High-frequency device with multiple rectangular waveguides
By allowing flexible arrangements of rectangular waveguide tubes with controlled conductor wavelengths and tapered structures, the device addresses the limitations of fixed lengths and temperature sensitivity, enhancing signal integrity and reducing loss.
Patent Information
- Authority / Receiving Office
- DE · DE
- Patent Type
- Patents
- Current Assignee / Owner
- DENSO CORP
- Filing Date
- 2009-03-05
- Publication Date
- 2026-05-21
AI Technical Summary
Existing high-frequency devices using rectangular waveguide tubes face limitations in arranging tubes freely and suffer from increased transmission loss and deteriorated propagation characteristics due to fixed tube lengths and temperature changes, affecting phase relationships.
The device allows for varying lengths of rectangular waveguide tubes with controlled conductor wavelengths, maintaining phase relationships and reducing temperature-induced deterioration by adjusting longitudinal side lengths and using tapered grooves or through holes to minimize transmission loss.
Enables flexible tube arrangements while suppressing propagation characteristic degradation and reducing transmission loss, thereby improving signal integrity and efficiency.
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Abstract
Description
BACKGROUND OF THE INVENTION (Field of Invention)
[0001] The present invention relates to a high-frequency device with several rectangular waveguide tubes. (State of the art)
[0002] A high-frequency device that transmits high-frequency signals using rectangular waveguide tubes is known. For example, JP 2004-221 718 A, considered the closest patent, discloses a high-frequency device for transmitting high-frequency signals in which two metal plates are joined and several rectangular waveguide tubes are formed on the joint surface. In this type of high-frequency device, when a phase relationship between the high-frequency signals to be transmitted must be maintained, the rectangular waveguide tubes are arranged such that the conductor lengths of the rectangular waveguide tubes are equal, or that the conductor lengths differ from each other only by an integer multiple of a conductor wavelength.
[0003] In both cases, however, the rectangular waveguide tubes cannot be freely arranged, as the tube lengths are determined in a fixed manner. Furthermore, the transmission loss is unnecessarily increased, particularly if the tubes are arranged so that the tube lengths are equal, since the tube lengths are fixed to the longest possible length.
[0004] If, on the other hand, the lines are arranged in such a way that the line lengths differ from each other only by an integer multiple of the line wavelength, the changes in loss between the channels increase and the deterioration of the propagation characteristics caused by a temperature change increases, since the line lengths differ from each other.
[0005] This means that if the conductor lengths of two rectangular waveguide tubes differ, the rectangular waveguide tube with the longer conductor length will be more significantly affected by temperature changes, proportional to the length difference. This leads to a difference in the phase relationship between the high-frequency signals at an input terminal and an output terminal of the rectangular waveguide tube, thus degrading the propagation characteristics.
[0006] US 4,588,962 A mentions that the phase relationship of microwaves split in waveguides must be standardized. FR 2,685,821 A deals with waveguides of different widths and phase adjustment. SUMMARY OF THE INVENTION
[0007] The present invention was created to avoid the disadvantages discussed above. It is an object of the present invention to provide a high-frequency device that allows a high degree of freedom in an arrangement of rectangular waveguide tubes and can suppress a deterioration of the propagation characteristics caused by temperature changes.
[0008] To solve the above problem, a high-frequency device is provided, comprising: several rectangular waveguide tubes that transmit high-frequency signals and have different lengths along their longitudinal axis, wherein the high-frequency signals are transmitted in the several rectangular waveguide tubes such that a phase relationship between the high-frequency signals at the input terminals of the several rectangular waveguide tubes is maintained at the output terminals of the several rectangular waveguide tubes, wherein the rectangular waveguide tube has a rectangular cross-section cut perpendicular to the longitudinal direction of the waveguide tube, the rectangular cross-section has longitudinal side edges and short side edges, these lengths are defined as a longitudinal side length and a short side length, and the longitudinal side length is defined such that it is longer as the waveguide lengths decrease.to allow the conductor wavelength in the hollow conductor tube to become shorter.
[0009] If a free-space wavelength of a high-frequency signal to be transmitted is described by λ and a length of the rectangular waveguide tube in a longitudinal side direction (i.e., magnetic field direction) is described by a (where a > λ / 2), a conductor wavelength λg is described by the following equation 1. λg=λ1−(λ2a)2
[0010] That is, the conductor wavelength λg increases as the pipe width a decreases and approaches λ / 2. Conversely, the conductor wavelength λg decreases (approaches λ) as the conductor width a increases. BRIEF DESCRIPTION OF THE DRAWING
[0011] The attached drawing shows: Fig. 1A and Fig. 1B Perspective views, each showing an overall structure of a high-frequency device according to a first embodiment of the present invention; Fig. 2A, Fig. 2B and Fig. 2C a top view and cross-sectional views of a waveguide tube plate according to the first embodiment; Fig. 3 a cross-sectional view of the near area of input and output connections of a rectangular waveguide tube in the high-frequency device; Fig. 4 a top view of a hollow conductor tube plate according to a second embodiment of the present invention; Fig. 5 a cross-sectional view of the near area of input and output connections of a rectangular waveguide tube in the high-frequency device according to a further embodiment of the present invention; Fig. 6A and Fig. 6B Cross-sectional views of the near area of input and output connections of a rectangular waveguide tube in the high-frequency device according to the further embodiment; Fig. 7 a diagram with simulation results showing a ratio between the length (cone length) of the inner wall formed by the tapered shape and a transmission loss; Fig. Figure 8 shows an exemplary illustration of a rectangular waveguide tube model used in the simulation. DETAILED DESCRIPTION OF PREFERRED EXECUTION FORMS
[0012] The embodiments of the present invention are described below with reference to the attached drawing. (First embodiment)
[0013] Fig. Figure 1A shows a perspective view of the overall setup of a high-frequency device 1 to which the present invention is applied. Fig. Figure 1B shows a perspective exploded view of the high-frequency device 1.
