Filter module

Abstract

The present invention provides a filter module, which can obtain the target filter characteristics in a state where a filter element is mounted on a module substrate and a shielding member is configured. The filter element is mounted on the module substrate and covered by the shielding member. The filter element has a first side surface and a second side surface facing opposite directions to each other, and a ground terminal and a signal terminal are formed on the bottom surface. The shielding member has a side wall portion facing the first side surface and the second side surface. The filter element includes a plurality of LC parallel resonant circuits inside. The inductors of the LC parallel resonant circuits are arranged in a direction parallel to both the first side surface and the bottom surface, and the inductors extend upward from the ends electrically connected to the grounding terminal, and then extend in a direction from the first side surface toward the second side surface, and then extend in a direction toward the bottom surface. The interval between the first side surface and the side wall portion of the shielding member is narrower than the interval between the second side surface and the side wall portion of the shielding member.

Description

Technical Field

[0001] The invention relates to a filter module. Background Art

[0002] In the fifth generation mobile communication system (5G), for example, frequency band n77 with a frequency of 3.3 GHz or more and 4.2 GHz or less, frequency band n78 with a frequency of 3.3 GHz or more and 3.8 GHz or less, frequency band n79 with a frequency of 4.4 GHz or more and 5.0 GHz or less, etc. are specified. As a bandpass filter used in these frequency bands, for example, a filter element in which a plurality of parallel resonant circuits of inductors and capacitors are configured is studied (for example, Patent Document 1). The filter element is implemented as a stacked high-frequency filter, that is, a given conductor pattern is formed on a plurality of insulating layers, and the conductor patterns formed on different insulating layers are connected to each other by via conductors.

[0003] Prior Art Literature

[0004] Patent Literature

[0005] Patent Document 1: International Publication No. 2011 / 114851

[0006] The filter element is mounted on a common module substrate together with a high-frequency switch, a low-noise amplifier, etc., for example. These circuit components mounted on the module substrate are electromagnetically shielded by a shielding member. The inventor of the present application has found that when the filter element is mounted on the module substrate and electromagnetically shielded by the shielding member, the characteristics of the filter element sometimes deviate from the characteristics of the filter element alone. If the characteristics of the filter element deviate, the target filter characteristics may sometimes not be obtained. Summary of the invention

[0007] Problems to be solved by the invention

[0008] An object of the present invention is to provide a filter module capable of obtaining target filter characteristics in a state where a filter element is mounted on a module substrate and electromagnetically shielded by a shield member.

[0009] Means for solving problems

[0010] According to one aspect of the present invention, there is provided a filter module having:

[0011] Module substrate;

[0012] A filter element, comprising a bottom surface and an upper surface facing opposite directions, and a first side surface and a second side surface facing opposite directions, wherein a ground terminal, a first signal terminal, and a second signal terminal are formed on the bottom surface, and the filter element is mounted on the module substrate in a posture where the bottom surface faces the module substrate; and

[0013] a shielding member including a first side wall portion and a second side wall portion respectively facing the first side surface and the second side surface, and covering the filter element;

[0014] The filter element includes a plurality of parallel resonant circuits therein, each of which includes an inductor and a capacitor connected in parallel to each other.

[0015] The inductors of the plurality of parallel resonant circuits are arranged in a direction parallel to both the first side surface and the bottom surface.

[0016] The inductors of the plurality of parallel resonant circuits extend upward from the ends on the ground side electrically connected to the ground terminal, further extend in a direction from the first side surface toward the second side surface, and further extend in a direction toward the bottom surface.

[0017] An end of the inductor of one of the plurality of parallel resonant circuits on the signal side opposite to the end on the ground side is electrically connected to the first signal terminal, and an end of the inductor of another parallel resonant circuit on the signal side opposite to the end on the ground side is electrically connected to the second signal terminal.

[0018] A distance between the first side surface and the first side wall portion is narrower than a distance between the second side surface and the second side wall portion.

[0019] According to another aspect of the present invention, a filter module is obtained, comprising:

[0020] Module substrate;

[0021] A filter element, comprising a bottom surface and an upper surface facing opposite directions, and a first side surface and a second side surface facing opposite directions, wherein a ground terminal, a first signal terminal, and a second signal terminal are formed on the bottom surface, and the filter element is mounted on the module substrate in a posture where the bottom surface faces the module substrate; and

[0022] a shielding member including a first side wall portion and a second side wall portion respectively facing the first side surface and the second side surface, and covering the filter element;

[0023] The filter element includes a plurality of parallel resonant circuits therein, each of which includes an inductor and a capacitor connected in parallel to each other.

[0024] The plurality of parallel resonant circuits are arranged in a direction parallel to both the first side surface and the bottom surface.

[0025] The inductors of the plurality of parallel resonant circuits extend upward from the ends on the ground side electrically connected to the ground terminal, further extend in a direction from the first side surface toward the second side surface, and further extend in a direction toward the bottom surface.

