LC resonators and LC filters

Abstract

This invention improves the characteristics of LC filters and suppresses their large size. One embodiment of the LC resonator (1A) includes a first planar electrode (102), a second planar electrode (103), a first line electrode (101), a first conducting conductor (111), a second conducting conductor (112), and a third planar electrode (104). The second planar electrode (103) is opposite to at least a portion of the first planar electrode (102) in a specific direction (Z). The first conducting conductor (111) and the second conducting conductor (112) extend from the first line electrode (101) along the specific direction (Z) and are connected to the first planar electrode (102) and the second planar electrode (103), respectively. The third planar electrode (104) is opposite to at least a portion of the second planar electrode (103) in a specific direction. The second planar electrode (103) is disposed between the first planar electrode (102) and the third planar electrode (104) in the specific direction (Z).

Description

Technical Field

[0001] This invention relates to LC resonators and LC filters. Background Technology

[0002] Previously, LC resonators and LC filters were known. For example, International Patent Publication No. 2007 / 119356 (Patent Document 1) discloses a stacked bandpass filter. This stacked bandpass filter comprises multiple LC parallel resonators. In each of the multiple LC parallel resonators, two conducting electrodes extend from a line electrode to a capacitor electrode and a ground connection electrode, respectively. A ring-shaped inductor is formed by the line electrode and the two conducting electrodes, and a capacitor is formed by the capacitor electrode and the ground connection electrode. When viewed from the arrangement direction of the multiple LC parallel resonators, the LC parallel resonators are configured such that at least a portion of the respective ring surfaces of the multiple LC parallel resonators overlap each other, thereby improving the coupling (inductive coupling) between adjacent LC parallel resonators. As a result, broadbanding of the stacked bandpass filter can be achieved.

[0003] Patent Document 1: International Publication No. 2007 / 119356

[0004] In many cases, the characteristics of an LC filter (such as transmission, reflection, or attenuation) are achieved by adjusting the resonant frequency of an LC resonator whose impedance reaches an extreme value. To improve the characteristics of an LC filter, the number of LC resonators in the filter needs to be increased. However, increasing the number of LC resonators results in a larger filter size, which may increase the insertion loss. Summary of the Invention

[0005] This invention was made to solve the aforementioned problems, and its purpose is to improve the characteristics of LC filters and suppress the large size of LC filters.

[0006] An LC resonator according to one embodiment of the present invention includes a first planar electrode, a second planar electrode, a first line electrode, a first conducting conductor, a second conducting conductor, and a third planar electrode. The second planar electrode is opposed to at least a portion of the first planar electrode in a specific direction. The first and second conducting conductors extend from the first line electrode along the specific direction and are respectively connected to the first and second planar electrodes. The third planar electrode is opposed to at least a portion of the second planar electrode in the specific direction. The second planar electrode is disposed between the first and third planar electrodes in the specific direction.

[0007] According to one embodiment of the present invention, in an LC resonator, a third planar electrode is opposed to at least a portion of a second planar electrode in a specific direction, and the second planar electrode is disposed between the first planar electrode and the third planar electrode in a specific direction, thereby improving the characteristics of the LC filter and suppressing the enlargement of the LC filter. Attached Figure Description

[0008] Figure 1 This is the equivalent circuit diagram of the LC resonator in Implementation Method 1.

[0009] Figure 2 yes Figure 1 A three-dimensional view of the appearance of an LC resonator.

[0010] Figure 3 It was formed in Figure 2 A three-dimensional view of the internal electrode structure of the laminate.

[0011] Figure 4 Viewed from the Y-axis Figure 3 A diagram of the electrode structure.

[0012] Figure 5 Viewed from the X-axis Figure 3 A diagram of the electrode structure.

[0013] Figure 6 This is the equivalent circuit diagram of the LC parallel resonator in Comparative Example 1 of Implementation Method 1.

[0014] Figure 7 This is the equivalent circuit diagram of the LC resonator in Comparative Example 2 of Implementation Method 1.

[0015] Figure 8 It is shown together Figure 1 LC resonator Figure 6 LC parallel resonator and Figure 7 The respective throughput characteristics of the LC resonators are shown in the figure.

[0016] Figure 9 This is an equivalent circuit diagram of the LC resonator in a modified example of implementation method 1.

[0017] Figure 10 This is an equivalent circuit diagram of a bandpass filter, which is an example of an LC filter in Implementation Method 2.

[0018] Figure 11 yes Figure 10 A 3D view of the appearance of a bandpass filter.

[0019] Figure 12 It was formed in Figure 11 A three-dimensional view of the internal electrode structure of the laminate.

[0020] Figure 13 Viewed from the Y-axis Figure 12 A diagram of the electrode structure.

[0021] Figure 14 Viewed from the X-axis Figure 12 A diagram of the electrode structure.

[0022] Figure 15 This is the equivalent circuit diagram of the bandpass filter in the comparative example of Implementation Method 2.

[0023] Figure 16 yes Figure 15 A three-dimensional view of the electrode structure of a bandpass filter.

[0024] Figure 17 Viewed from the Y-axis Figure 16 A diagram of the electrode structure.

[0025] Figure 18 Viewed from the X-axis Figure 16 A diagram of the electrode structure.

[0026] Figure 19 It is shown together Figure 10 The pass characteristics (straight line) of the bandpass filter and Figure 15 The graph shows the pass characteristics (dashed line) of the bandpass filter.

[0027] Figure 20 This is the equivalent circuit diagram of the bandpass filter in a modified example of implementation method 2.

[0028] Figure 21 This is an equivalent circuit diagram of a bandpass filter, which is an example of an LC filter in implementation method 3.

[0029] Figure 22 yes Figure 21 A 3D view of the appearance of a bandpass filter.

[0030] Figure 23 It was formed in Figure 22 A three-dimensional view of the internal electrode structure of the laminate.

[0031] Figure 24 Viewed from the Y-axis Figure 23 A diagram of the electrode structure.

[0032] Figure 25 Viewed from the X-axis Figure 23 A diagram of the electrode structure.

