Patent Grant
10224588
This application claims priority from German Patent Application No. 10 2015 005 613.1 filed Apr. 30, 2015, incorporated herein by reference.
None.
The technology herein relates to a multiplex filter which is particularly suitable for the transmission of TM modes in the transverse direction.
In the context of the transmission of TM modes and/or TM waves, only the electrical field has a component in the direction of propagation, and the magnetic fields are entirely perpendicular to the direction of propagation. TM waves are therefore also called E waves. A multiplex filter in this context comprises a common connection and at least two signal line connections, wherein the at least two signal line connections are each connected to the common connection via one signal transmission path. The direction of signal transmission can be from the common connection to one of the multiple signal line connections (for example in the form of a diplexer or multiplexer), and also simultaneously from another one of the signal line connections to the common connection (for example in the form of a duplexer which has two further connections in addition to the first common connection). Each signal transmission path passes through different resonator chambers such that different frequency ranges are filtered in the same.
The publication by M. Höft and T. Magath, “Compact Base-Station Filters Using TM-Mode Dielectric Resonators,” describes the construction of a high-frequency filter which has multiple dielectric resonators. In this case, the individual resonators are coupled parallel to the direction of propagation of the H field.
A disadvantage of this construction is that more space is required to implement the desired filter properties. This space requirement increases in proportion to the number of signal transmission paths which should be included.
Therefore, the problem addressed herein is that of creating a multiplex filter which is particularly suitable for the transmission of TM modes in the transverse direction, wherein this multiplex filter should be constructed in both a space-saving and cost-effective manner.
This problem is addressed with respect to a multiplex filter and a method for tuning such a multiplex filter. Advantageous non-limiting implementations of the multiplex filter or of the method for tuning the multiplex filter are provided.
The multiplex filter has a housing which has a housing base, a housing cover spaced apart from the housing base, and a circumferential housing wall between the housing base and the housing cover. The housing base and the housing cover are preferably intersected by a central axis. The multiplex filter also has at least n filter chambers which are surrounded by the housing and/or at least one insert positioned in the housing.
A dividing device which consists of metal or which comprises metal is constructed in each of the n filter chambers, dividing each filter chamber into m resonator chambers, wherein m≥2, and wherein each of the same form one resonator. The dividing devices are arranged parallel to the central axis or with a component substantially parallel to the central axis and divide the filter chamber into m resonator chambers parallel to the central axis or with a component substantially parallel to the central axis. The resonator chambers in each filter chamber, and therefore each of the resonators, are decoupled from each other by the dividing devices situated in each filter chamber. In addition, at least n dielectrics are included, of which at least one is arranged in each filter chamber. The multiplex filter has n−1 separators. The n filter chambers are arranged along a central axis which is perpendicular to the H field, or with a component essentially perpendicular to the H field, wherein every two filter chambers which are adjacent or are adjacent along the central axis are separated by one separator. Each of the n−1 separators has at least m coupling openings via which every two resonator chambers which are adjacent in the signal transmission direction are coupled to each other. The resonator chambers are coupled perpendicular to the H fields and/or parallel to the central axis or with a component essentially perpendicular to the H fields and/or parallel to the central axis. A common connection is guided into the first filter chamber via a first opening in the housing, and is coupled in the same to the m resonators of the m resonator chambers. As a result of the fact that the coupling is established perpendicular to the H field, the resonator can have a very compact construction. In addition, m signal line connections are coupled via m openings in the housing to the m resonators in the m resonator chambers in the nth filter chamber.
It is particularly advantageous in this case that the individual filter chambers, and accordingly the individual resonator chambers with the resonators are stacked one above the other, wherein the same are coupled by coupling openings which are constructed inside the separators. The coupling is in the signal transmission direction, and therefore perpendicular to the H field. This enables a very compact construction of the resonator because multiple signal transmission directions are established parallel to the central axis and are uncoupled from each other.
The method for tuning the multiplex filter comprises various method steps. In one method step, at the beginning, all coupling openings of the 1+Xth separator and/or the n−1−Xth separator are closed, wherein X is equal to 0 at the beginning. In a further method step, a reflection parameter is measured at the common connection and/or at least one, and preferably all, signal line connections. Subsequently, the resonance frequency and/or the coupling bandwidth, and/or the input coupling bandwidth, is/are adjusted to a desired value. This method can be used to adjust the resonance frequency and/or the coupling bandwidth of m resonator chambers of a filter chamber to the desired value independently of further resonator chambers in other filter chambers.
There is a further advantage when one or both end faces of each of the n dielectrics are coated with a metal layer, wherein this metal layer then constitutes one of the n−1 separators, and wherein at least one recess inside the metal layer forms the at least one coupling opening. The use of accordingly coated dielectrics enables a further reduction of the size of the high-frequency filter.
There is also a further advantage for the multiplex filter if a diameter of at least one, and preferably all, filter chambers is defined and/or prespecified by at least one insert in each case, and particularly by an annular insert which leans against the housing wall. The resonance frequency can be tuned in this way. The configuration of the insert leaning against the housing wall in a form-fitting manner also ensures that the insert cannot slide from its position over time.
The insert of one, and preferably of each, filter chamber has wall segments adjacent to the inner wall of the housing with different thicknesses, such that it is possible to adjust the volumes of individual resonator chambers of a filter chamber independently of each other, and/or for said volumes to differ from each other. The use of such inserts further increases the flexibility of the multiplex filter.
