Microwave cooking device having a patch antenna

Abstract

A microwave cooking appliance includes a cooking chamber delimited by a cooking chamber wall, and a microwave apparatus configured to introduce microwaves into the cooking chamber. The microwave apparatus includes a patch antenna having a planar base body and a planar emission body, which are electrically insulated from one another. The emission body is configured to cover the base body at a distance and capable of being fed with microwave energy, with the base body corresponding to a region of the cooking chamber wall.

Claims

1. A microwave cooking appliance, comprising: a cooking chamber delimited by a cooking chamber wall; and a microwave apparatus configured to introduce microwaves into the cooking chamber, said microwave apparatus including a patch antenna having a planar base body and a planar emission body, which are electrically insulated from one another, said emission body configured to cover the base body at a distance and capable of being fed with microwave energy, said base body corresponding to a region of the cooking chamber wall, wherein the base body corresponds to a recess in the cooking chamber wall, said emission body being inserted into the recess, with the base body and the emission body being insulated electrically from one another by a peripheral gap, and an electrically insulating closing material configured to close the peripheral gap.

2. The microwave cooking appliance of claim 1, wherein the electrically insulating closing material covers the emission body and the peripheral gap on a side of the cooking chamber.

3. The microwave cooking appliance of claim 1, wherein the electrically insulating closing material is glass or glass ceramic.

4. The microwave cooking appliance of claim 1, wherein the electrically insulating closing material is light-permeable, and further comprising a light source to emit light such as to be capable of being coupled into the electrically insulating closing material from outside the cooking chamber.

5. The microwave cooking appliance of claim 4, wherein the recess in the cooking chamber wall corresponds to a recess in a cooking chamber light.

6. The microwave cooking appliance of claim 4, wherein the patch antenna has inner surfaces configured to reflect light.

7. The microwave cooking appliance of claim 1, wherein the emission body is arranged flush with the cooking chamber wall on a side facing the cooking chamber.

8. The microwave cooking appliance of claim 1, wherein the microwave apparatus includes a microwave supply, which is coupled capacitively to the emission body.

9. The microwave cooking appliance of claim 8, wherein the microwave supply is a coaxial line.

10. The microwave cooking appliance of claim 9, wherein the coaxial line includes an inner conductor inserted freely into a sleeve-type holding region of the emission body, and further comprising a dielectric material filling an intermediate space between the inner conductor and the sleeve-type holding region.

11. The microwave cooking appliance of claim 1, further comprising a number of said patch antenna arranged on the cooking chamber wall and aligned with different rotations from one another.

12. The microwave cooking appliance of claim 11, wherein the number of patch antennas are arranged on a side of the cooking chamber wall.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The properties, features and advantages of the present invention described above and the manner in which these are achieved will become clearer and more readily comprehensible in conjunction with the schematic description which follows of an exemplary embodiment, which is described in more detail in conjunction with the drawings.

(2) FIG. 1 shows an oblique sectional view of a detail of a cooking chamber wall in the region of a patch antenna according to a first exemplary embodiment;

(3) FIG. 2 shows a side sectional view of a first variant of a capacitive coupling of an inner conductor and an emission body of the patch antenna;

(4) FIG. 3 shows a side sectional view of a second variant of a capacitive coupling of an inner conductor and an emission body of the patch antenna;

(5) FIG. 4 shows a frequency response curve of the patch antenna; and

(6) FIG. 5 shows an oblique sectional view of a detail of a cooking chamber wall in the region of a patch antenna according to a second exemplary embodiment.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS OF THE PRESENT INVENTION

(7) FIG. 1 shows an oblique sectional view of a detail of a cooking chamber wall 1 of a household cooking appliance H in the region of a patch antenna 2. The patch antenna 2 is in particular built with mirror symmetry along the sectional plane.

(8) The cooking chamber wall 1 delimits a cooking chamber G. The patch antenna 2 has a planar base body 3 in the form of a sub-region of the cooking chamber wall 1, on which a recess 4 is present. The base body 3 therefore corresponds to a region of the cooking chamber wall 1. The recess 4 here is configured as a recess produced by removing material.

(9) A cooking chamber side flat base 5 of the recess 4 is covered by a plate-type emission body (“patch” 6). The patch 6 is inserted into the recess 4 in such a manner that it is arranged with its top face 7 facing the cooking chamber G practically flush with the cooking chamber wall 1. The base body 3 corresponds in particular to a region of the cooking chamber wall 1 below the flat base 5, in some instances also below the side edges of the recess 4.

(10) The base 5 and patch 6 are electrically conductive. They can have corresponding metal regions for this purpose, each having a metal sheet for example. The metal of base 5 and patch 6 can be the same or different. The base 5 and patch 6 can therefore both have steel sheet or be made of steel sheet. Alternatively the base can have steel sheet or be made of steel sheet and the patch 6 can have copper sheet or be made of copper sheet.

(11) The base 5 and patch 6 are arranged parallel to one another. The recess 4 and patch 6 form and delimit a hollow space 8. The base 5 and patch 6 have a basic shape that is rectangular when viewed from above, the corners of which can be rounded.

(12) The edge of the cooking chamber wall 1 delimiting the recess 4 and an edge of the patch 6 are separated from one another by a peripheral rectangular annular gap 9. The annular gap 9 is filled with an electrically insulating closing material 10 in the form of glass or glass ceramic. The base body 3 and patch 6 are therefore insulated electrically from one another, as the hollow space 8 also has an electrically insulating effect. The hollow space 8 can be filled with air or glass wool, etc. to this end.

