Power division device, waveguide antenna, and method for manufacturing power division device

Abstract

A power dividing device for a waveguide antenna includes a plurality of hollow waveguide sections, each of which has an input hollow waveguide section capable of coupling an electromagnetic wave therein and a plurality of feed hollow waveguide sections, each of which is configured to feed an electromagnetic wave into a respective output element of the waveguide antenna for outputting the electromagnetic wave. The hollow waveguide sections each have a rectangular cross section with a narrow side and a long side. At least one branch section is provided for power division, in which one input hollow waveguide section branches into at least two output hollow waveguide sections, wherein the narrow side of the input hollow waveguide section and the narrow side of the at least two output hollow waveguide sections are at least partially different in size. The hollow waveguide sections are arranged symmetrically with respect to a plane of symmetry, which extends parallel to the narrow side of the rectangular cross section of the hollow waveguide sections.

Description

[Technical Field]

[0001] The present invention relates to a power divider for a waveguide antenna, and to a method for manufacturing a waveguide antenna and a power divider. [Background technology]

[0002] In a hollow waveguide, or wave guide, electromagnetic energy is carried through a hollow space in a metal. A hollow waveguide can be part of a waveguide antenna, and in the simplest case, a slot is formed in the hollow waveguide, which forms an interface between the interior region of the hollow waveguide and free space, i.e., acts as a radiating element. The slot does not need to extend perfectly parallel to the flow of electromagnetic waves traveling through the hollow waveguide.

[0003] Because a single slot has low directivity, hollow waveguide antennas usually have multiple slots, which form an antenna array. The simplest way to form a hollow waveguide antenna array is to place the slots on the long sides of the rectangular cross section of the hollow waveguide, maintaining a half-wavelength distance between them, so that they form a zigzag structure relative to the center of the hollow waveguide. This zigzag structure causes all slots to radiate with the same phase.

[0004] To serially produce such hollow waveguide antenna arrays in a cost-effective manner, two metal parts can be fabricated and then joined together. The hollow waveguide can be oriented vertically, leaving the narrow side free for radiation. The joining of the two parts is performed parallel to the narrow side of the hollow waveguide, so the current flowing through the hollow waveguide is not impeded. The two metal parts do not even need to be in galvanic contact, and as a result, the wave-guiding performance of the hollow waveguide is barely affected.

[0005] To allow for the necessary spacing between radiating elements, US Patent Application Publication No. 2020 / 0203841 proposes a centrally fed open hollow waveguide antenna array, where the feeding waveguide is connected to the formed elements through two openings. Summary of the Invention

[0006] The invention provides a power dividing device for a waveguide antenna, a method for manufacturing a waveguide antenna and a power dividing device, with the features of the independent patent claims.

[0007] Preferred embodiments are the subject of the respective dependent claims.

[0008] According to a first aspect, the present invention provides a power dividing device for a waveguide antenna, comprising a plurality of hollow waveguide sections, each of which has an input hollow waveguide section into which an electromagnetic wave can be coupled, and a plurality of feed hollow waveguide sections, each of which is configured to feed an electromagnetic wave into a respective output element of the waveguide antenna for outputting the electromagnetic wave. Each of the hollow waveguide sections has a rectangular cross section with a narrow side and a long side. At least one branch section is provided for power division, in which one input hollow waveguide section branches into at least two output hollow waveguide sections. The hollow waveguide sections are arranged symmetrically with respect to a plane of symmetry, which plane of symmetry extends parallel to the narrow side of the rectangular cross section of the hollow waveguide sections.

[0009] According to a second aspect, the present invention relates to a waveguide antenna comprising a plurality of emitting elements configured to emit electromagnetic waves, the waveguide antenna further comprising a power dividing device according to the first aspect, the feed hollow waveguide portion of the power dividing device being configured to feed the electromagnetic waves to a respective one of the emitting elements.

