Power dividing device, waveguide antenna, and method for manufacturing a power dividing device
Patent Information
- Application Number
- EP2023790653
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-01-18
- Filing Date
- 2023-10-17
- Publication Date
- 2025-11-26
AI Technical Summary
Waveguide antennas with single slots have low directivity, requiring multiple slots forming an array, and existing manufacturing methods are costly and complex, especially when trying to maintain phase coherence and symmetry without galvanic contact between metal parts.
A power dividing device for waveguide antennas with symmetrically arranged waveguide sections, featuring branches for power distribution and quarter-wave impedance transformers, allowing for independent feeding of radiating elements with precise amplitude and phase control, and enabling connection of metal parts without galvanic contact.
This solution simplifies the construction of waveguide antennas by allowing for closer placement of radiating elements, minimizing side lobes, and reducing manufacturing costs by eliminating the need for galvanic connections, while maintaining symmetry and phase coherence.
Smart Images
Figure EP2023078825_25072024_PF_FP_ABST
Abstract
Description
[0001] Description
[0002] title
[0003] Power splitting device, waveguide antenna and method for manufacturing a power splitting device
[0004] The present invention relates to a power splitting device for a waveguide antenna, a waveguide antenna and a method for manufacturing a power splitting device.
[0005] State of the art
[0006] In a waveguide, electromagnetic energy is transported within a metallic cavity. The waveguide can be part of a waveguide antenna, in which case, in the simplest case, a slot is formed in the waveguide that forms an interface between the inner region of the waveguide and free space, i.e., serves as a radiating element. This slot does not have to run completely parallel to the currents of the electromagnetic wave traveling through the waveguide.
[0007] Since a single slot has only a low directivity, waveguide antennas typically comprise multiple slots forming an antenna array. The simplest way to create a waveguide antenna array is to place the slots along the long side of a rectangular cross-section of the waveguide, maintaining a spacing of half a wavelength, creating a zigzag pattern relative to the center of the waveguide. This zigzag pattern ensures that all slots radiate with the same phase.
[0008] In the series production of such waveguide antenna arrays using cost-effective processes, two metal parts can be manufactured and then joined together. The waveguide channels can be arranged vertically, leaving the narrow side free for radiation. The two parts are connected parallel to the narrow side of the waveguide, thus ensuring that the currents flowing through the waveguide are not disturbed. The two metal parts do not even need to be in galvanic contact, so the guiding performance of the waveguide is hardly affected. To achieve the required distance between the radiating elements, US 2020 / 203841 A1 proposes a center-fed open waveguide antenna array, with the feeding waveguide connected to elements formed by two openings.
[0009] Disclosure of the invention
[0010] The invention provides a power splitting device for a waveguide antenna, a waveguide antenna and a method for manufacturing a power splitting device having the features of the independent claims.
[0011] Preferred embodiments are the subject of the respective subclaims.
[0012] According to a first aspect, the invention accordingly relates to a power splitting device for a waveguide antenna, having a plurality of waveguide sections, comprising an input waveguide section into which an electromagnetic wave can be coupled, and a plurality of feed waveguide sections, wherein each feed waveguide section is designed to feed the electromagnetic wave into a respective radiating element of the waveguide antenna for radiating the electromagnetic wave. The waveguide sections each have a rectangular cross-section with a narrow side and a long side. At least one branch for power splitting is provided, at which an incoming waveguide section branches into at least two outgoing waveguide sections.The waveguide sections are arranged symmetrically with respect to a plane of symmetry, whereby the plane of symmetry runs parallel to the narrow sides of the rectangular cross-section of the waveguide sections.
[0013] According to a second aspect, the invention relates to a waveguide antenna having a plurality of radiating elements configured to radiate an electromagnetic wave. Furthermore, the waveguide antenna comprises a power splitting device according to the first aspect, wherein the feed waveguide sections of the power splitting device are configured to feed the electromagnetic wave into a respective one of the radiating elements.
[0014] According to a third aspect, the invention relates to a method for manufacturing a power splitting device. A first half of the power splitting device is manufactured. A second half of the power splitting device is then manufactured. The two halves of the power splitting device are connected in the plane of symmetry of the power splitting device.
[0015] Advantages of the invention
[0016] The power splitting device is constructed vertically symmetrically, meaning there is symmetry with respect to the vertical direction parallel to the long side of the rectangular cross-section of the waveguide sections. No or very low currents flow in the (horizontal) plane of symmetry. This allows for a simpler design of the power splitting device, since a perfect galvanic connection within this plane of symmetry is not required.
[0017] By using at least one power-splitting branch, the power of the electromagnetic wave can be distributed to the outgoing waveguide sections and thus ultimately to the incoming waveguide sections. This allows the amplitude and, over the length of the waveguide sections, also the phase of the emitted electromagnetic radiation to be adjusted.
