DE10348909A1 - Filter element for filtering electromagnetic waves, especially bandpass filter or band blocking filter, has resonator held at distance from contacting structure in recess in circuit board by suitable attachment arrangement - Google Patents

Abstract

The device has a cylindrical dielectric resonator (1) and one or more lines (2) carrying electromagnetic waves to and/or from the resonator, ending in a contacting structure (4) and forming part of a circuit board structure. The resonator is held by the circuit board at a distance from the contacting structure and in a recess in the circuit board by a suitable attachment arrangement. An independent claim is also included for an oscillator, especially for radar systems, LMDS distribution services or satellite receivers, with a filter element.

Description

The The present invention relates to a filter element suitable for filtering electromagnetic waves, in particular bandpass filters or bandstop filters, also executed as a reflection filter or the like, comprising a dielectric, cylindrical Resonator and one or more lines, which electromagnetic Waves to the dielectric resonator or remove. The present The invention also relates to one of such a filter element built-up oscillator.

Commercially available resonators, So vibratory Systems whose individual elements are tuned to a desired (eigen) frequency are such that when excited, the resonator settles at this frequency, find many in both the low-frequency technology and in high-frequency technology Application. Depending on the structure, material and shape, for example, they are suitable as the simplest (narrowband) filter, as a frequency-determining element an oscillator, for the measurement of material properties in the RF field or as a short-term memory of electromagnetic energy (used in particle accelerators).

in the In the field of high-frequency technology, depending on the application microstrip line resonators, Cavity resonators or so-called dielectric, i. mostly from one Ceramic material formed resonators use. Latter become in cylindrical Shape often as electrical or electromagnetic filters and thus also as Filter used for vibration generation in resonator circuits. The thereby he-targetable properties of such filters and consequently also the oscillators produced therewith (such as their power level and Noise characteristics), however, are crucial to the coupling of the dielectric resonator to the supply and discharge lines dependent.

Cylindrical dielectric resonators are currently applied predominantly with one of their flat end surfaces formed at a certain distance from the top of a circuit board on this. On the top side of the circuit board, there are one or more lines, which supply electromagnetic waves to the dielectric resonator. A typical design widely used in products such as local oscillators and filters for radars, satellite receivers, wireless distribution services for digital television such as local multipoint distribution services (LMDS) or the like is disclosed in US Pat 8th outlined.

The in 8th shown construction can lead to significant problems in the production of oscillators with increasing operating frequencies, in particular in the so-called. K-band, ie in the microwave range of 18-26.5 GHz. The energy coupled over from the first line to the second line is in most cases not sufficient here to enable oscillation circuits to oscillate. Therefore, in most practical applications with such ceramic resonators, only oscillators with operating frequencies below 18 GHz are produced.

Of the Invention is based on the object, a resonator circuit for a filter element to provide for filtering electromagnetic waves, which avoids the disadvantages mentioned above. In this regard, should an improved coupling of the line (s) to cylindrical, dielectric Resonators, in particular for Oscillators, are specified, preferably for operating frequencies above 18 GHz.

These Task is by a filter element for filtering electromagnetic Shafts having the features according to claim 1 and by an oscillator with the features according to claim 14 solved. Advantageous training and further education, which individually or in combination can be used together are the subject of the dependent Claims.

The invention is based on generic filter elements for filtering electromagnetic waves, comprising a dielectric, cylindrical resonator and one or more lines, the electromagnetic waves to the dielectric resonator zoom in and out, in that the lines terminate in a Ankontaktierungsstruktur, which at least partially Crescent-shaped, which advantageously a certain desired filter characteristics can be achieved. As already mentioned, it is crucial for the operation of such filter elements or oscillators constructed therewith that sufficient signal power is emitted or transmitted by the line (s). By means of the contact-connection structure according to the invention, the transmittable signal power is compared to previous structures, eg according to FIG 8th , advantageously increased substantially. Thus, secure oscillation and stable operation of an oscillator manufactured with such a filter element can be achieved under practical operating conditions, particularly over a wide temperature range.

Preferably each line terminates in a separately formed Ankontaktierungsstruktur. Alternatively, you can two or more lines also in a jointly formed Ankontaktierungsstruktur end up.