[0033] Figure 26 It means Figure 21 The graph shows the pass-through characteristics of the bandpass filter.

[0034] Figure 27 This is the equivalent circuit diagram of the bandpass filter in a modified example of implementation method 3.

[0035] Figure 28 This is the equivalent circuit diagram of the bandpass filter in Implementation Method 4.

[0036] Figure 29 It means Figure 28 The graph shows the pass-through characteristics of the bandpass filter.

[0037] Figure 30 This is the equivalent circuit diagram of the bandpass filter in a modified example of implementation method 4.

[0038] Figure 31 This is an equivalent circuit diagram of a bandpass filter, which is an example of an LC filter in Implementation Method 5.

[0039] Figure 32 It means Figure 31 The diagram shows the pass-through characteristics of the bandpass filter.

[0040] Figure 33 This is the equivalent circuit diagram of the bandpass filter in a modified example of implementation method 5.

[0041] Figure 34 It means Figure 33 The diagram shows the pass-through characteristics of the bandpass filter.

[0042] Figure 35 This is the equivalent circuit diagram of the bandpass filter in Implementation Method 6.

[0043] Figure 36 It means Figure 35 The diagram shows the pass-through characteristics of the bandpass filter. Detailed Implementation

[0044] Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings. Furthermore, the same reference numerals are used to label the same structures in the drawings.

[0045] [Implementation Method 1]

[0046] Figure 1 This is the equivalent circuit diagram of the LC resonator 1A in Embodiment 1. Figure 1 As shown, the LC resonator 1A is connected between the connection node of the input and output terminals P11 and P12 and the ground point GND.

[0047] The LC resonator 1A includes an inductor 10A, a capacitor 11A, and a capacitor 12A. Inductor 10A and capacitor 11A are connected in parallel between one electrode of capacitor 12A and the connection point of input / output terminals P11 and P12, forming an LC parallel resonant circuit. The other electrode of capacitor 12A is grounded. Inductor 10A and capacitor 12A are connected in series between ground point GND and the connection point of input / output terminals P11 and P12, forming an LC series resonant circuit.

[0048] Figure 2 yes Figure 1 A three-dimensional view of the external appearance of the LC resonator 1A. Figure 2 In this diagram, the X, Y, and Z axes are orthogonal to each other. Figures 3-5 , Figures 11-14 , Figures 16-18 , Figures 22-25 The same applies to China. For example... Figure 2 As shown, the LC resonator 1A is formed as a laminate 180 consisting of multiple dielectric layers stacked in the Z-axis direction. A grounding terminal G1 is formed on the bottom surface of the laminate 190.

[0049] Figure 3 It was formed in Figure 2 A three-dimensional view of the internal electrode structure of the 180-layer stack. Figure 4 Viewed from the Y-axis Figure 3 A diagram of the electrode structure. Figure 5 Viewed from the X-axis Figure 3 A diagram of the electrode structure. (See diagram below.) Figures 3-5 As shown, the LC resonator 1A includes a line electrode 101 (first line electrode), a planar electrode 102 (first planar electrode), a planar electrode 103 (second planar electrode), a conducting conductor 111 (first conducting conductor), a conducting conductor 112 (second conducting conductor), a ground electrode 104 (third planar electrode), and conducting conductors 131, 132, 133, and 134.

[0050] Planar electrode 103 is opposite at least a portion of planar electrode 102 in the Z-axis direction (a specific direction). Planar electrodes 102 and 103 form capacitor 11A.

[0051] Line electrode 101 extends along the X-axis. Conductors 111 and 112 extend from both ends of line electrode 101 along the Z-axis and are connected to planar electrodes 102 and 103, respectively. Conductor 111, line electrode 101, and conductor 112 form inductor 10A.

[0052] A planar electrode 103 is disposed between the planar electrode 102 and the ground electrode 104 in the Z-axis direction. The ground electrode 104 is opposite at least a portion of the planar electrode 103 in the Z-axis direction. The planar electrode 103 and the ground electrode 104 form a capacitor 12A.

[0053] The grounding electrode 104 is grounded by connecting to the grounding terminal G1 through each conductive conductor 131-134. Furthermore, Figure 1 The input / output terminals P11 and P21 are connected, for example, to the planar electrode 102 or the conductive conductor 111.

[0054] In the LC resonator 1A, the conducting conductors 111 and 112 forming the inductor 10A have different lengths along the Z-axis, with conductor 112 being longer than conductor 111. Therefore, current concentration is directed from the central portion of the line electrode 101 between the conducting conductors 112. As a result, the deterioration of losses caused by current concentration at the edges of the line electrode 101 can be mitigated.

[0055] Figure 6 This is the equivalent circuit diagram of the LC parallel resonator 9A in Comparative Example 1 of Embodiment 1. The structure of the LC parallel resonator 9A is derived from... Figure 1 The structure of the LC resonator 1A after removing the capacitor 12A is shown. Since the rest of the structure is the same, it will not be described further. Figure 6 As shown, inductor 10A and capacitor 11A are grounded.

[0056] Figure 7 This is an equivalent circuit diagram of the LC resonator 9B in Comparative Example 2 of Embodiment 1. The structure of the LC resonator 9B is... Figure 6 The structure of the 9A LC parallel resonator with the addition of a 13A capacitor is shown. Since the rest of the structure is the same, it will not be described further. Figure 7 The inductor 10A and capacitor 13A are connected in series between the ground point GND and the connection node of the input / output terminals P11 and P12. Capacitors 11A and 13A are connected in parallel between the ground point GND and the connection node of the input / output terminals P11 and P12. The LC resonator 9B includes an LC parallel resonator formed by the inductor 10A and capacitor 11A, and an LC series resonator formed by the inductor 10A and capacitor 13A.

[0057] Figure 8 It is shown together Figure 1 LC resonator 1A, Figure 6 LC parallel resonator 9A and Figure 7 The respective through-characteristics of the LC resonator 9B are shown in the diagram. Figure 8In the diagram, curves C1, C9A, and C9B represent the throughput characteristics of LC resonator 1A, LC parallel resonator 9A, and LC resonator 9B, respectively. Furthermore, Figure 8 The throughput characteristics shown are those of capacitors 11A to 13A with the same capacitance.