A further advantage of the multiplex filter arises when the inserts of at least two of the n filter chambers which do not directly follow each other—that is, are not adjacent to each other—have an opening, and the at least two openings are connected to each other by a channel which runs, by way of example, at last partially inside the housing wall. An electrical line runs in this channel, and the electrical line couples the two resonator chambers of the different filter chambers to each other capacitively and/or inductively. In this way, despite the compact construction of the multiplex filter, it is possible to achieve an overcoupling of resonators which are not directly adjacent.
An advantage also arises when at least one anti-turning element is attached between at least one of the n−1 separators and the at least one insert and/or the adjacent dielectric, to prevent these elements from turning with respect to each other. In this case, it is possible for at least one anti-turning element to be attached in each case between the housing base and/or the housing cover and/or the housing wall and the insert in the first filter chamber and the nth filter chamber, the same preventing these elements from turning with respect to each other. This ensures that the resonance frequencies and the group delays of the individual resonators do not change over time due to vibration in the high-frequency filter.
The n dielectrics inside the multiplex filter can have a disk shape, and/or all or some of the n dielectrics can have completely or partially differing dimensions. It is also possible for all or at least one of the n dielectrics to fully or partially fill in the volume of their respective filter chambers, and therefore of the m resonator chambers. The behavior of each resonator with respect to its resonance frequency and its coupling bandwidth can be accordingly adjusted by the geometric form and the arrangement of the dielectrics.
The dividing device is preferably formed by a plurality of through-connections inside the dielectric, which are arranged in the filter chamber parallel, or at least with one component parallel, to the central axis, thereby dividing the dielectric into m parts, wherein each of the m parts is found in one of the m resonator chambers of a filter chamber. This enables the use of a single dielectric, which is preferably made of a ceramic. In contrast, it would be possible for the dielectric to be composed inside each filter chamber of m parts which are preferably the same size, wherein each of the m parts is found in one of the m resonator chambers in a filter chamber, and wherein a metal layer is formed inside each filter chamber between the m parts as a dividing device. This metal layer separates the individual resonator chambers inside a filter chamber from each other, wherein the metal layer is arranged parallel to, or at least with one component parallel to, the central axis. A metal layer can be, by way of example, an electrically conductive coating on the lateral peripheral surface of the dielectric. Such an electrically conductive coating must be applied only at the locations of the m parts which are not in contact with the insert or with another already coated part of the m parts.
At least two or all of the n dielectrics, or two or all of the m parts of at least one dielectric, are made of a different material. In this case, it is also possible that at least one or all of the n dielectrics preferably have at least one recess filled with air. In this way, it is possible to separately change the resonance frequency for each resonator of a resonator chamber inside a filter chamber.
The first filter chamber has a region in which the dividing device only extends through the first dielectric over a sub-length of the diameter, thereby forming an opening region in which the common connection is coupled in the first filter plane to all m resonators, wherein the opening region has a size or length which is less than 10%, preferably less than 20%, more preferably less than 30%, more preferably less than 40%, and more preferably less than 50% of the smallest diameter of the first filter chamber. In this way, it is possible for a common connection to be used as a shared connector. By way of example, a mobile radio antenna can be connected to the common connection, wherein signals are transmitted via the same and signals are received by the same.
The signal transmission direction runs through each of the m signal line connections either from the signal line connection to the common connection or from the common connection to the signal line connection. If the signal transmission direction runs from one or more of the signal line connections to the common connection, one resonator of one resonator chamber of a filter chamber is coupled to precisely one resonator of one resonator chamber of a filter chamber which is adjacent in the signal transmission direction. This ensures that one resonator chamber is coupled to precisely one further resonator chamber along the route toward the common connection in the signal transmission direction. In the opposite direction, in the case in which the signal transmission direction runs from the common connection to one or more of the m signal line connections, one resonator of one resonator chamber of a filter chamber is coupled to one or more resonators of one filter chamber which is adjacent in the signal transmission direction. This means that in this case one resonator of one resonator chamber is coupled to more than one resonator of multiple resonator chambers of a further filter chamber. As such, it is possible to create additional signal transmission paths. However, this is preferably only true if the signal transmission direction runs from the common connection to the m signal line connections.
The coupling between the individual resonators is increased by the dielectric in the first resonator being in contact with the first separator, and the dielectric in the nth resonator being in contact with the n−1th separator, wherein the remaining dielectrics of the remaining n−2 resonators are in contact with both of the separators bounding the filter chamber in question. This is particularly advantageous if the dielectric in the first resonator is additionally in contact with the housing cover and the dielectric in the nth resonator is in contact with the housing base. The phrase “in contact” is used to indicate that two entities at least touch. The dielectrics of the n filter chambers in this case are preferably fixed to the respective separator or the respective separators, thereby improving the coupling.
In a further embodiment of the multiplex filter, the common connection contacts the dielectric in the first filter chamber either centrally or off-center. The dielectric in the first filter chamber has a depression into which the common connection projects, and as a result the common connection is in contact with the first dielectric, or the dielectric in the first filter chamber has a recess which passes through the same, through which the common connection extends such that the common connection is in contact with the first dielectric and is in contact with the first separator. The same is true for the m signal line connections. These have a central or off-center contact with the dielectric which is arranged in the m resonator chambers of the nth filter chamber. The dielectric in the nth filter chamber has up to m depressions into which the m signal line connections project, and as a result the m signal line connections are in contact with the nth dielectric, and/or the dielectric in the nth filter chamber has up to m recesses passing through the same, through which the m signal line connections extend such that the m signal line connections are in contact with the nth dielectric and are in contact with the n−1th separator.
