Abstract
A transition unit providing a radio frequency signal transition between a radio frequency hollow waveguide system and a planar transmission line comprises two or more transition sections of transmission line arranged adjacent to each other at a first surface of the first substrate layer of a substrate layer arrangement. The hollow waveguide system comprises a distribution section. One input waveguide is separated into one dedicated output waveguide for each of the transition sections. For each of the transition sections of the transmission lines a corresponding end section of a respective output waveguide is directed perpendicular to the first surface of the first substrate layer. For each end section an open end of the end section of the waveguide system superposes the corresponding transition section. The two or more end sections are arranged adjacent to each other in order to provide for favorable boundary conditions for electromagnetic wave propagation.
Claims
1.-11. (canceled)
12. A radio frequency device with a transition unit (1) providing a radio frequency signal transition between a radio frequency hollow waveguide system (2) and a planar transmission line (3), the radio frequency device comprising a substrate layer arrangement (15) with the planar transmission line (3) arranged on a first surface (14) of a first substrate layer (4) of the substrate layer arrangement (15), wherein the transition unit (1) comprises a transition section (22) of the transmission line (3) that is configured as a radio frequency signal transition pattern, and wherein the transition unit (1) further comprises an end section (11, 20) of the waveguide system (2) for radio frequency electromagnetic waves that is attached to the substrate layer arrangement (15) and that superposes the radio frequency signal transition pattern, wherein the transition unit (1) comprises two or more transition sections (22) of a corresponding number of transmission lines (3) that are arranged adjacent to each other, wherein the hollow waveguide system (2) comprises a distribution section wherein one input waveguide (5, 8) is separated into one dedicated output waveguide (10, 19) for each of the transition sections (22), wherein for each of the transition sections (22) of the transmission lines (3) a corresponding end section (11, 20) of a respective output waveguide (10, 19) is directed perpendicular to the first surface (14) of the first substrate layer (4) of the substrate layer arrangement (15), wherein for each end section (11, 20) an open end of the end section (11, 20) of the waveguide system (2) superposes the corresponding transition section (22), and wherein the two or more end sections (11, 20) of the waveguide system (2) are arranged adjacent to each other in order to provide for favorable boundary conditions for electromagnetic wave propagation that result in reduced radio frequency signal power leakage from the transition unit (1) when compared to a transition unit with only one end section (11, 20) of the waveguide system (2).
13. The radio frequency device according to claim 12, wherein the hollow waveguide system (2) comprises N output waveguides (10, 19) and N−1 corresponding waveguide splitting units (6, 9, 18) that each split-up one input waveguide (5, 8, 17) into two output waveguides (7, 10, 19), with N being an even integer number.
14. The radio frequency device according to claim 12, wherein the hollow waveguide system (2) comprises 2N output waveguides (7, 10, 19), with N being an integer number and with N>1.
15. The radio frequency device according to claim 12, wherein the end sections (11, 20) of the output waveguides (10, 19) that are attached to the substrate layer arrangement (15) are symmetric in shape.
16. The radio frequency device according to claim 12, wherein the end sections (11, 20) of the output waveguides (10, 19) that are attached to the substrate layer arrangement (15) are of rectangular shape.
17. The radio frequency device according to claim 12, wherein several or all end sections (11, 20) of the output waveguides (10, 19) that are attached to the substrate layer arrangement (15) are arranged along a straight line.
18. The radio frequency device according to claim 12, wherein the end sections (11, 20) of the output waveguides (10, 19) that are attached to the substrate layer arrangement (15) are arranged in two or more rows (21) running parallel and at a distance towards each other.
19. The radio frequency device according to claim 17, wherein the transition unit (1) comprises for each end of a row (21) one waveguide section element (25) arranged adjacent to the last output waveguide (19) within the row (21).
20. The radio frequency device according to claim 19, wherein the waveguide section element (25) is identical to the end section (20) of the last output waveguide (19) within the row (21).
21. The radio frequency device according to claim 12, wherein the transition unit (1) comprises at least one or more back cavities (24), wherein each back cavity (24) is arranged opposite to a corresponding end section (20) of an output waveguide (19) that is attached to the substrate layer arrangement (15) with an open end of the back cavity (24) directed towards the first substrate layer (4), wherein the back cavity (24) prevents a part of a radio frequency signal emission that is emitted from the emission pattern from leaking outside of the end section (20) of the output waveguide (19).
