Multiplex filter with dielectric substrate for the transmission of TM modes in the transverse direction

A multiplex filter has at least n filter chambers which are surrounded by a housing and/or at least one insert positioned in the housing. A metal dividing device is constructed in each of the n filter chambers, dividing each filter chamber into m resonator chambers, wherein m≥2. 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.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from German Patent Application No. 10 2015 005 613.1 filed Apr. 30, 2015, incorporated herein by reference.

FIELD

The technology herein relates to a multiplex filter which is particularly suitable for the transmission of TM modes in the transverse direction.

BACKGROUND

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,

DETAILED DESCRIPTION OF EXAMPLE NON-LIMITING EMBODIMENTS

FIG. 1shows one embodiment of the multiplex filter1in an exploded view. The multiplex filter1has a housing2which has a housing base3, a housing cover4spaced apart from the housing base3, and a circumferential housing wall5between the housing base3and the housing cover4. For better viewability, inFIG. 1the housing2, together with the housing base3, the housing cover4, and the housing wall5, are not shown. These are shown beginning inFIG. 6A. Both the housing cover4and the housing base3have at least one opening via which the one common connection14and the up to m signal line connections15can be inserted. In this case, a common connection14is fed to the multiplex filter1through the opening of the housing cover4, and up to m further signal line connections15are fed through m openings in the housing base3. The opening in the housing cover4need not be arranged in the center of the housing cover4. It is also possible that the opening is arranged off-center.

The multiplex filter1also has n filter chambers71,72, . . . ,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 chambers71,72, . . . ,7nare arranged up to m resonator chambers61_1,61_2, . . . ,61_m, to6n_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 as61_m, the first subscript number—in this case “1”—indicates the number of the filter chamber71,72, . . . ,7nand 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 chamber71,72, . . . ,7nand can therefore range up to “m.” Using such a nomenclature, it is possible to address all resonator chambers61_1,61_2, . . . ,61_m, to6n_1,6n_2, . . . ,6n_minside the filter chambers71,72, . . . ,7n.

The individual resonator chambers61_1,61_2, . . . ,61_m, to6n_1,6n_2, . . . ,6n_mof each filter chamber71,72, . . . ,7nare decoupled from each other by means of n dividing devices131,132, . . . ,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 devices131,132, . . . ,13nare preferably arranged parallel to the central axis12and/or parallel to the m signal transmission devices211, . . .21m, and therefore divide each of the n filter chambers71,72, . . . ,7nparallel to the central axis12into m resonator chambers61_1,61_2, . . . ,61_m, to6n_1,6n_2, . . . ,6n_m.

The n dividing devices131,132, . . . ,13nare, by way of example, formed by a plurality of through-connections inside the dielectric81,82, . . . ,8n. The through-connections are arranged in the dielectrics81,82, . . . ,8n, the same arranged in the filter chambers71,72, . . . ,7n, parallel to, or at least with one component parallel to, the central axis12and/or to one of the signal transmission directions212, . . .21m. As a result, the n dielectrics81,82, . . . ,8nare divided into m parts, and each of the m parts is in one of the m resonator chambers61_1,61_2, . . . ,61_m, to6n_1,6n_2, . . . ,6n_mof a filter chamber71,72, . . . ,7n. It can also be said that the m resonator chambers61_1,61_2, . . . ,61_m, to6n_1,6n_2, . . . ,6n_mare created by the n dividing devices131,132, . . . ,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 dielectric81,82, . . . ,8nto be composed inside each filter chamber71,72, . . . ,7nof m parts which are preferably the same size, wherein each of the m parts is found in one of the m resonator chambers61_1,61_2, . . . ,61_m, to6n_1,6n_2, . . . ,6n_min a filter chamber71,72, . . . ,7n. A metal layer is formed inside each filter chamber71,72, . . . ,7nbetween the m parts, forming the dividing device131,132, . . . ,13n. As a result, the individual resonator chambers61_1,61_2, . . . ,61_m, to6n_1,6n_2, . . . ,6n_minside a filter chamber71,72, . . . ,7nare separated from each other, wherein the metal layer is arranged parallel to, or at least with one component parallel to, the central axis12or to a signal transmission direction211, . . .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 dielectric81,82, . . . ,8nwhich 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 dielectrics81,82, . . . ,8ninside the filter chamber71,72, . . . ,7nare made of a different material. The same is naturally also true for the n dielectrics81,82, . . . ,8nthemselves, in the event they are constructed as separate parts.

