth frequency components.
In addition, when the first frequency component is higher than the second to Nth frequency components, a low-pass filter that passes the first frequency component and reflects the second to Nth frequency components is used. The filter circuit 5 may be configured.

Embodiment 5 FIG.
5 is an exploded perspective view showing a filter circuit 3 of a filter circuit according to Embodiment 5 of the present invention.
6 is a top view showing the top surface 42 of the dielectric substrate 41 of FIG. 5, and FIG. 7 is a bottom view showing the bottom surface 52 of the dielectric substrate 51 of FIG.
Further, FIG. 8 is a sectional view of the filter circuit 3 taken along the line AA of FIG.
5 to 8, the same reference numerals as those in FIG. 2 and FIG.

On the upper surface 42 (first surface) of the dielectric substrate 41 which is a one-layer printed circuit board, the main line 11 and the resonators 12 and 15 constituting the filter circuit 3 are formed. A ground conductor is formed on the lower surface 43 (second surface).
The resonator 21 constituting the filter circuit 3 is formed on the lower surface 52 of the dielectric substrate 51 which is a printed circuit board, and the ground conductor is formed on the upper surface 53 of the dielectric substrate 51.
The one-layer dielectric substrate 41 and the one-layer dielectric substrate 51 have a stack structure electrically and physically connected by a plurality of solder balls 60, and the dielectric substrates 41 and 51 are multilayer printed circuit boards. Is configured.

The short-circuit portions of the resonators 12 and 15 are short-circuited to the ground conductor formed on the lower surface 43 by vias 44, and ground conductors 45 formed on both sides of the upper surface 42 of the dielectric substrate 41 are also formed. The via 44 is short-circuited to the ground conductor formed on the lower surface 43.
Further, the connection position 46 of the solder ball 60 is arranged in a region between the vias 44.
Here, an example in which the short-circuit portion of the resonators 12 and 15 is short-circuited to the ground conductor formed on the lower surface 43 by the via 44 is shown, but the ground formed on the lower surface 43 by the through hole is shown. You may make it short-circuit with a conductor.

The short-circuit portion of the resonator 21 is short-circuited to the ground conductor formed on the upper surface 53 by vias 54 (or through holes), and is formed on both sides of the lower surface 52 of the dielectric substrate 51. The ground conductor 55 is also short-circuited with the ground conductor formed on the upper surface 53 by the via 54.
Further, the connection position 56 of the solder ball 60 is disposed in the region between the vias 54.

The following operation will be described.
In the fifth embodiment, as shown in FIG. 6, the resonators 12 and 15 of the one-sided short-circuited and one-sided open line coupled to the main line 11 are formed on the upper surface 42 of the dielectric substrate 41. It is a band rejection filter that passes the first frequency component and reflects the second frequency component.
The resonator 15 is a band rejection filter that passes the first frequency component and reflects the third frequency component.

Similar to the second and third embodiments, the line length 13 of the coupled line constituting the resonator 12 is an odd multiple of approximately 0.25λ with respect to the second frequency component.
In addition, the resonator 12 is located at an open position when viewed from the signal branching unit 2, that is, a position where the distance 14 from the signal branching unit 2 is an odd multiple of approximately 0.25λ with respect to the second frequency component. Is arranged. However, the distance 14 varies depending on various conditions in mounting.
The line length 16 of the coupled line constituting the resonator 15 is an odd multiple of approximately 0.25λ with respect to the third frequency component, as in the second and third embodiments.
Further, the resonator 15 is a position that is open when viewed from the signal branching section 2, that is, a position where the distance 17 from the signal branching section 2 is an odd multiple of approximately 0.25λ with respect to the third frequency component. Is arranged. However, the distance 17 varies depending on various conditions in mounting.

In the fifth embodiment, as shown in FIG. 7, the resonator 21 of the one-sided short-circuited and one-sided open line coupled to the main line 11 is formed on the lower surface 52 of the dielectric substrate 51. This is a band rejection filter that passes the frequency component and reflects the fourth frequency component.
The line length 22 of the coupled line constituting the resonator 21 is an odd multiple of approximately 0.25λ with respect to the fourth frequency component, as in the third embodiment.
The resonator 21 is located at a position that is open when viewed from the signal branching unit 2, that is, a position at which the distance 23 from the signal branching unit 2 is an odd multiple of approximately 0.25λ with respect to the fourth frequency component. Is arranged. However, the distance 23 varies depending on various conditions in mounting.

Note that the short-circuit portions of the resonators 12 and 15 are short-circuited to the ground conductor formed on the lower surface 43 of the dielectric substrate 41 by the vias 44, and the short-circuit portions of the resonators 21 are dielectric by the vias 54. The ground conductor formed on the upper surface 53 of the substrate 51 is short-circuited.
Therefore, the filter circuit of the fifth embodiment operates in the same manner as the filter circuit of the third embodiment.
Specifically, it is as follows.