[0026] An end of the inductor of one of the plurality of parallel resonant circuits on the signal side opposite to the end on the ground side is electrically connected to the first signal terminal, and an end of the inductor of another parallel resonant circuit on the signal side opposite to the end on the ground side is electrically connected to the second signal terminal.

[0027] The distance between the second side surface and the second side wall portion is narrower than the distance between the first side surface and the first side wall portion and is equal to or greater than 0.5 mm.

[0028] Effects of the Invention

[0029] By setting the positional relationship between the filter element and the shield member as described above, it is possible to obtain the target filter characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is an equivalent circuit diagram of a filter element mounted in a filter module according to the embodiment.

[0031] Figure 2 This is an exploded perspective view of the filter element according to the first embodiment.

[0032] Figure 3A , Figure 3B ,as well as Figure 3C 1 and 2 are respectively a top view, a front view, and a bottom view of the filter element according to the first embodiment.

[0033] Figure 4 This is a block diagram of the filter module according to the first embodiment.

[0034] Figure 5A as well as Figure 5B 1 and 2 are respectively a perspective view and a cross-sectional view of a filter module according to an embodiment.

[0035] Figure 6 It is a graph showing the measured results of the pass coefficient S21 of a circuit composed of a filter element and a low-noise amplifier.

[0036] Fig. 7A is a schematic diagram showing the positional relationship between the filter element and the shielding member, Figure 7B is shown by the filter elements and the low noise amplifier ( Figure 4 ) is a curve graph of the simulation results of the pass coefficient S21 of the circuit constructed.

[0037] Fig. 8A is a schematic diagram showing the positional relationship between the filter element and the shielding member, Figure 8B is shown by the filter elements and the low noise amplifier ( Figure 4 ) is a curve graph of the simulation results of the pass coefficient S21 of the circuit constructed.

[0038] Fig.9A is the equivalent circuit diagram of the filter element, Fig. 9B It is shown Fig.9A Graph showing the calculation result of the pass coefficient S21 from the first signal terminal to the second signal terminal of the equivalent circuit diagram shown.

[0039] Fig. 10A is the equivalent circuit diagram of the filter element, Fig. 10B It is shown Fig. 10A Graph showing the calculation result of the pass coefficient S21 from the first signal terminal to the second signal terminal of the equivalent circuit diagram shown.

[0040] Fig.11A as well as Fig. 11B The figure shows the electromagnetic field simulator used to analyze the signal from the first signal terminal T1 to the second signal terminal T2 of the filter element. Figure 1 , Figure 2 ) is a graph showing the results of a simulation using the coefficient S21.

[0041] Fig.12 This is a cross-sectional view of a filter module according to the second embodiment.

[0042] Fig.13A as well as Fig. 13B The figure shows the electromagnetic field simulator used to analyze the signal from the first signal terminal T1 to the second signal terminal T2 of the filter element. Figure 1 , Figure 2 ) is a graph showing the results of a simulation using the coefficient S21.

[0043] Description of Reference Numerals

[0044] 20 filter elements;

[0045] 21, 22, 23, 24 Parallel resonant circuit;

[0046] 25 1st side;

[0047] 26 2nd side;

[0048] 27 Bottom;

[0049] 28 upper surface;

[0050] 30 filter elements;

[0051] 35, 36 High frequency switching;

[0052] 37, 38 Low noise amplifier;

[0053] 41, 42 antenna terminals;

[0054] 45, 46 output terminals;

[0055] 50 filter modules;

[0056] 51 module substrate;

[0057] 52 ground plane;

[0058] 54 regions;

[0059] 55 shielding member;

[0060] 55A first side wall portion;

[0061] 55B second side wall portion;

[0062] 100, 100A, 100B, ..., 100M dielectric layer;

[0063] 101A, 101B, 101C conductor pattern;

[0064] 101D A ground conductor consisting of a conductor pattern;

[0065] 101E, 101F, ..., 101M conductor pattern;

[0066] 102A, 102B, ..., 102N via conductors;

[0067] C1, C2, ...C7 capacitors;

[0068] L1, L2, ...L5 inductors;

[0069] T1 1st signal terminal;

[0070] T2 2nd signal terminal;

[0071] TG ground terminal. DETAILED DESCRIPTION

[0072] [First embodiment]

[0073] Reference Figures 1 to 11B The filter module according to the first embodiment is described with reference to the accompanying drawings.

[0074] Figure 1This is an equivalent circuit diagram of a filter element 20 mounted on a filter module based on the first embodiment. The filter element 20 includes four parallel resonant circuits 21, 22, 23, and 24 of the first to fourth stages. The parallel resonant circuit 21 of the first stage includes an inductor L1 and a capacitor C1 connected in parallel. The parallel resonant circuit 22 of the second stage includes an inductor L2 and a capacitor C2 connected in parallel. The parallel resonant circuit 23 of the third stage includes an inductor L4 and a capacitor C4 connected in parallel. The parallel resonant circuit 24 of the fourth stage includes an inductor L5 and a capacitor C5 connected in parallel. The filter element 20 is, for example, a bandpass filter for the frequency band n77 of 5G.