A further advantage of the multiplex filter is a result of the fact that the arrangement and/or the size and/or cross-section shape of at least one coupling opening of one of the n−1 separators differs entirely or partially from the arrangement and/or the size and/or the cross-section shape of another coupling opening of the same n−1 separator or from a coupling opening of another of the n−1 separators. As an alternative or in addition thereto, the number of the coupling openings in the n−1 separators can be entirely or partially different among the same, and/or the number of the coupling openings of one of the n−1 separators used for the coupling of a resonator is different from the number of the coupling openings of the same separator used for the coupling of another resonator. This enables an adjustment of the coupling between the individual resonators to the desired value.
For further tuning of the high-frequency filter, it is also possible that at least one, and preferably all of the resonator chambers of at least one, and preferably all of the filter chambers have at least one additional opening toward the outside of the housing, wherein at least one tuning element can be inserted via this additional opening into the resonator chamber of at least one filter chamber. The distance between the tuning element which is inserted through the at least one additional opening into the at least one resonator chamber of at least one filter chamber can be modified for the corresponding, respective dielectric inside the at least one resonator chamber in the at least one filter chamber. In this case, multiple tuning elements can also be inserted into one resonator chamber, wherein one tuning element consists, by way of example, entirely of a metal or a metallic coating, whereas the other tuning element comprises a dielectric material. The tuning element which consists of a metallic material can be used for coarse tuning, and the tuning element which comprises a dielectric material can be used for fine tuning of the resonator frequency and/or the coupling bandwidth of the corresponding resonator.
In this case, the distance between the at least one spacer element and the respective dielectric inside the at least one of the m resonator chambers of the at least one of the n filter chambers can also be reduced to such an extent that it is in direct contact with the same. The dielectric of at least one of the n filter chambers can also have at least one indentation, wherein the distance between the tuning element and the dielectric can be reduced in such a manner that the tuning element dips into the indentation of the respective dielectric and is in contact with the same. The tuning element in this case enters into the at least one of the m resonator chambers of at least one of the n filter chambers particularly perpendicularly to the signal transmission direction—that is, preferably perpendicular to the central axis.
A method for tuning the multiplex filter is accordingly repeated for the remaining filter chambers. After the resonance frequency and/or the coupling bandwidth of at least one resonator, and preferably all resonators in the first and/or last—that is, nth—filter chamber have been adjusted to the desired value, in a further method stop at least one, and preferably m or more coupling openings of the 1+Xth separator and/or the n−1−Xth separator are opened. Then the value of the counter variable X is increased by 1. The previous method steps are then carried out once more. Once again, a reflection factor is measured on the common connection and/or a reflection factor is measured on at least one, and preferably on all m signal line connections. Subsequently, the coupling openings to the following resonators in the following filter chambers are opened and the value of the counter variable is once again increased. The tuning of the multiplex filter begins with the resonators into which the common connection and the m signal line connections engage—that is, with the resonators of the outermost filter chamber—and ends with the resonators which are arranged in the filter chamber (for an odd number n) or the filter chambers (for an even number n) in the center of the multiplex filter.
In the event that the multiplex filter has an uneven number of filter chambers, the filter chambers in the center of the multiplex filter must be utilized once for the measurement of the reflection factor on the common connection, and another time for the measurement of the reflection factor on at least one, and preferably all, of the m signal line connections. The coupling openings of the two separators which surround the filter chamber in the center of the multiplex filter must be closed to the other connector in each case—that is, to the common connection or to at least one, and preferably all, of the m signal line connections, according to the measurement of the respective reflection factor.
Subsequently, or if, for an even number of filter chambers, all coupling openings are open, the forward transmission factor and/or the reverse transmission factor can be measured, in addition to the reflection factors on the common connection and/or on at least one, and preferably all, of the m signal line connections.
The resonance frequencies and/or the coupling bandwidths can be modified for each resonator chamber of a filter chamber and thereby for each resonator in a filter chamber by modifying the diameter of at least one resonator chamber of a filter chamber, which is possible, by way of example, by exchanging the at least one insert for another insert with a modified size. The arrangement and/or the number and/or the size and/or the cross-section shape of the at least one coupling opening can also be modified by turning and/or exchanging the at least one separator. Likewise, the resonance frequency and/or the coupling bandwidth can be modified by rotating inward or outward at least one tuning element into/out of at least one resonator chamber of a filter chamber. Finally, the dielectric in a filter chamber can be exchanged for another dielectric with modified dimensions and/or recesses.
Various non-limiting embodiments are described in detail below as examples with reference to the drawings. Objects which are the same have the same reference numbers. In the corresponding figures of the drawings,
The following detailed description of exemplary non-limiting illustrative embodiments is to be read in conjunction with the drawings of which:
The multiplex filter 1 also has n filter chambers 71, 72, . . . , 7n. n is a natural number, wherein n≥1, preferably n≥2, more preferably n≥3, more preferably n≥4, more preferably n≥5. In each of the n filter chambers 71, 72, . . . , 7n are arranged up to m resonator chambers 61_1, 61_2, . . . , 61_m, to 6n_1, 6n_2, . . . , 6n_m. m is likewise a natural number, wherein m≥1, preferably m≥2, more preferably m≥3, more preferably m≥4, and more preferably m≥5.
Regarding the nomenclature use, for a term such as 61_m, the first subscript number—in this case “1”—indicates the number of the filter chamber 71, 72, . . . , 7n and the value for this number can therefore range up to “n.” The second number, in this case “m,” indicates the number of the resonator chamber insides the respective filter chamber 71, 72, . . . , 7n and can therefore range up to “m.” Using such a nomenclature, it is possible to address all resonator chambers 61_1, 61_2, . . . , 61_m, to 6n_1, 6n_2, . . . , 6n_m inside the filter chambers 71, 72, . . . , 7n.