[0018] The radiating elements of the waveguide antenna can be treated as independent elements and are supplied with an electromagnetic wave of the required amplitude and phase via the power splitter. Thus, a specific amplitude distribution can be achieved at the radiating elements without breaking the vertical symmetry of the waveguides.
[0019] Furthermore, the radiating elements can be placed very close to each other, thereby minimizing side lobes in the antenna pattern. According to another embodiment of the power splitting device, the dimensions of the narrow side of the incoming and the at least two outgoing waveguide sections differ at least partially from each other.
[0020] According to a further embodiment of the power splitting device, the waveguide sections comprise at least one waveguide section designed as a quarter-wave impedance transformer. This enables impedance matching at the at least one branch without requiring the waveguides to be overly wide.
[0021] According to a further embodiment of the power splitting device, for the at least one branch, the sum of the dimensions of the narrow side of the rectangular cross-section of the at least two outgoing waveguide sections essentially corresponds to the dimension of the narrow side of the rectangular cross-section of the incoming waveguide section. This adapts the impedance at the branch.
[0022] According to a further embodiment of the power splitting device, the dimensions of the long side of the rectangular cross-section are identical for all waveguide sections. The power splitting device is thus constructed very symmetrically.
[0023] According to a further embodiment of the power splitting device, the total lengths from a coupling region of the input waveguide section to a feed region of the feed waveguide section differ by an integer multiple of half a wavelength of the electromagnetic radiation (in empty space). This can reduce the occurrence of side lobes.
[0024] According to a further embodiment of the power splitting device, the power splitting device is made of two halves that are connected to each other in the plane of symmetry. The connection is thus made within the plane of symmetry, where no or only very low currents of the electromagnetic wave flow. The requirements for the way in which the two halves are connected to each other can thus be greatly reduced. For example, a perfect galvanic connection between the two halves is not required, which makes the construction significantly cheaper, since no soldering process is required. According to a further embodiment of the power splitting device, the connection between the two halves of the power splitting device is therefore non-galvanic. This can be understood as a non-conductive or at least only weakly conductive connection.
[0025] Further advantages, features and details of the invention will become apparent from the following description, in which various embodiments are described in detail with reference to the drawings.
[0026] Short description of the drawings
[0027] They show:
[0028] Figure 1 is a schematic oblique view of a waveguide antenna with a power splitting device according to an embodiment of the invention;
[0029] Figure 2 is a further schematic oblique view of the waveguide antenna shown in Figure 1;
[0030] Figure 3 is a schematic cross-sectional view of the power splitting device of the waveguide antenna shown in Figures 1 and 2;
[0031] Figure 4 is a schematic oblique view of a waveguide section;
[0032] Figure 5 is a schematic oblique view of a power splitting branch for use in a power splitting device according to an embodiment of the invention;
[0033] Figure 6 is a schematic plan view of the branch shown in Figure 5;
[0034] Figure 7 is an equivalent circuit diagram of the branching shown in Figures 5 and 6; and Figure 8 is a flowchart of a method for manufacturing a power splitting device for a waveguide antenna according to an embodiment of the invention.
[0035] In all figures, identical or functionally equivalent elements and devices are provided with the same reference numerals. The numbering of process steps serves the purpose of clarity and is generally not intended to imply a specific chronological order. In particular, several process steps can be performed simultaneously.
[0036] Description of the embodiments
[0037] Figure 1 shows a schematic oblique view of a waveguide antenna 1 (or waveguide antenna array) with a power splitting device 3 and a plurality of radiating elements 21 to 24 configured to radiate an electromagnetic wave. The radiating elements 21 to 24 are configured as waveguide sections that are closed on one side and open on the other. The electromagnetic wave is radiated from the open side.
[0038] Figure 2 shows a further schematic oblique view of the waveguide antenna 1 shown in Figure 1, wherein the outer housing can be seen.
[0039] Figure 3 shows a schematic cross-sectional view of the power splitting device 3 of the waveguide antenna shown in Figures 1 and 2. The power splitting device 3 comprises a plurality of waveguide sections 301-312. The waveguide sections 301-312 comprise an input waveguide section 301, into which an electromagnetic wave can be coupled or fed. Furthermore, the power splitting device 3 comprises four feed waveguide sections 302-305, via which the electromagnetic wave is fed into a respective radiating element 21-24, which then radiates the electromagnetic wave.
[0040] The invention is not limited to a specific number of
[0041] Feed waveguide sections 302-305 or radiating elements 21 to 24. Furthermore, the power splitting device 3 comprises a plurality of waveguide sections 306-312, which connect the input waveguide section 301 to the feed waveguide sections 302-305. The power splitting device 3 thus comprises a total of a plurality of fluidically connected waveguide sections 301-312.