[0075] One terminal (hereinafter referred to as a terminal on the ground side) of each of the four parallel resonant circuits 21, 22, 23, and 24 is connected to the ground terminal TG via a common inductor L3. The terminal on the opposite side of the terminal on the ground side of each of the parallel resonant circuits 21, 22, 23, and 24 is referred to as a terminal on the signal side. The terminal on the signal side of the first-stage parallel resonant circuit 21 is connected to the first signal terminal T1. A capacitor C3 is connected between the terminal on the signal side of the first-stage parallel resonant circuit 21 and the terminal on the signal side of the second-stage parallel resonant circuit 22. The terminal on the signal side of the fourth-stage parallel resonant circuit 24 is connected to the second signal terminal T2. A capacitor C6 is connected between the terminal on the signal side of the third-stage parallel resonant circuit 24 and the terminal on the signal side of the fourth-stage parallel resonant circuit 24. A capacitor C7 is connected between the first signal terminal T1 and the second signal terminal T2. The capacitor C7 is composed of two capacitors connected in series. The inductors L1 , L2 , L3 , and L4 of the four parallel resonant circuits 21 , 22 , 23 , and 24 are inductively coupled to each other.

[0076] Figure 2 This is an exploded perspective view of the filter element according to the first embodiment. Figure 3A , Figure 3B ,as well as Figure 3C 1 and 2 are respectively a top view, a front view, and a bottom view of the filter element according to the first embodiment.

[0077] The filter element 20 has a rectangular shape. The shape when viewed from above is a rectangle, for example, the length of the long side is about twice the length of the short side. The filter element 20 is surface mounted on a module substrate, for example. The surface opposite to the module substrate is called the bottom surface 27, and the surface facing the opposite direction to the bottom surface 27 is called the top surface 28. In addition, the two side surfaces facing opposite directions are respectively referred to as the first side surface 25 and the second side surface 26. The first side surface 25 and the second side surface 26 connect the long sides of the bottom surface 27 and the top surface 28 to each other. The direction from the bottom surface 27 toward the top surface 28 is called the height direction.

[0078] Thirteen dielectric layers 100A, 100B, ... 100M are stacked in order in the height direction from the bottom surface 27. When the plurality of dielectric layers 100A, 100B, ... 100M are not distinguished, they are simply described as dielectric layers 100. For example, low temperature co-fired ceramics (LTCC) are used for these dielectric layers 100. In addition, as dielectric layers 100, in addition to LTCC substrates, dielectric substrates such as glass substrates, epoxy resins, and liquid crystal polymers can also be used.

[0079] At least one conductor pattern is formed in some dielectric layers 100. The via conductor connects the conductor patterns in different dielectric layers 100 to each other.

[0080] The first signal terminal T1, the ground terminal TG, and the second signal terminal T2, which are formed of conductor patterns, are formed on the outwardly facing surface (bottom surface 27) of the bottom dielectric layer 100A. Three conductor patterns 101A, 101B, and 101C are formed on the third dielectric layer 100C. A ground conductor 101D, which is formed of a conductor pattern, is formed on the fourth dielectric layer 100D. The two conductor patterns 101A and 101C function as one electrode of the capacitors C1 and C4, respectively. The two conductor patterns 101A and 101C arranged on the third dielectric layer 100C are opposed to the ground conductor 101D with the dielectric layer sandwiched therebetween, thereby forming capacitors C1 and C4.

[0081] The two conductor patterns 101A and 101C functioning as one electrode of the capacitors C1 and C4 are connected to the first signal terminal T1 and the second signal terminal T2 via via-hole conductors 102A and 102D, respectively. The ground conductor 101D is connected to the ground terminal TG via via-hole conductors 102E and 102F, the conductor pattern 101B arranged on the third dielectric layer 100C, and the via-hole conductors 102B and 102C. The parasitic inductance of the via-hole conductors 102B, 102C, 102E, and 102F is represented by the inductor L3 ( Figure 1 ).

[0082] Two conductor patterns 101E and 101F are formed on the fifth dielectric layer 100E. The two conductor patterns 101E and 101F function as one electrode of capacitors C2 and C5, respectively. The two conductor patterns 101E and 101F face the ground conductor 101D with the dielectric layer interposed therebetween, thereby forming capacitors C2 and C5.

[0083] Two conductor patterns 101G and 101H are formed on the sixth dielectric layer 100F. The two conductor patterns 101G and 101H face the two conductor patterns 101E and 101F therebelow with the dielectric layer interposed therebetween, respectively, to form capacitors C3 and C6.

[0084] One conductor pattern 101I is arranged on the seventh dielectric layer 100G. Two conductor patterns 101G and 101H arranged on the sixth dielectric layer 100F face the conductor pattern 101I with the dielectric layers interposed therebetween, thereby constituting two capacitors C7 connected in series.

