JP5454471B2 - Filter, printed circuit board, and noise suppression method - Google Patents

Description

  The present invention realizes a frequency selective noise suppression effect and a filter effect by using a waveguide that is surrounded by a plurality of conductor plates around the cross section in the traveling direction or that has a partially open end in the traveling direction section. The present invention relates to a filter, a printed circuit board, and a noise suppression method.

  A structure sandwiched between or surrounded by a plurality of conductor plates such as a pair of parallel plate conductors can propagate electromagnetic waves in a direction parallel to the conductor plates. It can be applied to a vessel, a filter, a leaky wave antenna, and the like. In the case where such a structure is used as a filter, a structural device for blocking or transmitting the propagation of electromagnetic waves over a specific frequency band is made. In recent years, an EBG (Electromagnetic Band Gap) structure has attracted attention as a method for blocking the propagation of electromagnetic waves over a wide frequency band.

  In the following, as a well-known structure as a waveguide to which this EBG structure is applied, the literature “O. Ramahi, S. Shahparnia and B. Mohajer-Irvani,“ TOWARDS NEW PARADIGMS IN NOISE MITIGATION IN AND FROM PRINTED CIRCUIT BOARDS USING METALLO-DIELECTRIC ” ELECTROMAGNETIC BAND GAP STRUCTURES ”, EMC Europe 2004 (6th International Symposium on EMC), September 6-10 2004, ISBN: 90-6144-990-1, p.372-377” An example will be described. 26 and 27 are diagrams showing a structure in which a mushroom-type EBG structure is applied to a space between parallel plate conductors in a three-dimensional orthogonal coordinate system. 26 is a cross-sectional view when the EBG structure is cut along the xz plane, and FIG. 27 is a cross-sectional view when the EBC structure is cut along the xy plane at the position of z = h in FIG. 101 and 102 are two conductor plates parallel to each other. In the example of FIGS. 26 and 27, the position of the lower surface of the conductor plate 101 is z = 0, the position of the upper surface of the conductor plate 102 is z = h + p, and the position of the upper surface of the conductor patch 103 is z = h. Further, the lower left corner in FIG. 27 is set to x = 0 and y = 0.

  A waveguide structure 106 that propagates the electromagnetic wave 107 in the xy direction is formed in the space between the conductor plates 101 and 102. Reference numeral 108 denotes an electromagnetic wave generation source. An LSI is also included as an example of the electromagnetic wave generation source 108. The conductor patch 103 is periodically connected to the conductor plate 102 by the periodic arrangement via 104 and is sandwiched between the two conductor plates 101 and 102. By using the structures of FIGS. 26 and 27, the electromagnetic wave 107 that should propagate between the conductor plates 101 and 102 (0 <z <h + p) in any direction on the xy plane is transmitted in a specific frequency band. The patch 103 can hardly propagate through an area.

This is because the capacitance Cpatch between the conductor plate 101 and the conductor patch 103 and the frequency band estimated by the series resonance frequency 2π / (Lvia × Cpatch) ^1/2 of the via inductance Lvia immediately below the conductor patch 103, the period This is because a resonance phenomenon occurs for each conductor patch 103 that is arranged in a random manner, and it becomes difficult for the electromagnetic wave 107 to propagate between the conductor plate 101 and the conductor plate 102. Therefore, by applying the EBC structure shown in FIGS. 26 and 27 between the power supply ground planes, it is possible to design a mounting circuit capable of suppressing power supply noise in a specific frequency band.

  Japanese Patent Publication No. 2007-522735 discloses a configuration of a device capable of adjusting the dielectric constant of a dielectric between conductors.

  As mentioned above, the literature “O.Ramahi, S. Shahparnia and B. Mohajer-Irvani,“ TOWARDS NEW PARADIGMS IN NOISE MITIGATION IN AND FROM PRINTED CIRCUIT BOARDS USING METALLO-DIELECTRIC ELECTROMAGNETIC BAND GAP STRUCTURES ”, EMC Europe 2004 (6th International Symposium on EMC), September 6-10 2004, ISBN: 90-6144-990-1, p.372-377 ”, by using the mushroom type EBG structure in the waveguide, in a specific frequency band A band rejection filter can be realized. For example, by applying the mushroom type EBG structure to the power supply ground plane pair of the printed circuit board, it is possible to realize a mounting circuit structure capable of blocking power supply system switching noise and electromagnetic noise leaking from signal vias. However, the mushroom-type EBG structure has a problem in that it can only prevent propagation of electromagnetic waves in a specific single frequency band, and cannot prevent propagation of electromagnetic waves in various frequency bands.

  Further, according to JP-T-2007-522735, the dielectric constant of the dielectric between the conductors can be adjusted, so that the electrical characteristics of the device can be controlled. However, the structure of the device described in JP-T-2007-522735 relates to an antenna, and does not solve the above-described problem in the filter.