22. The radio frequency device according to claim 12, wherein at least two adjacent transmission lines (3) each comprise a transmission section (27) that runs into the transition section (22), wherein the transition section (22) is superposed by the end section (11, 20) of the corresponding output waveguide (10, 19) and wherein the transmission section (27) is arranged outside of a surface area on the first surface (14) of the first substrate layer (4) that is superposed by this end section (11, 20) of the corresponding output waveguide (10, 19).
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] 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.
[0025] FIG. 1 illustrates a sectional view of a small region within a radio frequency device with a transition unit with four transition sections of transmission lines and corresponding end sections of a hollow waveguide system, the transition sections and the corresponding end sections each arranged in a row adjacent to each other,
[0026] FIG. 2 illustrates a perspective view of a hollow waveguide system with one input waveguide and 32 output waveguides,
[0027] FIG. 3 illustrates a top view of a region of a substrate layer that is part of a substrate layer arrangement with a large number of transmission lines parallel to each other and with transition sections of the transmission lines arranged in a row adjacent to each other,
[0028] FIG. 4 illustrates the schematic representation of simulation results of the S-Parameter S11 and S21 that characterizes the transmission of a radio frequency signal from the hollow waveguide system to a transmission line,
[0029] FIG. 5 illustrates a perspective view of an end section of an output waveguide that is arranged on top of a substrate layer arrangement with a transition section of a transmission line, whereby a back cavity is arranged at the substrate layer arrangement opposite to the end section of the output waveguide,
[0030] FIG. 6 illustrates a sectional view of an end region of the transition unit with a waveguide section element at the end of the row of end sections of the waveguide system,
[0031] FIG. 7 illustrates a schematic view of the transition sections of two transmission lines that are aligned with each other, whereby the cross-section of the corresponding end section of the output waveguide that superposes the transition sections is represented by a dashed line,
[0032] FIG. 8 illustrates a schematic view similar to FIG. 7 for a different embodiment of the transmission lines,
[0033] FIG. 9 illustrates a schematic view for an arrangement of several transmission lines similar to the transmission line shown in FIG. 8,
[0034] FIG. 10 illustrates a perspective view of a substrate layer arrangement with a number of transmission lines arranged between a first substrate layer and a second substrate layer,
[0035] FIG. 11 illustrates a perspective view of the arrangement of transmission lines shown in FIG. 10 and a corresponding number of end sections of output waveguides, whereby the several end sections are formed within a monolithic structure of an electroconductive material, and
[0036] FIG. 12 illustrates a sectional view through the end sections within the monolithic structure shown in FIG. 11 along the line XII-XII in FIG. 11.
DETAILED DESCRIPTION
[0037] In FIG. 1 a sectional view of a schematic representation of a transition unit 1 is shown. Such a transition unit 1 can be incorporated into many different radio frequency devices and allows for a radio frequency signal transition between a hollow waveguide system 2 and a planar transmission line 3. An exemplary embodiment of such a hollow waveguide system 2 is shown in FIG. 2, and an exemplary embodiment of a first substrate layer 4 with a large number of transmission lines 3 arranged on a top side of the first substrate layer 4 is shown in FIG. 3.
[0038] The hollow waveguide system 2 is made from an electroconductive material, whereby the shape and dimensions of the hollow waveguide system 2 is adapted to allow for low-loss transmission of radio frequency signals along the waveguides within the waveguide system 2. The waveguide system 2 comprises an input waveguide 5 that is split-up within a waveguide splitting unit 6 into two separate output waveguides 7 that emerge from the waveguide splitting unit 6. Each of the two output waveguides 7 runs into a corresponding input waveguide 8 and a corresponding waveguide splitting unit 9. Each of the two waveguide splitting units 9 divides the input waveguide 8 into two emerging output waveguides 10, resulting in a total of four output waveguides 10 that are arranged in a row adjacent to each other. Thus, a radio frequency input signal that is feed into the input waveguide 5 will be split-up into four similar radio frequency output signals that are transmitted towards the four output waveguides 10.
[0039] Each of the output waveguides 10 runs into an open-ended end section 11 of the output waveguide 10. The end section 11 of each of the output waveguides 10 is mounted on a top side 12 of a second substrate layer 13. The second substrate layer 13 covers the first substrate layer 4 with the planar transmission lines 3 arranged on the top side 14 of the first substrate layer 4 and thus between the first and second substrate layer 4, 13. Within this exemplary embodiment a substrate layer arrangement 15 comprises these two substrate layers 4, 13. Each of the planar transmission lines 3 comprises two electroconductive transmission line sections 16 arranged parallel and at a distance towards each other.