[0085] Four conductor patterns 101J, 101K, 101L, and 101M are arranged on the 10th dielectric layer 100J. Four conductor patterns 101J, 101K, 101L, and 101M of the same shape are arranged on the 11th dielectric layer 100K and the 12th dielectric layer 100L, respectively. The three conductor patterns 101J arranged on the three dielectric layers 100J, 100K, and 100L overlap in a plan view. The same is true for the conductor patterns 101K, 101L, and 101M.

[0086] The via-hole conductor 102G connects the ground conductor 101D and the vicinity of the end on the first side 25 side of the three conductor patterns 101J. The via-hole conductor 102H connects the vicinity of the end on the second side 26 side of the three conductor patterns 101J and the conductor pattern 101A. The via-hole conductor 102H is also connected to the conductor pattern 101G at the middle portion. The via-hole conductor 102G, the conductor pattern 101J, and the via-hole conductor 102H constitute the inductor L1. That is, the inductor L1 extends upward from the end on the ground side connected to the ground conductor 101D, and then extends from the first side 25 to the second side 26 in the short side direction of the dielectric layer 100, and further extends in the direction toward the bottom surface 27. The end of the inductor L1 on the opposite side to the end on the ground side (the end on the signal side) is connected to the conductor pattern 101A.

[0087] The inductor L2 is composed of a via-hole conductor 102I extending upward from the ground conductor 101D, a conductor pattern 101K extending from the via-hole conductor 102I in the short-side direction of the dielectric layer 100 from the first side surface 25 to the second side surface 26, and a via-hole conductor 102J extending from the conductor pattern 101K in the direction toward the bottom surface 27. The inductor L3 is composed of a via-hole conductor 102K extending upward from the ground conductor 101D, a conductor pattern 101L extending from the via-hole conductor 102K in the short-side direction of the dielectric layer 100 from the first side surface 25 to the second side surface 26, and a via-hole conductor 102L extending from the conductor pattern 101L in the direction toward the bottom surface 27. Inductor L4 includes via-hole conductor 102M extending upward from ground conductor 101D, conductor pattern 101M extending from via-hole conductor 102M in the short-side direction of dielectric layer 100 from first side surface 25 toward second side surface 26 , and via-hole conductor 102N extending from conductor pattern 101M toward bottom surface 27 .

[0088] The inductors L1, L2, L3, and L4 are arranged in a direction parallel to both the first side surface 25 and the bottom surface 27, that is, in the long side direction of the dielectric layer 100. The direction in which the inductors L1, L2, L3, and L4 are arranged is referred to as an arrangement direction. In any of the inductors L1, L2, L3, and L4, the via-hole conductors 102G, 102I, 102K, and 102M connected to the ground conductor 101D are arranged on the side closer to the first side surface 25 than the via-hole conductors 102H, 102J, 102L, and 102N on the other side.

[0089] As an example, the dimensions Lx and Ly of the filter element 20 in the long and short directions ( Figure 3A ) are 1.6 mm and 0.8 mm respectively. The interval Gy1 ( Figure 3A ) is 0.075 mm. The interval Gy2 ( Figure 3A ) is also 0.075mm.

[0090] Figure 4 This is a block diagram of a filter module 50 according to the first embodiment. The filter module 50 has two antenna terminals 41 and 42, and two output terminals 45 and 46. The two antenna terminals 41 and 42 are connected to two filter elements 20 and 30 via a high-frequency switch 35. One filter element 20 is a bandpass filter that allows signals in the frequency band n77 of 5G to pass, and the other filter element 30 is a bandpass filter that allows signals in the frequency band n79 of 5G to pass.

[0091] The signals that have passed through the filter elements 20 and 30 are respectively input to the low noise amplifiers 37 and 38. The signals amplified by the low noise amplifiers 37 and 38 are output from the output terminals 45 and 46 to the outside via the high frequency switch 36.

[0092] Figure 5A as well as Figure 5B 1 and 2 are a perspective view and a cross-sectional view of the filter module 50 according to the first embodiment. The filter elements 20 and 30 are surface mounted on the mounting surface of the module substrate 51. The mounting surface of the module substrate 51 ensures space for mounting the low noise amplifiers 37 and 38 ( Figure 4 ) etc. area 54.

[0093] The module substrate 51 includes a ground plane 52 disposed therein. The ground terminal TG of the filter element 20 is electrically connected to the ground plane 52. Similarly, the ground terminal of the filter element 30 is also electrically connected to the ground plane 52. The shielding member 55 protects the filter elements 20, 30, and the low noise amplifiers 37, 38 ( Figure 4 ) etc. The shield member 55 is electrically connected to the ground plane 52. The shield member 55 and the ground plane 52 provide electromagnetic shielding for the circuit components mounted on the module substrate 51.

