Radio frequency device

Abstract

A transition unit of a radio frequency device provides a transition between a planar differential pair transmission line and a hollow radio frequency waveguide. A substrate layer arrangement with a planar differential pair transmission line is arranged on one or more surfaces of at least one substrate layer. An end section of the transmission line is configured as a radio frequency signal emission pattern. The transition unit has an end section of a waveguide for electromagnetic waves that is attached to the substrate layer arrangement and superposes the radio frequency signal emission pattern. The waveguide is directed perpendicular to the substrate layer arrangement. An open end of the end section of the waveguide is attached to a first outer surface or a second outer surface of the substrate layer arrangement. Opposite to the end section a back cavity is attached with an open end towards the substrate layer arrangement.

Claims

1.-8. (canceled)

9. A radio frequency device (1) with a transition unit (2) providing a transition from a planar differential pair transmission line (7) to a hollow radio frequency waveguide (15, 27), the radio frequency device (1) comprising a substrate layer arrangement (3) with a planar differential pair transmission line (7) arranged on one or more surfaces (10, 11) of at least one substrate layer (4, 5) of the substrate layer arrangement (3), and with the transition unit (2) comprising an end section (12) of the differential pair transmission line (7) that is configured as a radio frequency signal emission pattern (13), the transition unit (2) further comprising an end section (14) of the waveguide (15) for radio frequency electromagnetic waves that is attached to the substrate layer arrangement (3) and that superposes the radio frequency signal emission pattern (13), wherein the end section (14) of the waveguide (15) is directed perpendicular to the one or more surfaces (10, 11) of the substrate layer arrangement (3) with the planar differential pair transmission line (7), wherein an open end (17) of the end section (14) of the waveguide (15) is attached to a first outer surface (16) or a second outer surface (19) of the substrate layer arrangement (3), and wherein opposite to the end section (14) of the waveguide (15) a back cavity (18) is attached with an open end (21) of the back cavity (18) to the substrate layer arrangement (3), whereby the back cavity (183) prevents a part of the radio frequency signal emission that is emitted from the emission pattern (13) from leaking outside of the end section (14) of the waveguide (15).

10. The radio frequency device (1) according to claim 9, wherein a distance between the planar differential pair transmission line (7) and a back side (20) of the back cavity (18) that opposes the first or second surface (10, 11) of the substrate layer arrangement (3) is larger than at least one distance between opposing parts (22, 23) of the circumferential line of a cross-section of the open end (21) of the back cavity (18).

11. The radio frequency device (1) according to claim 9, wherein the end section (14) of the waveguide (15) is a first end section (14) of a first waveguide (15), and wherein the back cavity (18) is a second end section (28) of a second waveguide (27) that is directed into an opposite direction of the first end section (14) of the first waveguide (15), whereby a part of the radio frequency signal emission that is emitted from the emission pattern (13) is transmitted into the second end section (28) of the second waveguide (27).

12. The radio frequency device (1) according to claim 9, wherein a cross-section area of the open end (21) of the back cavity (18) and a cross-section area of the open end (17) of the end section (14) of the waveguide (15) are identical and wherein the open end (21) of the back cavity (18) superposes the open end (17) of the end section (14) of the waveguide (15).

13. The radio frequency device (1) according to claim 9, wherein the radio frequency device (1) comprises several transition units (2) arranged adjacent to each other.

14. The radio frequency device (1) according to claim 13, wherein the several transition units (2) are arranged in two or more rows (24, 25) running parallel and at a distance towards each other.

15. The radio frequency device (1) according to claim 14, wherein a distance (26) between adjacent transition units (2) of a first row (24) or of a second row (25) is larger or identical to the lateral extension of the transition units (2), and wherein at least some of the transition units (2) of the first row (24) are arranged within a corresponding gap (26) between adjacent transition units (2) of the second row (25).

16. The radio frequency device (1) according to claim 13, wherein the design of two or more back cavities (18) that are arranged adjacent to each other is identical.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present invention will be more fully understood, and further features will become apparent, when reference is made to the following detailed description and the accompanying drawings. The drawings are merely representative and are not intended to limit the scope of the claims. In fact, those of ordinary skill in the art may appreciate upon reading the following specification and viewing the present drawings that various modifications and variations can be made thereto without deviating from the innovative concepts of the invention. Like parts depicted in the drawings are referred to by the same reference numerals.

[0017] FIG. 1 illustrates a perspective sectional view of a transition unit of a radio frequency device with an arrangement of two substrate layers with a planar differential pair transmission line arranged between facing surfaces of the substrate layers, with an end section of a hollow waveguide positioned at a top surface of a substrate layer arrangement comprising the two substrate layers, whereby an end section of the hollow waveguide superposes the radio frequency signal emission pattern of the planar differential pair transmission line, and with a back cavity opposingly attached to a back surface of the substrate layer arrangement,

[0018] FIG. 2 illustrates a sectional view along the line II-II of the transition unit shown in FIG. 1,

[0019] FIG. 3 illustrates a perspective view of several planar differential pair transmission lines arranged within a substrate layer arrangement adjacent to each other, whereby each end section of the respective differential pair transmission line is configured as a radio frequency signal emission pattern,

[0020] FIG. 4 illustrates a perspective view of the substrate layer arrangement of FIG. 3 with end sections of the respective hollow waveguides mounted on top of the radio frequency signal emission patterns and back cavities arranged opposite to the hollow waveguides at the substrate layer arrangement, and

[0021] FIG. 5 illustrates another embodiment of a transition unit with a first hollow waveguide and a second hollow waveguide arranged on the substrate layer arrangement opposing towards each other.