(13) The patch 6 can be fed with microwave energy. A coaxial cable 11 is used for this purpose, being coupled to a microwave generator (not shown). An inner conductor 12 of the coaxial line 11 is passed through a hole 13 in the base body 3 and on through the hollow space 8 to a rear face 14 of the patch 6. The inner conductor 12 is insulated electrically from the cooking chamber wall 1, to which end an intermediate space between inner conductor 12 and base body 3 is filled with a dielectric material 15. The dielectric material 15 also serves to fix the inner conductor 12 mechanically.

(14) The inner conductor 12 is also insulated electrically from the patch 6, so there is a capacitive coupling for microwaves between said components.

(15) In one variant the closing material 10 is light-permeable. The household appliance H has at least one light source, e.g. an LED 16, the light L from which can be coupled into the closing material 10 from outside the cooking chamber G. The LED 16 can radiate its light L directly into the closing material 10, for example into a side edge. The closing material 10 then acts as a light guide and distributes the light L around its periphery. The light L is then radiated into the cooking chamber G, in some instances with a portion also being radiated into the hollow space 8. The closing material 10 thus serves to light the cooking chamber.

(16) Alternatively or additionally at least one light source, e.g. an LED 17, can radiate its light directly into the hollow space 8. To this end the LED 17 can be arranged in the region of the base 5 of the recess 4. The closing material 10 then serves as a window for the passage of light into the cooking chamber G.

(17) To increase luminous efficiency the inner surfaces of the patch antenna 2 facing the hollow space 8 can be configured to reflect, e.g. the surface of the recess 4, including the base 5, and/or the rear face 14 of the patch 6.

(18) If there are a number of patch antennas 2 present in the cooking chamber wall 1, in particular in a side of the cooking chamber wall 1, these can be aligned with different rotations from one another when viewed from above.

(19) FIG. 2 shows a side sectional view of a detail of a first variant of a capacitive coupling of the inner conductor 12 and the patch 6 of the patch antenna 2.

(20) To this end the patch 6 has a tube or sleeve-type holding region 18 projecting backward into the hollow space 8. The holding region 18 here is formed continuously by the patch 6 and therefore opens into the cooking chamber G. The inner conductor 12 is introduced freely into the holding region 18. A tube-shaped intermediate space 19 between the inner conductor 12 and the sleeve-type holding region 18 is filled with a dielectric material 20. This has the advantage that the inner conductor 12 can be positioned and fixed easily and precisely and the capacitive coupling can be established easily. The sleeve-type holding region 18 in particular forms a cylindrical capacitor together with the inner conductor 12 of the coaxial line and the dielectric material 20 in between. The cylindrical capacitor here is passed through to the cooking chamber side surface 7 of the patch 6.

(21) The dielectric materials 15 and 20 can be the same or different.

(22) FIG. 3 shows a side sectional view of a detail of a second variant of a capacitive coupling of the inner conductor 12 and a patch 21 of a patch antenna 2. The patch 21 is configured in the same manner as the patch 6, but with the sleeve-type holding region 22 not being here but adjoining the plate-type sub-region of the patch 21. The holding region 22 is therefore closed at the front or facing the cooking chamber G. The front face 7 of the patch 21 facing the cooking chamber G forms a continuous plane.

(23) FIG. 4 shows a frequency response curve FGE of the patch antenna 2 with a reflection factor |11| in dB plotted on the y-axis against a frequency in GHz on the x-axis. The frequency response curve FGE has a much wider band than a frequency response curve FGH of a conventional patch antenna. Both frequency response curves FGE and FGH have an extremes for the known microwave frequency of 2.45 GHz.

(24) FIG. 5 shows an oblique sectional view of a detail of a cooking chamber wall 23 in the region of a patch antenna 24. The patch antenna 24 has the same basic structure as the patch antenna 2. However a base body 25, the surface of which forms the recess 4 (optionally only its base 5) of the cooking chamber wall 23, has not simply been produced by removing material but by embossing and the like.

(25) The closing material 10 now also covers the patch 21 and the cooking chamber wall 23 outside the recess 4 in the manner of a coating. A smooth layer of the closing material 10 facing the cooking chamber G is provided overall.

(26) The patch antenna 24 can also be configured to radiate light into the cooking chamber (not shown).

(27) The present invention is of course not limited to the illustrated exemplary embodiment.

(28) Generally “one”, etc. can refer to one or a number, in particular in the sense of “at least one” or “one or more”, unless this is specifically excluded, for example by the expression “just one”, etc.

(29) A number can also refer to just the cited number as well as a standard tolerance range, unless this is specifically excluded.

LIST OF REFERENCE CHARACTERS

(30) 1 Cooking chamber wall 2 Patch antenna 3 Base body 4 Recess 5 Base 6 Patch 7 Top face 8 Hollow space 9 Annular gap 10 Closing material 11 Coaxial line 12 Inner conductor 13 Hole 14 Rear face of patch 15 Dielectric material 16 LED 17 LED 20 Holding region 19 Intermediate space 20 Dielectric material 21 Patch 22 Holding region 23 Cooking chamber wall 24 Patch antenna 25 Base body FGE Frequency response curve FGH Frequency response curve G Cooking chamber H Household cooking appliance L Light