  The present invention has been made to solve the above problems, and an object thereof is to provide a filter, a printed circuit board, and a noise suppression method that can prevent propagation of electromagnetic waves in various frequency bands.

In the filter of the present invention, a conductor is arranged at least in the vertical direction of a space in which a signal propagates, and a signal is supplied between opposing conductors in at least one place in the signal propagation direction. It has a waveguide for outputting a signal from between opposing conductors in the above locations, and one or more unit cells periodically arranged on the waveguide, each unit cell having a single plate shape Or two or more plate-like conductor patches arranged in parallel to each other and at least one of the two or more conductor patches connected to the one conductor patch One or more conductor posts connected to each other, and the conductor posts protruding from each unit cell are connected to at least one conductor of the waveguide and insulated from other conductors of the waveguide. It is characterized by being edged.

  A printed circuit board according to the present invention includes the above-described filter.

In the present invention, a conductor is disposed at least in the vertical direction of a space in which a signal propagates, and a signal is supplied between opposing conductors in at least one place in the signal propagation direction. In the noise suppression method using the waveguide in which a signal is output from between the opposing conductors in the above place, one plate-like conductor patch or two or more plate-like conductor patches arranged in parallel to each other ; A unit cell connected to the one conductor patch or one or more conductor posts connected to at least one conductor patch of the two or more conductor patches on the waveguide. The conductor posts protruding periodically from each unit cell are connected to at least one conductor of the waveguide and insulated from other conductors of the waveguide. It is a sign.

  According to the present invention, one or more unit cells are periodically arranged on a waveguide, and each unit cell is arranged with one or more plate-like conductor patches arranged in parallel to each other and at least one or more sheets. It is composed of one or more conductor posts connected to a conductor patch, and the conductor posts protruding from each unit cell are connected to at least one conductor of the waveguide and insulated from other conductors, thereby providing wide bandwidth and various A filter having a proper cut-off frequency band can be realized. The cutoff frequency band of the filter of the present invention includes a combination of conductor patches and conductor posts, a relative permittivity and a relative permeability of the space between the conductor patches of each unit cell, and a relative permittivity of the space between the conductor patch and the conductor of the waveguide. It can be set as appropriate according to the relative permeability, the relative permittivity of the space inside the waveguide, and the relative permeability. Therefore, according to the present invention, it is possible to select an appropriate structure from a plurality of combinations according to mounting constraints, and it is possible to widen the range of filter mounting design.

FIG. 1 is a perspective view showing the structure of a unit cell according to the first embodiment of the present invention. FIG. 2 is a perspective view of the waveguide according to the first embodiment of the present invention in a state where no unit cell is mounted. FIG. 3 is a cross-sectional view showing the positional relationship and connection relationship between the waveguide shown in FIG. 2 and the unit cell shown in FIG. FIG. 4 is a plan view of a filter in which a plurality of unit cells are periodically mounted in the first embodiment of the present invention. FIG. 5 is a sectional view of a filter in which a plurality of unit cells are periodically mounted in the first embodiment of the present invention. FIG. 6 is a sectional view showing another structural example of the filter according to the first embodiment of the present invention. FIG. 7 is a sectional view showing another structural example of the filter according to the first embodiment of the present invention. FIG. 8 is a sectional view showing another structural example of the filter according to the first embodiment of the present invention. FIG. 9 is a sectional view showing another structural example of the filter according to the first embodiment of the present invention. FIG. 10 is a sectional view showing another structural example of the filter according to the first embodiment of the present invention. FIG. 11 is a perspective view showing the structure of a unit cell according to the second embodiment of the present invention. FIG. 12 is a perspective view of the waveguide according to the second embodiment of the present invention in a state where no unit cell is mounted. 13 is a cross-sectional view showing the positional relationship and connection relationship between the waveguide shown in FIG. 12 and the unit cell shown in FIG. FIG. 14 is a plan view of a filter in which a plurality of unit cells are periodically mounted in the second embodiment of the present invention. FIG. 15 is a diagram for explaining the connection between the power feeding unit and the load with respect to the filter of FIG. 14. FIG. 16 is a diagram showing the input / output coupling rate characteristics of the filter according to the second embodiment of the present invention. 17A to 17C are plan views of unit cells according to a third embodiment of the present invention. 17D to 17F are cross-sectional views illustrating the connection relationship between the unit cell and the parallel plate waveguide according to the third embodiment of the present invention. FIG. 18 is a graph showing the input / output coupling rate characteristics of the filter according to the third example of the present invention. FIG. 19 is a perspective view showing the structure of a unit cell according to the fourth embodiment of the present invention. 20 is a cross-sectional view showing the positional relationship and connection relationship between the parallel plate waveguide and the unit cells shown in FIG. FIG. 21 is a diagram showing the coupling rate characteristics between the input and output of the filter according to the fourth embodiment of the present invention. FIG. 22 is a sectional view of a filter according to a fifth embodiment of the present invention. FIG. 23 is a diagram showing the input / output coupling rate characteristics of the filters of FIGS. 14 and 22. FIG. 24 is a diagram for explaining the connection between the waveguide and the DC voltage source in the sixth embodiment of the present invention. FIG. 25 is a cross-sectional view showing a configuration in which a filter is mounted on a printed circuit board in the seventh embodiment of the present invention. FIG. 26 is a cross-sectional view of a mushroom type EBG structure applied to a parallel plate waveguide, taken along the xz plane. FIG. 27 is a cross-sectional view of a mushroom type EBG structure applied to a parallel plate waveguide, taken along the xy plane.

