EP2920840A1

EP2920840A1 - Radio-frequency blocking filter

Info

Publication number: EP2920840A1
Application number: EP13792597.0A
Authority: EP
Inventors: Wolfgang Haeupler
Original assignee: Kathrein Austria GmbH
Current assignee: Kathrein Mobilcom Austria GmbH
Priority date: 2012-11-15
Filing date: 2013-11-14
Publication date: 2015-09-23
Anticipated expiration: 2033-11-14
Also published as: US20150303543A1; EP2920840B1; DE102012022433A1; US9923254B2; WO2014075805A1

Abstract

An improved radio-frequency filter is distinguished by the following features: the radio-frequency blocking filter (1) comprises an input terminal (20, 40) and an output terminal (30, 40), wherein the signal line (50) is galvanically connected or capacitively coupled firstly to the input terminal (20, 40) and secondly to the output terminal (30, 40), the signal line (50), with the formation in each case of a capacitive inner conductor and/or resonator coupling (65), runs past the relevant inner conductor (16) through the resonators (10) of the radio-frequency blocking filter (1), in this case the signal line (50) has at least one galvanic isolation location in the form of a capacitive isolation location (60'), the capacitive isolation location (60') is spaced apart from the inner conductors (16) and capacitively coupled thereto, and the resonators (10) and/or the inner conductors (16) are in each case capacitively coupled to the signal line (50).

Description

High frequency blocking filter

The invention relates to a high-frequency cut filter in coaxial design according to the preamble of claim 1.

In radio systems, especially in the mobile sector, a common antenna is often used for transmit and receive signals. The transmit and receive signals each use different frequency ranges, and the antenna must be suitable for transmitting and receiving in both frequency ranges. For the separation of the transmit and receive signals, therefore, a suitable frequency filtering is required with which the transmit signals from the transmitter to the antenna and the reception signals from the antenna to the receiver are forwarded on the one hand. For the division of the transmit and receive signals, high frequency filters in coaxial design are used today.

For example, a pair of high frequency filters may be used, both of which pass a particular frequency band (bandpass filter). Alternatively, a pair of high frequency filters may be used, both of which block a certain frequency band (band elimination filter). Further For example, a pair of high frequency filters may be used, one filter of which filters frequencies below a frequency between transmit and receive bands and blocks frequencies above that frequency (low pass filter) and blocks the other filter frequencies below a frequency between transmit and receive bands and passes frequencies thereabove ( High pass filter). Other combinations of the just mentioned filter types are conceivable. High-frequency filters are often constructed from coaxial resonators, since they consist of milling or casting parts, whereby they are easy to produce. In addition, these resonators ensure a high electrical quality and a relatively high temperature stability.

A high-frequency filter known from the prior art comprises an input terminal and an output terminal, which are galvanically connected to one another via a connecting line. Furthermore, the high-frequency filter comprises at least two coaxial resonators, which are each capacitively coupled to the connecting line, so that the resonators are also capacitively coupled to the input terminal and the output terminal. The coupling points of the resonators with the connecting line must have on the connecting line a distance of one quarter of the wavelength of the high-frequency filter to be filtered center frequency signal, so that the individual resonators are resonantly coupled together. E-GSM signals used in mobile radio use the frequency range of 880-915 MHz for the so-called uplink and the frequency range of 925-960 MHz for the so-called downlink. By eliminating analog via satellites In the case of broadcast television programs, the so-called "digital dividend" in the 790-862 MHz band is available for mobile communications. The frequency band of 791-821 MHz is used for the uplink, whereas the frequency band of 832-862 MHz is used for the downlink.

A high-frequency filter has become known, for example, from US Pat. No. 4,276,525. This is a conventional bandpass filter in which capacitive coupling elements are provided, coming from an input up to an output at the level of the free ends of the inner conductors (which are designed as coaxial resonators). As such, in such bandpass filters, signal transmission occurs directly across the resonators, i. the resonant frequencies are within the Nutzfrequenzbereich.es.

A similar prior art can also be taken from US Pat. No. 6,366,184 B1. Again, a high-frequency band-pass filter is described with a plurality of adjacent resonators, in which the individual resonators are coupled to each other via different additional coupling devices, for example in the form of coupling wires. Finally, the same applies to the high-frequency band-pass filter previously known from US Pat. No. 4,268,809. Also there is a series of line members to form a capacitive transmission path across the resonators away.

In contrast to the above-mentioned bandpass filters, so-called notch filters are also known, which, if they have a coaxial design similar to those explained above, th filters are usually constructed - usually comprise a plurality coupled together coaxial resonators, wherein adjacent to the inner conductors of these resonators, a signal line from an input to an output. With blocking filters of this type, the smaller the blocking frequency, the longer the signal line between two adjacent resonators must be. One of the reasons for this is that the length of the signal line between two resonators is often supposed to be one quarter of the wavelength of the blocking frequency. For a signal with a frequency of 790 MHz, a quarter of this wavelength is 0.1 m. In a high-frequency filter, the distance between two inner conductors of two adjacent resonators is usually about 2 cm to 3 cm, so that the approximately 10 cm long connecting lines between adjacent resonators must be folded consuming. The production of a correspondingly constructed high-frequency filter is complicated and expensive. The object of the present invention is, starting from the generic state of the art, to realize an improved and simpler high-frequency filter in the form of a high-frequency blocking filter, which does not require complicated laying of a connecting line through the high-frequency blocking filter and at the same time achieves space-saving and cost-effective is.