The m parts of one of the n dielectrics81,82, . . . ,8n, or the n dielectrics81,82, . . . ,8nconstructed as separate parts, have one or more recesses16which are preferably filled with air. Rather than being filled with air, these recesses16can also be filled with a material which has a permeability which differs from a permeability of the n dielectrics81,82, . . . ,8n.

The individual filter chambers71,72, . . . ,7nare separated from each other by separators91,92, . . .9n−1. These separators91,92, . . .9n−1are preferably separating disks. These separators91,92, . . .9n−1consist of an electrically conductive material or are coated with such a material. Each of these separators91,92, . . .9n−1has at least one coupling opening10. The size, the geometric shape, the number, and the arrangement of the coupling opening10inside the respective separator91,92, . . .9n−1can be selected arbitrarily and can differ from one separator91,92, . . .9n−1to another separator91,92, . . .9n−1. The diameter of the coupling openings10is, 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 separators91,92, . . .9n−1are preferably thinner that the dielectrics81,82, . . . ,8n. The separators91,92, . . .9n−1are preferably only several millimeters thick. They are preferably thinner than 3 millimeters, and they are more preferably thinner than 2 millimeters.

Each filter chamber71,72, . . . ,7ncan also have at least one insert111,112, . . . ,11n. Such an insert111,112, . . . ,11nis preferably a ring which is preferably supported in a form-fitting manner by its outer surface on an inner surface of the housing wall5. Such an insert111,112, . . . ,11n, which is electrically conductive, can be used to adjust the volume of the filter chamber71,72, . . . ,7nand therefore to adjust the volume of the individual resonator chambers61_1,61_2, . . . ,61_m, to6n_1,6n_2, . . . ,6n_m, and thereby enables the adjustment of the resonance frequency of the multiplex filter.

In the embodiment inFIG. 1, a central axis12is also illustrated which runs through the multiplex filter1. The central axis12in this case passes through the entire housing2, particularly the housing base3and the housing cover4. Preferably, all filter chambers71,72, . . . ,7nare intersected by the central axis12either centrally or off-center. In the embodiment inFIG. 1, there are two signal transmission directions211and212, because m assumes the value of “2.” There are fundamentally “m” signal transmission directions211,212, . . . ,21m. The signal transmission directions211,212, . . . ,21mpreferably run parallel to the central axis12. The filter chambers71,72, . . . ,7nin this case are arranged one above the other. Each filter chamber71,72, . . . ,7ntherefore has a maximum of two directly adjacent filter chambers71,72, . . . ,7n, and the filter chambers71,72, . . . ,7nare separated from each other by each respective separator91,92, . . .9n−1. The individual resonators of the resonator chambers61_1,61_2, . . . ,61_m, to6n_1,6n_2, . . . ,6n_mof two filter chambers71,72, . . . ,7ncan only be coupled via the respective coupling openings inside the separators91,92, . . .9n−1. It is not possible to couple the individual resonators of the resonator chambers61_1,61_2, . . . ,61_m, to6n_1,6n_2, . . . ,6n_mof a filter chamber71,72, . . . ,7n, and/or the coupling is weaker by more than a factor of 100, and preferably by more than a factor of 1000, than the coupling of two resonators of two resonator chambers61_1,61_2, . . . ,61_m, to6n_1,6n_2, . . . ,6n_m6which are coupled to each other via the coupling openings10inside the separators91,92, . . .9n−1.

The individual resonators of the resonator chambers61_1,61_2, . . . ,61_m, to6n_1,6n_2, . . . ,6n_min this case are coupled parallel to the respective signal transmission direction211,212, . . . ,21m. The H field20in this case propagates perpendicular to the respective signal transmission direction211,212, . . . ,21m.

All filter chambers71,72, . . . ,7nare intersected by the central axis12. The central axis12in this case meets the end face of each dielectric81,82, . . . ,8ninside the filter chambers71,72, . . . ,7nat a right angle.

The inner wall of the housing5of the multiplex filter1is preferably cylindrical in cross-section. The same is also true for the inner wall of each insert111,112, . . . ,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.

InFIG. 1, this is true both when the signal transmission direction211, . . .21mruns from one or from more of the m signal line connections151,152, . . . ,15mto the common connection14, and when the signal transmission direction211, . . .21mruns from the common connection14to one or more m signal line connections151,152, . . . ,15m.