[First embodiment]
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing the structure of a unit cell according to the first embodiment of the present invention. Reference numeral 309 denotes the entire unit cell. The unit cell 309 has a structure in which M (N is a natural number of 1 or more) conductor posts 305 to 307 vertically penetrate N conductor patches 301 to 304 (N is a natural number of 1 or more). Reference numerals 301, 302, 303, and 304 represent a first conductor patch, a second conductor patch, a third conductor patch, and an Nth conductor patch, respectively. Reference numerals 305, 306, and 307 denote a first conductor post, a second conductor post, and an Mth conductor post, respectively.

  In FIG. 1, reference numeral 310 denotes a coordinate system. In the present embodiment, the conductor patches 301 to 304 are assumed to be parallel to the xy plane. In this embodiment, N is 4 or more and M is 3 or more. However, N may be a number smaller than 4, and M may be a number smaller than 3.

  Reference numeral 308 denotes a connection portion between the conductor patches 301 to 304 and the conductor posts 305 to 307. In FIG. 1, only one connection portion 308 is shown, but naturally a plurality of connection portions 308 exist in the unit cell 309. The conductor posts 305 to 307 may be electrically connected directly to the conductor patches 301 to 304, or may be insulated from the conductor patches 301 to 304 by clearance holes (not shown) provided in the conductor patches 301 to 304. Sometimes it is.

  FIG. 2 is a perspective view of the waveguide according to the first embodiment of the present invention in a state where no unit cell is mounted. Reference numeral 405 denotes the entire waveguide on which no unit cell is mounted. The traveling direction of the waveguide 405 is the y direction. Regarding the cross-sectional dimension of the waveguide 405, the thickness in the z direction is h, and the width in the x direction is w.

  Reference numeral 401 denotes a conductor plate which is a conductor wall parallel to the xy plane, which is disposed on the upper surface of the waveguide 405, and 402 is a conductor plate which is a conductor wall parallel to the xy plane, which is disposed on the lower surface of the waveguide 405. Therefore, the conductor plates 401 and 402 are disposed to face each other. Reference numeral 403 denotes a waveguide wall surface arranged parallel to the yz plane in FIG. 2, and 404 denotes a waveguide wall surface arranged parallel to the yz plane in FIG.

  When the waveguide 405 is a parallel plate type waveguide, the waveguide wall surfaces 403 and 404 are open walls. On the other hand, when the waveguide 405 is a rectangular waveguide, the waveguide wall surfaces 403 and 404 are opposing conductor walls. Furthermore, a waveguide structure is also formed when one or more conductor posts conduct between parallel conductors of parallel plate conductors. Of course, a microstrip line structure and a strip line structure widely used in a printed circuit board can also be regarded as a waveguide structure.

  3 is a cross-sectional view showing the positional relationship and connection relationship between the waveguide 405 shown in FIG. 2 and the unit cell 309 shown in FIG. More specifically, FIG. 3 shows a structure in which the conductor posts 305 to 307 protruding from the unit cell 309 are connected to the conductor plates 401 and 402 of the waveguide 405 of FIG. It is the figure seen from.

  The conductor posts 305 to 307 protruding from the unit cell 309 are electrically connected to the conductor plate 401 at the connection portion 501. In FIG. 3, only one connection portion 501 is shown, but there are naturally a plurality of connection portions 501 per unit cell 309. Each of the conductor posts 305 to 307 may be electrically connected to the conductor plate 401 at the connection portion 501 or may be insulated from the conductor plate 401 by a clearance hole (not shown) provided in the conductor plate 401. is there.

  Similarly, the conductor posts 305 to 307 protruding from the unit cell 309 are electrically connected to the conductor plate 402 at the connection portion 502. In FIG. 3, only one connection portion 502 is shown, but there are naturally a plurality of connection portions 502 per unit cell 309. Each of the conductor posts 305 to 307 may be electrically connected to the conductor plate 402 at the connection portion 502, or may be insulated from the conductor plate 402 by a clearance hole (not shown) provided in the conductor plate 402. is there.