[0010] According to a third aspect, the present invention relates to a method for manufacturing a power splitter device, comprising manufacturing a first half of the power splitter device, manufacturing a second half of the power splitter device, and connecting the two halves of the power splitter device at a plane of symmetry of the power splitter device.

[0011] The power divider is constructed with vertical symmetry, i.e., symmetry exists in the vertical direction parallel to the long side of the rectangular cross section of the hollow waveguide section. No current or only very small current flows in the (horizontal) plane of symmetry. This makes the power divider simpler to construct, since a perfect galvanic connection is not required in this plane of symmetry.

[0012] The power of the electromagnetic waves can be split into the output hollow waveguide section and then finally into the supply hollow waveguide section by at least one branch for power division, which allows the amplitude and, via the length of the hollow waveguide section, also the phase of the emitted electromagnetic radiation to be adjusted.

[0013] The emitting elements of a waveguide antenna can be treated as independent elements and fed with electromagnetic waves of the required amplitude and phase via a power divider, thus achieving a specific amplitude distribution at the emitting elements without breaking the vertical symmetry of the hollow waveguide.

[0014] Additionally, the emitting elements can be placed very close to each other, thereby minimizing side lobes in the antenna diagram.

[0015] According to a further embodiment of the power dividing device, the dimensions of the narrow sides of the one input hollow waveguide section and the at least two output hollow waveguide sections are at least partially different from one another.

[0016] According to a further embodiment of the power dividing device, the hollow waveguide sections comprise at least one hollow waveguide section configured as a quarter-wave impedance transformer, which allows impedance matching in at least one branch without requiring the hollow waveguide to be configured too wide.

[0017] According to a further embodiment of the power splitting device, for at least one branch, the sum of the dimensions of the narrow sides of the rectangular cross sections of the at least two output hollow waveguide sections substantially matches the dimension of the narrow side of the rectangular cross section of the input hollow waveguide section, thereby providing impedance matching at the branches.

[0018] According to a further embodiment of the power dividing device, the dimension of the long side of the rectangular cross section is the same for all hollow waveguide sections, which results in a highly symmetrical configuration of the power dividing device.

[0019] According to a further embodiment of the power dividing device, the total length from the coupling region of the input hollow waveguide section to the feed region of the feed hollow waveguide section differs by an integer multiple of half wavelengths of electromagnetic radiation (in empty space), which allows to reduce the occurrence of side lobes.

[0020] According to a further embodiment of the power splitting device, the power splitting device consists of two halves connected to each other in a plane of symmetry. The connection is thus made within the plane of symmetry, where no or only very low electromagnetic currents flow. This significantly reduces the requirements for the method of connecting the two halves to each other. In this way, for example, a full galvanic connection between the two halves is not required, and a soldering process is not required, making the construction substantially cheaper. According to a further embodiment of the power splitting device, the connection between the two halves of the power splitting device is therefore not a galvanic connection. This can be understood as meaning that there is no conductive connection, or at least only a very weak conductive connection.

[0021] Further advantages, features and details of the invention will become apparent from the following description in which various embodiments are explained in detail with reference to the drawings. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a schematic perspective view of a waveguide antenna with a power dividing device according to an embodiment of the present invention; [Figure 2] 2 is a further schematic perspective view of the waveguide antenna shown in FIG. 1. [Figure 3] 3 is a schematic cross-sectional view of the power dividing device of the waveguide antenna shown in FIGS. 1 and 2. FIG. [Figure 4] FIG. 2 is a schematic perspective view of a hollow waveguide portion. [Figure 5] 1 is a schematic perspective view of a branch for power division for use in a power division apparatus according to one embodiment of the present invention; [Figure 6] FIG. 6 is a schematic top view of the branching section shown in FIG. 5. [Figure 7] FIG. 7 is an equivalent circuit diagram of the branch shown in FIGS. 5 and 6. [Figure 8] 4 is a flowchart of a method for manufacturing a power divider device for a waveguide antenna according to an embodiment of the present invention.