The n−1 separators91,92, . . .9n−1preferably comprise a separating plate which is made of metal. The coupling openings10can be created in this separating plate by means of a laser or a punching process, or a milling process, by way of example.

FIG. 2shows an illustration which explains that a magnetic field (H field) is arranged perpendicular to the signal transmission direction211. The magnetic field lines in this case propagate radially outward about the signal transmission direction211. The central axis12and the signal transmission direction211in the embodiment inFIG. 1do not cover the same area, but are parallel to each other. The same is also true for the further signal transmission direction211, . . .21mwith respect to the central axis12.

FIG. 3Ashows a cross-section through the first filter chamber71with two resonator chambers61_1,61_m, wherein the dielectric81of a resonator chamber61_1has multiple recesses16.

The volume of the first filter chamber71is bounded by a first insert111, and the first insert111is arranged adjacent thereto on an inner wall of the housing wall5. The common connection14is centered—that is, arranged centrally in the first filter chamber71and coupled to the same. The common connection14couples to the first and second (m=2) resonator chambers61_1,61_m, wherein the first resonator chamber has a plurality of recesses16. These recesses16are preferably filled with air and are arranged symmetrically with respect to an axis A-A′. The axis A-A′ runs transverse to the central axis12and divides the first resonator chamber61_1into two identical regions. The m resonator chambers61_1,61_mof the first filter chamber71are the same size. This is also true for the further m resonator chambers61_1,61_mof the further filter chambers72, . . . ,7n. Also, the m resonator chambers61_1,61_mof the n filter chambers71,72, . . . ,7ncan have different sizes.

The first filter chamber71comprises a region in which the dividing device131only extends through the first dielectric81by a sub-length of the diameter. This forms an opening region30in which the common connection14is coupled to all m resonators of the m resonator chambers61_1,61_min the first filter chamber71. The opening region30has 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 chamber71.

Depending on the desired strength of the coupling in one of the m resonator chambers61_1,61_m, the common connection can be arranged near to one or nearer to the other resonator chamber61_1,61_m, and therefore off-center. The first dividing device131can also be designed in such a manner that the coupling between the common connection14and one of the two resonator chambers61_1,61_mis stronger than the coupling to the other.

FIG. 3Bshows a cross-section through the nth filter chamber7nwith two resonator chambers6n_1,6n_m, wherein the dielectric8nof the filter chamber7nhas a recess16in the region of one resonator chamber6n_1. The figure also shows that the insert11nhas a smaller inner diameter than the insert111inFIG. 3A. This means that the volume of the nth filter chamber7nis less than the volume of the first filter chamber71inFIG. 3A. In contrast toFIG. 3A, there is no opening region30. The signal line connections151,15m(in this case, m=2) are arranged off-center on the housing base3, which is not illustrated, and are therefore off-center on the dielectric8n.

The number of recesses16in each resonator chamber6n_1,6n_mcan partially or entirely differ from the number of the recesses in the other resonator chambers6n_1, 6 nm of the same filter chamber7n.

FIG. 4Ashows a cross-section of the first filter chamber71, wherein the common connection14is coupled to three resonator chambers61_1,61_2,61_mof the first filter chamber71, all of which have the same size. The dividing device131in this case consists of m bars which are arranged apart from each other by a measure of α=360°/m. Again, an opening region30is formed around the common connection14, which in this case is characterized by a diameter rather than by a length, wherein the diameter 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 chamber71. The dividing device131is not constructed inside this opening region30, such that there can be a coupling between the common connection14and the m resonator chambers61_1,61_2,61_m. The points of the dotted opening region30have no through-connections of any kind, and only serve to symbolize the opening region30.

The m resonator chambers61_1,61_2,61_mhave a different number of recesses16which in turn have, at least to some degree, different sizes.

FIG. 4Bshows a cross-section through the nth filter chamber7nwith three resonator chambers6n_1,6n_2,6n_m, each of which are the same size. The m resonator chambers6n_1,6n_2, 6 nm are not coupled to each other. One of the m signal line connections151,152, . . . ,15mis situated inside each of these m resonator chambers6n_1,6n_2, 6 nm to establish a coupling in or out of the same. The dielectric8mhas a different number of recesses16, which differ at least to some degree in their sizes, and the recesses16are each arranged in different resonator chambers6n_1,6n_2,6n_m.