  4 is a plan view of a filter in which a plurality of unit cells 309 are periodically mounted in the present embodiment, and FIG. 5 is a cross-sectional view of the filter of FIG. 4 is a view of the filter as viewed from above, and FIG. 5 is a cross-sectional view of the filter of FIG. 4 taken along the yz plane. In FIG. 4, each unit cell 309 has a width c in the x direction and a length a in the y direction. The interval between the unit cells 309 in the x direction is d, and the interval in the y direction is b. That is, the unit cells 309 are periodically arranged such that the cycle in the x direction is (c + d) and the cycle in the y direction is (a + b). Each unit cell 309 is connected to the waveguide 405 so as to satisfy the connection relationship described in FIG.

  6, 7 and 8 are cross-sectional views showing other structural examples of the filter according to this embodiment. In the example of FIG. 6, a part of the conductor patch of each unit cell 309 (conductor patch 304 in the example of FIG. 6) is disposed inside the waveguide 405, that is, between the conductor plates 401 and 402. In the example of FIG. 7, some unit cells 309 are arranged so as to penetrate the waveguide 405 from below.

  Further, in the examples of FIGS. 1 and 3 to 7, the conductor patches 301 to 304 of each unit cell 309 have the same shape, and the lengths of the conductor posts 305 to 307 are all the same. On the other hand, as shown in FIG. 8, the conductor patches 301 to 304 of each unit cell 309 may have different shapes, or the conductor posts 305 to 307 may have different lengths.

  As is clear from the above, not all the conductor posts need to penetrate the waveguide 405. Furthermore, the space between the conductor patches 301 to 304 and the space inside the waveguide 405 may be filled with a material having a specific relative dielectric constant and relative magnetic permeability. For example, when the filter of this embodiment is mounted on a printed circuit board, a space other than the conductor is occupied by a medium having a relative dielectric constant of about 4.3 such as FR (flame retardant) -4.

  Furthermore, as shown in FIG. 9, a layer 2501 in the space between the conductor patches 301 to 304 of each unit cell 309, a layer 2502 in the space between the conductor patches 301 to 304 and the conductor plates 401 and 402, and the inside of the waveguide 405 The space layer 2503 may be filled with a material having a different relative dielectric constant for each layer or a material having a different relative permeability for each layer. Furthermore, as shown in FIG. 10, a plurality of unit cells 309 may be disposed so as to penetrate the waveguide 405 from the upper side and the lower side.

  As described above, according to the present embodiment, a filter having a wide band and various cut-off frequency bands can be realized. The cutoff frequency band of the filter includes a combination of conductor patches 301 to 304 and conductor posts 305 to 307, a relative permittivity and a relative permeability of a space between the conductor patches 301 to 304 of each unit cell 309, and the conductor patches 301 to 304 and the conductor. It can be appropriately set according to the relative permittivity and relative permeability of the space between the plates 401 and 402 and the relative permittivity and relative permeability of the space inside the waveguide 405. Therefore, in this embodiment, it is possible to select an appropriate structure from a plurality of combinations according to mounting constraints, and the range of filter mounting design can be expanded.

[Second Embodiment]
Next, a filter according to a second embodiment of the present invention will be described with reference to the drawings and calculation examples. In addition, a present Example shows the example which actualizes the band stop filter which has two cut-off frequency bands. FIG. 11 is a perspective view showing the structure of a unit cell according to the second embodiment of the present invention.

  The unit cell 1109 has a structure in which a conductor post 305 having a length h1 and a conductor post 306 having a length h2 are connected to two rectangular conductor patches 301 and 302 having a width L1 and a length L2. It has become. The conductor post 305 is electrically connected to the conductor patch 302 at one point 1101 at the four corners of the conductor patch 302, and protrudes along the z direction perpendicular to the conductor patch 302. The conductor post 306 is electrically connected to the conductor patch 301 at the center point 1102 of the conductor patch 301, and is insulated from the conductor patch 302 by a clearance hole provided at the center point 1103 of the conductor patch 302.

  FIG. 12 is a perspective view of the waveguide according to the second embodiment of the present invention in a state where no unit cell is mounted. The waveguide 1201 has a parallel plate type waveguide structure in which two conductors 401 and 402 each having a width in the x direction wx and a length in the y direction wy are opposed to each other with a distance h. Waveguide walls 1203 and 1204 parallel to the yz plane and waveguide walls 1205 and 1206 parallel to the xz plane are open walls.

  13 is a cross-sectional view showing the positional relationship and connection relationship between the waveguide 1201 shown in FIG. 12 and the unit cell 1109 shown in FIG. More specifically, FIG. 13 shows a structure in which the conductor posts 305 and 306 protruding from the unit cell 1109 are connected to the conductor plates 401 and 402 of the waveguide 1201 of FIG. It is the figure seen from.