[0023] In all figures, identical or functionally identical components and devices are designated by the same reference numerals. The numbering of method steps is for the purpose of clarity and generally does not imply a particular chronological order. In particular, multiple steps may be performed simultaneously. DETAILED DESCRIPTION OF THE INVENTION

[0024] 1 is a schematic perspective view of a waveguide antenna 1 (i.e., a waveguide antenna array) including a power dividing device 3 and a plurality of emitting elements 21-24 configured to emit electromagnetic waves. The emitting elements 21-24 are formed as hollow waveguide sections that are closed on one side and open on the other side. The electromagnetic waves are emitted from the open side.

[0025] FIG. 2 is a further schematic perspective view of the waveguide antenna 1 shown in FIG. 1, in which the outer housing is visible.

[0026] 3 is a schematic cross-sectional view of the power dividing device 3 of the waveguide antenna shown in FIGS. 1 and 2. The power dividing device 3 includes a plurality of hollow waveguide sections 301-312. Each of the hollow waveguide sections 301-312 includes an input hollow waveguide section 301 into which an electromagnetic wave can be coupled or fed. The power dividing device 3 further includes four feed hollow waveguide sections 302-305 through which the electromagnetic wave is fed into each of the emitting elements 21-24, and each of the emitting elements 21-24 radiates the electromagnetic wave.

[0027] In this regard, the present invention is not limited to any particular number of feed hollow waveguide sections 302-305 or exit elements 21-24.

[0028] The power splitting device 3 further comprises a plurality of hollow waveguide sections 306-312, which connect the input hollow waveguide section 301 to the supply hollow waveguide sections 302-305. Thus, the power splitting device 3 as a whole comprises a plurality of hollow waveguide sections 301-312 that are fluidly connected to one another.

[0029] Each of these hollow waveguide sections 301-312 has a rectangular cross section with a narrow side (parallel to the horizontal XZ plane) and a long side (parallel to the vertical Y axis), the dimension of the long side of the rectangular cross section being the same for all hollow waveguide sections 301-312.

[0030] To distribute the electromagnetic wave supplied to the input hollow waveguide section 301 to the output elements 21-24, a plurality of branches are provided, which function to divide the power, i.e., to distribute the power of the electromagnetic wave. Each branch has one input hollow waveguide section 301-312, which branches into two output hollow waveguide sections 301-312. The invention is not limited to this, and the input hollow waveguide section 301-312 may also branch into three or more output hollow waveguide sections 301-312.

[0031] The dimensions of the narrow sides of the input hollow waveguide section and the at least two output hollow waveguide sections 301-312 are at least partially different from one another. Preferably, impedance matching is performed at the branch, i.e. the sum of the dimensions of the narrow sides of the output hollow waveguide sections 301-312 substantially matches the dimension of the narrow sides of the input hollow waveguide sections 301-312.

[0032] The hollow waveguide sections 301-312 are all symmetrically arranged with respect to a common plane of symmetry, which extends parallel to the narrow side of the rectangular cross section of the hollow waveguide sections 301-312 and therefore extends parallel to the XZ plane through the center of the power dividing device 3.

[0033] The power splitter device 3 preferably consists of two halves connected to each other in a plane of symmetry. Thus, the power splitter device 3 consists of a lower half and an upper half, which are mirror images in the plane of symmetry but can otherwise be identical. The halves are preferably not galvanically connected, which simplifies manufacturing.

[0034] In the structure shown in Figure 3, an input hollow waveguide section 301 (first hollow waveguide section) with impedance Zi is first connected to a second hollow waveguide section 306, which has impedance Zti and is formed as a quarter-wave impedance transformer. This second hollow waveguide section 306 branches into two output hollow waveguide sections 307 and 308 (third and fourth hollow waveguide sections, respectively). This branch corresponds to a first power divider. The impedance Z1 is the same for both output hollow waveguide sections 307 and 308 and is calculated as follows: Zi'=2·Z1 Zi'=Zti 2 / Zi where Zi′ denotes the impedance at the input hollow waveguide section 306.