The object is achieved according to the features specified in claim 1. Advantageous embodiments of the invention are specified in the subclaims.

As mentioned and as is known differs one High frequency cutoff filter from a high frequency bandpass filter through its signal transmission path.

In a high-frequency band-pass filter, the signal transmission path takes place directly via the resonators. That is, the resonance frequencies are within the useful frequency range of the high-frequency filter. In other words, the resonators oscillate with those frequencies that are to be transmitted.

In contrast, high-frequency cutoff filters have a completely different signal transmission path. In the case of high-frequency blocking filters, the useful signal transmission takes place via a separately provided line, which usually runs continuously from an input to an output of the blocking filter according to the prior art. In addition, it is provided that this connecting line, also referred to below as a signal line, can be connected by approaching the resonators, i. an approximation to the inner conductors of the capacitive resonators is capacitively coupled. In this case, therefore, the resonators oscillate at a frequency that is outside the transmission frequency range that is to be transmitted via the Verbindüngsleitung.

In particular, but at low frequencies, this requires a comparatively long Verbindüngsleitung, with the result that the high-frequency filter must have a considerable size.

This is where the invention starts.

In the context of the invention it is proposed that the after The prior art in a high-frequency blocking filter continuous connection or signal line now has at least one or more galvanic separation points, which are designed as capacitive separation points in this line. These capacitive separation points are also capacitively coupled to individual resonators. As a result, a significant reduction in the size of corresponding high-frequency cut filter in coaxial design is possible. Because of the galvanic separation points in the form of the aforementioned coupling capacitance, a phase shift of the signal on the connecting line is made possible, which corresponds to the effect of a shortened continuous connecting line. In other words, the invention thus comprises a signal line running through the high-frequency cutoff filter, which is provided with at least one or more galvanic separation points (corresponding to the number of resonators), wherein the resonators are arranged by means of one each at the separation point and with two free ends the connecting line connected coupling capacity are interconnected. It is therefore sometimes spoken of capacitive separation points. The signal line thus comprises two galvanically separated line sections. In the equivalent circuit diagram of the corresponding high-frequency filter, the input terminal and the output terminal are connected to one another by the coupling capacitance arranged between the line sections.

The capacitive coupling of the respective resonators with the signal line and thus with the input terminal and the Output terminal is realized in that the signal line in each case has a further coupling surface in the region of the respective inner conductor of the respective resonators.

In the prior art, corresponding high-frequency cutoff filters are built comparatively large. A large size of such a filter is also necessary to achieve a high quality and a high insertion loss per se. In this case, the distance between the individual domes, ie the adjacent inner conductor of two adjacent resonators, must have a certain order of magnitude, so that the signal lines passing here at the two adjacent domes also have a corresponding size for generating a specific high-frequency blocking frequency. At this point, the invention starts and creates a highly miniaturized solution. Due to the connection of the at least two resonators by the coupling capacitance, the length of the signal line between the coupling points of the at least two resonators with the signal line, as mentioned, be shortened, since the coupling capacitance leads to a phase shift of the signal to be filtered, wherein the phase shift of the signal has the same effect as the transmission of the signal to be filtered over a correspondingly long connection line, ie a correspondingly long signal line. The inventive connection of the resonators via the coupling capacitance, which is arranged at the separation point of the connecting line, thus not only reduces the length of the necessary signal line but the High-frequency blocking filter according to the invention are very compact and nevertheless simple and therefore inexpensive to manufacture. In the high-frequency blocking filter according to the invention, the inner conductors preferably extend from the housing bottom perpendicularly in the direction of the housing cover.

Furthermore, in the high-frequency blocking filter according to the invention, the inner conductors are preferably designed as inner conductor tubes. This makes it possible for a tuning element to be introduced with variable spacing in the correspondingly formed cavity of the inner conductor tube, so that the high-frequency filter can be tuned.

Preferably, the connecting line comprises at least two line sections, which are galvanically separated from one another at the separation point of the connecting line. In this case, a first line section is galvanically connected to the input terminal and / or capacitively coupled and comprises a first coupling surface, and a second line section is galvanically connected to the output terminal and / or capacitively coupled and comprises a second coupling surface. The first coupling surface and the second coupling surface are at least partially opposite each other in such a way that the first coupling surface and the second coupling surface form the coupling capacitance.

A correspondingly constructed high-frequency filter is particularly simple in its construction. The coupling surfaces of the respective line sections can be parallel to the longitudinal extent of the high-frequency filter and parallel to the vertical extent of the respective inner conductors of the resonator. be aligned. This makes the geometry of a correspondingly constructed high-frequency filter particularly simple. The size of the respective coupling surfaces of the respective line sections can be adapted very simply by simply exchanging the corresponding line sections, the line sections having large coupling surfaces adapted to their requirements at their respective ends. Preferably, the line sections are offset parallel to each other and the first coupling surfaces and the second coupling surfaces arranged offset parallel to each other. As a result, the positioning of the respective coupling surfaces with each other is particularly easy. Furthermore, the distance of the coupling surfaces to each other is easily adjustable.