[0058] like Figure 8 As shown, in the transmission characteristics of LC parallel resonator 9A, the attenuation becomes minimal at frequency f90. In the transmission characteristics of LC resonator 9B, the attenuation becomes maximum at frequency f91 and minimal at frequency f92 (>f91). In the transmission characteristics of LC resonator 1A, the attenuation becomes maximum at frequency f11 and minimal at frequency f12 (>f11).

[0059] Comparing the throughput characteristics of LC resonator 1A and LC parallel resonator 9A, since LC parallel resonator 9A does not contain an LC series resonator, it exhibits a very large attenuation pole by not generating attenuation. Using LC resonator 1A to form an LC filter improves the attenuation characteristics compared to using LC parallel resonator 9A, which is a performance indicator that prevents signals outside the passband from passing through. Furthermore, since no additional LC resonator is needed to generate the attenuation pole, the size of the LC filter can be reduced.

[0060] Comparing the throughput characteristics of LC resonator 1A and LC resonator 9B, the frequencies at which attenuation becomes extremely large and extremely small are both lower in LC resonator 1A. These frequencies depend on the resonant frequencies of the LC series resonator and the LC parallel resonator, respectively. The smaller the inductance of the inductor and the capacitance of the capacitor forming the LC resonator, the higher the resonant frequency of the LC resonator. By making the inductance of the inductor and the capacitance of the capacitor in LC resonator 1A smaller than those in LC resonator 9B, the throughput characteristics of LC resonator 1A can be made closer to those of LC resonator 9B. That is, when achieving an LC filter with the desired throughput characteristics, the size of the LC filter can be reduced by using LC resonator 1A compared to using LC resonator 9B.

[0061] In the LC resonator 1A, the structure with capacitor 12A grounded is explained. Capacitor 12A can also be left ungrounded. Figure 9 This is an equivalent circuit diagram of the LC resonator 1B in a modified example of Embodiment 1. Figure 9 In Figure 1The third planar electrode of the 12A capacitor grounded in the middle is connected to the input / output terminal P10. Since the rest of the structure is the same, it will not be described in detail.

[0062] According to the LC resonator of Embodiment 1 and its variations, the characteristics of the LC filter can be improved and the large size of the LC filter can be suppressed.

[0063] In embodiments 2 to 6, an LC filter incorporating the LC resonator of embodiment 1 will be described. In embodiment 2, a two-stage LC filter incorporating two LC resonators will be described; in embodiments 3, 4, and 5, a four-stage LC filter incorporating four LC resonators will be described; and in embodiment 6, a five-stage LC filter incorporating five LC resonators will be described.

[0064] [Implementation Method 2]

[0065] Figure 10 This is an equivalent circuit diagram of a bandpass filter 200, which is an example of an LC filter in Embodiment 2. Figure 10 As shown, the bandpass filter 200 includes input / output terminal P21 (first terminal), input / output terminal P22 (second terminal), LC resonator 1 (first LC resonator), LC resonator 2 (second LC resonator), capacitor C12, and inductor LG. The bandpass filter 200 is a two-stage bandpass filter.

[0066] One end of inductor LG is connected to ground GND. LC resonator 1 is connected between input / output terminal P21 and the other end of inductor LG. LC resonator 2 is connected between input / output terminal P22 and the other end of inductor LG. Magnetic coupling M12 is generated between LC resonators 1 and LC resonators 2. Capacitor C12 is connected between LC resonators 1 and LC resonators 2. Capacitor C12 represents the capacitive coupling generated between LC resonators 1 and LC resonators 2.

[0067] LC resonator 1 includes an inductor 10 and capacitors 11 and 12. LC resonator 2 includes an inductor 20 and capacitors 21 and 22. LC resonators 1 and LC resonators 2 respectively have... Figure 1 The LC resonator 1A shown has the same structure. That is, inductor 10, capacitor 11, and capacitor 12 correspond to inductor 10A, capacitor 11A, and capacitor 12A, respectively. Inductor 20, capacitor 21, and capacitor 22 correspond to inductor 10A, capacitor 11A, and capacitor 12A, respectively.

[0068] Figure 11 yes Figure 10 A three-dimensional view of the appearance of the bandpass filter 200. (See image below.) Figure 11As shown, the bandpass filter 200 is formed as a stack 280 consisting of multiple dielectric layers stacked in the Z-axis direction. Input / output terminals P21 and P22, and a ground terminal G2 are formed on the bottom surface of the stack 280. The input / output terminals P21 and P22, and the ground terminal G2, are, for example, LGA (Land Grid Array) terminals with planar electrodes regularly arranged on the bottom surface of the stack 280. The bottom surface of the stack 280 is connected to a circuit board (not shown).

[0069] Figure 12 It was formed in Figure 11 A three-dimensional view of the internal electrode structure of the laminate 280. Figure 13 Viewed from the Y-axis Figure 12 A diagram of the electrode structure. Figure 14 Viewed from the X-axis Figure 12 A diagram of the electrode structure. (See diagram below.) Figures 12-14 As shown, the bandpass filter 200 includes a line electrode 211 (first line electrode), a planar electrode 212 (first planar electrode), a planar electrode 213 (second planar electrode), a conducting conductor 231 (first conducting conductor), and a conducting conductor 232 (second conducting conductor). The bandpass filter 200 also includes a line electrode 221 (first line electrode), a planar electrode 222 (first planar electrode), a planar electrode 223 (second planar electrode), a conducting conductor 241 (first conducting conductor), and a conducting conductor 242 (second conducting conductor). The bandpass filter 200 further includes a ground electrode 204 (third planar electrode) and conducting conductors 251, 252, 261, 262, 263, 271, and 272.

[0070] Planar electrode 213 is opposite to at least a portion of planar electrode 212 in the Z-axis direction. Planar electrodes 212 and 213 form capacitor 11. Planar electrode 212 is connected to input / output terminal P21 via conductive conductors 251 and 252.

