Coupling conductors for a yig filter or yig oscillator and method for producing said conductors

p0001The invention relates to a YIG filter or a YIG oscillator.

p0002YIG bandpass filters or YIG oscillators have at least one resonator which is preferably spherical in shape and is composed of an yttrium-iron garnet (<u>Y</u>trium-<u>I</u>ron-<u>G</u>Arnet YIG). The resonator effect is mediated by means of coupling lines, which must be designed and arranged in such a way that the center point of the resonator and the center point of the bending radius of a coupling line exactly correspond.

p0003A YIG band-pass filter with appropriately designed coupling lines is, for example, from the printed copy <patcit id="pcit0001" dnum="US4480238A"><text>U.S. 4,480,238</text></patcit> known. The tunable YIG bandpass filter in this case has a basic body, which has slots for receiving insulated platelets, which have a conductive coating at one edge, which serves as coupling lines. Furthermore, filter chambers for receiving the YIG elements are provided. The platelets are inserted into the slots via the YIG elements such that the YIG elements are arranged in recesses in the edges provided with the conductive coating. The YIG elements and the platelets are fixed in fixed positions.

p0004A disadvantage of the YIG bandpass filter known from the abovementioned printed publication is, in particular, the complex production of the platelets forming the coupling lines. The insulator serving as carrier must first be appropriately shaped and then provided with the conductive coating. This is costly and rough, since the coating is sensitive to damage due to the low layer thickness.

p0005The object of the present invention is to provide a YIG filter or YIG oscillator, with coupling lines which are simple to manufacture, insensitive to damage and easy to install.

p0006The object is achieved with respect to the coupling lines by the characterizing features of claim 1.

p0007Advantageous further developments of the arrangements according to the invention are given in the subclaims.

p0008<patcit id="pcit0002" dnum="FR2616972"><text>FR 2 616 972</text></patcit>, <figref idrefs="f0001">Figure 2</figref>, Discloses a YIG arrangement according to the preamble of claim 1.

p0009BRIEF DESCRIPTION OF THE DRAWINGS Preferred exemplary embodiments of the invention are illustrated by way of example with reference to the drawing and are explained in more detail in the following description. Show it:<dl id="dl0001"><dt>Fig. 1A</dt><dd>A schematic, perspective illustration of a preferred exemplary embodiment of a basic body of a YIG hand-held filter with resonators and coupling lines, </dd><dt>1B</dt><dd>A schematic perspective view of the resonators and coupling lines without a basic body,</dd><dt>FIG. 2A</dt><dd>2 shows a schematic representation of an exemplary coupling line for two resonators according to the prior art,</dd><dt>2B</dt><dd>2 shows a schematic illustration of an exemplary embodiment of a coupling line designed according to the invention for two resonators, and FIG</dd><dt>FIG.</dt><dd>3A-C show schematic illustrations of coupling lines configured according to the invention during the production process before the separation.</dd></dl>

p0010<figref idrefs="f0001">Fig. 1A</figref> Shows, in a schematic, perspective view, an exemplary embodiment of a YIG bandpass filter 2 which has a basic body 3 and, in the exemplary embodiment, four filter elements 4 formed in the base body 3 with as many YIG elements 6.

p0011In this case, the YIG elements 6 are spherical in shape from an yttrium-iron garnet, mounted on holders 10, for example, by gluing them with epoxy resin, and by electromagnetic coupling.

p0012The filter chambers 4 are connected to each other by slots 5, into which the coupling lines 1 are inserted. In the exemplary embodiment, two of the filter chambers 4 are designed in the same way. Coaxial cables 11, through which the signal input or output leads, open into the filter chambers 4 designated 4a. The filter chambers 4 designated 4b, on the other hand, have only the YIG elements 6. The number of filter chambers 4b is not limited to two, but may be one or more, so that the total number of filter chambers 4 can be three or more.

p0013<figref idrefs="f0001">1B</figref> Shows the arrangement of the coupling lines 1 as well as of the YIG elements 6 mounted on their holders 10 without the surrounding basic body 3 for the sake of clarity.

p0014In the exemplary embodiment, the coupling lines 1 are designed in two different forms. The coupling line 1, which connects the filter chambers 4b one below the other, is designed as an input or output line 1a, whereas in the exemplary embodiment three further coupling lines 1 are embodied as connecting lines 1b.