Preferably, a partition wall comprising a dielectric material is arranged between the first coupling surface and the second coupling surface.

In a correspondingly constructed high-frequency filter, the capacitance of a correspondingly formed coupling capacitance can be influenced by selecting the dielectric material.

Preferably, the high-frequency filter further comprises a holding and / or on immeeinrichtung which is supported on the inner conductor and / or attachable to the inner conductor and has two pocket-shaped receiving spaces, which are separated by a partition wall. In this case, the first coupling surface is arranged in a first receiving space of the holding and / or receiving means, and the second Coupling surface is arranged in a second receiving space of the holding and / or receiving device.

By providing a correspondingly constructed holding and / or receiving device, the attachment of the respective line sections to the inner conductor is particularly simple. Furthermore, the arrangement of the respective line sections and consequently of the respective coupling surfaces to one another by the holding and / or receiving device is particularly simple, since the corresponding coupling surfaces are simply inserted into the receiving spaces or receiving pockets of the holding and / or receiving device provided for this purpose have to. The holding and / or receiving device can either be simply supported on the respective inner conductors of the resonators. Furthermore, it is also possible that the holding and / or receiving device is connected, for example, by a bond with the inner conductors or attached thereto. The respective second coupling surfaces of the line sections are preferably arranged opposite the respective inner conductors, so that the respective resonators are capacitively coupled to the respective line sections. Between the respective second coupling surfaces and the respective inner conductors while a supporting wall of the holding and / or on imputation device is arranged.

By a corresponding arrangement of the respective second coupling surfaces of the line sections, the capacitive coupling of the resonators with the respective line sections is achieved in a structurally particularly simple manner. Furthermore, by selecting the material of the supporting wall, which is located between the inner conductors and the second coupling surface. Chen, the capacitive coupling between the coupling surfaces and the inner conductors are adjusted.

Preferably, the high-frequency filter further comprises a further connection. This additional connection can also be referred to as the send / receive connection. The further connection is arranged between the input connection and the output connection and is galvanically connected to the connection line. In this case, the further connection between coupling points of the resonators is arranged with the connecting line.

By a corresponding structure of the high-frequency filter, this can form a duplex switch in a corresponding embodiment of the resonators. In this case, the input terminal may be provided for a transmitter, whereas the output terminal may be provided for a receiver. The further connection or the transmitting / receiving connection can then be connected to an antenna which is provided and designed for the transmission and reception of signals.

Preferably, at least two resonators are capacitively coupled to the connection line between the further connection and the input connection. Furthermore, at least two resonators are also capacitively coupled to the connection line between the further connection and the output connection. By means of a corresponding design of the high-frequency blocking filter, it can have a high attenuation over a broad frequency range, so that a wider frequency range can be achieved by the correspondingly constructed frequency range Radio frequency cutoff filter can be disabled.

The inventive high-frequency notch filter preferably operates in the range between 790 MHz to 862 MHz and / or in the range between 880 MHz to 960 MHz and / or in the range of the 1800 MHz mobile radio frequency and / or the 2000 MHz mobile radio frequency.

The invention will be explained in more detail with reference to drawings. In detail:

FIG. 1 shows a three-dimensional representation of a high-frequency blocking filter according to the invention with the housing cover removed;

FIG. 2: a top view of that shown in FIG

High frequency blocking filter;

Figure 3: a side view of the in Figures 1 and

2, which is cut along the sectional plane P-P of FIG. 2;

FIG. 4 a: a side view of that in FIGS

3, high frequency cutoff filter cut along the sectional plane PI-PI of FIG. 2;

Figure 4b: an enlargement of the bordered in Figure 4a

Area of the high frequency cutoff filter;

FIG. 5 shows a spatial representation of the inventive high-frequency blocking filter with a Input terminal, an output terminal and a transmission / reception terminal; the high-frequency blocking filter shown in Figure 5 without holding and / or receiving devices; a side view along a longitudinal section of the high frequency blocking filter shown in Figures 5 and 6; a plan view of the high frequency blocking filter shown in Figures 5 to 7; an equivalent circuit diagram of a high-frequency cutoff filter according to the invention with only two coupled resonators; and

FIG. 10 shows an equivalent circuit diagram of the high-frequency blocking filter shown in FIGS.

In the following description, like reference numerals denote like components, and like features, so that a description made with respect to a figure with respect to a component also applies to the other figures, whereby a repetitive description is avoided.