[0071] Line electrode 211 extends along the X-axis. Conductors 231 and 232 extend from both ends of line electrode 211 along the Z-axis and are connected to planar electrodes 212 and 213, respectively. Conductor 231, line electrode 211, and conductor 232 form inductor 10.

[0072] Planar electrode 213 is disposed between planar electrode 212 and ground electrode 204 in the Z-axis direction. Ground electrode 204 is opposite to at least a portion of planar electrode 213 in the Z-axis direction. Planar electrode 213 and ground electrode 204 form capacitor 12.

[0073] Planar electrode 223 is opposite to at least a portion of planar electrode 222 in the Z-axis direction. Planar electrodes 222 and 223 form capacitor 21. Planar electrode 222 is connected to input / output terminal P22 via conductive conductors 271 and 272.

[0074] Line electrode 221 extends along the X-axis. Conductors 241 and 242 extend from both ends of line electrode 221 along the Z-axis and are connected to planar electrodes 222 and 223, respectively. Conductor 241, line electrode 221, and conductor 242 form inductor 20.

[0075] A planar electrode 223 is disposed between the planar electrode 222 and the ground electrode 204 in the Z-axis direction. The ground electrode 204 is opposite to at least a portion of the planar electrode 223 in the Z-axis direction. The planar electrode 223 and the ground electrode 204 form a capacitor 22.

[0076] The grounding electrode 204 is grounded by connecting to the grounding terminal G2 through each of the conductive conductors 261 to 263. The conductive conductors 261 to 263 form an inductor LG.

[0077] Figure 15 This is an equivalent circuit diagram of the bandpass filter 900 in the comparative example of Embodiment 2. The structure of the bandpass filter 900 is to... Figure 10 The LC resonators 1 and 2 are replaced with LC parallel resonators 91 and 92, respectively. The structure of LC parallel resonator 91 is the result of removing capacitor 12 from LC resonator 1. The structure of LC parallel resonator 92 is the result of removing capacitor 22 from LC resonator 2. Since everything else is the same, further details are omitted. Figure 15 As shown, inductor 10 and capacitor 11 are grounded. Inductor 20 and capacitor 21 are grounded.

[0078] The bandpass filter 900, like the bandpass filter 200, is formed as a stack of multiple dielectric layers layered along the Z-axis. The three-dimensional view of the bandpass filter 900 is shown below. Figure 11 The appearance of the bandpass filter 200 shown is the same as the stereoscopic view shown, so it will not be described again. Use Figures 16-18 The electrode structure formed inside the laminate is described.

[0079] Figure 16 yes Figure 15 A three-dimensional view of the electrode structure of the bandpass filter 900. Figure 17 Viewed from the Y-axis Figure 16 A diagram of the electrode structure. Figure 18 Viewed from the X-axis Figure 16 A diagram of the electrode structure. (See diagram below.) Figures 16-18As shown, the bandpass filter 900 includes a line electrode 911, a planar electrode 912, and conducting conductors 931 and 932. The bandpass filter 900 also includes a line electrode 921, a planar electrode 922, and conducting conductors 941 and 942. The bandpass filter 900 further includes a ground electrode 904, a planar electrode 903, and conducting conductors 950, 961, 962, 963, and 970.

[0080] Line electrode 911 extends along the X-axis. Conductors 931 and 932 extend from both ends of line electrode 911 along the Z-axis and are connected to planar electrode 912 and ground electrode 904, respectively. Conductor 931, line electrode 911, and conductor 932 form inductor 10.

[0081] Ground electrode 904 is opposed to at least a portion of planar electrode 912 in the Z-axis direction. Planar electrode 912 and ground electrode 904 form capacitor 11. Planar electrode 912 is connected to input / output terminal P21 via conductive conductor 950.

[0082] Line electrode 921 extends along the X-axis. Conductors 941 and 942 extend from both ends of line electrode 921 along the Z-axis and are connected to planar electrode 922 and ground electrode 904, respectively. Conductor 941, line electrode 921, and conductor 942 form inductor 20.

[0083] Ground electrode 904 is opposite at least a portion of planar electrode 922 in the Z-axis direction. Planar electrode 922 and ground electrode 904 form capacitor 21. Planar electrode 922 is connected to input / output terminal P22 via conductive conductor 970.

[0084] Planar electrode 903 is opposed to at least a portion of planar electrode 912 and at least a portion of planar electrode 922 in the Z-axis direction. Planar electrodes 912, 903, and 922 form capacitor C12. Ground electrode 904 is grounded by connecting to ground terminal G2 through conductive conductors 961 to 963. Conductive conductors 961 to 963 form inductor LG.

[0085] Figure 19 It means together Figure 10 The pass characteristics (straight line) of the bandpass filter 200 and Figure 15 The graph shows the pass characteristics (dashed line) of the 900 bandpass filter. Figure 19As shown, in the pass characteristics of bandpass filter 900, no attenuation poles are generated in the frequency band lower than the passband. On the other hand, in the pass characteristics of bandpass filter 200, an attenuation pole is generated at a frequency f2 lower than the passband. In bandpass filter 200, the steepness near the boundary of the low-frequency side of the passband is improved compared to bandpass filter 900 due to this attenuation pole. That is, in bandpass filter 200, the function of the bandpass filter, which limits the frequency of the passable signal to the desired frequency band, is improved compared to bandpass filter 900.

[0086] In the bandpass filter 200, the case where the LC resonator is directly connected to the input / output terminals is explained. The LC resonator can be electrically connected to the input / output terminals, or it can be disconnected. The case where the LC resonator is electrically connected to the input / output terminals includes the case where the LC resonator is capacitively coupled to the input / output terminals.

[0087] Figure 20 This is an equivalent circuit diagram of the bandpass filter 200A, a variation of Embodiment 2. The structure of the bandpass filter 200A is... Figure 10 The bandpass filter 200 has the following structure after adding capacitors Cio1 and Cio2. Since the structure is the same except for these components, it will not be described in detail.