The recesses16can pass entirely through the dielectric8m, or rather can be formed as blind holes.

FIG. 5Ashows a cross-section through the first filter chamber71with four resonator chambers61_1,61_2,61_3,61_m, wherein the insert111has a wall segment45with thicknesses which differs from the thickness of the other wall segments such that the volumes of the at least one resonator chamber61_3differ from the volumes of the other resonator chambers6n_1,6n_2,6n_m. The thicknesses of the at least one wall segment45can also alternate. By way of example, in the cross-section shown inFIG. 5A, the wall segment can have a sawtooth profile.

The opening region30is selected in such a manner that the common connection14is coupled to all m resonators of the m resonator chambers61_1,61_2,61_3,61_m, wherein the m resonator chambers611,61_2,61_3,61_mhave a different number of recesses16, 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 walls16can 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 recesses16can also be rounded off, for example.

The dividing device131consists 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°.

FIG. 5Bshows a cross-section through the nth filter chamber7nwith four resonator chambers6n_1,6n_2,6n_3,6n_m, each of which are the same size but have different numbers of recesses16. The dividing device11nprevents the individual resonator chambers6n_1,6n_2,6n_3,6n_mfrom being coupled to each other. The dividing device11nconsists of m bars which are preferably connected to each other in the center—that is, in the center of the nth filter chamber7n. One of the n signal line connections151,152,153,15mis coupled to each of the m resonator chambers6n_1,6n_2,6n_3,6n_m.

FIG. 6Ashows a longitudinal cross-section through the multiplex filter1, showing multiple filter chambers71,72, . . . ,7neach with resonator chambers61_1,61_2, . . . ,61_m, to6n_1,6n_2, . . . ,6n_mwhich are coupled to each other via coupling openings10in the separator91,92, . . .9n−1. The common connection14is inserted through an opening in the housing cover4into the first filter chamber71. On the other side, each of the m signal line connections151, . . . ,15mis guided through one opening in the housing base3and coupled to the m resonators6n_1, . . . ,6n_mof the nth filter chamber7n.

There is no distance between the first dielectric81and the housing cover4. The same is true for the nth dielectric8nwhich is likewise in contact with the housing base3via its end face. There is no distance between the nth dielectric8nand the housing base3. The elements of the high-frequency filter1—that is, by way of example, the inserts111, . . . ,11n, the dielectrics81, . . . ,8n, the separators91, . . . ,9n−1and the housing cover4and/or the housing base3—are preferably press-fit to each other. This press fitting is expressed, by way of example, by the fact that the individual dielectrics81,82, . . . ,8npartially project into the individual separators91,92, . . .9n−1.

The first dielectric81in the first filter chamber71has a depression into which the common connection14projects. As a result, it is in contact with the first dielectric81. The same is true for the nth dielectric8nin the nth filter chamber7nas regards the m signal line connections151, . . . ,15m.

In the embodiment inFIG. 6A, the individual dielectrics81,82, . . . ,8nentirely fill in the volumes of the respective filter chambers71,72, . . . ,7n. The dielectrics81,82, . . . ,8nin this embodiment have the same dimensions with respect to their heights, but differ from each other as concerns their respective diameters. They could also have the same diameter. In this case, the inserts111,112,113,114, . . . ,11nwould all have the same inner diameter. InFIG. 6A, the outer diameter is the same for all of the inserts111,112,113,114, . . . ,11n, but the wall thickness—that is, the inner diameter—is different. This means that the volumes of the individual filter chambers71,72, . . . ,7nare different. The outer surfaces of the inserts111,112, . . . ,11n—that is, the peripheral wall—is in contact with an inner surface of the housing wall5. The electrically conductive housing cover4is in electrical contact with both an end face of the housing5and an end face of the first insert111. The housing base3is likewise in electrical contact with the housing5and an end face of the nth insert11n.

It is hereby noted that the housing5can be electrically conductive—that is, can be made of metal, for example—but need not be. In other words, the housing5can consist of any other arbitrary material—particularly a non-conductive material such as a dielectric or plastic. The function of the housing5is to hold the components situated in the interior of the housing5together mechanically, and fix the same mechanically in place. In any case, the housing5can only consist of a dielectric if it is ensured that the filter chambers71,72, . . . ,7nare shielded from the surroundings of the multiplex filter1. Such a shielding can be realized, by way of example, by the inserts111,112, . . . ,11n.