[0035] The fourth hollow waveguide section 308 branches into a third feed hollow waveguide section 304 (fifth hollow waveguide section) having an impedance Z3 and a sixth hollow waveguide section 309 having an impedance Zt2, and a seventh hollow waveguide section 310 having an impedance Zt3 is connected to this sixth hollow waveguide section, whereby the sixth hollow waveguide section 309 and the seventh hollow waveguide section 310 form a quarter-wave impedance converter. A fourth feed hollow waveguide section 305 (eighth hollow waveguide section) having an impedance Z2 is connected to the seventh hollow waveguide section 310.

[0036] The third hollow waveguide section 307 branches symmetrically into a second feed hollow waveguide section 303 (ninth hollow waveguide section) having an impedance Z3 and a tenth hollow waveguide section 311 having an impedance Zt2, to which an eleventh hollow waveguide section 312 having an impedance Zt3 is connected, the tenth hollow waveguide section 311 and the eleventh hollow waveguide section 312 forming a quarter-wave impedance transformer. The eleventh hollow waveguide section 312 is connected to a first feed hollow waveguide section 302 (twelfth hollow waveguide section) having an impedance Z2.

[0037] This branch corresponds to a second power divider, where: Z2' = Z2 Zt2 2 / Zt3 2 Z3=2·Z2' Z1=Z3+Z2' where Z2' denotes the impedance towards the tenth hollow waveguide section 311.

[0038] The length of the third hollow waveguide section 307 corresponds to half the wavelength of the electromagnetic radiation, and similarly corresponds to the combined lengths of the sixth hollow waveguide section 309 and the seventh hollow waveguide section 310, and the combined lengths of the tenth hollow waveguide section 311 and the eleventh hollow waveguide section 312.

[0039] This results in the feed hollow waveguide sections 302-305 being in phase, with the second feed hollow waveguide section 303 and fourth feed hollow waveguide section 305 being 180 degrees out of phase with respect to the first feed hollow waveguide section 302 and third feed hollow waveguide section 304. This phase shift can be compensated for by coupling on opposite sides of the launch elements 302-305, as shown in Figure 1, so that all launch elements 302-305 radiate in phase.

[0040] Thus, the total lengths from the coupling region of the input hollow waveguide section 301 to the feed regions of the feed hollow waveguide sections 302-305 differ by an integer number of half wavelengths of electromagnetic radiation.

[0041] Impedance transformation using hollow waveguide sections 306, 309, 310, 311, 312 configured as quarter-wave impedance transformers allows for achieving impedances that are not achievable by simply changing the dimensions of the hollow waveguide. For example, to achieve impedance Z2', impedance Z2 is multiplied by a factor (Zt2 / Zt3). 2 On the other hand, to achieve Zi', the input impedance is increased by Zti.

[0042] FIG. 4 is a schematic perspective view of a hollow waveguide section 313 having a rectangular cross section in the XY plane, where the hollow waveguide section 313 extends along the Z axis. The maximum and minimum amplitudes of the electromagnetic waves in the Y direction within the hollow waveguide section 313 occur in regions 1A and 1B located outside the Y axis, i.e., in the narrow end regions of the hollow waveguide. In region 1c, which includes the XZ plane passing through the center of the hollow waveguide, the amplitude in the Y direction essentially vanishes. Therefore, when assembling a hollow waveguide from multiple metal components, it is advantageous to assemble the metal components along the XZ plane passing through the center of the hollow waveguide, because the amplitude of the electromagnetic waves in the Y direction essentially vanishes in this region. The connection of the metal components does not necessarily have to be galvanic.