[0088] like Figure 20 As shown, capacitor Cio1 is connected between the input / output terminal P21 and the connection node of inductor 10 and capacitor 11. That is, the first planar electrode included in capacitor 11 is electrically connected to the input / output terminal P21. Capacitor Cio1 represents the capacitive coupling generated between the input / output terminal P21 and LC resonator 1.

[0089] Capacitor Cio2 is connected between the input / output terminal P22 and the connection node of inductor 20 and capacitor 21. That is, the first planar electrode contained in capacitor 21 is electrically connected to the input / output terminal P22. Capacitor Cio2 represents the capacitive coupling generated between the input / output terminal P22 and the LC resonator 2.

[0090] According to the above, the LC filter based on Embodiment 2 and its variants can improve the characteristics of the LC filter and suppress the large size of the LC filter.

[0091] [Implementation Method 3]

[0092] Figure 21 This is an equivalent circuit diagram of a bandpass filter 300, which is an example of an LC filter in Embodiment 3. Figure 21As shown, the bandpass filter 300 includes input / output terminal P31 (first terminal), input / output terminal P32 (second terminal), LC resonator 1 (first LC resonator), LC resonators 2, 3, and LC resonator 4 (second LC resonator), and capacitors C12, C23, and C34. The bandpass filter 300 is a 4-stage bandpass filter.

[0093] Capacitor C12 of LC resonator 1 is connected to input / output terminal P31. Capacitor C12 is connected between LC resonator 1 and LC resonator 2. Capacitor C12 represents capacitive coupling between LC resonator 1 and LC resonator 2. Capacitor C23 is connected between LC resonator 2 and LC resonator 3. Capacitor C23 represents capacitive coupling between LC resonator 2 and LC resonator 3. Capacitor C34 is connected between LC resonator 3 and LC resonator 4. Capacitor C34 represents capacitive coupling between LC resonator 3 and LC resonator 4. Capacitor 42 of LC resonator 4 is connected to input / output terminal P32.

[0094] Magnetic coupling M12 is generated between LC resonators 1 and LC resonators 2. Magnetic coupling M23 is generated between LC resonators 2 and LC resonators 3. Magnetic coupling M34 is generated between LC resonators 3 and LC resonators 4.

[0095] LC resonators 1 and 2 respectively have the same characteristics as... Figure 9 LC resonator 1B and Figure 1 It has the same structure as the LC resonator 1A. Capacitor 12 and inductor 10 are connected in series between input / output terminals P31 and P32. Capacitor 12 represents the capacitive coupling between the LC parallel resonator formed by inductor 10 and capacitor 11 and input / output terminal P31.

[0096] LC resonator 3 includes an inductor 30 and capacitors 31 and 32. LC resonator 4 includes an inductor 40 and capacitors 41 and 42. LC resonators 3 and 4 respectively have... Figure 1 LC resonator 1A and Figure 9 The structure is the same as that of LC resonator 1B. That is, inductor 30, capacitor 31, and capacitor 32 correspond to inductor 10A, capacitor 11A, and capacitor 12A, respectively. Inductor 40, capacitor 41, and capacitor 42 correspond to inductor 10A, capacitor 11A, and capacitor 12A, respectively. Capacitor C42 and inductor 40 are connected in series between input / output terminal P32 and input / output terminal P31. Capacitor 42 represents the capacitive coupling between the LC parallel resonator formed by inductor 40 and capacitor 41 and input / output terminal P32.

[0097] Figure 22 yes Figure 21 A three-dimensional view of the appearance of the bandpass filter 300. (See image below.) Figure 22 As shown, the bandpass filter 300 is formed as a stack 380 consisting of multiple dielectric layers stacked in the Z-axis direction. Input / output terminals P31 and P32, and a ground terminal G3 are formed on the bottom surface of the stack 380. The input / output terminals P31 and P32, and the ground terminal G3, are, for example, LGA (Land Grid Array) terminals with planar electrodes regularly arranged on the bottom surface of the stack 380. The bottom surface of the stack 380 is connected to a circuit board (not shown).

[0098] Figure 23 It was formed in Figure 22 A three-dimensional view of the internal electrode structure of the laminate 380. Figure 24 Viewed from the Y-axis Figure 23 A diagram of the electrode structure. Figure 25 Viewed from the X-axis Figure 23 A diagram of the electrode structure. (See diagram below.) Figures 23-25 As shown, the bandpass filter 300 includes a line electrode 311 (first line electrode), a planar electrode 312 (first planar electrode), a planar electrode 313 (second planar electrode), a planar electrode 314 (third planar electrode), a conducting conductor 334 (first conducting conductor), and a conducting conductor 335 (second conducting conductor). The bandpass filter 300 also includes a line electrode 321 (first line electrode), a planar electrode 322 (first planar electrode), a planar electrode 323 (second planar electrode), a conducting conductor 336 (first conducting conductor), and a conducting conductor 337 (second conducting conductor). The bandpass filter 300 further includes a line electrode 331 (first line electrode), a planar electrode 332 (first planar electrode), a planar electrode 333 (second planar electrode), a conducting conductor 351 (first conducting conductor), and a conducting conductor 352 (second conducting conductor). The bandpass filter 300 also includes a line electrode 341 (first line electrode), a planar electrode 342 (first planar electrode), a planar electrode 343 (second planar electrode), a planar electrode 344 (third planar electrode), a conducting conductor 361 (first conducting conductor), and a conducting conductor 362 (second conducting conductor). The bandpass filter 300 also includes a ground electrode 304 (third planar electrode), planar electrodes 301 and 302, and conducting conductors 371, 372, 373, 374, 381, and 382.

[0099] Planar electrode 313 is opposite to at least a portion of planar electrode 312 in the Z-axis direction. Planar electrodes 312 and 313 form capacitor 11.

[0100] Line electrode 311 extends along the X-axis. Conductors 334 and 335 extend from both ends of line electrode 311 along the Z-axis and are connected to planar electrodes 312 and 313, respectively. Conductor 334, line electrode 311, and conductor 335 form inductor 10.