[0040] Due to the symmetric shape and arrangement of the four output waveguides 10 any undesired leakage from the end sections 11 and possible cross-talk between adjacent output waveguides 10 is significantly reduced in comparison with a single output waveguide that is arranged in between other components of a radio frequency device, but at a large distance to a neighboring output waveguide. Thus, the efficiency of the transition of the radio frequency signal between the hollow waveguide system 2 and the corresponding transmission lines 3 is enhanced.
[0041] The exemplary embodiment of the hollow waveguide system 2 that is shown in FIG. 2 comprises five levels 17 of waveguide splitting units 6, 9, 18 with one waveguide splitting unit 6 in a first level 17, two waveguide splitting units 9 in a second level 16, and with 2.sup.n−1 waveguide splitting units 18 in a level n, with n an integer number between 2 and 5. At the end of the hollow waveguide system 2 a total of 32 output waveguides 19 run into a total of 32 end sections 20 of the output waveguides 19. The end sections 20 are arranged along a row 21 adjacent to each other. The part of the hollow waveguide system 2 between the first input waveguide 2 and the final output waveguides 19 can be labeled as distribution section, as the incoming radio frequency signal is distributed into a number of output waveguides 19. Preferably each of the waveguide splitting units 6, 9, 18 divides the corresponding incoming radio frequency signal into two outgoing radio frequency signals of similar intensity and signal characteristics.
[0042] It is easily understood by a person skilled in the art to modify the exemplary embodiment of the hollow waveguide system 2 to comprise additional levels up to a level N with N a positive integer number and further comprising 2.sup.N−1 waveguide splitting units 6, 9, 18. Thus, each level n with n an integer number between 0 and N comprises 2.sup.n−1 waveguide splitting units 6, 9, 18 resulting in 2.sup.N output waveguides 19 with corresponding end sections 20 that can be mounted onto a substrate layer arrangement
[0043] In FIG. 3 a top view towards the top surface 14 of the first substrate layer 4 of the substrate layer arrangement 15 shown in FIG. 1 is shown. A large number of transmission lines 3 is arranged on the top surface of the first substrate layer 4, whereby the transmission lines 3 are aligned in parallel and run into transition sections 22 with a radio frequency signal transition pattern, which is shown and described in more detail in FIGS. 7 and 8. The hollow waveguide system 2 can be mounted or arranged on top of the substrate layer arrangement 15 in a manner so that each of the end sections 20 of the output waveguides 19 of the hollow waveguide system 2 superposes a corresponding transition section 22 of the transmission lines 3.
[0044] In FIG. 4 a schematic diagram of the results of a simulation of two S-parameters S1,1 and S2,1 of a signal transition of a radio frequency signal between a single output waveguide 19 and the corresponding transition section 22 of a corresponding transmission line 3 within a frequency range between 17 and 21 GHz, whereby the output waveguide 19 and the transition section 22 are part of the transition unit 1. The magnitude in dB of the two S-parameters S1,1 and S2,1 is plotted along the ordinate, whereas the frequency range of the signal frequency is depicted along the abscissa of the diagram. It can be seen that the magnitude of the undesirable signal leakage that corresponds to the S-parameter S2,1 is very low over a large frequency range between 17.5 GHz and 20.5 GHz.
[0045] In FIG. 5 an end section 20 of a single output waveguide 19 is shown that is arranged on a top surface 23a of the substrate layer arrangement 15 of the first substrate layer 4 and the second substrate layer 13. At a bottom surface 23b of the substrate layer arrangement 15 and opposite to the output waveguide 19 a back cavity 24 is arranged such that a cross-section of an open end of the back cavity 24 superposes a cross-section of the end section 20 of the output waveguide 19. The back cavity 24 is a section of a waveguide similar to the single output waveguide 19 at the opposite side of the substrate layer arrangement. The back cavity 24 has an opening towards the substrate layer arrangement 15 and a closed back side opposite to the opening and the substrate layer arrangement 15. By adding a back cavity 24 for each of the end sections 20 of the output waveguides 19 an unwanted signal leakage during the signal transition between the hollow waveguide system 2 and the transmission lines 3 can be further reduced. A person skilled in the art has knowledge and is able to determine and adapt the shape and dimensions of the back cavity 24 to match the end section 20 of the output waveguide 19 and to reduce any unwanted signal leakage as much as possible.