[0094] The shielding member 55 is formed of a conductive film of metal or the like covering the surface of the sealing resin that seals the plurality of circuit components mounted on the module substrate 51. The shielding member 55 includes: four side wall portions rising upward from the mounting surface of the module substrate 51, and a flat plate portion parallel to the module substrate 51. The filter element 20 is mounted in a posture where its first side surface 25 is opposed to one side wall portion. The side wall portion opposed to the first side surface 25 of the filter element 20 is referred to as the first side wall portion 55A. The side wall portion on the opposite side to the first side wall portion 55A is referred to as the second side wall portion 55B. The second side wall portion 55B is opposed to the second side surface 26 of the filter element 20 via the filter element 30, other circuit components, etc.

[0095] A distance G1 between the first side surface 25 of the filter element 20 and the first side wall portion 55A of the shield member 55 is narrower than a distance G2 between the second side surface 26 and the second side wall portion 55B.

[0096] As an example, the height H1 from the bottom surface of the module substrate 51 to the bottom surface of the filter element 20 is 0.12 mm. The height H2 of the filter element 20 is 0.325 mm. The height H3 from the upper surface of the filter element 20 to the flat plate portion of the shield member 55 is 0.305 mm.

[0097] Before describing the excellent effects of the first embodiment, the following will be described with reference to the problem of mounting the filter element 20 on the module substrate 51 and performing electromagnetic shielding by the shield member 55. Figure 6 To explain.

[0098] Figure 6 is a diagram showing the filter element 20 and the low noise amplifier 37 ( Figure 4 ) is a graph showing the measured results of the pass coefficient S21 of a circuit composed of ). The horizontal axis represents the frequency in GHz, and the vertical axis represents the pass coefficient S21 in dB. Figure 6 The dotted line in the graph is the result of measurement in a state where the shield member 55 is not mounted, and the solid line is the result of measurement in a state where the shield member 55 is mounted.

[0099] In either case, the pass coefficient S21 becomes higher in the frequency band of 5G frequency band n77, that is, in the range of 3.2 GHz to 4.2 GHz. In addition, in the frequency band of 5 GHz to 7 GHz higher than the pass band, if the shielding member 55 is installed, two attenuation poles showing minimum values ​​of the pass coefficient S21 appear. It is clear that if the shielding member 55 is installed, the two attenuation poles move. Figure 6 In the example shown, it can be seen that when the shield member 55 is installed, the interval between the two poles becomes wider, and the pass coefficient S21 becomes larger in the frequency band between the poles. That is, the attenuation characteristics in the attenuation band other than the pass band deteriorate.

[0100] The movement of the attenuation pole is considered to be caused by the fact that, when the shield member 55 is installed, coupling is generated between the plurality of inductors in the filter element 20 due to mutual induction via the shield member 55, and the circuit constant of the resonance circuit changes. Therefore, the movement amount of the attenuation pole varies depending on the positional relationship between the inductor and the shield member 55.

[0101] Secondly, refer to 7A to 8B The accompanying drawings illustrate the results of simulating the change in the attenuation pole of the pass coefficient S21 by changing the positional relationship between the filter element 20 and the shield member 55 using an electromagnetic field simulator.

[0102] Fig. 7A is a schematic diagram showing the positional relationship between the filter element 20 and the shielding member 55. Fig. 7A In the example shown, the interval G2 between the second side surface 26 of the filter element 20 and the second side wall portion 55B of the shield member 55 is narrower than the interval G1 between the first side surface 25 and the first side wall portion 55A. Figure 5A as well as Figure 5BThis is achieved by rotating the filter element 20 180 degrees in a plan view. In this case, the side wall portion close to the filter element 20 becomes the second side wall portion 55B, and the side wall portion close to the other filter element 30 becomes the first side wall portion 55A.

[0103] Figure 7B is a diagram showing a filter element 20 and a low noise amplifier 37 ( Figure 4 ) is a graph of simulation results of the pass coefficient S21 of a circuit constructed with a 212A circuit. The horizontal axis represents the frequency in GHz, and the vertical axis represents the pass coefficient S21 in dB. Figure 7B The dotted line in the graph shows the pass coefficient S21 in a state where the shield member 55 is not attached, and the solid line shows the pass coefficient S21 in a state where the filter element 20 and the shield member 55 are arranged so that the interval G2 becomes 0.8 mm.

[0104] When the shielding member 55 is not installed, one attenuation pole appears, and when the shielding member 55 is installed, two attenuation poles appear. One attenuation pole appears on the high-frequency side compared to the attenuation pole when the shielding member 55 is not installed, and the other attenuation pole appears on the low-frequency side compared to the attenuation pole when the shielding member 55 is not installed.

[0105] Fig. 8A is a schematic diagram showing the positional relationship between the filter element 20 and the shielding member 55. Fig. 8A In the illustrated example, a distance G1 between the first side surface 25 of the filter element 20 and the first side wall portion 55A of the shield member 55 is narrower than a distance G2 between the second side surface 26 and the second side wall portion 55B.