[0101] Planar electrode 313 is disposed between planar electrode 312 and planar electrode 314 in the Z-axis direction. Planar electrode 314 is opposite to at least a portion of planar electrode 313 in the Z-axis direction. Planar electrodes 313 and 314 form capacitor 12. Planar electrode 314 is connected to input / output terminal P31 via conductive conductor 371.

[0102] Planar electrode 323 is opposite to at least a portion of planar electrode 322 in the Z-axis direction. Planar electrodes 322 and 323 form capacitor 21.

[0103] Line electrode 321 extends along the X-axis. Conductors 336 and 337 extend from both ends of line electrode 321 along the Z-axis and are connected to planar electrodes 322 and 323, respectively. Conductor 336, line electrode 321, and conductor 337 form inductor 20.

[0104] A planar electrode 323 is disposed between the planar electrode 322 and the ground electrode 304 in the Z-axis direction. The ground electrode 304 is opposite to at least a portion of the planar electrode 323 in the Z-axis direction. The planar electrode 323 and the ground electrode 304 form a capacitor 22.

[0105] Planar electrode 301 is connected to planar electrode 312 via conductive conductor 381. Planar electrode 301 is opposite to planar electrode 322 in the Z-axis direction. Planar electrodes 301 and 322 form capacitor 12.

[0106] Planar electrode 333 is opposite to at least a portion of planar electrode 332 in the Z-axis direction. Planar electrodes 332 and 333 form capacitor 31.

[0107] Line electrode 331 extends along the X-axis. Conductors 351 and 352 extend from both ends of line electrode 331 along the Z-axis and are connected to planar electrodes 332 and 333, respectively. Conductor 351, line electrode 331, and conductor 352 form inductor 30.

[0108] A planar electrode 333 is disposed between the planar electrode 332 and the ground electrode 304 in the Z-axis direction. The ground electrode 304 is opposite to at least a portion of the planar electrode 333 in the Z-axis direction. The planar electrode 333 and the ground electrode 304 form a capacitor 32.

[0109] The grounding electrode 304 is grounded by connecting to the grounding terminal G3 through each conductive conductor 372, 373. The conductive conductors 372, 373 form the inductor LG.

[0110] Planar electrode 343 is opposite to at least a portion of planar electrode 342 in the Z-axis direction. Planar electrodes 342 and 343 form capacitor 41.

[0111] Line electrode 341 extends along the X-axis. Conductors 361 and 362 extend from both ends of line electrode 341 along the Z-axis and are connected to planar electrodes 342 and 343, respectively. Conductor 361, line electrode 341, and conductor 362 form inductor 40.

[0112] Planar electrode 343 is disposed between planar electrode 342 and planar electrode 344 in the Z-axis direction. Planar electrode 344 is opposite to at least a portion of planar electrode 343 in the Z-axis direction. Planar electrodes 343 and 344 form capacitor 42. Planar electrode 344 is connected to input / output terminal P32 via conductive conductor 374.

[0113] Planar electrode 302 is connected to planar electrode 342 via conductive conductor 382. Planar electrode 302 is opposite to planar electrode 332 in the Z-axis direction. Planar electrodes 302 and 332 form capacitor C34.

[0114] Figure 26 It means Figure 21 The graph shows the pass characteristics of a 300 bandpass filter. Figure 26 As shown, attenuation poles are generated at frequencies below the passband, such as f31, f32 (>f31), and f33 (>f32), and at frequencies above the passband, such as f34 and f35 (>f34).

[0115] The capacitive coupling generated between the structures contained in the bandpass filter is not limited to, for example, through... Figure 21 The capacitors C12, C12, C23, C34, and C42 represent capacitive coupling that occurs between adjacent structures in an equivalent circuit, similar to capacitive coupling. In a bandpass filter formed as a stack of multiple dielectric layers, capacitive coupling may also occur between non-adjacent structures in the equivalent circuit. Figure 27 This is an equivalent circuit diagram of the bandpass filter 300A, a variation of Embodiment 3. The structure of the bandpass filter 300A is... Figure 21 The bandpass filter 300 adds capacitors C30 and C14. Since the rest of the structure is the same, it will not be described further.

[0116] like Figure 27As shown, capacitor C30 is connected between input / output terminals P31 and P32. Capacitor C30 represents the capacitive coupling generated between input / output terminals P31 and P32. Capacitor C14 is connected between LC resonator 1 and LC resonator 4. Capacitor C14 represents the capacitive coupling generated between LC resonator 1 and LC resonator 4.

[0117] According to the above, the LC filter based on Embodiment 3 and its variations can improve the characteristics of the LC filter and suppress the large size of the LC filter.

[0118] [Implementation Method 4]

[0119] In Embodiment 3, a structure was described in which the LC resonator electrically connected to the input / output terminals was not grounded. In Embodiment 4, a structure was described in which the LC resonator electrically connected to the input / output terminals was grounded in the same way as other LC resonators.

[0120] Figure 28 This is the equivalent circuit diagram of the bandpass filter 400 in embodiment 4. The structure of the bandpass filter 400 is as follows: Figure 21 The bandpass filter 300 has LC resonators 1 and 4 grounded and additional capacitors Ci1, C14, and Ci2. Since the rest of the structure is the same, it will not be described further.

[0121] like Figure 28 As shown, capacitors 12 and 42 are grounded. Capacitor Ci1 is connected between input / output terminal P31 and LC resonator 1. Capacitor Ci1 represents the capacitive coupling generated between input / output terminal P31 and LC resonator 1. Capacitor Ci2 is connected between input / output terminal P32 and LC resonator 4. Capacitor Ci2 represents the capacitive coupling generated between input / output terminal P32 and LC resonator 4. Capacitor C14 is connected between LC resonator 1 and LC resonator 4. Capacitor C14 represents the capacitive coupling generated between LC resonator 1 and LC resonator 4.

[0122] Figure 29 It means Figure 28 The graph shows the pass characteristics of a 400 bandpass filter. (See figure.) Figure 29 As shown, attenuation poles are generated at frequencies below the passband, f41 and f42 (> f41), and at frequencies above the passband, f43.