The Ankontaktierungsstruktur can preferably as a circular ring of 360 ° or as Arc segment formed with a variable opening angle less than 360 ° be. In particular, in the latter case can be a clever selection of the opening angle α in advantageous Way the coupling efficiency between the or the lines and resonator, and minimize unwanted phase noise. For example, contact lines have two contact lines with an opening angle α of about 160 ° proven, at three lines Ankontaktierungsstrukturen with an opening angle from about 110 ° and with four lines Ankontaktierungsstrukturen with an opening angle from e.g. about 75 °; the above angle data being only examples potential Embodiments acts.

In a simple design the invention has the Ankontaktierungsstruktur larger dimensions than the cylindrical Resonator on. For size minimization and / or increasing the efficiency of the overcoupling can alternatively For this the Ankontaktierungsstruktur also smaller dimensions than the cylindrical Resonator have.

In a development of the invention is the resonator to the lines variably spaced, with spacings in both positive as well as negative longitudinal extension (Z-axis) of the resonator are conceivable. So can from the Ankontaktierungsstruktur out in positive longitudinal extent the resonator looks at any object or also a device, for example a holding surface, a cover or the like be more appropriate, which is located in the vicinity of Ankontaktierungsstruktur. Alternatively, the resonator by means of a suitable fastening material be mounted on a circuit board, with the lines next to their Ankontaktierung are preferably part of the printed circuit board structure.

When example for an arrangement in negative longitudinal extent considered a recess is provided in the circuit board, in which resonator is e.g. by means of a suitable fastening means is arranged. Preferably, the recess is dimensioned in such a way that a self-centering mounting of the resonator is made possible, for example, slightly conical at least on the inlet side or provided with a chamfer or chamfer. Such a recess may alternatively or cumulatively also in the previously mentioned device (Surface component, Cover, etc.) may be provided.

Prefers becomes an adhesive or silicone or the like as a fastener for the Resonator used.

Appropriate way the resonator is substantially centered or centered to Ankontaktierungsstruktur aligned, wherein at Ankontaktierungen according to the present invention in advantageously coarser Allow for deviation tolerances in its positioning, as with conventional circuits the case is where already relatively small Deviations from the inoperability of the Resonator circuit and thus can lead to rejects.

The The present invention is particularly suitable for dielectric cylindrical resonators a filter element with operating frequencies greater than 18 GHz. It persists in an oscillator, in particular for radar installations, LMDS distribution services, satellite receivers or The like, comprising a previously described filter element for filtering electromagnetic waves. Come this way the advantages of the invention also in the context of an overall system for Validity.

The Invention will now be described with reference to the accompanying drawings preferred embodiments exemplified.

In this show schematically:

1 in a plan view of a first structure of a filter element comprising a cylindrical resonator, to which a line is introduced, at the end of a crescent Ankontaktierungsstruktur is formed;

2 in a plan view of a second structure of a filter element comprising a cylindrical resonator, to which a line is introduced, at the end of an annular Ankontaktierungsstruktur is formed;

3 in a plan view of a third structure of a filter element comprising a cylindrical resonator, to which two lines are introduced, at the end of each a separate crescent Ankontaktierungsstruktur is formed;

4 in a plan view of a fourth structure of a filter element comprising a cylindrical resonator, to which two lines are brought, which terminate in a common crescent Ankontaktierungsstruktur;

5 in a side view of the structure of a filter element according to one of the previous 1 to 4 with a resonator variably spaced from the contacting structure in the positive z-axis and disposed on a cover;

6 in a side view the structure of an oscillator according to one of the previous 1 to 4 with a resonator arranged on the contacting structure;

7 in a side view of the structure of a filter element according to one of the previous 1 to 4 with a resonator which is variably spaced from the contacting structure in a negative z-axis and arranged in a recess of the printed circuit board; and

8th in a plan view of a conventional construction of a filter element comprising a cylindrical resonator, to which two leads are introduced.

at the following description of the preferred embodiments In the present invention, like reference characters designate like or comparable components.

1 shows in a plan view a first structure of a filter element comprising a cylindrical dielectric resonator 1 on which a supply line 2 is introduced, at the end of a crescent Ankontaktierungsstruktur 4 is trained. The crescent Ankontaktierungsstruktur 4 consists of a circular arc segment with a variable opening angle α, at which a common line 2 connected. The opening angle α is for the in 1 example shown about 160 °. The width of the pipe 2 and the crescent Ankontaktierungsstruktur 4 can be adapted to the appropriate ratio and is considered variable. In particular, a (cf. 4 ), two (cf. 3 ) or several (not shown) Ankontaktierungen 4 . 4a . 4b to the dielectric, ceramic resonator 1 be attached. For this purpose, only the opening angle α of the individual Ankontaktierungsstrukturen need to be adjusted accordingly.