[0106] Figure 8B is a diagram showing a filter element 20 and a low noise amplifier 37 ( Figure 4 ) is a graph of simulation results of the pass coefficient S21 of a circuit constructed with a 212A circuit. The horizontal axis represents the frequency in GHz, and the vertical axis represents the pass coefficient S21 in dB. Figure 8B The dotted line in the curve graph shows the pass coefficient S21 when the shielding component 55 is not assembled, the thin solid line shows the pass coefficient S21 when the filter element 20 and the shielding component 55 are configured so that the interval G1 becomes 0.6 mm, and the thick solid line shows the pass coefficient S21 when the filter element 20 and the shielding component 55 are configured so that the interval G1 becomes 0.8 mm.

[0107] When the shielding member 55 is not provided, two attenuation poles appear. If the interval G1 is set to 0.6 mm, the attenuation pole disappears, and the pass coefficient S21 near 6 GHz and 7 GHz becomes larger. If the interval G1 is set to 0.8 mm, there is only one attenuation pole, and the pass coefficient S21 near 6 GHz becomes smaller.

[0108] according to 7A to 8B From the simulation results shown in the accompanying drawings, it can be seen that the pass coefficient S21 around 6 GHz and 7 GHz changes significantly depending on the positional relationship between the shield member 55 and the filter element 20 .

[0109] Secondly, refer to 9A to 10B The reason why the transmission coefficient S21 changes depending on the positional relationship between the shield member 55 and the filter element 20 is described with reference to the accompanying drawings.

[0110] Fig.9A is an equivalent circuit diagram of the filter element 20 . Fig. 9B It is shown Fig.9A Graph showing the calculation result of the pass coefficient S21 from the first signal terminal T1 to the second signal terminal T2 of the equivalent circuit diagram shown in FIG. It is assumed that the mutual inductance M12 of the inductors L1 and L2 and the mutual inductance M45 of the inductors L4 and L5 vary according to the positional relationship between the filter element 20 and the shielding member 55. The pass coefficient S21 is calculated for two cases, a case where the mutual inductances M12 and M45 are relatively small and a case where they are relatively large.

[0111] Fig. 9B The horizontal axis represents the frequency in GHz, and the vertical axis represents the pass coefficient S21 in dB. Fig. 9B The dotted line in the graph shows the calculation result when the mutual inductances M12 and M45 are relatively small, and the solid line shows the calculation result when the mutual inductances M12 and M45 are relatively large.

[0112] It can be seen that if the mutual inductances M12 and M45 increase, the interval between the two attenuation poles will increase. Figure 7B The change in attenuation pole when changing from the state without shielding member 55 to the state with shielding member 55 is similar. Therefore, it is considered that shielding member 55 disposed near second side surface 26 of filter element 20 acts in the direction of increasing mutual inductances M12 and M45.

[0113] Fig. 10A is an equivalent circuit diagram of the filter element 20 . Fig. 10B It is shown Fig. 10A Graph showing the calculation result of the pass coefficient S21 from the first signal terminal T1 to the second signal terminal T2 of the equivalent circuit diagram shown in FIG. It is assumed that the mutual inductance M14 of the inductors L1 and L4 and the mutual inductance M25 of the inductors L2 and L5 vary according to the positional relationship between the filter element 20 and the shielding member 55. The pass coefficient S21 is calculated for two cases where the mutual inductances M14 and M25 are relatively small and relatively large.

[0114] Fig. 10BThe horizontal axis represents the frequency in GHz, and the vertical axis represents the pass coefficient S21 in dB. Fig. 10B The solid line in the graph shows the calculation result when the mutual inductances M14 and M25 are relatively small, and the dotted line shows the calculation result when the mutual inductances M12 and M45 are relatively large.

[0115] It can be seen that if the mutual inductances M14 and M25 increase, the two attenuation poles will disappear. Figure 8B The change in attenuation pole when there is no shielding member 55 and the gap G1 is 0.6 mm is similar. Therefore, it is considered that the shielding member 55 disposed near the first side surface 25 of the filter element 20 acts in the direction of increasing the mutual inductances M14 and M25.

[0116] Secondly, refer to Fig.11A , Fig. 11B , indicating the use of an electromagnetic field simulator to make the interval G1 ( Figure 5B ) is changed. In this simulation, the spacing G1 is made larger than the spacing G2 ( Figure 5B ) is narrow, the interval G2 is fixed, and only the interval G1 is changed. The passband of the filter element 20 is 3.3 GHz or more and 4.2 GHz or less, which is equivalent to the frequency band n77 of G5.

[0117] Fig.11A as well as Fig. 11B 20 from the first signal terminal T1 to the second signal terminal T2 ( Figure 1 , Figure 2 ) is a graph of simulation results of the pass coefficient S21 of the transmission element. The horizontal axis represents the frequency in GHz, and the vertical axis represents the pass coefficient S21 in dB. Fig. 11B It is magnified Fig.11A The frequency axis of the diagram ranges from 5.5 GHz to 7.5 GHz.