[0123] In bandpass filters formed as a stack of multiple dielectric layers, capacitive coupling can occur between various structures. The capacitive coupling generated in bandpass filters is not limited to... Figure 28 The capacitive coupling shown. Figure 30This is an equivalent circuit diagram of the bandpass filter 400A, a variation of embodiment 4. The structure of the bandpass filter 400A is... Figure 28 The bandpass filter 400 adds capacitors Ci03, C13, C25, and Ci04. Since the rest of the structure is the same, it will not be described further.

[0124] like Figure 30 As shown, capacitor Cio3 is connected between input / output terminal P31 and LC resonator 2. Capacitor Cio3 represents the capacitive coupling generated between input / output terminal P31 and LC resonator 2. Capacitor C13 is connected between LC resonator 1 and LC resonator 3. Capacitor C13 represents the capacitive coupling generated between LC resonator 1 and LC resonator 3. Capacitor C25 is connected between LC resonator 2 and LC resonator 5. Capacitor C25 represents the capacitive coupling generated between LC resonator 2 and LC resonator 5. Capacitor Cio4 represents the capacitive coupling generated between input / output terminal P32 and LC resonator 3.

[0125] According to the above, the LC filter based on Embodiment 4 and its variations can improve the characteristics of the LC filter and suppress the large size of the LC filter.

[0126] [Implementation Method 5]

[0127] In Embodiment 4, the case where the multiple LC resonators included in the LC filter each have the same structure as the LC resonator in Embodiment 1 is described. In Embodiment 5, the case where the LC filter includes the LC resonator of Embodiment 1 and the LC parallel resonator of the comparative example of Embodiment 1 is described.

[0128] Figure 31 This is an equivalent circuit diagram of a bandpass filter 500, which is an example of an LC filter in Embodiment 5. The structure of the bandpass filter 500 is as follows: Figure 28 The LC resonators 2 and 3 of the bandpass filter 400 are replaced with LC parallel resonators 92 and 93, respectively. The structure of LC parallel resonator 92 is the structure after removing capacitor 22 from LC resonator 2. The structure of LC parallel resonator 93 is the structure after removing capacitor 32 from LC resonator 3. Since the other structures are the same, they will not be described in detail.

[0129] Figure 32 It means Figure 31 The graph shows the pass characteristics of a 500 bandpass filter. Figure 32 As shown, attenuation poles are generated at frequencies below the passband, such as f51, f52 (>f51), and f53 (>f52), and at a frequency above the passband, such as f54.

[0130] In the bandpass filter of Embodiment 5, the case where the LC resonator electrically connected to the input / output terminals has the same structure as the LC resonator of Embodiment 1 is described. The bandpass filter of this embodiment can include the LC resonator of Embodiment 1, or the LC resonator may not be connected to the input / output terminals.

[0131] Figure 33 This is an equivalent circuit diagram of the bandpass filter 500A, a variation of embodiment 5. The structure of the bandpass filter 500A is to... Figure 28 The LC resonators 1 and 4 of the bandpass filter 400 are replaced with LC parallel resonators 91 and 94, respectively. The structure of LC parallel resonator 91 is the structure obtained by removing capacitor 12 from LC resonator 1. The structure of LC parallel resonator 94 is the structure obtained by removing capacitor 42 from LC resonator 4. Since the other structures are the same, they will not be described in detail.

[0132] Figure 34 It means Figure 33 The graph shows the pass characteristics of a 500A bandpass filter. Figure 33 As shown, attenuation poles are generated at frequencies below the passband, f55 and f56 (>f55), and at frequencies above the passband, f57 and f58 (>f57).

[0133] Each of the multiple LC resonators included in the bandpass filter does not need to have the same structure as the LC resonator in Embodiment 1. By making a portion of these multiple LC resonators a parallel LC resonator with one less capacitor than the LC resonator in Embodiment 1, the manufacturing cost and size of the bandpass filter can be reduced. According to Embodiment 5 and its variations, since the structure of the bandpass filter can be determined according to the desired characteristics, manufacturing cost, and size, the design freedom of the bandpass filter can be increased.

[0134] Furthermore, the capacitive coupling generated in a bandpass filter formed as a stack of multiple dielectric layers is not limited to Figure 31 as well as Figure 33 The capacitive coupling shown is the same as in embodiment 4.

[0135] According to the LC filter of Embodiment 5 and its variations, the characteristics of the LC filter can be improved, the large size of the LC filter can be suppressed, and the design freedom of the LC filter can be increased.

[0136] [Implementation Method 6]

[0137] Figure 35 This is the equivalent circuit diagram of the bandpass filter 600 in implementation method 6. For example... Figure 35As shown, the bandpass filter 600 has an input / output terminal P61 (first terminal) and an input / output terminal P62.

[0138] (Second terminal), LC resonator 1 (first LC resonator), LC parallel resonators 92, 93, 94, LC resonator 5 (second LC resonator), and capacitors Ci1, C12, C23, C34, C45, Ci2, C15. Bandpass filter 600 is a 5-stage bandpass filter.

[0139] Capacitor Cio1 is connected between input / output terminal P61 and LC resonator 1. Capacitor Cio1 represents the capacitive coupling generated between input / output terminal P61 and LC resonator 1.

[0140] Capacitor C12 is connected between LC resonator 1 and LC parallel resonator 92. Capacitor C12 represents the capacitive coupling generated between LC resonator 1 and LC parallel resonator 92.

[0141] Capacitor C23 is connected between LC parallel resonators 92 and 93. Capacitor C23 represents the capacitive coupling generated between LC parallel resonators 92 and 93.

[0142] Capacitor C34 is connected between LC parallel resonators 93 and 94. Capacitor C34 represents the capacitive coupling generated between LC parallel resonators 93 and 94.

[0143] Capacitor C45 is connected between LC parallel resonators 94 and LC resonators 5. Capacitor C45 represents the capacitive coupling generated between LC parallel resonators 94 and LC resonators 5.