At least one dielectric 81, 82, . . . , 8n is positioned inside each filter chamber 71, 72, . . . , 7n. This dielectric 81, 82, . . . , 8n preferably has a disk-shaped or cylindrical design. It extends over the entire volume of the respective filter chamber 71, 72, . . . , 7n, or only over a part thereof.
The individual resonator chambers 61_1, 61_2, . . . , 61_m, to 6n_1, 6n_2, . . . , 6n_m of each filter chamber 71, 72, . . . , 7n are decoupled from each other by means of n dividing devices 131, 132, . . . , 13n. The at least one dividing device is arranged parallel to the central axis and divides the filter chamber into m resonator chambers parallel to the central axis. These dividing devices 131, 132, . . . , 13n are preferably arranged parallel to the central axis 12 and/or parallel to the m signal transmission devices 211, . . . 21m, and therefore divide each of the n filter chambers 71, 72, . . . , 7n parallel to the central axis 12 into m resonator chambers 61_1, 61_2, . . . , 61_m, to 6n_1, 6n_2, . . . , 6n_m.
The n dividing devices 131, 132, . . . , 13n are, by way of example, formed by a plurality of through-connections inside the dielectric 81, 82, . . . , 8n. The through-connections are arranged in the dielectrics 81, 82, . . . , 8n, the same arranged in the filter chambers 71, 72, . . . , 7n, parallel to, or at least with one component parallel to, the central axis 12 and/or to one of the signal transmission directions 212, . . . 21m. As a result, the n dielectrics 81, 82, . . . , 8n are divided into m parts, and each of the m parts is in one of the m resonator chambers 61_1, 61_2, . . . , 61_m, to 6n_1, 6n_2, . . . , 6n_m of a filter chamber 71, 72, . . . , 7n. It can also be said that the m resonator chambers 61_1, 61_2, . . . , 61_m, to 6n_1, 6n_2, . . . , 6n_m are created by the n dividing devices 131, 132, . . . , 13n. The through-connections are preferably bore holes with inner walls which are galvanized with an electrically conducting layer. The through-connections can be arranged in a row. However, multiple rows of through-connections can also be arranged parallel and directly adjacent to each other.
It is also possible for the dielectric 81, 82, . . . , 8n to be composed inside each filter chamber 71, 72, . . . , 7n of m parts which are preferably the same size, wherein each of the m parts is found in one of the m resonator chambers 61_1, 61_2, . . . , 61_m, to 6n_1, 6n_2, . . . , 6n_m in a filter chamber 71, 72, . . . , 7n. A metal layer is formed inside each filter chamber 71, 72, . . . , 7n between the m parts, forming the dividing device 131, 132, . . . , 13n. As a result, the individual resonator chambers 61_1, 61_2, . . . , 61_m, to 6n_1, 6n_2, . . . , 6n_m inside a filter chamber 71, 72, . . . , 7n are separated from each other, wherein the metal layer is arranged parallel to, or at least with one component parallel to, the central axis 12 or to a signal transmission direction 211, . . . 21m. The metal layer can be, by way of example, an electrically conductive coating. Preferably only the specific surfaces of the lateral peripheral surfaces of the m parts are coated which directly adjoin other m parts of the dielectric 81, 82, . . . , 8n which are not coated with such an electrically conductive layer. Of course, all of the lateral peripheral surfaces of the m parts can also be coated with the electrically conductive layer.
In this context, it is also possible that two, or all, of the m parts which together form one of the n dielectrics 81, 82, . . . , 8n inside the filter chamber 71, 72, . . . , 7n are made of a different material. The same is naturally also true for the n dielectrics 81, 82, . . . , 8n themselves, in the event they are constructed as separate parts.
The m parts of one of the n dielectrics 81, 82, . . . , 8n, or the n dielectrics 81, 82, . . . , 8n constructed as separate parts, have one or more recesses 16 which are preferably filled with air. Rather than being filled with air, these recesses 16 can also be filled with a material which has a permeability which differs from a permeability of the n dielectrics 81, 82, . . . , 8n.
The individual filter chambers 71, 72, . . . , 7n are separated from each other by separators 91, 92, . . . 9n−1. These separators 91, 92, . . . 9n−1 are preferably separating disks. These separators 91, 92, . . . 9n−1 consist of an electrically conductive material or are coated with such a material. Each of these separators 91, 92, . . . 9n−1 has at least one coupling opening 10. The size, the geometric shape, the number, and the arrangement of the coupling opening 10 inside the respective separator 91, 92, . . . 9n−1 can be selected arbitrarily and can differ from one separator 91, 92, . . . 9n−1 to another separator 91, 92, . . . 9n−1. The diameter of the coupling openings 10 is, by way of example, only a fraction of a millimeter according to the frequency range. It can—particularly for low frequencies—also be multiple millimeters. The separators 91, 92, . . . 9n−1 are preferably thinner that the dielectrics 81, 82, . . . , 8n. The separators 91, 92, . . . 9n−1 are preferably only several millimeters thick. They are preferably thinner than 3 millimeters, and they are more preferably thinner than 2 millimeters.
Each filter chamber 71, 72, . . . , 7n can also have at least one insert 111, 112, . . . , 11n. Such an insert 111, 112, . . . , 11n is preferably a ring which is preferably supported in a form-fitting manner by its outer surface on an inner surface of the housing wall 5. Such an insert 111, 112, . . . , 11n, which is electrically conductive, can be used to adjust the volume of the filter chamber 71, 72, . . . , 7n and therefore to adjust the volume of the individual resonator chambers 61_1, 61_2, . . . , 61_m, to 6n_1, 6n_2, . . . , 6n_m, and thereby enables the adjustment of the resonance frequency of the multiplex filter.