In the following, a high-frequency filter 1 according to the invention in coaxial design will be described with reference to FIGS. 1 to 10. This high-frequency filter 1 is hereinafter also referred to as high-frequency cut filter. 1 referred to as it is a blocking filter. It comprises an outer conductor housing with a housing bottom 11 and a housing cover 12, which is at a distance from the housing bottom 11 and arranged opposite to the latter, and which is only shown in FIG. The outer conductor housing in this case comprises the so-called resonator interior 10a. In the remaining figures, the high frequency blocking filter is shown with the housing cover 12 removed. Between the housing bottom 11 and the housing cover 12, a housing wall 13 is provided circumferentially. The high frequency blocking filter 1 shown in FIGS. 1 to 8 comprises six resonators 10, which are separated from each other by partitions 14. The six resonators 10 each comprise an inner conductor 16, wherein the inner conductors 16 are each electrically connected to the housing bottom 11 and extend perpendicularly from the housing bottom 11 in the direction of the housing cover 12. The outer conductor housing may be formed in one piece with the inner conductors 16, for example as a milling, turning or casting part.

As can be seen from FIGS. 1 and 4a as well as 4b, the respective inner conductors 16 each terminate at a distance in front of the housing cover 12. Alternatively, the respective inner conductors 16 can extend to the housing cover 12, which is then galvanically separated from the housing cover 12 by an insulating layer have to be. It can be seen from FIGS. 5 to 8 that the high-frequency blocking filter 1 comprises an input terminal 20, an output terminal 30 and a further terminal 40 in the form of a transmitting / receiving terminal 40. This In this respect, the transmitting and receiving connection has a dual function as output and input connection. The input terminal 20, the output terminal 30 and the transmitting / receiving terminal 40 are coupled to one another via a (continuous) connection line 50, ie connected, which is also referred to below as the signal line 50. Via this signal line corresponding high-frequency signals are transmitted in the passband, whereby the so-called passband is ultimately defined or defined. In this case, the so-called high-frequency blocking frequency is also generated by the resonators, that is to say that band-stop filter in whose frequency range a signal transmission can not take place. In this case, the transmitting / receiving terminal 40 is arranged between the input terminal 20 and the output terminal 30. As can be seen from FIG. 7, the input connection 20, the output connection 30 and the send / receive connection 40 are each designed as an oaxial connection, wherein the respective outer conductors are galvanically connected to the outer -lexter housing and the respective inner conductors are electrically connected to the connection line 50.

In the illustrated blocking filter, the resonators are usually not directly coupled, but only via the signal line 50. In this case, the individual resonators are each preferably in the correct phase, e.g. capacitively coupled. In an optimal arrangement, it is then possible to detune or change the individual Sperrpolfrequenzen a respective resonator without affecting the remaining Sperrpole (resonators).

As can be seen from the drawings, for example, in FIGS. 5, 6, 7, 8, 9 or 10, the signal line leads 50 from the one end of the input terminal 20 closer to the high-frequency cut-off filter 1 to the output terminal 30 adjacent to the opposite end of the notch filter 1, passing through all the resonators 10, ie through all the resonator interiors 10a. For this purpose, recesses or openings 14a are formed in the partition walls 50 separating the individual resonators from one another in the region and at the level of the connecting line 50, through which the connecting line 50 extends (electrically isolated from the partitions 40).

In the exemplary embodiment shown, the connecting line 50 has three galvanic separation points, which electrically isolate four line sections 51, 52, 53, 54 of the connection line 50. Here, in each case one - which will be discussed in detail below - capacitive separation point 60 'is formed. The line section 51 comprises a first coupling surface 51.1 facing the output connection 30 and a second coupling surface 51.2 facing the input connection 20. The line section 52 comprises a first coupling surface 52.1 facing the output connection 30 and a second coupling surface 52.2 facing the input connection 20. The line section 53 comprises a first coupling 53.1 facing the outlet connection 30 and a second coupling surface 53.2 facing the inlet connection 20. The line sections 54 in turn comprises three second coupling surfaces 54.2.

The respective first coupling surfaces 51.1, 52.1, 53.1 and second coupling surfaces 51.2, 52.2, 53.2 and 54.2 run parallel to a longitudinal extension of the outer conductor housing of the high-frequency blocking filter 1. In particular from FIGS. 2 and 8, it can be seen that the line sections 51, 52, 53, 54 run parallel to one another and are offset relative to one another such that the first coupling surface 51. 1 of the line section 51 faces the second coupling surface 52. 2 of the line section 52. Because the first coupling surface 51.1 faces the second coupling surface 52.2, these two coupling surfaces form a capacitive separation point 60 'in the form of a first coupling capacitance 60, which is arranged at this capacitive separation point between the two line sections 51 and 52, and which are shown in FIGS the leftmost two resonators 10 capacitively interconnects.