The separators91,92, . . .9n−1have an outer diameter which preferably corresponds to an inner diameter of the housing wall5. This means that an outer surface—that is, a peripheral wall of each separator91,92, . . .9n−1—contacts the inner surface of the housing—that is, has a mechanical contact with the same. The coupling openings10of a separator91,92, . . .9n−1can differ from the coupling openings of the other separator91,92, . . .9n−1with respect to their arrangement—that is, their orientation and/or their number and/or their size and/or their cross-section shape. The coupling openings10of a separator91,92, . . .9n−1can 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 inFIG. 6A, the coupling openings10of the individual separators91,92, . . . ,9n−1have a different diameter, and are arranged by way of example at different points on the separators91,92, . . . ,9n−1. The number of the coupling openings10can also differ. The coupling openings10connect the individual resonator chambers61_1,61_2, . . . ,61_m, to6n_1,6n_2, . . . ,6n_mof the individual filter chambers71,72, . . . ,7nto each other, and they are surrounded by the dielectric81,82, . . . ,8nof the adjacent filter chamber71,72, . . . ,7n. An electrically conductive insert111,112, . . . ,11ncannot cover a coupling opening10. It is also possible that the cross-section shape of the individual coupling openings10varies over the length—that is, over the height. There is typically no hollow space between the individual separators91,92, . . .9n−1and the inserts111,112, . . . ,11n. The same is preferably true for the first insert111and the housing cover4, as well as for the nth insert11nand the housing base3.

There is likewise typically no hollow space between the inserts111,112, . . . ,11nalong with the separator91,92, . . .9n−1and the housing wall5.

The inserts111,112, . . . ,11nare also preferably press-fitted and/or soldered to the corresponding separators91,92, . . .9n−1with 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 filter1remain unchanged over a longer period of time.

The dividing devices131, . . . ,13nare likewise illustrated. The same divide the filter chambers71,72, . . . ,7ninto the m resonator chambers61_1, . . . ,61_m, to6n_1, . . . ,6nover the entire thickness of the dielectrics81, . . . ,8n. The first dividing device is illustrated with a dashed line because the opening region30for the shared coupling with the common connection14is also indicated in the same.

FIG. 6Bshows a longitudinal cross-section of a further embodiment of the multiplex filter1. The first dielectric81is arranged with its end face spaced apart from the housing cover4.

The common connection14contacts the end face of the first dielectric81. The common connection therefore is in contact with the first dielectric81. The further m signal line connections151, . . . ,15mlikewise contact an end face of the nth dielectric8nand are in contact with the same. The end face of the nth dielectric8nis likewise spaced apart from the housing base3and does not touch the same. As such, it is not in contact with the same.

In the embodiment inFIG. 6B, the individual dielectrics81,82, . . . ,8ndo not entirely fill in the volumes of the respective filter chambers71,72, . . . ,7n.

The distance from the at least one tuning element401_1, . . . ,401_m, to40n_1. . . ,40n_mto the respective dielectric81,82, . . . ,8nin the filter chamber71,72, . . . ,7ncan be reduced to such an extent that it touches the dielectric81,82, . . . ,8n—that is, is in contact with the same.

The nth dielectric8nin the nth filter chamber7nalso has an indentation such that the nth tuning element40n−1, . . . ,40n−mcan dip into the nth dielectric8n.

FIG. 7Bshows a longitudinal cross-section of a further embodiment of the multiplex filter1. The dielectric81in the first filter chamber71has a recesses which passes through the same, wherein the common connection14extends through said recess. The common connection14in this case comes into direct contact with the first separator91. The same is also true for at least one or all of the m signal line connections151, . . . ,15mwhich extend through one or m recesses in the nth dielectric8nof the nth filter chamber7n, and are in contact with the n−1th separator9n−1.

The part of the common connection14or the m signal line connections151, . . . ,15mwhich is in contact with the respective dielectric81,8nor with the respective separator91,9n−1runs parallel to the central axis12and/or parallel to the signal transmission direction211, . . . ,21m. The other parts of the common connection14or the m signal line connections151, . . . ,15mneed not necessarily run parallel to the signal transmission direction211, . . .21mand/or the central axis12. The parts of the common connection14or the m signal line connections151, . . . ,15mwhich are situated inside the first or nth filter chamber71,7nare preferably those which run parallel to the signal transmission direction211, . . .21m.

