JPH06318801A - Multi-layered filter - Google Patents

Abstract

PURPOSE:To obtain the small sized multi-layered filter with an excellent out- band characteristic even at a high frequency region. CONSTITUTION:A signal inputted from an input section 1 formed to a 3rd layer L3 is delivered from a coupling line 6 formed to be a meander to a strip conductor 8 and delivered from a strip conductor 11 of a coupling line 10 formed on a 2nd layer L2 to the strip conductor 12 through a throughhole conductor 9 at the tip of the conductor 8 and similarly delivered from a throughhole conductor 13 to an output section 2 via a coupling line 14 formed on a 1st layer L1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small-sized multi-layered filter using a multi-layered IC circuit and excellent in frequency selectivity.

[0002]

2. Description of the Related Art FIG. 5 shows a configuration of a distributed constant type filter using a conventional microstrip line. Reference numeral 1 is an input portion, 2 is an output portion, and 3, 4 ... 5 are resonators, which are formed on different layers. For designing a filter of this type, see G. L. By Matthaei “Mi
crowave Filters, Impedance
-Matching Networks, and Co
"Upling Structures", the length 1 of the resonators 3 to 5 is set to 1 = λg / 2 (where λg is the wavelength) in the operating frequency band, and the filter has the frequency. It operates as a band-pass filter in the band.In general, in order to increase the amount of attenuation in the stop band, it is sufficient to increase the number of steps with this type of filter, but if the number of steps increases, the shape of the filter becomes clear as shown in FIG. In the present situation, however, in such a filter, the frequency selectivity as a filter and the transmission loss in the pass band are limited by the Q value of the circuit. As one improvement measure, a method of increasing the attenuation amount in the stop band by coupling the resonators apart from each other is proposed as described below. To have.

FIG. 6 is a report example of a filter using a dielectric multistage resonator (Nishikawa et al., "800 MHz band polar type dielectric bandpass filter", (Electronic Communication Institute General Conference 1986)). FIG. 7 is a diagram showing the equivalent circuit, and FIG. 8 is a diagram showing the characteristics in that case. In FIG. 6, Ct is a polarized capacitor for forming a pole, Cout is an external coupling capacitor to which an external load is connected, Se is a dielectric ceramics, Sl is a coupling slit, Rc is a resonator internal conductor, and C is a resonator.
c is a coaxial conductor for coupling, and Ca is a shield case.

In FIG. 7, Cin is an external coupling capacitor, which is omitted in FIG. Zoi is the resonator characteristic impedance, Qi is the resonator electrical angle, Xij is the inter-resonator coupling reactance, and Cout and Ct are the same external coupling capacitors and polarization capacitors as in FIG. Also,
A and B show the corresponding points with FIG.

In FIG. 8, FIG. 8 (a) is an example of the calculation result. The solid line shows the characteristics when the polarization capacitor Ct is not used, and the broken line and the one-dot chain line show the characteristics when the polarization capacitor Ct is used. Is an example of the calculation result when the capacity values are different. FIG. 8B is an example of the actual measurement result. In the case of the example shown in FIG. 6, a polarized capacitor Ct is added to the outside and the resonators are separated (in this case, the second and fifth stages are capacitively coupled).
An anti-resonance state is realized between A and B by capacitively coupling, thereby providing a pole in the stop band and increasing the amount of attenuation in the stop band as shown in FIG.

[0006]

However, in the case of coupling distant resonators to each other, in the conventional two-dimensional configuration (for example, the configuration shown in FIGS. 5 and 6), the distant resonators are coupled to each other. It is difficult to insert, and as shown in FIG. 6, a coupling coaxial conductor Cc or the like is required outside. Therefore, this method has a drawback in that the effect of the length of the coupling coaxial conductor Cc and the like is remarkably exerted when the frequency is increased, and the designability is deteriorated.

An object of the present invention is to solve the above-mentioned problems of the filter and to realize a small-sized filter having excellent out-of-band characteristics even in a high frequency region with good designability.

[0008]

According to the present invention, in a multi-layered IC circuit in which dielectrics are stacked in multiple layers, a plurality of resonators formed by microstrip lines or the like are formed in different layers, and the resonators are formed. In a filter circuit constructed by connecting resonators in cascade connection, adjacent resonators are arranged in the same layer, and the other resonators are arranged in the upper and lower layers facing each other and coupled.

[0009]

In the present invention, since the resonators other than the adjacent resonators are arranged in the upper and lower layers facing each other, the coaxial conductors for coupling can be short and the characteristics in the high frequency band can be reduced. There is no deterioration.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a first embodiment in which the filter having the structure shown in FIG. 5 is constituted by a multi-layer IC (this figure shows an example realized by a three-layer structure). FIG. 1A is a perspective view of a main portion, and FIG. 1B is a schematic configuration diagram for explaining the overall configuration, which is shown in plan view, but the first to third layers L are shown.
As shown by 1 to L3, they are formed in different layers.