The crescent Ankontaktierungsstruktur 4 . 4a . 4b can also accept dimensions which are smaller than the dimensions of the cylindrical resonator 1 , In this case, the cylindrical resonator covers 1 the metallic Ankontaktierungsstrukturen 4 . 4a . 4b at least partially (not shown).

2 shows in a plan view a second construction of a filter element comprising a cylindrical resonator 1 on which a line 2 is introduced, at the end of a circular Ankontaktierungsstruktur 4 is trained.

3 shows in a plan view a third construction of a filter element comprising a cylindrical resonator 1 on which two lines 2 . 3 are introduced, at the ends in each case a separate crescent Ankontaktierungsstruktur 4a . 4b is formed, wherein both Ankontaktierungsstrukturen 4a . 4b are galvanically isolated from each other. Such Ankontaktierungsstrukturen are esp. In feedback circuits for the production of oscillators: in these circuits, the cylindrical resonator 1 used as a narrow-band bandpass, which is permeable, for example, in a defined modes only for a certain frequency, which is why one speaks in this regard of a multi-mode bandpass filter, because, for example, the basic mode or higher-order modes can be used. The resonator 1 becomes like in 3 shown with two wires 2 . 3 ankontaktiert. Decisive for the oscillator operation is that sufficient signal power from the first line 2 to the second line 3 submitted or transmitted. This is due to the crescent-shaped Ankontaktierungsstrukturen 4a . 4b guaranteed.

4 shows in a plan view a fourth structure of a filter element comprising a cylindrical resonator 1 on which two lines 2 . 3 are introduced, which in a common crescent Ankontaktierungsstruktur 4 end up. Such structures, where the leads 2 . 3 a crescent Ankontaktierungsstruktur 4 . 4a . 4b divide, are particularly suitable as a band rejection filter.

5 shows in a side view the structure of a filter element according to one of the preceding 1 to 4 with an Ankontaktierungsstruktur 4 . 4a . 4b in the positive direction of the z-axis variably spaced, for example on a cover 5 arranged resonator 1 ,

6 shows in a side view the structure of a filter element according to one of the preceding 1 to 4 with one on the Ankontaktierungsstruktur 4 . 4a . 4b arranged, in particular glued, resonator 1 ,

7 Finally, in a side view shows the structure of a filter element according to one of the previous 1 to 4 with an Ankontaktierungsstruktur 4 . 4a . 4b in the negative direction of the z-axis variably spaced, in a recess 8th the circuit board 6 arranged resonator 1 ,

The height of the cylindrical ceramic resonator 1 , which incidentally is sometimes referred to as a pill, over the surface of a circuit board 6 so it does not have to be fixed, it is variable. Thus, the electrical or electromagnetic behavior of the structure can be additionally tuned. The mechanical attachment of the cylindrical resonator 1 can help with that a suitable fastening material, in particular an adhesive 7 or the like, on the circuit board 6 Himself (cf. 6 ) or on any object 5 which may be, for example, a simple holding surface located in the vicinity of the surface of the circuit board 6 is attached (cf. 5 ). Advantageously, the object is 5 However, a cover, as in the design of oscillator circuits or electrical or electromagnetic filters in almost all practical cases above the pill (ie in the positive z-direction) is to be formed. This cover can for example be made of metal or absorptive materials, such as plastic.

Finally, the cylindrical ceramic resonator 1 even in the negative value range to Ankontaktierungsstruktur 4 . 4a . 4b be arranged, in particular - as in 7 shown - if in the circuit board 6 a recess 8th for the resonator 1 is trained. Particularly advantageous in this case are embodiments of recesses 8th , which is a kind of self-centering assembly of the resonator 1 to Ankontaktierungsstruktur 4 . 4a . 4b allow. Merely in addition, it should be mentioned again that in the embodiment of oscillator circuits, a cover (not shown) is to be formed above the pill (ie in the positive z-direction) of such filter elements.