  The conductor post 305 protruding from the unit cell 1109 is electrically connected to the conductor plate 401 at the connection portion 1301. The conductor post 306 protruding from the unit cell 1109 is electrically connected to the conductor plate 402 at the connection portion 1303. The conductor post 306 is insulated from the conductor plate 401 by a clearance hole provided at a point 1302 of the conductor plate 401. In other words, the conductor post 306 is connected to the conductor patch 301 on the side far from the waveguide 1201, insulated from the conductor patch 302 on the side close to the waveguide 1201, and the conductor post 306 of the waveguide 1201 on the side facing the conductor patch 302. It is insulated from the conductor plate 401 and is connected to the conductor plate 402 on the side not facing the conductor patch 302. The conductor post 305 is insulated from the conductor patch 301, connected to the conductor patch 302, connected to the conductor plate 401 of the waveguide 1201 on the side facing the conductor patch 302, and the side not facing the conductor patch 302. It is insulated from the conductor plate 402.

  The unit cell 1109 having the above connection relationship is periodically arranged on the waveguide in the same manner as in the examples of FIGS. 4 and 5, thereby realizing a band stop filter having two close cutoff frequency bands. it can. Hereinafter, calculation examples of the characteristics of this filter will be described with reference to the drawings.

  FIG. 14 is a plan view of a filter in which a plurality of unit cells 1109 are periodically mounted in the present embodiment. In FIG. 14, the lower left is the origin O. In the example of FIG. 14, a unit cell 1109 using a square conductor patch with a side of 5 mm is 10 mm in both the x and y directions with respect to the waveguide 1201 having a width in the x direction of 100 mm and a length in the y direction of 70 mm. Arranged in a cycle. Each unit cell 1109 is connected to the waveguide 1201 so as to satisfy the connection relationship described in FIG. In FIG. 14, reference numeral 1401 denotes an input port of the waveguide, and 1402 denotes an output port of the waveguide.

  As physical parameters of the unit cell 1109 and the waveguide 1201, the length h1 of the conductor post 305 is 0.2 mm, the length h2 of the conductor post 306 is 1.4 mm, and the thickness h in the z direction of the waveguide 1201 is 1.0 mm. To do. Further, the space between the conductor patches 301 and 302, the space between the conductor patches 301 and 302 and the conductor plates 401 and 402, and the space inside the waveguide 1201 have a relative permittivity of 4.05 and a relative permeability of 1. It is assumed that the medium is 0 and the dielectric loss tangent tan δ is 0.025.

  As shown in FIG. 15, assuming that a current source 1501 serving as a power feeding unit is connected between conductor plates 401 and 402 at the input port 1401 of the waveguide, the conductor plate 401 and the output port 1402 of the waveguide are connected to each other. Assuming that a 50 Ω resistor 1502 serving as a load is connected between 402, the propagation characteristics of the filter of FIG. 14 are analyzed using an equivalent circuit analysis method of a multilayer conductor, and the calculation result is between input and output. A binding rate (S21) was obtained. The current source 1501 includes an internal resistance of 50Ω. An equivalent circuit analysis method for multilayer conductors is described in, for example, the document “Kobayashi et al.,“ Analysis of multilayered power distribution systems using SPICE ”, EMCJ, October 2005”.

  FIG. 16 shows the input / output coupling rate characteristics of the filter of FIG. 14 calculated using the equivalent circuit analysis method. According to FIG. 16, it can be seen that the propagation rate of the filter of FIG. 14 has a markedly reduced coupling rate around 2 GHz and around 6 GHz. Therefore, it can be seen that the waveguide structure of this example is effective as a band stop filter having a plurality of cutoff frequency bands.

[Third embodiment]
Next, a filter according to a third embodiment of the present invention will be described with reference to the drawings and calculation examples. 17A, 17B, and 17C are plan views of the unit cells 1701, 1702, and 1703, respectively. FIGS. 17D, 17E, and 17F are cross-sectional views showing the connection relationship between the unit cells 1701, 1702, and 1703 and the parallel plate waveguide, respectively. FIG. Similar to the first embodiment and the second embodiment, the parallel plate waveguide has conductor plates 401 and 402.

  As shown in FIGS. 17A, 17B, and 17C, each of the conductor patches 301 used in the unit cells 1701, 1702, and 1703 is a square having a side of 5 mm. The distance between the unit cells 1701, 1702, 1703 and the parallel plate waveguide is 0.2 mm. The thickness of the parallel plate waveguide is 1 mm.

  In the unit cell 1701, one conductor post 305 is connected to the center point of the conductor patch 301. In the unit cell 1702, conductor posts 305 and 306 are connected near the midpoints of the two sides of the conductor patch 301. In the unit cell 1703, conductor posts 305 to 307 and 311 are connected to the four corners of the conductor patch 301. The conductor posts 305 to 307, 311 are not connected to the conductor plate 401 of the parallel plate waveguide on the side facing the conductor patch 301, and are connected to the conductor plate 402 on the side not facing the conductor patch 301. Has been.