The signal input from the input port 1 is branched by the signal branching unit 2 and output to the input side of the filter circuits 3 and 5, but the filter circuit 5 opens the first frequency component on the input side. It is configured as follows.
For this reason, the first frequency component is equivalent to the fact that the load when the filter circuit 5 and the terminator 6 are viewed from the signal branching unit 2 is opened, and the filter circuit 5 and the terminator 6 are not electrically connected. become.
Therefore, the first frequency component included in the signal branched by the signal branching unit 2 is not input to the filter circuit 5 but is input only to the filter circuit 3.

The filter circuit 3 passes the first frequency component and reflects the second frequency component. The resonator 12 is a band rejection filter, and the first frequency component is allowed to pass and the third frequency component is reflected. The first frequency component is composed of the resonator 15 that is a band-stop filter to be caused to pass through and the resonator 21 that is a band-stop filter that transmits the first frequency component and reflects the fourth frequency component. Passes through the filter circuit 3 and is output from the output port 4.
Since the resonators 12, 15, and 21 constituting the filter circuit 3 are band-stop filters that reflect the second, third, and fourth frequency components, the first is compared with the case that the filter circuit 3 is configured by a band-pass filter. The insertion loss of frequency components can be reduced.

Further, since the space between the main line 11 and the resonator 21 is air, the loss due to the dielectric loss tangent can be reduced as compared with the case where it is constituted by a multilayer substrate.
In the fifth embodiment, a single-layer dielectric substrate 41 and a dielectric substrate 51 form a stack structure with a plurality of solder balls 60. Usually, the dielectric tangent of a single-layer substrate is the dielectric tangent of a multilayer substrate. Since it can be made smaller, the insertion loss of the first frequency component can be reduced.

On the other hand, the resonators 12, 15, and 21 constituting the filter circuit 3 are configured such that the second, third, and fourth frequency components are open on the input side.
For this reason, the second, third, and fourth frequency components are opened when the signal branching unit 2 sees the filter circuit 3 and the output port 4 (load of the output port 4), and the filter circuit 3 and the output port 4 are It is equivalent to not being electrically connected.
Therefore, the second, third, and fourth frequency components included in the signal branched by the signal branching unit 2 are not input to the filter circuit 3 but are input only to the filter circuit 5.
Since the filter circuit 5 is a filter that passes the second, third, and fourth frequency components to the terminator 6, the second, third, and fourth frequency components pass through the filter circuit 5 and are output to the terminator 6. Is done. As a result, the second, third, and fourth frequency components are absorbed by the terminator 6.

  As apparent from the above, according to the fifth embodiment, the main line 11 and the resonators 12 and 15 are formed on the upper surface 42 of the dielectric substrate 41 which is a single-layer printed circuit board. Since the 15 short-circuit portions are configured to be short-circuited to the ground conductor formed on the lower surface 43 of the dielectric substrate 41 by the vias 44, similarly to the second embodiment, a plurality of unnecessary frequency components are used. The second and third frequency components can be absorbed, and the insertion loss of the first frequency component, which is a desired frequency component, can be reduced.

  Further, according to the fifth embodiment, the resonator 21 of the one-side short-circuited one-side open line coupled to the main line 11 is formed on the lower surface 52 of the dielectric substrate 51, and the one-layer dielectric substrate 41 and the dielectric Since the substrate 51 is configured to have a stack structure with the plurality of solder balls 60, the fourth frequency component, which is an unnecessary plurality of frequency components, can be absorbed, and the first frequency component, which is a desired frequency component, can be absorbed. There is an effect that the insertion loss of the frequency component can be reduced.

  Further, the distances 14, 17, and 23 from the signal branching unit 2 to the resonators 12, 15, and 21 can be set independently of the first frequency component that is a desired frequency component and other resonators. Therefore, when the resonators 12, 15, and 21 are viewed from the signal branching unit 2, it is possible to easily construct a configuration in which the second, third, and fourth frequency components are open.

In the fifth embodiment, the frequency of the second, third, and fourth frequency components absorbed by the terminator 6 is arbitrary, and a filter characteristic with a small insertion loss of the first frequency component can be obtained. When the second to fourth frequency components are selected to be an integer multiple of 2 to 4 of the first frequency component, and the filter circuit of the fifth embodiment is provided in the subsequent stage of the amplifier, the desired signal is obtained. By passing the fundamental wave of the amplifier with low loss, it is possible to absorb 2 to 4 times higher harmonics (2 to 4 times the fundamental wave) of the amplifier which becomes an unnecessary signal. In particular, when the filter circuit according to the fifth embodiment is provided in the subsequent stage of the amplifier that achieves high efficiency by matching not only the fundamental wave component but also the harmonic component, a load of 2 to 4 times higher harmonics is provided. Can be made constant.
For this reason, stable operation of the amplifier, unnecessary resonance in the communication device or radar device, and reduction of harmonic output can be achieved.

In the fifth embodiment, the terminator 6 absorbs the second, third, and fourth frequency components, but a circuit having a load equivalent to that of the terminator 6 is connected to the subsequent stage of the filter circuit 5. The second, third, and fourth frequency components may be absorbed. For example, a circuit having a load equivalent to that of the terminator 6 may be an output port or an antenna element.
In the fifth embodiment, the filter circuit 3 includes the resonators 12, 15, and 21 that are band-stop filters that reflect the second, third, and fourth frequency components. The frequency component absorbed by the terminator 6 is increased by adding a resonator that reflects the fifth frequency component, a resonator that reflects the sixth frequency component, and a resonator that reflects the Nth frequency component. You may do it.