FIG. 8shows a longitudinal cross-section of a further embodiment of the multiplex filter1, wherein there is an overcoupling between the two resonator chambers61_1, . . . ,61_m, to6n_1, . . . ,6n_mwhich are arranged in filter chambers71,72, . . . ,7nwhich are not adjacent to each other, wherein additional anti-turning elements62are arranged in the housing.

The inserts111,112, . . . ,11nof at least two resonator chambers61_1, . . . ,61_m, to6n_m, . . . ,6n_mwhich are not directly adjacent each have one opening501,502. The at least two openings501,502are connected to each other by a channel51, and this channel51preferably runs parallel to the signal transmission direction211, . . .21m—that is, parallel to the central axis12. This channel51runs at least partially inside the housing wall5. It is also possible for the parallel routing of this channel51to be entirely inside the housing wall5. It is also possible that this channel51does not run entirely inside the housing wall5, but rather solely through the inserts111,112, . . . ,11nand the separators91,92, . . .9n−1which are situated between the same.

An electrical line52runs inside this channel51, and the electrical line52couples the at least two resonator chambers61_m,63_mto each other capacitively and/or inductively. The at least two resonator chambers61_m,63_mare part of a signal transmission path even without the overcoupling. A first end531of the electrical conductor52is connected to the first separator91. The first end531of the electrical conductor52in this case preferably runs parallel to the signal propagation direction211, . . .21m, and therefore parallel to the central axis12. A second end532of the electrical conductor52is galvanically connected to the third separator93. The second end532likewise preferably runs parallel to the signal propagation direction211, . . .21m, and therefore parallel to the central axis12. The first and the second end531,532can be connected to the respective separator91,92, . . .9n−1, for example by means of a soldered connection. An overcoupling between two resonators inside the resonator chambers61_1, . . . ,61_m, to6n_1, . . . ,6n_1s achieved by the electrical conductor52, such that as a result it is possible to achieve a steeper filter flank of the multiplex filter1.

The electrical conductor52which runs inside the channel51is 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 channel51.

However, a first end531of the electrical conductor52can also be connected to the housing cover4, as shown by a dashed line.

A second end532of the electrical conductor52can also be connected to the second separator92, as shown by a dashed line.

The first dielectric81and the third dielectric83, wherein an overcoupling should take place between the resonator chambers61_m,63_mthereof, preferably have a slot80passing through the same longitudinally. This slot80can be made in the ceramic dielectric81,82, . . . ,8nby means of a diamond saw, for example. At least the first end531and the second end532of the electrical conductor52are arranged inside this slot80.

So that the filter properties do not change during operation, the elements arranged inside the multiplex filter1are secured from rotating. This is performed by multiple anti-turning elements62which prevent rotation. The anti-turning elements62can be a combination of a projection and a receptacle opening. By way of example, the housing cover4can have a projection which engages in a corresponding receptacle opening inside the first insert111. The anti-turning elements62are preferably attached between at least one of the n−1 separators91,92, . . .9n−1and the at least one insert111and/or the adjacent dielectric81,82, . . . ,8n. However, preferably one anti-turning element62is attached in each case between the housing base3and/or the housing cover4and/or the housing wall5and the insert111in the first filter chamber71and the insert11nin the nth filter chamber7n, the same preventing the elements which are arranged next to the common connection14and/or the m signal line connections151, . . . ,15mfrom turning with respect to each other. This also prevents the elements which are arranged further inside the multiplex filter1from rotating.

The multiplex filter1is preferably realized with a stacked construction in which all filter chambers71,72, . . . ,7nare arranged one above the other. The anti-turning elements62in this case prevent change in the electrical properties of the individual resonator chambers61_1, . . . ,61_m, to6n_m, . . . ,6n_minside the filter chambers71,72, . . . ,7n, including, for example, the resonance frequencies.

FIG. 9shows a longitudinal cross-section of a further embodiment of the multiplex filter1. The separator91,92, . . .9n−1in this case is an integral component of each dielectric81,82, . . . ,8n. This means that one or both end faces of each of the n dielectrics81,82, . . . ,8nis coated with a metal layer. This metal layer then constitutes one of the n−1 separators91,92, . . .9n−1. A recess90inside the metal layer—that is, inside the coating—is then a coupling opening10between two resonator chambers61_1, . . . ,61_m, to6n_1, . . . ,6n_m. Adjacent dielectrics81,82, . . . ,8neach have the recesses90inside the coating of the metal layer at the same positions, to thereby enable a coupling in the signal propagation direction211, . . .21m.