Characterized in that the mentioned line sections 51, 52, 53, 54 not only to each other but also parallel to the longitudinal extension of the outer conductor housing, ie parallel to the long housing walls 13 and thereby the individual line sections 51, 52, 53, 54 in the region of the capacitive separation points are offset parallel to each other with the formation of a small coupling distance, resulting in an arrangement as shown with reference to Figure 8 in plan view. In other words, in the case of the first resonators located on the left in FIG. 8, the distance between each line section between the lateral housing wall 3 located at the bottom in FIG. 8 and a subsequent capacitive separation point 60 'increases by the thickness of the coupling stand. At the same time, a distance between the corresponding line section and the side housing wall 13 located at the top in FIG. 8 becomes smaller by the same amount. However, since the coupling distances between the individual line sections and the respective inner conductor 16 remain the same (should be the same), it can also be seen from FIG. 8 that the inner conductor of the first to fourth resonator in different relative position between the two parallel, extending in the longitudinal direction housing walls 13 is located. In this case, the inner conductors execute the same lateral offset, with which the successive line sections are also arranged with the respective side offset caused by the coupling section. The first coupling surface 52.1 of the line section 52 faces the second coupling surface 53.2 of the line section 53 in such a way that the first coupling surface 52.1 and the second coupling surface 53.2 form a further coupling capacitance 60 capacitively interconnecting the second and third resonators 10 counted in the figures from the left couples.

Furthermore, the first coupling surface 53.1 of the line section 53 is arranged opposite the second coupling surface 54.2 of the line section 54, so that the first coupling surface 53.1 and the second coupling surface 54.2 form a further coupling capacitance 60 which interconnects the third and fourth resonators 10 counted from the left capacitively coupled.

The fourth, fifth and sixth resonators 10 counted from the left in the figures are not coupled to one another via separate coupling capacitances 60, but the individual resonators 10 are coupled to one another only via the line section 54.

The line sections 51, 52, 53, 54 each have second coupling surfaces 51.2, 52.2, 53.2, 54.2, which correspond to the respective internal resonators 16 of the resonators 10 are arranged opposite to each other, so that the respective resonators 10 and the inner conductor 16 are capacitively coupled to the corresponding line sections 51, 52, 53, 54, namely via the so-called capacitive Innenleiter- or resonator coupling 65th

It can be seen from the figures that the high-frequency blocking filter 1 according to the invention comprises a number of holding and / or receiving devices 70 corresponding to the number of resonators 10. The positioning of the holding and / or receiving devices 70 with respect to the respective inner conductors 16 of the resonators 10 is shown by way of example in FIGS. 4a and 4b. The holding and / or receiving device 70 comprises a support wall 74, by means of which the holding and / or receiving device 70 is in direct contact with the inner conductor 16, or which is arranged at a small distance from the inner conductor 16 spaced. It can also be seen that the corresponding line sections 51, 52, 53, 54 as well as the respectively associated coupling surfaces 51.2, 52.2, 53.2, 54.2 of the signal line 50 are arranged at the lateral spacing from the respective inner conductors 16 of the resonators 10. Since the corresponding line sections 51, 52, 53, 54 are designed strip-shaped, ie transverse to the longitudinal direction of the lines have a more or less rectangular cross-section (ie at least two parallel side surfaces 50, which are aligned in the embodiment shown also parallel to the inner conductors), be formed by the correspondingly dimensioned cooperating coupling surfaces on the galvanic separation points without additional measures. That is, the line sections form at the galvanic separation points the so-called capacitive separation points 60 'with the respectively associated end portions of the line sections, which form the coupling surfaces of a coupling capacitance formed thereby. The mentioned holding and / or receiving device 70 is supported on the upper free end 16 a of the inner conductor 16 and / or fixed to the inner conductor 16. The attachment of the holding and / or Aufnahmee- device 70 to the inner conductor 16 may be realized for example by gluing.

From the figures it can be seen that the holding and / or receiving device 70 has two receiving spaces 72, 73, which are separated from one another by a partition wall 71. The first coupling surface 52.1 of the line section 52 is arranged in a first receiving space 72 of the holding and / or receiving device 70, whereas the second coupling surface 53.2 of the line section 53 is arranged in a second receiving space 73 of the holding and / or receiving device 70.

Thus, the line sections 51, 52, 53, 54 are each arranged in the region of the upper free ends 16 a of the corresponding inner conductor 16. It can be seen from the drawings that extend the line sections with their parallel to the inner conductor height sections then also from the upper free end 16a of the inner conductor 16, starting over a certain vertical distance parallel to the inner conductor 16 down toward housing bottom 11, but preferably only in a range of not more than 10% or 20% or up to 30% of the axial length of the inner conductor 16. In this height range with respect to the inner conductor 16 then the recesses or openings 14a mentioned at the partition walls 14 are then excluded. forms, over which the connecting line runs at the same height or at the same distance from the housing cover 12 and the housing bottom. The holding and / or receiving device 70 is preferably made of a dielectric material, in particular a plastic. After attaching the respective holding and / or receiving devices 70 to the respective inner conductors 16, the respective line sections 51, 52, 53, 54 with demounted housing cover 12 from above into the corresponding receiving spaces 72, 73, which are formed as receiving pockets pushed become. Thereby, the positioning of the line sections 51, 52, 53, 54 to each other and to the inner conductors 16 in a very simple manner possible, so that the desired resonance properties of the respective resonators 10 and thus the filter characteristics of the high-frequency blocking filter 1 are always relatively easily achieved because the positions of the line sections are determined by the holding and / or receiving device 70.