In the embodiment in
The individual resonators of the resonator chambers 61_1, 61_2, . . . , 61_m, to 6n_1, 6n_2, . . . , 6n_m in this case are coupled parallel to the respective signal transmission direction 211, 212, . . . , 21m. The H field 20 in this case propagates perpendicular to the respective signal transmission direction 211, 212, . . . , 21m.
All filter chambers 71, 72, . . . , 7n are intersected by the central axis 12. The central axis 12 in this case meets the end face of each dielectric 81, 82, . . . , 8n inside the filter chambers 71, 72, . . . , 7n at a right angle.
The inner wall of the housing 5 of the multiplex filter 1 is preferably cylindrical in cross-section. The same is also true for the inner wall of each insert 111, 112, . . . , 11n. However, other cross-section shapes are also possible. By way of example, the inner walls can have the cross-section shape, viewed from above, of a rectangle or a square or an oval or a regular or irregular n-polygon, or approximately the same.
The signal transmission direction 211, . . . 21m runs through each of the m signal line connections 151, 152, . . . , 15m either from the signal line connection 151, 152, . . . , 15m to the common connection 14 or from the common connection 14 to the signal line connection 151, 152, . . . , 15m. The signal transmission direction 211, . . . 21m can run in a different direction for each of the individual signal line connections 151, 152, . . . , 15m. The signal transmission direction 211, . . . 21m runs from one or more of the signal line connections 151, 152, . . . , 15m to the common connection 14, wherein one resonator of one resonator chamber 61_1, 61_2, . . . , 61_m, to 6n_m, 6n_2, . . . , 6n_m of a filter chamber 71, 72, . . . , 7n is coupled to precisely one resonator of one resonator chamber 61_1, 61_2, . . . , 61_m, to 6n_1, 6n_2, . . . , 6n_m of a filter chamber 71, 72, . . . , 7n which is adjacent in the signal transmission direction 211, . . . 21m. This circumstance is shown in
In
In an embodiment which is not illustrated, individual resonator chambers 61_1, 61_2, . . . , 61_m, to 6n_1, 6n_2, . . . , 6n_m of a filter chamber 71, 72, . . . , 7n can be coupled in the signal transmission direction 211, . . . 21m to more than just one resonator chamber 61_1, 61_2, . . . , 61_m, to 6n_1, 6n_2, . . . , 6n_m of a filter chamber 71, 72, . . . , 7n arranged in the signal transmission direction 211, . . . 21m. In this case, the signal transmission direction 211, . . . 21m runs from the common connection 14 to one or more of the m signal line connections 211, . . . 21m, wherein one resonator of one resonator chamber 61_1, 61_2, . . . , 61_m, to 6n_1, 6n_2, . . . , 6n_m of a filter chamber 71, 72, . . . , 7n is coupled to one or more resonators of one filter chamber 71, 72, . . . , 7n which is adjacent in the signal transmission direction 211, . . . 21m. As a result, it is possible for at least two signal transmission paths to run through individual resonator chambers 61_1, 61_2, . . . , 61_m, to 6n_1, 6n_2, . . . , 6n_m of a filter chamber 71, 72, . . . , 7n.
The n−1 separators 91, 92, . . . 9n−1 preferably comprise a separating plate which is made of metal. The coupling openings 10 can be created in this separating plate by means of a laser or a punching process, or a milling process, by way of example.
The volume of the first filter chamber 71 is bounded by a first insert 111, and the first insert 111 is arranged adjacent thereto on an inner wall of the housing wall 5. The common connection 14 is centered—that is, arranged centrally in the first filter chamber 71 and coupled to the same. The common connection 14 couples to the first and second (m=2) resonator chambers 61_1, 61_m, wherein the first resonator chamber has a plurality of recesses 16. These recesses 16 are preferably filled with air and are arranged symmetrically with respect to an axis A-A′. The axis A-A′ runs transverse to the central axis 12 and divides the first resonator chamber 61_1 into two identical regions. The m resonator chambers 61_1, 61_m of the first filter chamber 71 are the same size. This is also true for the further m resonator chambers 61_1, 61_m of the further filter chambers 72, . . . , 7n. Also, the m resonator chambers 61_1, 61_m of the n filter chambers 71, 72, . . . , 7n can have different sizes.
The first filter chamber 71 comprises a region in which the dividing device 131 only extends through the first dielectric 81 by a sub-length of the diameter. This forms an opening region 30 in which the common connection 14 is coupled to all m resonators of the m resonator chambers 61_1, 61_m in the first filter chamber 71. The opening region 30 has a size or length which is less than 10%, preferably less than 20%, more preferably less than 30%, more preferably less than 40%, and more preferably less than 50% of the smallest diameter of the first filter chamber 71.
Depending on the desired strength of the coupling in one of the m resonator chambers 61_1, 61_m, the common connection can be arranged near to one or nearer to the other resonator chamber 61_1, 61_m, and therefore off-center. The first dividing device 131 can also be designed in such a manner that the coupling between the common connection 14 and one of the two resonator chambers 61_1, 61_m is stronger than the coupling to the other.
The number of recesses 16 in each resonator chamber 6n_1, 6n_m can partially or entirely differ from the number of the recesses in the other resonator chambers 6n_1, 6 nm of the same filter chamber 7n.
The m resonator chambers 61_1, 61_2, 61_m have a different number of recesses 16 which in turn have, at least to some degree, different sizes.
The recesses 16 can pass entirely through the dielectric 8m, or rather can be formed as blind holes.