  The unit cells 1701, 1702, and 1703 having the above connection relation are periodically arranged on the waveguide in the same manner as in the examples of FIGS. FIG. 18 shows the result of calculating the coupling ratio characteristics between the input and output of the filter in which the unit cells 1701, 1702, and 1703 are periodically arranged using the above-described equivalent circuit analysis method. 18, S1701 is a characteristic of a filter in which unit cells 1701 are periodically arranged, S1702 is a characteristic of a filter in which unit cells 1702 are periodically arranged, and S1703 is a characteristic of a filter in which unit cells 1703 are periodically arranged. .

  According to FIG. 18, it can be seen that the waveguide functions as a band stop filter regardless of which unit cell 1701, 1702, or 1703 is used. However, the frequency characteristics change depending on the arrangement of vias (conductor posts). In the case of the unit cell 1702 in which one conductor post 305, 306 is arranged on each of the two sides of the conductor patch 301 than in the case of the unit cell 1701 in which one conductor post 305 is arranged in the center of the conductor patch 301, It can be seen that a cut-off frequency band is generated on the higher frequency side.

  Further, in the case of the unit cell 1703 in which the conductor posts 305 to 307 and 311 are arranged at the four corners of the conductor patch 301, the cut-off frequency band is shifted to the high frequency side, compared to the case of the unit cells 1701 and 1702, and It can be seen that the cutoff frequency band becomes wider.

[Fourth embodiment]
Next, a filter according to a fourth embodiment of the present invention will be described with reference to the drawings and calculation examples. FIG. 19 is a perspective view showing the structure of a unit cell according to the fourth embodiment of the present invention. The unit cell 1909 has a structure in which a conductor post 305 is connected to two rectangular conductor patches 301 and 302. The conductor post 305 is electrically connected to the conductor patch 301 at the connection portion 1904 and is electrically connected to the conductor patch 302 at the connection portion 1905.

  FIG. 20 is a cross-sectional view showing the positional relationship and connection relationship between the parallel plate waveguide 2009 and the unit cell 1909 shown in FIG. Similar to the other embodiments, the parallel plate waveguide 2009 includes conductor plates 401 and 402. In the example of FIG. 20, the conductor patch 302 of the unit cell 1909 is disposed inside the parallel plate waveguide 2009, that is, between the conductor plates 401 and 402.

  The conductor post 305 protruding from the unit cell 1909 is electrically connected to the conductor plate 402 at the connection portion 2004. The conductor post 305 is insulated from the conductor plate 401 by a clearance hole provided at a point 2003 of the conductor plate 401. That is, the conductor post 305 is insulated from the conductor plate 401 of the parallel plate waveguide 2009 on the side facing the conductor patch 301 and is connected to the conductor plate 402 on the side not facing the conductor patch 301.

  The unit cells 1909 having the above connection relation are periodically arranged on the waveguide in the same manner as in the examples of FIGS. FIG. 21 shows the calculation result of the input / output coupling rate characteristic of the filter in which the unit cells 1909 are periodically arranged using the finite element method. Here, the conductor patches 301 and 302 are squares each having a side of 9 mm, the thickness h of the parallel plate waveguide 2009 is 0.46 mm, the length h2 of the conductor post 305 is 0.52 mm, and the distance between the conductor plate 401 and the conductor patch 302. Is 0.06 mm, and the space between the conductor patch 301 and the conductor plate 401 and the space inside the parallel plate waveguide 2009 are filled with a dielectric material having a relative dielectric constant of 4.188 and a dielectric loss tangent of 0.02. To do. FIG. 21 shows that the waveguide structure of this example functions as a band stop filter.

[Fifth embodiment]
Next, a filter according to a fifth embodiment of the present invention will be described with reference to the drawings and calculation examples. In this embodiment, the connection relationship between the unit cell and the waveguide, and the conductor post and the waveguide is as shown in FIGS. 11 to 14, but the material constants between the opposing conductor patches are shown in FIGS. The value is different from.

  FIG. 22 is a sectional view of a filter according to a fifth embodiment of the present invention. In this embodiment, the space between the conductor patches 301 and 302 is 2201, the space between the conductor patch 302 and the conductor plate 401 is 2202, and the space between the conductor plates 401 and 402 is 2203. Here, only the space 2201 has a relative dielectric constant of 10, and the spaces 2202 and 2203 have a relative dielectric constant of 4.05, and the space 2202 has a relative dielectric constant of 10 and the spaces 2201 and 2203 have a relative dielectric constant. It is assumed that there are two types of filters when the value is 4.05. These filters are compared to the filter of FIG. 14, that is, a filter in which all layers except the conductor are filled with a material with a dielectric constant of 4.05.