It can be seen from the figures that the respective second coupling surfaces 51.2, 52.2, 53.2 and 54.2 are arranged opposite the respective inner conductors 16. As a result, the resonators 10 (and / or the inner conductors 16) are capacitively coupled to the respective line sections 51, 52, 53, 54 (capacitive inner conductor and / or resonator coupling 65). Between the second coupling surfaces 51.2, 52.2, 53.2, 54.2 and the respective inner conductors 16 is one, the upper end 16a of an inner conductor 16

(adjacent to the housing cover 12) partially overlapping support wall 74 (Figure 4b) of a corresponding holding and / or receiving device 70 is arranged. Since the wall 74 is made of a dielectric material, the capacitive coupling 65 (ie, the so-called capacitive inner conductor coupling 65, which is sometimes called capacitive resonator coupling 65) of the respective second coupling surface 51.2, 52.2, 53.2, 54.2 with the inner conductors 16 influenced by the material selection of the support wall 74.

It can be seen from the overall construction that the mutual coupling of the resonators 10 used in the notch filter is not effected by a direct coupling between the resonators, but only via the signal line 50. Therefore, no otherwise conventional coupling window or coupling diaphragms are provided between the individual resonators. The coupling of the resonators via the signal line 50 is preferably carried out in each case in the correct phase, e.g. through the capacitive coupling. In an optimal arrangement then the individual Sperrpolfrequenzen can be detuned or changed without affecting the remaining locking poles. In other words, therefore, the explained inventive construction of the high-frequency cut filter usually includes a plurality of coaxial resonators 10, wherein adjacent and z. B. capacitive coupled to the inner conductor 10 of these resonators, the signal line 50 between two terminals 20, 30, 40 extends.

The resonators 10 of the high-frequency blocking filter 1 shown in FIGS. 1 to 8 are designed such that the high-frequency blocking filter 1 is a duplexer 1. FIG. 10 shows an equivalent circuit diagram of the high-frequency blocking filter 1 shown in FIGS. 1 to 8. The transmitting / receiving terminal 40 can be connected to an antenna (not shown in the figures). About the not shown antenna, both output signals can be sent and receive signals are received. A transmitter not shown in the figures can be connected to the input connection 20, and a receiver, not shown in the figures, can be connected to the output connection 30.

E-GSM signals used in mobile radio use the frequency range from 880 to 915 MHz for the so-called uplink and the frequency range from 925 to 960 MHz for the so-called downlink. Thus, in this example, the transmitter operates in the frequency range 880-915 MHz. The duplexer 1 is then designed such that the three resonators 10 between the input terminal 20 and the transmitting / receiving terminal 40 are designed in size and geometry such that these three coupled resonators 10 pass signals in the frequency range from 880 to 915 MHz, however, strongly attenuate signals in the frequency range of 925 to 960 MHz. The three resonators 10 between the output terminal 30 and the transmitting / receiving terminal 40 in turn are designed in size and geometry such that these signals in the frequency range of 925 to 960 MHz pass, whereas signals in the frequency range from 880 to 915 MHz strongly attenuated, So be locked.

Consequently, a signal introduced from the transmitter into the duplex switch 1 via the input terminal 20 is forwarded to the transmitting / receiving terminal 40, whereas this signal is attenuated by the three resonators 10 between the transmitting / receiving terminal 40 and the output terminal 30, so that the signal does not reach the output terminal 30. That of the transmitter in The duplex switch 1 fed signal is emitted via the antenna, not shown, but does not pass through the output terminal 30 to the receiver, not shown, of the thus formed high frequency blocking filter 1. In other words, this means that a pass band or pass band along the signal line 50 is provided via which, for example, the receive signals received by an antenna or the radio frequency band received by the antenna are transmitted from the transmit / receive port 40 to the output port 30 to a receiver, not shown, whereas a corresponding radio frequency band relative to the transmit operation is transmitted from an input terminal 20 to the transceiver port 40 and supplied to an antenna not shown in detail there, so what about the corresponding signals in transmission mode can be transmitted. As a result, the receiving branch is separated from the transmitting branch by the corresponding high-frequency blocking bands or blocking regions, so that over-coupling is avoided.

Signals received by the antenna in the range of 925 to 960 MHz are fed to the duplex switch 1 via the transmission / reception port 40. These signals are forwarded via the three resonators 10 between the transmit / receive port 40 and the output port 30 to the receiver. However, these signals are so much attenuated by the three resonators between the transmitting / receiving port 40 and the input port 20 that they do not reach the transmitter via the input port 20.