The opening region 30 is selected in such a manner that the common connection 14 is coupled to all m resonators of the m resonator chambers 61_1, 61_2, 61_3, 61_m, wherein the m resonator chambers 611, 61_2, 61_3, 61_m have a different number of recesses 16, which differ entirely, or to some degree, from each other in both their number and their size, as well as in their shape. The inner walls 16 can have the cross-section shape, viewed from above, of a rectangle and/or a square and/or an oval and/or a regular or irregular n-polygon, or approximately the same. The corners of these recesses 16 can also be rounded off, for example.
The dividing device 131 consists of m bars which are arranged with a spacing from each other, wherein the individual bars are spaced from each other by a measure of α=360°/m. In this case, the bars are spaced apart by 90°.
There is no distance between the first dielectric 81 and the housing cover 4. The same is true for the nth dielectric 8n which is likewise in contact with the housing base 3 via its end face. There is no distance between the nth dielectric 8n and the housing base 3. The elements of the high-frequency filter 1—that is, by way of example, the inserts 111, . . . , 11n, the dielectrics 81, . . . , 8n, the separators 91, . . . , 9n−1 and the housing cover 4 and/or the housing base 3—are preferably press-fit to each other. This press fitting is expressed, by way of example, by the fact that the individual dielectrics 81, 82, . . . , 8n partially project into the individual separators 91, 92, . . . 9n−1.
The first dielectric 81 in the first filter chamber 71 has a depression into which the common connection 14 projects. As a result, it is in contact with the first dielectric 81. The same is true for the nth dielectric 8n in the nth filter chamber 7n as regards the m signal line connections 151, . . . , 15m.
The multiplex filter 1 in
In the embodiment in
It is hereby noted that the housing 5 can be electrically conductive—that is, can be made of metal, for example—but need not be. In other words, the housing 5 can consist of any other arbitrary material—particularly a non-conductive material such as a dielectric or plastic. The function of the housing 5 is to hold the components situated in the interior of the housing 5 together mechanically, and fix the same mechanically in place. In any case, the housing 5 can only consist of a dielectric if it is ensured that the filter chambers 71, 72, . . . , 7n are shielded from the surroundings of the multiplex filter 1. Such a shielding can be realized, by way of example, by the inserts 111, 112, . . . , 11n.
The separators 91, 92, . . . 9n−1 have an outer diameter which preferably corresponds to an inner diameter of the housing wall 5. This means that an outer surface—that is, a peripheral wall of each separator 91, 92, . . . 9n−1—contacts the inner surface of the housing—that is, has a mechanical contact with the same. The coupling openings 10 of a separator 91, 92, . . . 9n−1 can differ from the coupling openings of the other separator 91, 92, . . . 9n−1 with respect to their arrangement—that is, their orientation and/or their number and/or their size and/or their cross-section shape. The coupling openings 10 of a separator 91, 92, . . . 9n−1 can even be different with respect to their arrangement—that is, their orientation and/or their number and/or their size and/or their cross-section shape.
In the embodiment in
There is likewise typically no hollow space between the inserts 111, 112, . . . , 11n along with the separator 91, 92, . . . 9n−1 and the housing wall 5.
The dielectrics 81, 82, . . . , 8n are likewise in contact with their respective separator 91, 92, . . . 9n−1. The dielectrics 81, 82, . . . , 8n in this case can be press-fitted and/or soldered to the respective separators 91, 92, . . . 9n−1.
The inserts 111, 112, . . . , 11n are also preferably press-fitted and/or soldered to the corresponding separators 91, 92, . . . 9n−1 with a positive fit. This also prevents the individual elements from rotating with respect to each other, so that the electrical properties of the high-frequency filter 1 remain unchanged over a longer period of time.
The dividing devices 131, . . . , 13n are likewise illustrated. The same divide the filter chambers 71, 72, . . . , 7n into the m resonator chambers 61_1, . . . , 61_m, to 6n_1, . . . , 6n over the entire thickness of the dielectrics 81, . . . , 8n. The first dividing device is illustrated with a dashed line because the opening region 30 for the shared coupling with the common connection 14 is also indicated in the same.
The common connection 14 contacts the end face of the first dielectric 81. The common connection therefore is in contact with the first dielectric 81. The further m signal line connections 151, . . . , 15m likewise contact an end face of the nth dielectric 8n and are in contact with the same. The end face of the nth dielectric 8n is likewise spaced apart from the housing base 3 and does not touch the same. As such, it is not in contact with the same.
In the embodiment in
The coupling openings 10 connect the individual resonator chambers 61_1, . . . , 61_m, to 6n_1, . . . , 6n_m of the individual filter chambers 71, 72, . . . , 7n to each other, and they are surrounded either by the open volume of one of the resonators 61, 62, . . . , 6n or by the dielectric 81, 82, . . . , 8n of the resonator 61, 62, . . . , 6n.
At least one tuning element 401_1, . . . , 401_m, to 40n_1 . . . , 40n_m is inserted through an additional opening 411_1, . . . , 411_m, to 41n_1 . . . , 41n_m into each of the at least one filter chambers 71, 72, . . . , 7n. Preferably, multiple tuning elements 401_1, . . . , 401_m, to 40n_1 . . . 40n_m are inserted into the filter chamber 71, 72, . . . , 7n such that preferably at least one tuning element 401_1, . . . , 401_m, to 40n_1 . . . 40n_1 s arranged in each resonator chamber 61_1, . . . , 61_m, to 6n_1, . . . , 6n_m. The openings 411_1, . . . , 411_m, to 41n_1 . . . , 41n_m extend through the housing wall 5 and through the corresponding insert 111, 112, . . . , 11n into the filter chamber 71, 72, . . . , 7n. The corresponding tuning elements 401_1, . . . , 401_m, to 40n_1 . . . , 40n_m can then be rotated into or out of the respective filter chamber 71, 72, . . . , 7n. The distance between the tuning element 411_1, . . . , 411_m, to 41n_1 . . . , 41n_m and the respective dielectric 81, 82, . . . , 8n can be changed. The respective opening 401_1, . . . , 401_m, to 40n_1 . . . , 40n_m preferably runs perpendicular to the signal transmission direction 211, . . . 21m, and therefore likewise perpendicular to the central axis 12.