In FIG. 1A, 1 is an input part of a strip conductor formed on the third layer L3, 8 is a strip conductor, and together with the strip conductor 7 of the input part 1, a coupled line 6 is provided.
To form. Reference numeral 9 is a through-hole conductor at an end of the strip conductor 8 and is connected to an end of a strip conductor 11 formed on the second layer L2. Reference numeral 10 denotes a coupled line, which is composed of strip conductors 11 and 12 formed on the second layer L2. A through hole conductor 13 is connected to an end of the strip conductor 12 and is also formed on the first layer L1. The strip conductor 16 is connected to the strip conductor 15 and the coupling line 14.
And the end portion of the strip conductor 16 serves as the output portion 2. The coupled line 6 is located above the coupled line 14, and the two are coupled.

Next, the operation will be described. The signal input from the input unit 1 is a coupled line 6 configured in a meander shape.
To the third layer L3.
Is configured on the upper surface of. ). In this case, the length of the coupling line 6 is set to about λg / 4, and of the strip conductors 7 and 8 constituting the coupling line 6, the end of the strip conductor 8 which is not connected to the input section 1 is through. After being connected to the upper surface of the second layer L2 by the hole conductor 9, the coupled line 10 is again formed in a meander shape there (the length is also about λg / 4). Of the coupled line 10, the upper layer (third layer L
The top end of the strip conductor 11 connected to the upper surface (3) is open, and the other strip conductor 12 is connected to the upper surface of the lower layer (first layer L1) through the through-hole conductor 13. In this way, since the resonator is formed in a meander shape across each layer, there is an advantage that the entire size is much smaller than the conventional one, and
Since the separated resonators can be easily coupled by forming them in separate layers and arranging them on top of each other, as shown in the example of FIG. 8, the attenuation amount in the stop band is increased, etc. It is possible to increase the degree of freedom in designing the filter characteristics, and further, unlike the example of FIG. 6, a long line is not required to couple distant resonators. Therefore,
It is possible to realize effective blocking characteristics even in a high frequency band. In FIG. 1B, in order to make the relationship between the resonators easy to understand, the relationship between the resonators and with the through holes is shown two-dimensionally.

FIG. 2A shows a second embodiment of the multilayer distributed constant type filter according to the present invention. In addition, this FIG.
In the case of (a), in order to make the positional relationship of each resonator easy to understand, a configuration diagram viewed from directly above the multilayer structure is shown.
Further, as in the case of FIG. 1B, FIG. 2B shows the relationship between the resonators and the through holes two-dimensionally.
In the case of FIGS. 2A and 2B, an example realized by a four-layer structure of L1 to L4 is shown.

In FIG. 2 (a), 6, 10, 14, 1
Reference numeral 8 denotes a coupled line, which is strip conductors 7 and 8, respectively.
11 and 12, 15 and 16 and 19 and 20. Further, reference numerals 9, 13, and 17 indicate through-hole conductors.

Next, the operation will be described. The signal input from the input unit 1 is transmitted to the coupled line 6 configured in a meander shape (the input unit 1 and the coupled line 6 are in the fourth layer L).
4 is configured on the upper surface. ). In this case, the length of the coupling line 6 is set to about λg / 4, and the through-hole conductor 9 is provided at the tip of the strip conductor 8 of the strip conductors forming the coupling line 6 which is not connected to the input section 1. After being connected to the strip conductor 11 on the upper surface of the third layer L3, the coupled line 10 is again formed into a meander shape there (the length is also about λg / 4). In the coupled line 10, the end of the strip conductor 11 connected to the upper layer (upper surface of the fourth layer L4) is open, and the other strip conductor 12 is a through-hole conductor 13 and further to the lower layer (second layer). After being connected to the strip conductor 15 on the upper side of the layer L2), the coupling line 14 is again constructed here in the shape of a meander (the length is also about λg / 4). The strip conductor 15 of the coupling line 14 which is connected to the upper layer (upper surface of the third layer L3) has an open tip, and the other strip conductor 16 is a through-hole conductor 17 and is further lower layer (first layer). After being connected to the strip conductor 19 on the upper surface of (L1), the coupling line 18 is again formed in a meandering shape there (the length is also about λg / 4). One end of the strip conductor 19 of the coupling line 18 that is connected to the upper layer (the upper surface of the second layer L2) is open, and the other strip conductor 20 is connected to the output unit 2. At this time, as shown in the figure, the strip conductor 11 and the strip conductor 19 are arranged and coupled in the upper and lower layers facing each other, and the degree of freedom in designing the filter is improved by improving the out-of-band characteristics as described above. .