  FIG. 23 shows the result of calculating the coupling ratio characteristic between the input and output of the filter using the above-described equivalent circuit analysis method. 23, S1410 is a characteristic of the filter of FIG. 14, S2204 is a characteristic of a filter in which the relative permittivity of only the space 2201 is 10 and the relative permittivity of the spaces 2202 and 2203 is 4.05, and S2205 is the relative permittivity of only the space 2202. This is a filter characteristic in which the rate is 10 and the relative permittivity of the spaces 2201 and 2203 is 4.05.

  23 that when only the space 2201 has a relative dielectric constant of 10, the two cut-off frequency bands are shifted to the lower frequency side than in the case of the filter of FIG. Similarly, when the relative permittivity is set to 10 only in the space 2202, the two cut-off frequency bands are similarly shifted to the lower frequency side than in the case of the filter of FIG. You can see that

  In the present embodiment, the case where the relative dielectric constant of a specific layer is different from the relative dielectric constants of other layers using the structures of FIGS. 11 to 14 is shown. Needless to say, the present invention may be applied to the third and fourth embodiments. For example, when applied to the configuration of FIG. 17 of the third embodiment, if the relative dielectric constant of the layer between the conductor patch 301 and the conductor plate 401 is set to a value different from the relative dielectric constant of the layer between the conductor plates 401 and 402. Good. For example, when the relative dielectric constant of the layer between the conductor patch 301 and the conductor plate 401 is 10, and the relative dielectric constant of the layer between the conductor plates 401 and 402 is 4.05, the cutoff frequency band of the filter is calculated from the calculation result of FIG. Shift to the low frequency side.

[Sixth embodiment]
Next, a filter according to a sixth embodiment of the present invention will be described with reference to the drawings. In this embodiment, as in the fifth embodiment, the layers sandwiched between the conductor patch and the conductor plate of the waveguide are filled with different materials, and at the same time, the electrically insulated conductor is used as a material that fills these layers. A material in which the material constant of the space between them, that is, the relative permittivity and the relative permeability depend on the DC voltage value is used. By adopting the above structure, in this embodiment, an active filter capable of changing the cut-off frequency band by a DC voltage applied between the conductors can be realized.

  FIG. 24 is a diagram showing a state where a DC voltage source 2401 is connected to the filter shown in FIG. The DC voltage source 2401 applies a DC voltage between the conductor plates 401 and 402. Needless to say, the conductor plates 401 and 402 are electrically insulated. Here, since the conductor patches 301 and 302 are electrically insulated, as a material that fills the space 2201 between the conductor patches 301 and 302, a material whose relative dielectric constant depends on the voltage value applied from the DC voltage source 2401. , And the applied voltage is controlled by the DC voltage source 2401, so that the cut-off frequency band shown in FIG. 23 can be controlled.

  In the present embodiment, an example in which the relative permittivity of a specific layer is controlled by the DC voltage source 2401 using the structure of FIG. 22 is shown. Needless to say, the present invention may be applied to the fourth embodiment. When applied to the configuration of FIG. 17 of the third embodiment, a material whose relative dielectric constant depends on a DC voltage is used as a material that fills the space between the conductor patch 301 and the conductor plate 401. A DC voltage may be applied between the two.

[Seventh embodiment]
FIG. 25 is a cross-sectional view showing a configuration in which the filter described in the first to sixth embodiments is mounted on a printed circuit board. In the example of FIG. 25, the filter described in the first to sixth embodiments is realized on a microstrip line type waveguide in a printed circuit board and a parallel plate type waveguide used as a power supply ground plane pair. ing.

  In FIG. 25, 2701 is an LSI driver, 2702 is an LSI receiver, 2703 is a microstrip, 2704 is a ground plane, 2705 is a power plane, and 2706 is a dielectric material for a printed circuit board. In the present embodiment, unit cells 2707 are periodically arranged to remove specific frequency components of signals transmitted on the microstrip line, and further, specific frequency components of power supply noise transmitted between the power supply ground plane pairs are removed. Therefore, the unit cells 2708 are periodically arranged.

Although the present invention has been described with reference to the above-described embodiment, the present invention is not limited to the above-described embodiment. The configuration and details of the present invention may be used by appropriately combining the above-described embodiments, and may be modified as appropriate within the scope of the claims of the present invention.
This application claims the priority on the basis of Japanese application Japanese Patent Application No. 2008-137865 for which it applied on May 27, 2008, and takes in those the indications of all here.

  The present invention can be applied to a filter using a waveguide structure.