The distance from the at least one tuning element 401_1, . . . , 401_m, to 40n_1 . . . , 40n_m to the respective dielectric 81, 82, . . . , 8n in the filter chamber 71, 72, . . . , 7n can be reduced to such an extent that it touches the dielectric 81, 82, . . . , 8n—that is, is in contact with the same.
The nth dielectric 8n in the nth filter chamber 7n also has an indentation such that the nth tuning element 40n−1, . . . , 40n−m can dip into the nth dielectric 8n.
The part of the common connection 14 or the m signal line connections 151, . . . , 15m which is in contact with the respective dielectric 81, 8n or with the respective separator 91, 9n−1 runs parallel to the central axis 12 and/or parallel to the signal transmission direction 211, . . . , 21m. The other parts of the common connection 14 or the m signal line connections 151, . . . , 15m need not necessarily run parallel to the signal transmission direction 211, . . . 21m and/or the central axis 12. The parts of the common connection 14 or the m signal line connections 151, . . . , 15m which are situated inside the first or nth filter chamber 71, 7n are preferably those which run parallel to the signal transmission direction 211, . . . 21m.
The inserts 111, 112, . . . , 11n of at least two resonator chambers 61_1, . . . , 61_m, to 6n_m, . . . , 6n_m which are not directly adjacent each have one opening 501, 502. The at least two openings 501, 502 are connected to each other by a channel 51, and this channel 51 preferably runs parallel to the signal transmission direction 211, . . . 21m—that is, parallel to the central axis 12. This channel 51 runs at least partially inside the housing wall 5. It is also possible for the parallel routing of this channel 51 to be entirely inside the housing wall 5. It is also possible that this channel 51 does not run entirely inside the housing wall 5, but rather solely through the inserts 111, 112, . . . , 11n and the separators 91, 92, . . . 9n−1 which are situated between the same.
An electrical line 52 runs inside this channel 51, and the electrical line 52 couples the at least two resonator chambers 61_m, 63_m to each other capacitively and/or inductively. The at least two resonator chambers 61_m, 63_m are part of a signal transmission path even without the overcoupling. A first end 531 of the electrical conductor 52 is connected to the first separator 91. The first end 531 of the electrical conductor 52 in this case preferably runs parallel to the signal propagation direction 211, . . . 21m, and therefore parallel to the central axis 12. A second end 532 of the electrical conductor 52 is galvanically connected to the third separator 93. The second end 532 likewise preferably runs parallel to the signal propagation direction 211, . . . 21m, and therefore parallel to the central axis 12. The first and the second end 531, 532 can be connected to the respective separator 91, 92, . . . 9n−1, for example by means of a soldered connection. An overcoupling between two resonators inside the resonator chambers 61_1, . . . , 61_m, to 6n_1, . . . , 6n_1 s achieved by the electrical conductor 52, such that as a result it is possible to achieve a steeper filter flank of the multiplex filter 1.
The electrical conductor 52 which runs inside the channel 51 is electrically insulated and held in its position in the same preferably by dielectric spacer elements, which are not illustrated, of the walls which enclose the channel 51.
However, a first end 531 of the electrical conductor 52 can also be connected to the housing cover 4, as shown by a dashed line.
A second end 532 of the electrical conductor 52 can also be connected to the second separator 92, as shown by a dashed line.
The first dielectric 81 and the third dielectric 83, wherein an overcoupling should take place between the resonator chambers 61_m, 63_m thereof, preferably have a slot 80 passing through the same longitudinally. This slot 80 can be made in the ceramic dielectric 81, 82, . . . , 8n by means of a diamond saw, for example. At least the first end 531 and the second end 532 of the electrical conductor 52 are arranged inside this slot 80.
So that the filter properties do not change during operation, the elements arranged inside the multiplex filter 1 are secured from rotating. This is performed by multiple anti-turning elements 62 which prevent rotation. The anti-turning elements 62 can be a combination of a projection and a receptacle opening. By way of example, the housing cover 4 can have a projection which engages in a corresponding receptacle opening inside the first insert 111. The anti-turning elements 62 are preferably attached between at least one of the n−1 separators 91, 92, . . . 9n−1 and the at least one insert 111 and/or the adjacent dielectric 81, 82, . . . , 8n. However, preferably one anti-turning element 62 is attached in each case between the housing base 3 and/or the housing cover 4 and/or the housing wall 5 and the insert 111 in the first filter chamber 71 and the insert 11n in the nth filter chamber 7n, the same preventing the elements which are arranged next to the common connection 14 and/or the m signal line connections 151, . . . , 15m from turning with respect to each other. This also prevents the elements which are arranged further inside the multiplex filter 1 from rotating.
The multiplex filter 1 is preferably realized with a stacked construction in which all filter chambers 71, 72, . . . , 7n are arranged one above the other. The anti-turning elements 62 in this case prevent change in the electrical properties of the individual resonator chambers 61_1, . . . , 61_m, to 6n_m, . . . , 6n_m inside the filter chambers 71, 72, . . . , 7n, including, for example, the resonance frequencies.