p0015How <figref idrefs="f0001">1B</figref> The coupling lines 1 have contact lugs 8 which, on the one hand, serve for the ground connection of the coupling lines 1 in the base body 3 and, on the other hand, for the fixing of the coupling lines 1 in the slots 5. In this case, the contact lugs 8 are shaped rectangularly, an edge length of the contact lugs 8 corresponding approximately to the axial thickness of the basic body 2.

p0016Consider the <figref idrefs="f0001">Figures 2A and 2B</figref>, Can be seen, whereby the coupling lines 1 according to FIG <figref idrefs="f0001">2B</figref> Of conventional coupling lines 1 according to FIG <figref idrefs="f0001">FIG. 2A</figref> Respectively.

p0017The two embodiments have in common that in each case at least one curved section 17 is provided which at least partially surrounds a YIG element 6 in such a way that a center point of the YIG element 6 coincides with a center point of the curved section 17. Furthermore, at least one line section 18 is provided.

p0018In the <figref idrefs="f0001">FIG. 2A</figref> , According to the prior art, is bent from a wire. In this case, first the YIG elements 6 are moved into the position shown in FIG<figref idrefs="f0001">Figures 2A and 2B</figref> (Not shown), and then the coarse pre-bent wire is inserted into the slots 5. A measurement of the coupling degree results where the coupling line 1 still needs to be deflected. This is done manually by means of a suitable tool. After that you have to check again and re-adjust. For this purpose, the YIG filter 2 or YIG oscillator must be opened each time and then reassembled to make the measurement. The method is therefore extremely complex and often even leads to the fact that the workpiece has to be completely discarded after several iterations because no satisfactory coupling is achieved.

p0019On the other hand, the inventive coupling lines 1 according to FIG <figref idrefs="f0001">2B</figref> From a metallic foil by means of suitable methods such as etching, eroding, cutting, in particular laser cutting or water jet cutting and / or punching. This is followed by the correct positioning of the YIG elements 6 relative to the coupling lines 1.

p0020The foil consists of a copper-beryllium alloy to meet both the elasticity and the strength requirements. The thickness of the film is preferably about 50 μm.

p0021The production of the coupling lines 1 from the film takes place in several processing steps. First, the film is cleaned and applied on both sides with a positive lacquer at an alignment accuracy of approximately 5 μm in a layer thickness of approximately 5 μm in order to create a mask. Thereafter, the coupling lines 1 are produced, for example, by spray etching with iron chloride. (FeCl₃) Subsequently, in the form of a carrier 9, they are freed of lacquer residues with a predetermined number of coupling lines 1 and galvanically provided with a gold coating of approximately 5 μm. This is followed by a curing process for, for example, one hour at 325 ° C. The coupling lines can then be released from the foil carrier 9 and installed.

p0022The coupling lines 1 have a fixed shape with a precisely defined radius of curvature in the curved sections 17 with a uniform curvature due to the described production method. The YIG elements 6 are then aligned relative to the coupling lines 1. This is simpler compared with the prior art and involves considerably less effort because the manufacturing accuracy in the coupling lines 1 designed according to the invention is considerably greater than in the case of manually bent coupling lines 1.

p0023<figref idrefs="f0002">Fig. 3A</figref> Shows in a schematic representation a carrier 9 which contains the coupling lines 1 required for a YIG band-pass filter 2 with four YIG elements 6.

p0024As already mentioned above, in the exemplary embodiment, the coupling lines 1 are designed in the form of an input or output line 1a as well as three connecting lines 1b. The former is in<figref idrefs="f0002">Fig. 3A</figref> Are arranged at the very bottom in the film carrier 9, the latter above.

p0025The <figref idrefs="f0002">3B and 3C</figref> Show the <figref idrefs="f0002">Fig. 3A</figref> Sections designated by IIIB and IIIC from the carrier 9 <figref idrefs="f0002">3B</figref> One of the three connection lines 1b is shown, while FIG <figref idrefs="f0002">3C</figref> The input or output line 1a.

p0026From the <figref idrefs="f0002">3B and 3C</figref> It can be seen that after the process of etching, cutting, punching or eroding from the film, the coupling lines 1 are held, before being separated in the carrier 9, by webs 12, which are formed on the contact lugs 8. When the coupling lines 1 are separated, the coupling lines 1 are separated from the carrier 9 by breaking the webs 12. After the separation, the coupling lines 1 are mounted in the base body 3 according to their shape and fixed in the base body 3 by soldering, welding or another connection method which preserves the electrical conductivity.