FIG. 10shows a flow chart which explains how the resonance frequency and/or the coupling bandwidth of at least one or all of the resonators in the resonator chambers61_1, . . . ,61_m, to6n_1, . . . ,6n_mof the first and the nth filter chambers71,7nare adjusted in order to tune the multiplex filter1. At the start, a counter variable X is defined as 0. Then the method step S1is carried out. In method step S1, all coupling openings10of the 1+Xth separator and/or the n−1 separator are closed. In the longitudinal cross-section shown inFIG. 6A, this would be the coupling openings10in the first separator91and in the last separator9n−1.

Then the method step S2is carried out. In method step S2, the reflection factor is measured on the common connection14and/or on at least one, and preferably on all, signal line connections151, . . . ,15m. The measured reflection factor is determined solely from the geometric properties of the first and the nth resonator61,6n.

Then the method step S3is 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 chambers61_1, . . . ,61_m, to6n_1, . . . ,6n_mof the first and the nth filter stages71,7nare adjusted to a certain value. In alternation with the above, the method step S2is carried out in order to measure the modified reflection factor again, to then determine whether method step S3must 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 filter1is 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 connections151, . . . ,15m, i.e. the resonators in the resonator chambers61_1, . . . ,61_mand6n_1, . . . ,6n_mwhich are arranged on the common connection or on the m signal line connections151, . . . ,15m. Further resonators or resonator chambers62_1, . . . ,62_m, to6n-1_1, . . . ,6n−1_mof the filter chambers71,72, . . . ,7nare successively connected one after the other by opening the respective coupling openings. This process is described inFIG. 11, by way of example.

FIG. 11shows a further flow chart which explains how the resonance frequencies and/or the coupling bandwidths are adjusted for the further resonators of the resonator chambers62_1, . . . ,62_m, to6n−1_1, . . . ,6n−1_min order to tune the multiplex filter. In the event that the resonance frequencies and/or the coupling bandwidths have been adjusted for the first resonators in the resonator chambers61,6nof the first and/or nth filter chambers71,7n, the method step S4is carried out. In method step S4, at least one coupling opening10is opened for each resonator chamber61_1, . . . ,61_mand6n_1, . . . ,6n_mof the 1+Xth separator and/or the n−1−Xth separator. In the longitudinal cross-section shown inFIG. 6A, this would be the coupling openings10in the separators91and9n−1.

Subsequently, the method step S5is carried out. In method step S5, the value of X is increased by 1. Then the method step S6is carried out, in which the method steps S1S2, S3, S4, S5are carried out again, in particular until all coupling openings10are opened. This means that, subsequently, when viewingFIG. 6A, the coupling openings10of the separator92and the coupling openings10of the separator93are closed. The reflection factor is again measured on the common connection14and/or on at least one, and preferably on all m signal line connections151, . . . ,15m. Then, the resonance frequency and/or the coupling bandwidth of the resonators in the filter chambers72,7n−1, and preferably additionally the resonators in the filter chambers71,7n−1, are adjusted.

Next, the value of X is once again increased by 1—that is, the method step S5is carried out again.

InFIG. 6Ait can be seen that there is an uneven number of filter chambers71,72, . . . ,7n. In this method, to tune the multiplex filter1, the resonators of the resonator chambers63_1, . . . ,63_mof the central filter chamber73—that is, the resonators in the filter chamber which is arranged in the center of the multiplex filter1—are used one time for calculating the reflection factor on the common connection14, and one time for calculating the reflection factor on the at least one, and preferably on all, m signal line connections151, . . . ,15m.

This is represented in the flow chart inFIG. 12which explains how the resonance frequencies and/or the coupling bandwidths for the resonators in the resonator chambers63_1, . . . ,63_nof the filter chamber73in the center of the multiplex filter1are adjusted. In the event that X reaches the value (n−1)/2, which corresponds to the value of “2” in the embodiment inFIG. 6A, the method steps S7and/or S8and S9are carried out.

In method step S7, the coupling openings10of the Xth separator and the coupling openings10of the X+1th separator are closed. In the embodiment inFIG. 6A, the coupling openings10in the separator92would be open, and those in the separator93would be closed. Next, the reflection factor is measured on the common connection14and the resonance frequency and/or the coupling bandwidth is accordingly adjusted.