Then the method step S2 is carried out. In method step S2, the reflection factor is measured on the common connection 14 and/or on at least one, and preferably on all, signal line connections 151, . . . , 15m. The measured reflection factor is determined solely from the geometric properties of the first and the nth resonator 61, 6n.
Then the method step S3 is carried out. In method step S3, the resonance frequency and/or the coupling bandwidth of at least one, and preferably all, of the resonators in the resonator chambers 61_1, . . . , 61_m, to 6n_1, . . . , 6n_m of the first and the nth filter stages 71, 7n are adjusted to a certain value. In alternation with the above, the method step S2 is carried out in order to measure the modified reflection factor again, to then determine whether method step S3 must be carried out again, or whether the adjusted values for the resonance frequency and/or the coupling bandwidth already correspond to the desired values.
The tuning of the multiplex filter 1 is performed from the outside in—that is, starting with the resonators which are directly coupled to the common connection or to the m signal line connections 151, . . . , 15m, i.e. the resonators in the resonator chambers 61_1, . . . , 61_m and 6n_1, . . . , 6n_m which are arranged on the common connection or on the m signal line connections 151, . . . , 15m. Further resonators or resonator chambers 62_1, . . . , 62_m, to 6n-1_1, . . . , 6n−1_m of the filter chambers 71, 72, . . . , 7n are successively connected one after the other by opening the respective coupling openings. This process is described in
Subsequently, the method step S5 is carried out. In method step S5, the value of X is increased by 1. Then the method step S6 is carried out, in which the method steps S1 S2, S3, S4, S5 are carried out again, in particular until all coupling openings 10 are opened. This means that, subsequently, when viewing
Next, the value of X is once again increased by 1—that is, the method step S5 is carried out again.
In
This is represented in the flow chart in
In method step S7, the coupling openings 10 of the Xth separator and the coupling openings 10 of the X+1th separator are closed. In the embodiment in
Instead of this, or as an alternative, in the method step S8, the coupling opening 10 of the X+1th separator is opened and the coupling openings 10 of the Xth separator are closed. In the case of the embodiment in
The resonance frequencies and/or the coupling bandwidths of the resonators in the resonator chambers of the filter chamber in the center of the multiplex filter 1 must be adjusted in such a manner that an acceptable value is reached both for the reflection factor on the common connection 14 and for the reflection factors on one, and preferably on all, of the m signal line connections 151, . . . , 15m. It is possible that compromises will need to be found in this case.
Next, the method step S9 is carried out, and the coupling openings of the Xth and the X+1th separator are opened. In this configuration, all coupling openings 10 in all separators 91, 92, . . . 9n−1 are open. This configuration arises automatically after the flow chart in
In the event that at least one, and preferably m coupling openings are open in each separator 91, 92, . . . 9n−1, the method steps S2, S10, and S3 are carried out, as illustrated in the flow chart in
Subsequently, the method step S10 is carried out. In method step S10, the forward transmission factor and/or the reverse transmission factor are determined.
Next, the resonance frequency and/or the coupling bandwidth are adjusted and or finely adjusted to a certain value. This occurs in the method step S3. The method steps S2 and S10 can be repeated as long as the desired target value for the resonance frequency and/or the coupling bandwidth has not yet been reached in the method step S3.
As an alternative or in addition to the method step S11, the method step S12 can be carried out. In method step S12, a separator 91, 92, . . . 9n−1 can be rotated such that the coupling openings 10 have another arrangement. It is also possible for the separator 91, 92, . . . 9n−1 to be exchanged for another, wherein the coupling openings then have another arrangement and/or another number and/or another size and/or another geometry.
Optionally, or in addition to the method steps S11 and/or S12, the method step S13 can be carried out. A change of the resonance frequency and/or the coupling bandwidth can also be achieved by a further rotating of at least one tuning element 401_1, . . . , 401_m, to 40n_1 . . . , 40n_m in or out of the respective resonator chamber 61_1, . . . , 61_m, to 6n_1, . . . , 6n_m. In addition, more than one tuning element 401_1, . . . , 401_m, to 40n_1 . . . , 40n_m can be rotated into or out of a resonator chamber 61_1, . . . , 61_m, to 6n_1, . . . , 6n_m.
Alternatively, or in addition to the method steps S11 S12 and/or S13, the method step S14 can be carried out. In method step S14, at least one dielectric 81, 82, . . . , 8n in a filter chamber 71, 72, . . . , 7n can be exchanged for another dielectric 81, 82, . . . , 8n which has modified dimensions, particularly height and/or diameter.
In method step S1, or each time that coupling openings 10 are to be closed, this is preferably done by exchanging the respective separator 91, 92, . . . 9n−1 for another which does not have any coupling openings 10.
The dividing devices 131, 132, . . . , 13n are preferably, and fundamentally, constructed as components which are separate from the housing 2, but can nonetheless be connected to the housing 2 as a single piece.
The n dielectrics 81, 82, . . . , 8n as well are preferably constructed as components which are separate from the housing 2. These could also be connected to the housing 2 as a single piece.
In addition, the resonator chambers 61_1, . . . , 61_m, to 6n_1, . . . , 6n_m are free of any manner of inner resonator conductors which are galvanically connected by one end to the housing 2 and which extend into the resonator chambers 61_1, . . . , 61_m, to 6n_1, . . . , 6n_m, and end in the resonator chambers 61_1, . . . , 61_m, to 6n_1, . . . , 6n_m at the other end. Such a construction would be conventional in cavity resonators.
The invention is not limited to the described embodiments. In the context of the invention, all described and/or indicated features can be freely combined with each other.
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