The invention includes the formation of Ankontaktierungsstrukturen which one, two or more inlets and outlets 2 . 3 to have. With the present invention, the transmitted signal power can advantageously be compared with conventional coupling structures (cf. 8th shown bandpass filter) increase significantly. Thus, a secure oscillation and a stable operation of an oscillator constructed with this filter structure can be achieved under practical operating conditions (eg over a wide temperature range).

The positioning accuracy of the cylindrical resonator 1 is very low. This allows a simple and cost-effective production, in which the resonator 1 only eg in the middle of Ankontaktierungsstruktur 4 . 4a . 4b must be glued.

The present invention was based on a filter element with a cylindrical, dielectric resonator 1 described. However, it is not limited to this type of resonators. In particular, any type of rotationally symmetric resonators, regardless of whether they are solid ("disk-type") or hollow or hollow body parts ("cylinder-type"), may be the subject of contacting according to the invention.

The The present invention is particularly suitable for use in oscillator circuits with operating frequencies greater than 18 GHz, as they typically are in outdoor spaces of a motor vehicle such as Lane Departure Warning (LDW), Blind Spot Detection (BSD) or Rear View Detection.

Claims (14)

Filter element suitable for filtering electromagnetic waves, in particular bandpass filters or bandstop filters, also embodied as reflection filters or the like, comprising - a dielectric, cylindrical resonator ( 1 ); and - one or more lines ( 2 . 3 ), which electromagnetic waves to the dielectric resonator ( 1 ) move; characterized in that - the lines ( 2 . 3 ) in a contacting structure ( 4 . 4a . 4b ), which is at least partially sickle-shaped. Filter element according to claim 1, characterized in that each line ( 2 . 3 ) each in a separately formed Ankontaktierungsstruktur ( 4a . 4b ) ends. Filter element according to claim 1, characterized in that two or more lines ( 2 . 3 ) in a jointly formed Ankontaktierungsstruktur ( 4 ) end up. Filter element according to one of claims 1 to 3, characterized in that the Ankontaktierungsstruktur ( 4 ) is designed as a circular ring. Filter element according to one of claims 1 to 3, characterized in that the Ankontaktierungsstruktur ( 4 . 4a . 4b ) is formed as a circular arc segment with a variable opening angle (α) less than 360 °; in particular, about 160 ° in two lines; in particular three lines to about 110 °; in particular, about 75 ° in four lines. Filter element according to one of claims 1 to 5, characterized in that the Ankontaktierungsstruktur ( 4 . 4a . 4b ) larger dimensions than the cylindrical resonator ( 1 ) having. Filter element according to one of claims 1 to 5, characterized in that the Ankontaktierungsstruktur ( 4 . 4a . 4b ) smaller dimensions than the cylindrical resonator ( 1 ) having. Filter element according to one of the preceding claims, characterized in that the resonator ( 1 ) to Ankontaktierungsstruktur ( 4 . 4a . 4b ) varia bel is arranged spaced. Filter element according to one of the preceding claims 1 to 8, characterized in that the resonator ( 1 ) on any object ( 5 ), for example, a holding surface, a cover or the like, which in the vicinity of the Ankontaktierungsstruktur ( 4 . 4a . 4b ), attached, preferably glued, is. Filter element according to one of the preceding claims 1 to 8, wherein the lines ( 2 . 3 ) together with its Ankontaktierung ( 4 . 4a . 4b ) Are part of a printed circuit board structure, characterized in that the resonator ( 1 ) by means of a suitable fastening material ( 7 ) on the printed circuit board ( 6 ), preferably glued, is attached. Filter element according to one of the preceding claims 1 to 9, wherein the lines ( 2 ; 3 ) together with its Ankontaktierung ( 4 . 4a . 4b ) are part of a printed circuit board structure, for example, characterized in that in the printed circuit board ( 6 ) or the object ( 5 ) a recess ( 8th ) is provided, in which the resonator ( 1 ), preferably self-centering, by means of a suitable fastening means ( 7 ), preferably glued, is arranged. Filter element according to one of the preceding claims, characterized in that the resonator ( 1 ) to Ankontaktierungsstruktur ( 4 . 4a . 4b ) is aligned substantially centered. Filter element according to one of the preceding claims, characterized in that the resonator ( 1 ) has an operating frequency greater than 18 GHz. Oscillator, in particular for radar installations, LMDS distribution services, satellite receiver or the like, comprising a filter element for filtering electromagnetic waves according to one of the preceding claims.