In the example, the transmitter operates in the frequency range of 880 to 915 MHz. The spacing of the coupling points of adjacent resonators to the connecting line 50 must be a distance of λ / 4 of the center frequency of this frequency band. On the other hand, the three resonators 10, which are arranged between the transmitting / receiving terminal 40 and the output terminal 30, have a passband of 925 to 960 MHz, so that the distance of the coupling point from adjacent resonators 10 to the connecting line 50 is smaller, so that the connecting lines or the corresponding line sections between the respective resonators can be configured shorter than in the three resonators 10 facing the transmitter. To shorten the line sections 51, 52 and 53, the coupling capacitances described above are between them 60 arranged. These coupling capacitances 60 cause a phase shift of the signal. The sum of this phase shift with the phase shift corresponding to the transit time of the signal via the line sections 51, 52, 53 corresponds to the phase shift of an electrical line having a length of, for example, λ / 4 of the center frequency signal. The line section 54, which couples the three resonators 10 between the send / receive connection 40 and the output connection 30, has no corresponding coupling capacitances 60, since the distance of the coupling point from two adjacent resonators 10 to the conduction section 54 is smaller no coupling capacity 60 must be used for effective extension of the line section 54. However, it can be seen from FIGS. 1, 3 and 5 to 7 that the line section 54 is not straight but meander-shaped, so that the distances of the coupling points of two adjacent resonators 10 are just λ / 4 for center frequency signals in the band from 925 to 960 MHz.

It can be seen from FIGS. 2 and 8 that the respective inner conductors 16 of the resonators 10 each have different distances from the housing wall 13. On the one hand, this is due to the circumstance that the individual line sections 51, 52, 53, 54 can thereby be realized geometrically particularly simply by straight lines or plates. On the other hand, this is due to the fact that the respective resonators are to have different resonance frequencies, which differ from one another, so that a correspondingly wide (in the frequency width) stopband can be achieved.

FIG. 9 shows an equivalent circuit diagram of a high-frequency blocking filter according to the invention with a continuous signal line 50 (and the coupling capacitance 60 connected in the continuous signal line 50), which has only two resonators 10 which are capacitively connected to one another via a coupling capacitance 60. A corresponding high-frequency blocking filter 1 or a corresponding duplexer 1 has narrower blocking regions for the uplink and downlink, since only one resonator 10 is provided for the uplink and the downlink. However, the remaining mode of operation of the high-frequency blocking filter 1 shown in FIG. 9 is identical to the mode of operation of the high-frequency blocking filter 1 described with reference to FIGS. 1 to 8 and 10.

From the above description it is clear that in the explained high-frequency cutoff filter, the useful signal is transmitted via the connecting line 50 from one input to one output, wherein in the context of the invention, the connecting line is additionally capacitively coupled by approaching the resonators 10, ie to the inner conductor 16. The galvanic isolation points in the form of the capacitive separation points provided in the context of the connection lead to a virtual shortening of the entire length of the connection line 50, as a result of which the high-frequency cutoff filter is comparatively small even at low high frequencies. Without the aforementioned capacitive separation points, the line length between two resonators 10 would be approximately K / 2. In the context of the invention, this line route is significantly shorter.

In the case of the illustrated blocking filter, the desired blocking poles, which are located outside the transmission frequency range, then arise in the case of in-phase coupling. In this case, the in-phase blocking-pole coupling can be set correspondingly by an optimized combination between the individual line lengths between the capacitive separating points and the size of the capacitances at the separating points themselves.

Claims

Claims;

1. High-frequency blocking filter in coaxial design, wherein the high-frequency blocking filter has the following features: the high-frequency blocking filter (1) comprises a Außenlei- tergehäuse with a housing bottom (11) and one of the housing bottom (11) spaced and opposite this arranged housing cover ( 12), between which a housing wall (13) is provided circumferentially; the high-frequency cutoff filter (1) comprises at least two resonators (10) each comprising an inner conductor (16);

the inner conductors (16) are each with the housing bottom

(11) galvanically connected and extending from the housing bottom (11) in the direction of the housing cover (12); the inner conductors (16) each end at a distance in front of the housing cover (12) and / or are from the housing cover

(12) galvanically isolated,

The high-frequency blocking filter (1) comprises an input terminal (20, 40) and an output terminal (30, 40), the signal line (50) being connected to the input terminal (20, 40) on the one hand and to the output terminal (30 , 40) to the other is galvanically connected or capacitively coupled,

characterized by the following features:

the signal line (50) runs under training because of a capacitive inner conductor and / or resonator coupling (65) past the respective inner conductor (16) through the resonators (10) of the high-frequency blocking filter (1),

the signal line (50) has at least one galvanic separation point in the form of a capacitive separation point (60 '),

the capacitive separation point (60 ') is spaced from the inner conductors (16) and capacitively coupled thereto,

the resonators (10) and the inner conductors (16) are each capacitively coupled to the signal line (50).

2. High-frequency cutoff filter according to claim 1, characterized in that the at least one capacitive separation point (60 ') in the signal line (50) is provided at a lateral distance from the inner conductor (16), preferably in the region in front of the upper end (16a) of the inner conductor (16).

3. High-frequency cutoff filter according to claim 1 or 2, characterized in that at the capacitive separation point (60 '), the galvanically isolated signal line (50) each have a first coupling surface (51.1, 52.1, 53.1) and a second coupling surface (52.2, 53.2, 54.2), via which the two galvanically separated sections of the signal line (50) are capacitively coupled to each other.

4. High-frequency cutoff filter according to one of claims 1 to 3, characterized in that the signal line (50) is designed strip-shaped with a right-eckförmigen to the extension direction cross-section.