FIG. 3 is a diagram showing a third embodiment of the present invention, which is an embodiment in which a ring resonator is used as the resonator. This is an example in which the ring resonators 31 to 35 have five stages. The input section 1 and the ring resonator 31 are on the upper surface of the fifth layer L5, the ring resonator 32 is on the upper surface of the fourth layer L4, and the ring resonance is The resonator 33 is formed on the upper surface of the third layer L3, the ring resonator 34 is formed on the upper surface of the second layer L2, and the ring resonator 35 and the output unit 2 are formed on the upper surface of the first layer L1. Also, 2
The ring resonator 32 of the fourth stage and the ring resonator 34 of the fourth stage are arranged and coupled in the upper and lower layers facing each other, and the degree of freedom in designing the filter is improved as in the case of the embodiment of FIG. .

FIG. 4 is a diagram showing a fourth embodiment of the present invention. In this case, the strip lines 41 to 4 with the tips short-circuited.
5 is used as a basic constituent element of the filter, and an example of a two-layer structure is shown. Reference numerals 46 to 49 denote through-hole conductors. The short-circuited strip line 41 formed on the second layer L2, the short-circuited strip lines 42 and 43 formed on the first layer L1, and the strip lines 44 and 45 for interstage coupling thereof. Has been done. 1 is an input unit, 2 is an output unit, and an example in the case of a filter having a three-stage configuration is shown. In this case,
Short-circuited stripline 4 formed on the second layer L2
1 and the strip line 42 having a short-circuited tip formed on the first layer L1 are arranged in upper and lower layers facing each other, and are coupled to each other.

[0018]

As described above, the multi-layered filter according to the present invention has a multi-layered structure in which dielectrics are stacked in multiple layers.
In a C circuit, a plurality of resonators each composed of a microstrip line, a slot line, or a coplanar line are formed on different layers, and the resonators are connected in cascade. Are placed in the same layer, and the other resonators are placed in the upper and lower layers facing each other, and coupled, so that the circuit can be made smaller than the conventional filter and the attenuation in the stop band can be increased. In addition, the degree of freedom in designing the filter characteristics can be increased, and the designability is good even in the high frequency region.

[Brief description of drawings]

FIG. 1 is a first multilayer distributed constant filter according to the present invention.
3 is a perspective view and a schematic configuration diagram of a main part showing the configuration of the embodiment of FIG.

FIG. 2 is a second multilayer distributed constant filter according to the present invention.
2A is a plan view and a schematic configuration diagram of a main part showing the configuration of the embodiment of FIG.

FIG. 3 is a third multilayer distributed constant filter according to the present invention.
3 is a perspective view of a main part showing the configuration of the embodiment of FIG.

FIG. 4 is a fourth multilayer distributed constant filter according to the present invention.
3 is a perspective view of a main part showing the configuration of the embodiment of FIG.

FIG. 5 is a schematic configuration diagram of a distributed constant type filter using a conventional microstrip line.

FIG. 6 is a perspective view in which a part of a main part of a reported example of a filter using a dielectric multistage resonator is cut away.

7 is a diagram showing an equivalent circuit of the filter shown in FIG.

8 is a diagram showing a characteristic example of the filter shown in FIG.

[Explanation of symbols]

 1 Input Section 2 Output Section 3 λg / 2 Resonator 4 λg / 2 Resonator 5 λg / 2 Resonator 6 Coupling Line 7 Strip Conductor 8 Strip Conductor 9 Through Hole Conductor 10 Coupling Line 11 Strip Conductor 12 Strip Conductor 13 Through-hole conductor 14 Coupled line 15 Strip conductor 16 Strip conductor 17 Through-hole conductor 18 Coupled line 19 Strip conductor 20 Strip conductor 31 Ring resonator 32 Ring resonator 33 Ring resonator 34 Ring resonator 35 Ring resonator 41 Tip short-circuited strip line 42 tip short-circuit strip line 43 tip short-circuit strip line 44 inter-stage coupling strip line 45 inter-stage coupling strip line 46 through-hole conductor 47 through-hole conductor 48 through-hole conductor 49 through-hole conductor

Claims (1)

[Claims] 1. In a multi-layered IC circuit in which dielectrics are stacked in multiple layers, a plurality of resonators each composed of a microstrip line, a slot line or a coplanar line are formed in different layers, and the resonators are formed. In a filter circuit configured by cascading, the adjacent resonators are arranged in the same layer, and the other resonators are arranged in the upper and lower layers facing each other, and are coupled to each other.