[0046] In FIG. 6 and end region of the row 21 of end sections 20 of the output waveguides 19 of the hollow waveguide system 2 is shown, whereby the end sections 20 are mounted onto the substrate layer arrangement 15. For each end section 20 a corresponding back cavity 24 is arranged at the substrate layer arrangement 15 opposite to the respective end section 20. Next to the last end section 20 within the row 21 a waveguide section element 25 is mounted onto the substrate layer arrangement 15. The hollow waveguide section element 25 is made of an electroconductive material and matches the end sections 20 of the output waveguides 19 in shape and dimension. Furthermore, opposite to the waveguide section element 25 a corresponding back cavity 24 is arranged at the substrate layer arrangement 15. By adding a waveguide section element 25 that is not part of the hollow waveguide system 2 but adds to the row 21 of end sections 20 and establishes a symmetric counterpart of waveguide sections for the last end section 20 within the row 21, the unwanted leakage of radio frequency signal intensity during a signal transition is further reduced and the efficiency of the signal transition enhanced.
[0047] In FIGS. 7 and 8 two different exemplary embodiments of transition sections 22 of transmission lines 3 are shown.
[0048] The transition sections 22 shown in FIG. 7 comprise dipole shaped end sections 26 that runs parallel and backwards to the direction of the transmission line 3. Transmission sections 27 of the transmission line 3 are superposed by the cross-section 28 of the end section 20 of the corresponding output waveguide 19 that is depicted with a dashed line.
[0049] In another embodiment shown in FIG. 8, the corresponding transmission sections 27 of the transmission lines 3 run outside of the cross-section 28 of the end section 20 of the corresponding output waveguide 19 which allows for a more space saving design of the transition unit 1 within the radio frequency device, as the transmission sections 27 that are not superposed by the end sections 20 of the output waveguides 19 can be used for additional manipulation of the radio frequency signal that is transmitted along the transmission lines 3.
[0050] FIG. 9 illustrates the arrangement of several transmission lines 3 that run parallel with respect to each other on a top surface 14 of a substrate layer 4 that is not shown in FIG. 9. The transmission sections 27 of the transmission lines 3 fun into the transition sections 22. For each transmission line 3 comprising two transmission sections 27 that run into the corresponding transition sections 22 each of the two transition sections 22 is superposed by a cross-section 28 of a different, i.e. adjacent end section 20 of the corresponding output waveguide 19. Thus, a radio frequency signal that is transmitted through the adjacent output waveguides 19 couples into the corresponding transition sections 22 that are superposed by the respective end sections 20 of the waveguides 19. The waveguide system 2 can be designed in a manner that the two adjacent outgoing radio frequency signals that are emitted by adjacent output waveguides 19 have a phase difference of 180 degrees. Then, the output radio frequency signals that are coupled into the two transition sections 22 of a single transmission line 3 with two adjacent transmission sections 27 match with a phase difference of 180 degrees, resulting in a differential mode radio frequency signal transmission along the transmission lines 3.
[0051] FIG. 10 illustrates a perspective view of the substrate layer arrangement 15 with a number of transmission lines 3 arranged between the first substrate layer 4 and the second substrate layer 13. The shape of the transmission lines 3 with the transmission sections 27 that run into the transition sections 22 is similar to the shape of the transmission sections shown in FIGS. 8 and 9.
[0052] In FIG. 11 a monolithic structure 29 is arranged on top of the substrate layer arrangement 15 including the arrangement of transmissions lines 3 between the first substrate layer 4 and the second substrate layer 13. of the arrangement of transmission lines shown in FIG. 10 and a corresponding number of end sections of output waveguides, whereby the several end sections 20 are formed within a monolithic structure 29 of an electroconductive material. The end sections 20 of the output waveguides 19 that are formed within the monolithic structure 29 superpose the transition sections 22 of the transmission lines 3, whereby the arrangement of the end sections 20 of the output waveguides 19 within the monolithic structure 29 and the arrangement of the corresponding transmission lines 3 with the transition sections 22 that are superposed by the end sections 20 of the output waveguides 19 is similar to the arrangement shown in FIG. 9.
[0053] FIG. 12 illustrates a sectional view through the end sections 20 within the monolithic structure 29 shown in FIG. 11 along the line XII-XII in FIG. 11. The outgoing radio frequency signals that are transmitted through the end sections 20 of adjacent output waveguides 19 are transitioned into the transition sections 22 that are visible within the cross-sections 28 of the end sections 20 of the adjacent output waveguides 19.