[0043] FIG. 5 is a schematic perspective view of a power splitting branch for use in power splitting device 3, the branch consisting of a first half 3A and a second half 3B. FIG. 6 is a schematic top view of the branch shown in FIG. 5. An input hollow waveguide section 314 branches into two output hollow waveguide sections 315, 316. The narrow side dimension W_in of hollow waveguide section 314 corresponds substantially to the sum of the narrow side dimension W_1 of the first output hollow waveguide section 315 and the narrow side dimension W_2 of the second output hollow waveguide section 316. The narrow side dimensions W_1, W_2 of both output hollow waveguide sections 315, 316 can be different from each other, but can also be the same size.

[0044] Fig. 7 is an equivalent circuit diagram of the branching section shown in Fig. 5 and Fig. 6. The power P_input of the input electromagnetic wave is divided into the power P_output_1 and power P_output_2 of the output electromagnetic wave according to the ratio of the impedances Z_in, Z_1, and Z_2.

[0045] FIG. 8 is a flow chart of a method for manufacturing the above-described power dividing device 3 for a waveguide antenna 1.

[0046] In a first method step S1, a first half 3A of the power splitting device 3 is manufactured.

[0047] In a second method step S2, the second half 3B of the power splitting device 3 is manufactured.

[0048] In a third method step S3, both halves of the power splitting device 3 are connected in the plane of symmetry of the power splitting device 3.

Claims

1. A power dividing device (3) for a waveguide antenna (1), comprising: a plurality of hollow waveguide sections (301-316), each of which has an input hollow waveguide section (301) into which an electromagnetic wave can be coupled, and a plurality of feed hollow waveguide sections (302-305), each of which is configured to feed the electromagnetic wave into a respective output element (21-24) of the waveguide antenna (1) for outputting the electromagnetic wave; each of said hollow waveguide sections (301-316) having a rectangular cross section with a narrow side and a long side; At least one branch is provided for power division, in which one input hollow waveguide section (314) branches into at least two output hollow waveguide sections (315, 316); the hollow waveguide sections (301-316) are arranged symmetrically with respect to a plane of symmetry, the plane of symmetry extending parallel to a narrow side of the rectangular cross section of the hollow waveguide sections (301-316); Power splitting device (3).

2. 2. The power dividing device (3) of claim 1, wherein the hollow waveguide sections (301-316) comprise at least one hollow waveguide section (301-316) formed as a quarter-wave impedance transformer (306-310).

3. 3. The power dividing device (3) according to claim 1 or 2, wherein for the at least one branch, the sum of the dimensions (D1) of the narrow sides of the rectangular cross sections of the at least two output waveguide sections (315, 316) substantially matches the dimension (D1) of the narrow side of the rectangular cross section of the input hollow waveguide section (314).

4. The power dividing device (3) according to any one of claims 1 to 3, wherein the dimension (D2) of the long side of the rectangular cross section is the same for all hollow waveguide sections (301-316).

5. 5. The power dividing device (3) according to claim 1, wherein the total lengths from the coupling region of the input hollow waveguide section (301) to the feed regions of the feed hollow waveguide sections (302-305) differ by an integer multiple of half wavelengths of the electromagnetic radiation.

6. The power splitting device (3) according to any one of claims 1 to 5, wherein the power splitting device (3) consists of two halves connected to each other in the plane of symmetry.

7. The power splitting device (3) according to any one of the preceding claims, wherein the connection between the two halves of the power splitting device (3) is not a galvanic connection.

8. A waveguide antenna (1), a plurality of emission elements (21-24) configured to emit electromagnetic waves; A power dividing device (3) according to any one of claims 1 to 7, wherein the feed hollow waveguide sections (302-305) of the power dividing device (3) are configured to feed the electromagnetic waves to respective ones of the output elements (21-24). Waveguide antenna (1).

9. A method for manufacturing a power dividing device (3) for a waveguide antenna (1) according to any one of claims 1 to 7, comprising the steps of: manufacturing a first half of the power splitting device (3); manufacturing a second half of the power splitter device (3); connecting the two halves of the power splitting device (3) at the plane of symmetry of the power splitting device (3); A method comprising:

10. 10. The method of claim 9, wherein the two halves of the power splitting device (3) are connected in a non-galvanic connection.

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