[0042] Waveguide sections 301-312 each have a rectangular cross-section with a narrow side (parallel to a horizontal xz-plane) and a long side (parallel to a vertical y-axis). The dimensions of the long side of the rectangular cross-section are identical for all waveguide sections 301-312.
[0043] To distribute the electromagnetic wave fed into the input waveguide section 301 to the emitting elements 21 to 24, several branches are provided, which serve to divide the power, i.e., distribute the power of the electromagnetic wave. Each branch comprises an incoming waveguide section 301-312, which branches into two outgoing waveguide sections 301-312. The invention is not limited to this; rather, an incoming waveguide section 301-312 can also branch into more than two outgoing waveguide sections 301-312.
[0044] The dimensions of the narrow side of the incoming and at least two outgoing waveguide sections 301-312 differ at least partially from one another. Impedance matching is preferably performed at the branches, i.e., the sum of the dimensions of the narrow sides of the outgoing waveguide sections 301-312 essentially corresponds to the dimensions of the narrow side of the incoming waveguide section 301-312.
[0045] The waveguide sections 301-312 are all arranged symmetrically with respect to a common plane of symmetry, with the plane of symmetry running parallel to the narrow sides of the rectangular cross-section of the waveguide sections 301-312. The plane of symmetry thus runs parallel to the xz plane through the center of the power splitting device 3.
[0046] The power splitting device 3 is preferably made of two halves that are connected to each other in the plane of symmetry. The power splitting device 3 thus consists of a lower half and an upper half, which may be mirrored in the plane but otherwise identical in construction. The halves are preferably not galvanically connected, which simplifies manufacturing.
[0047] In the configuration shown in Figure 3, the input waveguide section 301 (first waveguide section) with impedance Zi is followed by a second waveguide section 306 with impedance Zti, designed as a quarter-wave impedance transformer. This second waveguide section branches into two outgoing waveguide sections 307, 308 (third and fourth waveguide sections, respectively). The branching corresponds to a first power divider. The impedance ZI is the same for the two outgoing waveguide sections 307, 308 and is calculated as follows:
[0048] Zi' = 2 - ZI Zi' = Zti 2 / Zi where Zi' denotes the impedance at the incoming waveguide section 306.
[0049] The fourth semiconductor section 308 branches into a third feed waveguide section 304 (a fifth waveguide section) with impedance Z3 and a sixth waveguide section 309 with impedance Zt2, which are adjoined by a seventh waveguide section 310 with impedance Zt3. The sixth waveguide section 309 and the seventh waveguide section 310 are configured as quarter-wave impedance transformers. A fourth feed waveguide section 305 (an eighth waveguide section) with impedance Z2 adjoins the seventh waveguide section 310.
[0050] The third semiconductor section 307 branches symmetrically into a second feed waveguide section 303 (a ninth waveguide section) with impedance Z3 and a tenth waveguide section 311 with impedance Zt2, to which an eleventh waveguide section 312 with impedance Zt3 is connected, wherein the tenth
[0051] Waveguide section 311 and the eleventh waveguide section 312 are designed as quarter-wave impedance transformers. A first feed waveguide section 302 (a twelfth waveguide section) with impedance Z2 is connected to the seventh waveguide section 312.
[0052] The branch corresponds to a second power divider, where: Z2' = Z2-Zt2 2 / Zt3 2
[0053] Z3 = 2-Z2'
[0054] Z1 = Z3+Z2', where Z2' denotes the impedance towards the tenth waveguide section 311.
[0055] The length of the third semiconductor section 307 corresponds to half a wavelength of the electromagnetic radiation, as does a combined length of the sixth and seventh waveguide sections 309, 310 and a combined length of the tenth and eleventh waveguide sections 311, 312.
[0056] This results in identical phases at the feed waveguide sections 302-305, with the second feed waveguide section 303 and the fourth feed waveguide section 305 being 180 degrees out of phase with the first feed waveguide section 302 and the third feed waveguide section 304. The phase shift can be compensated by coupling onto opposite sides of the radiating elements 302-305, as illustrated in Figure 1, so that all radiating elements 302-305 radiate in phase.
[0057] The total lengths from the coupling region of the input waveguide section 301 to a feed region of the feed waveguide sections 302-305 thus differ by an integer multiple of half the wavelength of the electromagnetic radiation.
[0058] The impedance transformations using the waveguide sections 306, 309, 310, 311, and 312, designed as quarter-wave impedance transformers, allow for realizable impedances that cannot be achieved by changing the waveguide dimensions alone. For example, the impedance Z2 is reduced by a factor of (Zt2 / Zt3). 2 reduced to reach Z2'. On the other hand, the input impedance is increased by Zti to reach Zi'.