DETAILED DESCRIPTION

[0022] In FIGS. 1 and 2 a perspective sectional view of an exemplary part of a radio frequency device 1 with a transition unit 2 is shown. The radio frequency device 1 comprises a substrate layer arrangement 3 that comprises a first substrate layer 4 and a second substrate layer 5, each made of an electrically non-conducting material like e.g. glass. The first and second substrate layer 4, 5 are arranged parallel and at a distance towards each other. The volume between the first and second substrate layer 4, 5 is filled with a tunable dielectric material 6 like e.g. a liquid crystal material with variable and controllable dielectric properties. The volume between the first and second substrate layer 4, 5 can be segmented to allow for many small segments or chambers that are filled with the tunable dielectric material 6. The dielectric properties of the tunable dielectric material 6 can be controlled e.g. by applying a bias voltage to bias electrodes on opposite sides of the volume or of a small segment for which the dielectric properties of the tunable dielectric material are to be preset or modified.

[0023] A planar differential pair transmission line 7 with two parallel line sections 8, 9 of an electrically conducting material is arranged on a first surface 10 of the first substrate layer 4 and on a second surface 11 of the second surface 5 of the substrate layer arrangement 3. The first surface 10 and the second surface 11 are facing each other and confine the volume between the first and second substrate layer 4, 5. The planar differential pair transmission line 7 runs into an end section 12 that is configured as a radio frequency signal emission pattern 13, resulting in a dipole-like configuration within this embodiment.

[0024] An end section 14 of a hollow waveguide 15 made from an electroconductive material is also arranged on a first outer surface 16 of the substrate layer arrangement 3. An open end 17 of the end section 14 of the hollow waveguide 15 superposes the radio frequency signal emission pattern 13 of the end section 12 of the planar differential pair transmission line 7, as can be seen in FIG. 2. Thus, a radio frequency signal that is transmitted along the planar differential pair transmission line 7 towards the end section 12 will be emitted from the frequency signal emission pattern 13. A part of the emitted signal power will be directed through the open end 17 and into the hollow waveguide 16. Another part of the emitted signal power will be directed into an opposite direction.

[0025] Opposite to the end section 14 of the hollow waveguide 15 there is a back cavity 18 that is mounted onto a second outer surface 19 of the substrate layer arrangement 3, whereby the second outer surface 19 is opposite to the first outer surface 16 of the substrate layer arrangement 3. A distance between the second outer surface 19 of the substrate layer arrangement 3 and a back side 20 of the back cavity 18 that opposes the second outer surface 19 is larger than the distance between opposing parts of the circumferential line of a cross-section of an open end 21 of the back cavity 18, i.e. larger than a distance between opposing wall sections 22, 23 around the open end 21 of the back cavity 18.

[0026] A shape of the open end 21 of the back cavity 18 equals the shape of the open end 17 of the hollow waveguide 15. Furthermore, the open end 21 of the back cavity 18 is positioned opposing to the end section 14 of the hollow waveguide 15 in a manner as to fully superimpose the open end 17 of the hollow waveguide 15. A large part of the signal power that is directed into the direction of the back cavity 18 will be reflected and fed into the hollow waveguide 15. By adding the back cavity 18 to the transition unit 2, an unwanted leakage of radio frequency signal emission from the transition unit 2 can be significantly reduced.

[0027] FIGS. 3 and 4 show a part of a radio frequency device 1 with several transition units 2 arranged in two rows 24, 25 along the first surface 10 of the first substrate layer 4 and along the second surface 11 of the second surface 5 of the substrate layer arrangement 3. In FIG. 3 the transition units 2 are shown without hollow waveguides 15 and without back cavities 18. In FIG. 4 the same transition units 2 are shown with hollow waveguides 15 and back cavities 18, whereby the end sections 14 of the hollow waveguides 15 and the respective open ends 21 of the back cavities 18 each superpose the frequency signal emission patterns 13 of the corresponding planar differential pair transmission lines 7.

[0028] A distance between adjacent transition units 2 of the first row 24 and of a second row 25 is larger than the lateral extension of each of the hollow waveguides 15 of the adjacent transition units 2. Thus, there is a gap 26 between adjacent hollow waveguides 15 along the first row 24 as well as along the second row 25. The transition units 2 of the first row 24 are arranged within a corresponding gap 26 between adjacent transition units 2 of the second row 25, and vice versa. The planar differential pair transmission lines 7 that run towards the transition units 2 of the second row 25 are arranged within the gap 26 between adjacent transition units 2 of the first row 24.

[0029] FIG. 5 illustrates another embodiment of the transition unit 2 of a radio frequency device 1. A second hollow waveguide 27 is used as the back cavity 18. Most part of the radio frequency signal emission from the frequency signal emission pattern 13 will be directed either into the first hollow waveguide 15 that is arranged on the first outer surface 16 of the substrate layer arrangement 3 or into the second hollow waveguide 27 that is arranged on the second outer surface 19 of the substrate layer arrangement 3 opposing the first hollow waveguide 15. The undesired leakage of radio frequency signal emission from the transition unit 2 will be significantly reduced. A signal transmission direction within the end section 14 of the first hollow waveguide 15 is opposite to a signal transmission direction within an end section 28 of the second waveguide 27.