Claims (18)

A conductor is arranged at least in the vertical direction of the space in which the signal propagates, a signal is supplied between opposing conductors at at least one place in the signal propagation direction, and faces at one or more other places in the signal propagation direction. A waveguide from which signals are output between conductors;
One or more unit cells periodically disposed on the waveguide,
Each unit cell
One plate-like conductor patch or two or more plate-like conductor patches arranged in parallel to each other ;
The one or more conductor posts connected to the one conductor patch or connected to at least one or more conductor patches of the two or more conductor patches,
The filter, wherein the conductor post protruding from each unit cell is connected to at least one conductor of the waveguide and insulated from other conductors of the waveguide. The filter of claim 1.
Each unit cell is composed of two conductor patches arranged outside the waveguide and two groups of conductor posts,
The first group of conductor posts is connected to a first conductor patch on the side far from the waveguide and insulated from a second conductor patch on the side near the waveguide. Insulated from the waveguide conductor on the facing side and connected to the waveguide conductor on the side not facing the second conductor patch;
The second group of the conductor posts are insulated from the first conductor patch, connected to the second conductor patch, connected to the waveguide conductor on the side facing the second conductor patch, and A filter which is insulated from a conductor of a waveguide on the side not facing the conductor patch of 2. The filter according to claim 2, wherein
The conductor patch is a square in plan view,
The two groups of conductor posts are composed of one first group of conductor posts and one second group of conductor posts,
The first group of conductor posts is disposed near the center of the conductor patch;
The filter according to claim 2, wherein the conductor posts of the second group are arranged near the corners of the conductor patch. The filter of claim 1.
Each unit cell is composed of one conductor patch and one conductor post arranged outside the waveguide,
The conductor post is connected to the conductor patch, insulated from a conductor of the waveguide facing the conductor patch, and connected to a conductor of the waveguide not facing the conductor patch. To filter. The filter of claim 1.
Each unit cell is composed of one conductor patch having a rectangular shape in plan view and two conductor posts arranged outside the waveguide,
The two conductor posts are respectively connected to the conductor patch in the vicinity of a midpoint between two opposing sides of the conductor patch, insulated from the conductor of the waveguide on the side facing the conductor patch, and face the conductor patch. A filter characterized by being connected to a conductor of a waveguide on the non-side. The filter of claim 1.
Each unit cell is composed of one conductor patch having a rectangular shape in plan view and four conductor posts arranged outside the waveguide,
The four conductor posts are connected to the conductor patch in the vicinity of the four corners of the conductor patch, insulated from the waveguide conductor on the side facing the conductor patch, and on the side not facing the conductor patch. A filter connected to a conductor of a waveguide. The filter of claim 1.
Each unit cell has two or more conductor patches, the one or more first conductor patches are arranged outside the waveguide, and the one or more second conductor patches are the waveguide. A filter characterized by being placed inside. The filter according to claim 7, wherein
Each unit cell has one or more conductor posts,
The conductor post is connected to the first and second conductor patches, insulated from the conductor of the waveguide on the side facing the first conductor patch, and on the side not facing the first conductor patch. A filter connected to a conductor of a waveguide. The filter according to claim 3.
The filter, wherein the waveguide is a parallel plate waveguide. The filter according to claim 4, wherein
The filter, wherein the waveguide is a parallel plate waveguide. The filter according to claim 5, wherein
The filter, wherein the waveguide is a parallel plate waveguide. The filter according to claim 6.
The filter, wherein the waveguide is a parallel plate waveguide. The filter according to claim 7, wherein
The filter, wherein the waveguide is a parallel plate waveguide. The filter of claim 1.
Furthermore, it has a DC voltage source whose voltage value is variable,
The material that fills at least one of the space between the conductor patches of the unit cell and the space between the conductors of the waveguide has a DC voltage dependency in material characteristics,
The DC voltage source applies a DC voltage between the conductor patches insulated from each other or between the conductors insulated from each other. The filter of claim 14,
The waveguide is a parallel plate waveguide,
One conductor sandwiching the material having the DC voltage dependency is at the same potential as one conductor of the waveguide, and the other conductor sandwiching the material having the DC voltage dependency is the other conductor of the waveguide. And the same potential as
The DC voltage source applies a DC voltage between mutually insulated conductors of the waveguide. The filter of claim 1.
The filter characterized in that the shape of the one or more conductor patches is different in each unit cell.   A printed circuit board comprising the filter according to claim 1. A conductor is arranged at least in the vertical direction of the space in which the signal propagates, a signal is supplied between opposing conductors at at least one place in the signal propagation direction, and faces at one or more other places in the signal propagation direction. In a noise suppression method using a waveguide in which a signal is output from between conductors,
One plate-like conductor patch or two or more plate-like conductor patches arranged in parallel to each other and at least one of the two or more conductor patches connected to the one conductor patch A unit cell consisting of one or more conductor posts connected to one or more conductor patches is periodically arranged on the waveguide;
The method according to claim 1, wherein the conductor post protruding from each unit cell is connected to at least one conductor of the waveguide and insulated from other conductors of the waveguide.

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