In the fifth embodiment, the resonator 21 for reflecting the fourth frequency component is formed not on the dielectric substrate 41 but on the lower surface 52 of the dielectric substrate 51, and the one-layer dielectric substrate 41 and the dielectric substrate 51 are formed. Although a stack structure is shown by a plurality of solder balls 60, the resonator 21 (consisting of a hole is formed by providing a hole in the ground conductor formed on the lower surface 43 of the dielectric substrate 41. (Resonator) may be formed.
In this case, the filter circuit 3 in which the resonators 12, 15, and 21 are mounted on the single-layer dielectric substrate 41 can be configured without multilayering the dielectric substrate 41 and the dielectric substrate 51.

  In the present invention, within the scope of the invention, any combination of the embodiments, or any modification of any component in each embodiment, or omission of any component in each embodiment is possible. .

  1 input port, 2 signal branching unit, 3 filter circuit (first filter), 4 output port, 5 filter circuit (second filter), 6 terminator, 11 main line, 12 resonator (band rejection filter), 13 Line length of the coupled line constituting the resonator 12, 14 Distance from the signal branching section 2 to the resonator 12, 15 Resonator (band rejection filter), 16 Line of the coupled line constituting the resonator 15 Length, 17 distance from the signal branching section 2 to the resonator 15, 18 resonator (band rejection filter), 19 line length of the coupled line constituting the resonator 18, 20 short-circuit position of the resonator 12 and the resonator 18 , 21 Resonator (band rejection filter), 22 Line length of the coupled line constituting the resonator 21, 23 Distance from the signal branching section 2 to the resonator 21, 31 Transmission line ( Phase adjustment transmission line), 32 transmission line 31 line length, 33 multi-stage short-circuited short stub, 41 dielectric substrate (printed substrate), 42 upper surface of dielectric substrate 41 (first surface), 43 dielectric substrate 41 lower surface (second surface), 44 via, 45 ground conductor, 46 connection position of solder ball 60, 51 dielectric substrate (printed substrate), 52 lower surface of dielectric substrate 51, 53 upper surface of dielectric substrate 51, 54 Via, 55 Ground conductor, 56 Solder ball 60 connection position, 60 Solder ball.

Claims (12)

A signal branching unit for branching a signal input from the input port;
A filter that passes the first frequency component included in the signal branched by the signal branching unit to the output port, and reflects the Nth frequency component from the second frequency component included in the signal. A first filter in which the second to Nth frequency components are open on the input side;
A filter that passes the second to Nth frequency components included in the signal branched by the signal branching unit to the terminator, and reflects the first frequency component included in the signal. And a second filter in which the first frequency component is opened on the input side. The first filter is composed of two or more band rejection filters,
Each band rejection filter passes the first frequency component included in the signal branched by the signal branching unit to the output port, and the second frequency component included in the signal to the Nth frequency. 2. The filter circuit according to claim 1, wherein the filter circuit reflects at least one frequency component among the components, and is arranged at a position where the frequency component is open on the input side. Each bandstop filter is
A main line having one end connected to the signal branching unit and the other end connected to the output port;
It consists of a resonator with one side short-circuited one side open line coupled with the main line,
The filter circuit according to claim 2, wherein the length and the short-circuit position of the resonator are determined according to a frequency component to be reflected.   The filter circuit according to any one of claims 1 to 3, wherein the second filter includes a band-pass filter, a low-pass filter, or a high-pass filter.   5. The filter circuit according to claim 1, wherein each of the second frequency component to the Nth frequency component is 2 to N times the first frequency component. 6. . The second filter is
A transmission line for phase adjustment in which one end is connected to the signal branching unit, and the first frequency component included in the signal branched by the signal branching unit is adjusted to a phase that is open on the input side; ,
One end is connected to the other end of the transmission line, and the other end is composed of a multi-stage tip short-circuited stub connected to a circuit having a load from the second frequency component to the Nth frequency component,
The length of each tip short-circuit stub and the arrangement interval of the tip short-circuit stubs are determined according to the frequency component to be reflected. Filter circuit.   7. The filter circuit according to claim 6, wherein the circuit having a load from the second frequency component to the Nth frequency component is a terminator.   The filter circuit according to claim 1, wherein the first filter is formed on a single-layer printed circuit board.   The main conductor and the resonator are formed on the first surface of the one-layer printed circuit board, and the short circuit portion of the resonator is formed on the second surface of the printed circuit board by the via or the through hole. The filter circuit according to claim 3, wherein the filter circuit is short-circuited.   The filter circuit according to claim 9, wherein a resonator including a punched hole is formed in the ground conductor on the second surface of the printed circuit board.   The one-layer printed circuit board in which the main line and the resonator are formed on the first surface is multilayered with another printed circuit board in which the resonator is formed on one surface. 9. The filter circuit according to 9.   12. The filter circuit according to claim 11, wherein the two printed circuit boards have a stacked structure with solder balls.

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