[0144] Capacitor Cio2 is connected between LC resonator 5 and input / output terminal P62. Capacitor Cio2 represents the capacitive coupling generated between LC resonator 5 and input / output terminal P62.

[0145] Capacitor C15 is connected between LC resonator 1 and LC resonator 5. Capacitor C15 represents the capacitive coupling generated between LC resonator 1 and LC resonator 5.

[0146] Magnetic coupling M12 is generated between LC resonators 1 and LC resonators 2. Magnetic coupling M23 is generated between LC resonators 2 and LC resonators 3. Magnetic coupling M34 is generated between LC resonators 3 and LC resonators 4. Magnetic coupling M45 is generated between LC resonators 4 and LC resonators 5.

[0147] LC resonator 1 is the same as LC resonator 1 in embodiments 4 and 5. LC resonator 5 includes an inductor 50 and capacitors 51 and 52. LC resonator 5 has the same characteristics as... Figure 1 It has the same structure as the LC resonator 1A. That is, inductor 50, capacitor 51, and capacitor 52 correspond to inductor 10A, capacitor 11A, and capacitor 12A, respectively.

[0148] LC parallel resonator 92 includes an inductor 20 and a capacitor 21. LC parallel resonator 93 includes an inductor 30 and a capacitor 31. LC parallel resonator 94 includes an inductor 40 and a capacitor 41. LC parallel resonators 92-94 each have... Figure 6 The structure is the same as that of the LC parallel resonator 9A. That is, inductor 20 and capacitor 21 correspond to inductor 10A and capacitor 11A, respectively. Inductor 30 and capacitor 31 correspond to inductor 10A and capacitor 11A, respectively. Inductor 40 and capacitor 41 correspond to inductor 10A and capacitor 11A, respectively.

[0149] Figure 36 It means Figure 35 The graph shows the pass characteristics of a 600 bandpass filter. Figure 36 As shown, attenuation poles are generated at frequencies below the passband, such as f61, f62 (>f61), and f63 (>f62), and at frequencies above the passband, such as f64, f65 (>f64), and f66 (>f65).

[0150] Furthermore, the capacitive coupling generated in a bandpass filter formed as a stack of multiple dielectric layers is not limited to Figure 35 The capacitive coupling points shown are the same as those in embodiments 4 and 5.

[0151] According to the above, the LC filter of embodiment 6 can improve the characteristics of the LC filter, suppress the large size of the LC filter, and increase the design freedom of the LC filter.

[0152] The various embodiments disclosed herein are also intended to be implemented in appropriate combinations without contradiction. It should be understood that the embodiments disclosed herein are illustrative in all respects and not restrictive. The scope of the invention is defined not by the foregoing description but by the claims, and is intended to include all modifications equivalent to and within the scope of the claims.

[0153] Explanation of reference numerals in the attached figures

[0154] 1-5, 1A, 1B, 9B…LC resonators; 9A, 91-94…LC parallel resonators; 10, 10A, 20, 30, 40, 50, LG…inductors; 11, 11A, 12, 12A, 13A, 21, 22, 31, 32, 41, 42, 51, 52, C12-C15, C23, C25, C30, C34, C42, C45, Ci1, Ci2, Ci Capacitors: 03, Ci04…; Line electrodes: 101, 211, 221, 311, 321, 331, 341, 911, 921…; Planar electrodes: 102, 103, 212, 213, 222, 223, 301, 302, 312-314, 322, 323, 332, 333, 342-344, 903, 912, 922…; Planar electrodes: 104, 204, 304, 90… 4… Grounding electrode, 111, 112, 131, 132, 133, 134, 231, 232, 241, 242, 251, 252, 261~263, 271, 272, 334~336, 351, 352, 361, 362, 371~374, 381, 382, ​​931, 932, 941, 942, 950, 961~963, 970… Conducting conductor, 180, 190, 280, 380… stacked bodies; 200, 200A, 300, 300A, 400, 400A, 500, 500A, 600, 900… bandpass filters; G1~G3… grounding terminals; GND… grounding point; M12, M23, M34, M45… magnetic couplings; P10~P12, P21, P22, P31, P32, P61, P62… input / output terminals.

Claims

1. An LC resonator, comprising: First planar electrode; The second planar electrode is opposed to at least a portion of the first planar electrode in a specific direction; First circuit electrode; The first and second conductive conductors extend from the first line electrode along the specific direction and are respectively connected to the first planar electrode and the second planar electrode; and The third planar electrode, which is positioned opposite at least a portion of the second planar electrode in the aforementioned specific direction, is connected to the grounding point. The second planar electrode is disposed between the first planar electrode and the third planar electrode in the aforementioned specific direction. The third planar electrode is disposed between the second planar electrode and the grounding point in the aforementioned specific direction; No electrode is disposed between the second planar electrode and the third planar electrode mentioned above; The first planar electrode and the second planar electrode constitute a first capacitor; The first conducting conductor, the first line electrode, and the second conducting conductor constitute an inductor; The second planar electrode and the third planar electrode constitute a second capacitor; The first capacitor, the inductor, and the second capacitor constitute a single resonator; When viewed from the aforementioned specific direction, the third planar electrode overlaps with the aforementioned grounding point.

2. An LC filter, comprising: First terminal and second terminal; and First LC resonator and second LC resonator. The first LC resonator and the second LC resonator described above are respectively the LC resonators according to claim 1. The first planar electrode of the first LC resonator is electrically connected to the first terminal. The first planar electrode of the second LC resonator is electrically connected to the second terminal.

3. An LC filter, comprising: First terminal and second terminal; and First LC resonator and second LC resonator. The first LC resonator and the second LC resonator described above are respectively the LC resonators according to claim 1. The first planar electrode of the first LC resonator is electrically connected to the first terminal. The first planar electrode of the second LC resonator is electrically connected to the second terminal. The third planar electrode of the first LC resonator and the second LC resonator are grounded.

4. The LC filter according to claim 2 or 3, wherein, It also includes an LC parallel resonator, which receives a signal from either the first LC resonator or the second LC resonator and transmits the signal to the other.

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