[0059] Figure 4 shows a schematic oblique view of a waveguide section 313 with a rectangular cross-section in an xy-plane, wherein the cross-section of a waveguide section 313 extends along a z-axis. The maxima and minima of the amplitude of the electromagnetic wave in the y-direction within the waveguide section 313 occur in outer regions 1a, 1b relative to the y-axis, i.e., in the region of the narrow ends of the waveguide. In a region 1c, which encompasses the xz-plane through the center of the waveguide, the amplitude in the y-direction essentially disappears. It is therefore advantageous, when assembling the waveguide from several metal parts, to assemble the metal parts along the xz-plane through the center of the waveguide, since in this region the amplitude of the magnetic wave in the y-direction essentially disappears. The connection between the metal parts does not even have to be galvanically connected.
[0060] Figure 5 shows a schematic oblique view of a power splitting branch for use in a power splitting device 3, which is constructed from a first half 3a and a second half 3b. Figure 6 shows a schematic plan view of the branch shown in Figure 5. An incoming waveguide section 314 branches into two outgoing waveguide sections 315, 316. A dimension W_in of the narrow side of the waveguide section 314 essentially corresponds to the sum of the dimension W_1 of the narrow side of the first outgoing waveguide section 315 and the dimension W_2 of the narrow side of the second outgoing waveguide section 316. The dimensions W_l, W_2 of the narrow sides of the two outgoing waveguide sections 315, 316 can differ from one another, but can also be the same.
[0061] Figure 7 shows an equivalent circuit of the junction shown in Figures 5 and 6. The power P_input of the incoming electromagnetic wave is divided into the powers P_output_1 and P_output_2 of the outgoing electromagnetic waves according to the ratio of the impedances Z_in, Z_l, Z_2.
[0062] Figure 8 shows a flowchart of a method for manufacturing a power splitting device 3 for a waveguide antenna 1 as described above.
[0063] In a first method step S1, a first half 3a of the power splitting device 3 is produced.
[0064] In a second process step S2, a second half 3b of the power splitting device 3 is produced. In a fourth process step S3, the two halves of the
[0065] Power division device 3 connected in the plane of symmetry of the power division device 3.
Claims
Claims 1. A power splitting device (3) for a waveguide antenna (1), comprising: a plurality of waveguide sections (301-316), comprising an input waveguide section (301) into which an electromagnetic wave can be coupled, and a plurality of feed waveguide sections (302-305), wherein each feed waveguide section (302-305) is designed to feed the electromagnetic wave into a respective radiating element (21-24) of the waveguide antenna (1) for radiating the electromagnetic wave; wherein the waveguide sections (301-316) each have a rectangular cross-section with a narrow side and a long side; wherein at least one branch is provided for power splitting, at which an incoming waveguide section (314) branches into at least two outgoing waveguide sections (315, 316);and wherein the waveguide sections (301-316) are arranged symmetrically with respect to a plane of symmetry, the plane of symmetry running parallel to the narrow sides of the rectangular cross-section of the waveguide sections (301-316); 2. Power division device (3) according to claim 1, wherein the waveguide sections (301-316) comprise at least one waveguide section (301-316) designed as a quarter-wave impedance transformer (306-310).
3. Power splitting device (3) according to claim 1 or 2, wherein for the at least one branch, the sum of the dimensions (dl) of the narrow side of the rectangular cross-section of the at least two outgoing waveguide sections (315, 316) substantially corresponds to the dimension (dl) of the narrow side of the rectangular cross-section of the incoming waveguide section (315).
4. Power splitting device (3) according to one of the preceding claims, wherein the dimension (d2) of the long side of the rectangular cross-section is identical for all waveguide sections (301-316).
5. Power division device (3) according to one of the preceding claims, wherein total lengths from a coupling region of the input waveguide section (301) to a feed region of the feed waveguide sections (302-305) differ by an integer multiple of half a wavelength of the electromagnetic radiation.
6. Power splitting device (3) according to one of the preceding claims, wherein the power splitting device (3) is made of two halves which are connected to each other in the plane of symmetry.
7. Power splitting device (3) according to one of the preceding claims, wherein a connection of the two halves of the power splitting device (3) is not galvanic.
8. A waveguide antenna (1) comprising: a plurality of radiating elements (21-24) configured to radiate an electromagnetic wave; and a power splitting device (3) according to any one of the preceding claims, wherein the feed waveguide sections (302-305) of the power splitting device (3) are configured to feed the electromagnetic wave into a respective one of the radiating elements (21-24).
9. A method for manufacturing a power splitting device (3) for a waveguide antenna (1) according to one of claims 1 to 7, comprising the steps: Producing a first half of the power splitting device (3); Producing a second half of the power splitting device (3); and Connecting the two halves of the power division device (3) in the plane of symmetry of the power division device (3).
10. The method according to claim 9, wherein the two halves of the power splitting device (3) are connected with a non-galvanic connection.