[0118] exist Fig. 11B The lines shown indicate the size of the interval G1. If the shielding member 55 is configured so that the interval G1 is narrower than the interval G2, the attenuation pole on the high-frequency side of the two attenuation poles is offset from 7 GHz to the low-frequency side. In addition, the attenuation pole on the low-frequency side is offset to the slightly high-frequency side, but does not become above 6 GHz. As a result, in the frequency band above 6 GHz and below 6.5 GHz, the pass coefficient S21 decreases compared to the case without shielding. In particular, by setting the interval G1 to be between 0.1 mm and 0.3 mm, the pass coefficient S21 can be reduced to below -60 dB in the frequency band above 6 GHz and below 6.5 GHz.

[0119] Next, the excellent effects of the first embodiment will be described.

[0120] In the first embodiment, the filter element 20 and the shield member 55 are arranged so that the interval G1 is smaller than the interval G2 ( Figure 5B ) is narrow, thereby being able to significantly improve the attenuation characteristics (increase the attenuation amount) in the frequency band above 6 GHz and below 6.5 GHz compared to the unshielded case. In particular, in the frequency band above 6 GHz and below 6.5 GHz, higher harmonics of signals in the lower frequency band are easily superimposed as noise. When the filter module 50 based on the first embodiment is used in an environment where a large noise may be generated in the frequency band above 6 GHz and below 6.5 GHz, a particularly significant effect can be obtained. By adopting the structure based on the first embodiment, a high-performance filter element 20 can be obtained that includes the frequency band n77 of 5G in the passband and includes the range above 6 GHz and below 6.5 GHz in the attenuation band.

[0121] In order to make the interval G1 narrower than the interval G2, it is preferred that no circuit components be installed between the first side surface 25 of the filter element 20 and the first side wall portion 55A of the shield member 55 facing the first side surface 25. Figure 5A )、Low noise amplifiers 37, 38 ( Figure 4 ) are preferably arranged between the second side surface 26 and the second side wall portion 55B of the shield member 55 opposite thereto.

[0122] The distance Gy1 ( Figure 3A ) is 0.075 mm, so when the interval G1 is 0.1 mm or more and 0.3 mm or less, the interval between the first side wall portion 55A and the ground conductor 101D is 0.175 mm or more and 0.375 mm or less. If attention is paid to the ground conductor 101D of the filter element 20, it is preferred that the interval between the first side wall portion 55A and the ground conductor 101D is set to 0.175 mm or more and 0.375 mm or less.

[0123] Next, a modification of the first embodiment will be described.

[0124] The filter element 20 used in the filter module 50 according to the first embodiment includes four parallel resonant circuits 21, 22, 23, and 24, but the number of parallel resonant circuits is not limited to 4. The filter element 20 is preferably configured to include a plurality of parallel resonant circuits.

[0125] [Second embodiment]

[0126] Secondly, refer to Fig.12 , Fig.13A as well as Fig. 13BA filter module according to the second embodiment will be described. Hereinafter, description of the common configurations with the filter module according to the first embodiment will be omitted.

[0127] Fig.12 2 is a cross-sectional view of a filter module 50 according to the second embodiment. Figure 5B As shown, the interval G1 is made narrower than the interval G2. In contrast, in the second embodiment, the interval G2 is made narrower than the interval G1. In other words, the second side surface 26 of the filter element 20 is arranged close to the second side wall portion 55B of the shielding member 55, and no circuit components are installed therebetween.

[0128] Fig.13A as well as Fig. 13B The figure shows the electromagnetic field simulator used to analyze the signal from the first signal terminal T1 to the second signal terminal T2 of the filter element 20. Figure 1 , Figure 2 ) is a graph showing the results of a simulation of the pass coefficient S21 of the 3D image sensor. The horizontal axis represents the frequency in GHz, and the vertical axis represents the pass coefficient S21 in dB. Fig. 13B Yes Fig.13A The range of the frequency axis from 5.5 GHz to 7.5 GHz is enlarged in the figure.

[0129] When the gap G2 is less than 0.5 mm, the attenuation pole on the low frequency side is shifted toward the low frequency side, and the attenuation pole on the high frequency side is shifted toward the high frequency side, compared to the case without shielding. This is considered to be due to the fact that Fig.9A as well as Fig. 9B As shown, by providing the shield member 55 , the mutual inductance M12 between the inductors L1 and L2 and the mutual inductance M45 between the inductors L4 and L5 are increased.

[0130] When the interval G2 is 0.5 mm or more, the pass coefficient S21 does not change much from the state without the shield even if the shielding member 55 is arranged. That is, the pass coefficient S21 is substantially not affected by the shielding member 55. When the second side surface 26 of the filter element 20 and the second side wall portion 55B of the shielding member 55 are opposed to each other and brought close to each other, it is preferable to set the interval G2 between the two to 0.5 mm or more.