Instead of this, or as an alternative, in the method step S8, the coupling opening10of the X+1th separator is opened and the coupling openings10of the Xth separator are closed. In the case of the embodiment inFIG. 6A, the coupling openings10in the separator92would be closed, whereas the coupling openings10inside the separator93would be open. Next, the method step S2is carried out again, and the reflection factor is measured on one or preferably on all m signal line connections151, . . . ,15m. Next, the method step S3is carried out, wherein the resonance frequency and/or the coupling bandwidth are adjusted.

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 filter1must be adjusted in such a manner that an acceptable value is reached both for the reflection factor on the common connection14and for the reflection factors on one, and preferably on all, of the m signal line connections151, . . . ,15m. It is possible that compromises will need to be found in this case.

Next, the method step S9is carried out, and the coupling openings of the Xth and the X+1th separator are opened. In this configuration, all coupling openings10in all separators91,92, . . .9n−1are open. This configuration arises automatically after the flow chart inFIG. 11has run through if there is an even number of filter chambers71,72, . . . ,7n.

In the event that at least one, and preferably m coupling openings are open in each separator91,92, . . .9n−1, the method steps S2, S10, and S3are carried out, as illustrated in the flow chart inFIG. 13. The method step S2, which has already been explained with reference toFIG. 10, is carried out. In this method step, a reflection factor is measured on the common connection14and/or on at least one, and preferably on all, m signal line connections15m.

Subsequently, the method step S10is 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 S2and S10can 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.

FIG. 14shows a further flow chart which explains which measures can be used to modify the resonance frequency and/or the coupling bandwidth inside a resonator in a resonator chamber61_1, . . . ,61_m, to6n_1, . . . , 6 nm. The following method steps can be carried out within the method step S3, individually or in combination with each other in any desired sequence. Method step S11describes how the resonance frequency and/or the coupling bandwidth can be adjusted by changing the diameter of the respective filter chamber71,72, . . . ,7nby exchanging the insert111,112, . . . ,11nfor another one with different dimensions—particularly with a different inner diameter. The inserts111,112, . . . ,11nin this case can also have wall segments45which differ from other wall segments of the same insert111,112, . . . ,11nby a modified thickness, such that the resonance frequencies of the individual resonator chambers61_1, . . . ,61_m, to6n_1, . . . ,6n_mof one filter chamber71,72, . . . ,7ndiffer from each other.

As an alternative or in addition to the method step S11, the method step S12can be carried out. In method step S12, a separator91,92, . . .9n−1can be rotated such that the coupling openings10have another arrangement. It is also possible for the separator91,92, . . .9n−1to 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 S11and/or S12, the method step S13can 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 element401_1, . . . ,401_m, to40n_1. . . ,40n_min or out of the respective resonator chamber61_1, . . . ,61_m, to6n_1, . . . ,6n_m. In addition, more than one tuning element401_1, . . . ,401_m, to40n_1. . . ,40n_mcan be rotated into or out of a resonator chamber61_1, . . . ,61_m, to6n_1, . . . ,6n_m.

Alternatively, or in addition to the method steps S11S12and/or S13, the method step S14can be carried out. In method step S14, at least one dielectric81,82, . . . ,8nin a filter chamber71,72, . . . ,7ncan be exchanged for another dielectric81,82, . . . ,8nwhich has modified dimensions, particularly height and/or diameter.

In method step S1, or each time that coupling openings10are to be closed, this is preferably done by exchanging the respective separator91,92, . . .9n−1for another which does not have any coupling openings10.

The dividing devices131,132, . . . ,13nare preferably, and fundamentally, constructed as components which are separate from the housing2, but can nonetheless be connected to the housing2as a single piece.

The n dielectrics81,82, . . . ,8nas well are preferably constructed as components which are separate from the housing2. These could also be connected to the housing2as a single piece.

In addition, the resonator chambers61_1, . . . ,61_m, to6n_1, . . . ,6n_mare free of any manner of inner resonator conductors which are galvanically connected by one end to the housing2and which extend into the resonator chambers61_1, . . . ,61_m, to6n_1, . . . ,6n_m, and end in the resonator chambers61_1, . . . ,61_m, to6n_1, . . . ,6n_mat 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.