5. High-frequency cutoff filter according to one of claims 1 to 4, characterized in that the inner conductors (16) are each formed as an inner conductor tube (16).

6. High-frequency blocking filter according to one of the preceding claims, characterized by the following features: the signal line (50) comprises at least two line sections (51, 52, 53, 54) connected to the capacitive separation point (60 ·) of the signal line (50) galvanically separated from each other;

a first line section (51, 52, 53) is galvanically connected to the input terminal (20, 40) and / or capacitively coupled and comprises a first coupling surface (51.1, 52.1, 53.1);

- A second line section (52, 53, 54) is galvanically connected to the output terminal (30, 40) and / or capacitively coupled and comprises a second coupling surface (52.2, 53.2, 54.2); and

the first coupling surface (51.1, 52.1, 53.1) and the second coupling surface (52.2, 53.2, 54.2) of the capacitive

Separation point (60 ') are at least partially opposite each other so that the first coupling surface (51.1, 52.1, 53.1) and the second coupling surface (52.2, 53.2, 54.2) form a coupling capacitance (60).

7. High-frequency blocking filter according to claim 6, characterized in that the line sections (51, 52, 53, 54) offset parallel to each other and the first coupling surfaces (51.1, 52.1, 53.1) and the second coupling surfaces (52.2, 53.2, 54.2) in parallel offset from one another.

8. High-frequency blocking filter according to claim 6 or 7, characterized in that between the first coupling surface che (51.1, 52.1, 53.1) and the second coupling surface (52.2, 53.2, 54.2) is arranged a dividing wall (71) comprising a dielectric material.

9. High-frequency cutoff filter according to one of the preceding claims, characterized by the following features: the high-frequency cut filter (1) further comprises a holding and / or receiving device (70) which is supported on the inner conductor (16) and / or on the Inner conductor (16) is fixed and has two receiving spaces (72, 73) which are separated by a partition (71) from each other; and

the first coupling surface (51.1, 52.1, 53.1) is arranged in a first receiving space (72) of the holding and / or receiving device (70), and the second coupling surface (51.2, 52.2, 53.2, 54.2) is in one second receiving space (73) of the holding and / or Aufmeeinrich- device (70) arranged.

10. High-frequency cutoff filter according to claim 9, characterized by the following features:

the respective second coupling surfaces (51.2, 52.2, 53.2, 54.2) are arranged opposite the respective inner conductors (16), so that the respective inner conductors (16) and / or resonators (10) are connected to the respective line sections (51, 52, 53, 54 ) capacitively coupled to form a capacitive inner conductor and / or resonator coupling (65), and between the respective second coupling surfaces (51.2, 52.2, 53.2, 54.2) and the respective inner conductors is a support wall (74) of the holding and / or receiving device (70) arranged.

11. High-frequency cutoff filter according to one of the preceding claims, characterized in that the resonators (10) have different sizes.

12. High-frequency blocking filter according to one of the preceding claims, characterized in that at least some inner conductors (16) of the respective resonators (10) to the housing wall (13) have different distances.

13. High-frequency cutoff filter according to one of the preceding claims, characterized in that the line sections (52, 53, 54) of the signal line (50) are aligned parallel to the longitudinally extending housing walls (13), and that at least two successive ing Line sections (52, 53, 54) with lateral offset to each other to form a coupling distance in the region of the capacitive separation point (60 ') are arranged, and that the thus coupled inner conductor (16) with a corresponding lateral offset to the housing walls (13) offset from each other are.

14. High-frequency cutoff filter according to one of the preceding claims, characterized in that the housing cover (12) is designed as a circuit board, the Resonator- inside is metallized.

15. High-frequency blocking filter according to one of the preceding claims, characterized in that the outer conductor housing is integrally formed with the inner conductors (16), in particular as a milling, turning or casting.

16. High-frequency cutoff filter according to one of the preceding claims, characterized in that the outer conductor housing and / or the inner conductor (16) consists of plastic / consist, wherein the respective inner surfaces are metallized.

17. High-frequency cutoff filter according to one of the preceding claims, characterized by the following features: the high-frequency cutoff filter (1) further comprises a further terminal (40);

the further terminal (40) is arranged between the input terminal (20) and the output terminal (30) and is galvanically connected to the signal line (50); and

the further connection (40) is arranged between coupling points of the inner conductors (16) or resonators (10) with the signal line (50).

18. High-frequency cutoff filter according to claim 17, characterized in that the resonators (10) are designed and coupled such that a duplex switch is formed

19. High-frequency cutoff filter according to claim 17 or 18, characterized by the following features:

between the further connection (40) and the input connection (20) at least two resonators (10) are capacitively coupled to the signal line (50); and between the further terminal (40) and the output terminal (30), at least two resonators (10) are capacitively coupled to the signal line (50).

20. High-frequency cutoff filter according to one of the preceding claims, characterized in that the high-frequency cutoff filter (1) with its blocking and its Passing range between 790 MHz to 862 MHz and / or in the range between 880 MHz to 960 MHz and / or in the range of 1800 MHz mobile radio frequency and / or the 2000 MHz mobile radio frequency operates.