[0131] Next, the excellent effects of the second embodiment will be described.

[0132] In the second embodiment, by making the interval G2 narrower than the interval G1 and setting the interval G2 to be 0.5 mm or more, the pass coefficient S21 of the filter element 20 is less susceptible to the influence of the shield member 55. The interval Gy1 ( Figure 3A) is 0.075 mm, so when the interval G2 is 0.5 mm or more, the interval between the second side wall portion 55B and the ground conductor 101D becomes 0.575 mm or more. If attention is paid to the ground conductor 101D of the filter element 20, it is preferred that the interval between the second side wall portion 55B and the ground conductor 101D is set to be 0.575 mm or more.

[0133] The above-mentioned embodiments are for illustration only, and it is self-evident that partial replacement or combination of the structures shown in different embodiments can be performed. The same effects of the same structures based on multiple embodiments are not mentioned one by one in each embodiment. Furthermore, the present invention is limited by the above-mentioned embodiments. For example, various changes, improvements, combinations, etc. can be performed, which is obvious to those skilled in the art.

Claims

1. A filter module, comprising: Module substrate; A filter element, comprising a bottom surface and an upper surface facing opposite directions, and a first side surface and a second side surface facing opposite directions, wherein a ground terminal, a first signal terminal, and a second signal terminal are formed on the bottom surface, and the filter element is mounted on the module substrate in a posture where the bottom surface faces the module substrate; and a shielding member including a first side wall portion and a second side wall portion respectively facing the first side surface and the second side surface, and covering the filter element; The filter element includes a plurality of parallel resonant circuits therein, each of which includes an inductor and a capacitor connected in parallel to each other. The inductors of the plurality of parallel resonant circuits are arranged in a direction parallel to both the first side surface and the bottom surface. The inductors of the plurality of parallel resonant circuits extend upward from the ends on the ground side electrically connected to the ground terminal, further extend in a direction from the first side surface toward the second side surface, and further extend in a direction toward the bottom surface. An end of the inductor of one of the plurality of parallel resonant circuits on the signal side opposite to the end on the ground side is electrically connected to the first signal terminal, and an end of the inductor of another parallel resonant circuit on the signal side opposite to the end on the ground side is electrically connected to the second signal terminal. A distance between the first side surface and the first side wall portion is narrower than a distance between the second side surface and the second side wall portion.

2. The filter module according to claim 1, wherein: A distance between the first side surface and the first side wall portion is greater than or equal to 0.1 mm and less than or equal to 0.3 mm.

3. A filter module, comprising: Module substrate; A filter element, comprising a bottom surface and an upper surface facing opposite directions, and a first side surface and a second side surface facing opposite directions, wherein a ground terminal, a first signal terminal, and a second signal terminal are formed on the bottom surface, and the filter element is mounted on the module substrate in a posture where the bottom surface faces the module substrate; and a shielding member including a first side wall portion and a second side wall portion respectively facing the first side surface and the second side surface, and covering the filter element; The filter element includes a plurality of parallel resonant circuits therein, each of which includes an inductor and a capacitor connected in parallel to each other. The plurality of parallel resonant circuits are arranged in a direction parallel to both the first side surface and the bottom surface. The inductors of the plurality of parallel resonant circuits extend upward from the ends on the ground side electrically connected to the ground terminal, further extend in a direction from the first side surface toward the second side surface, and further extend in a direction toward the bottom surface. An end of the inductor of one of the plurality of parallel resonant circuits on the signal side opposite to the end on the ground side is electrically connected to the first signal terminal, and an end of the inductor of another parallel resonant circuit on the signal side opposite to the end on the ground side is electrically connected to the second signal terminal. The distance between the second side surface and the second side wall portion is narrower than the distance between the first side surface and the first side wall portion and is equal to or greater than 0.5 mm.

4. The filter module according to any one of claims 1 to 3, wherein: The filter element includes a ground conductor disposed in parallel with the bottom surface, and ends of the inductors of the plurality of parallel resonant circuits on the ground side are connected to the ground conductor.

5. The filter module according to any one of claims 1 to 3, wherein: At least three of the multiple parallel resonant circuits are configured, and the end of the signal side of the inductor of the parallel resonant circuit configured at one end with respect to the arrangement direction of the multiple parallel resonant circuits is electrically connected to the first signal terminal, and the end of the signal side of the inductor of the parallel resonant circuit configured at the other end is electrically connected to the second signal terminal, and the inductors of two adjacent parallel resonant circuits are inductively coupled to each other.

6. The filter module according to any one of claims 1 to 3, wherein: The module substrate includes a ground plane inside, and the shield member and the ground terminal are electrically connected to the ground plane.

7. The filter module according to any one of claims 1 to 3, wherein: The filter element is a bandpass filter, the passband includes a range from 3.3 GHz to 4.2 GHz, and the attenuation band includes a range from 6 GHz to 6.5 GHz.

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