[0014] The high-frequency device 1 is applied to a radar device that uses millimeter waves, microwaves and the like.
[0015] The high-frequency device 1, as shown in the Fig. 1A and Fig. Figure 1B shows a waveguide tube plate 10, a first substrate 20, and a second substrate 30. Several (five according to the first embodiment) rectangular waveguide tubes 11 (11a to 11e) are formed on the waveguide tube plate 10, which is made from a metallic plate (conductor). The first substrate 20 and the second substrate 30 are attached to both sides of the waveguide tube plate 10 by screws and the like, so that the first substrate 20, the second substrate 30, and the waveguide tube plate 10 form a unit. Each of the rectangular waveguide tubes (11a to 11e) has a waveguide passage whose cross-section is rectangular perpendicular to the longitudinal direction. This rectangular cross-section has a short side edge in a short-side direction and a long side edge, the length of the long side edge, i.e., the passage length in the long-side direction, hereinafter referred to as the "long-side length," being set to "a".Reference is also made to the "short side length" for the passage length in the short side direction.
[0016] Of these elements, the first substrate 20 is a resin-based substrate. High-frequency circuits are formed (printed) on a surface (non-connecting surface) of the first substrate 20 on the side opposite the connection surface to the waveguide tube plate 10. The high-frequency circuits include, for example, an oscillator 21 that generates high-frequency signals, a high-frequency line 23 composed of striplines that transmit an output signal from the oscillator 21 to rectangular areas 22 that serve as the input terminal of each rectangular waveguide tube 11, and transistors 24 that convert electrical signals (output signals of the oscillator 21) provided via the high-frequency line 23 into electromagnetic waves and transmit the electromagnetic wave in the direction of the rectangular waveguide tubes 11.
[0017] Furthermore, the second substrate 30, like the first substrate 20, is a resin-based substrate. Antenna sections 31, transitions 33, high-frequency lines 34, and the like are formed (printed) on a surface of the second substrate 30 on the opposite side from the interface surface to the waveguide tube plate 10, such that they correspond to a respective rectangular waveguide tube 11. The antenna sections 31 are composed of several patch antennas arranged in a single row. The transitions 33 convert the high-frequency signals provided via the rectangular waveguide tubes 11 into electrical signals at rectangular areas 32, which serve as the output terminals of the rectangular waveguide tubes 11. The high-frequency lines 34 are formed by striplines that transmit the electrical signals converted by the transitions 33 to the antenna sections 31.
[0018] On the connecting surfaces of both the first substrate 20 and the second substrate 30 to the waveguide tube plate 10 are mass patterns 24 and 35 (see Fig. 3) formed (printed) on the entire surfaces, except for the rectangular areas 22 and 32, which serve as the input or output ports of the rectangular waveguide tubes 11.
[0019] In the rectangular areas 22 (22a to 22e) of the first substrate 20, the high-frequency lines 23, which extend from the oscillator 21 in the center of the first substrate 20 to each rectangular area 22, are arranged in a star configuration such that all high-frequency lines 23 have the same length. In contrast, the rectangular areas 32 (32a to 32e) of the second substrate 30 are arranged in a row along one side of the second substrate 30.
[0020] Fig. Figure 2A shows a top view of the waveguide tube plate 10 from the side of the connection surface with the first substrate 20. Fig. Figure 2B shows a cross-sectional view along line AA. Fig. Figure 2C shows a cross-sectional view along line BB. Fig. Figure 3 shows an exemplary cross-sectional view of an input and an output connection section of the rectangular waveguide tube 11.
[0021] Through holes 12 (12a to 12e) are, as in Fig. Figure 2 shows the waveguide tube plate 10 being formed at positions on the opposite side of the rectangular area 32 (32a to 32e) of the second substrate 30. The through holes 12 extend through the waveguide tube plate 10 in the plate thickness direction.
[0022] On the connecting surface of the waveguide tube plate 10 with the first substrate 20, grooves 14 (14a to 14e) are formed such that they extend from a respective through-hole 12 (12a to 12e) to an opposite area 13 (13a to 13e), which is opposite a respective rectangular area 22 (22a to 22e) of the first substrate 20.
[0023] That is, the rectangular waveguide tube 11 is, as in Fig. Figure 3 shows the through-hole 12, the groove 14, the opposite area 13, and the ground pattern 25 on the first substrate 20, which covers the groove 14. In both end sections of the rectangular waveguide tube 11, E-bends, which serve as input and output connections, are formed from the rectangular areas 22 and 32.
[0024] Consequently, the grooves 14 have depths equal to the length of the short side edge of the rectangular waveguide tubes 11 and widths equal to the length of the long side of the rectangular waveguide tubes 11. The groove 14 in the middle (14c) is, as in Fig. Figure 2 shows the structure formed in such a way that it has a linear shape. The shape of the grooves 14 becomes more curved in one direction towards the outside. The groove 14 in the middle has the widest width and the shortest conductor length. The width decreases and the conductor length increases as the grooves 14 are located closer to the outside.
[0025] In particular, the longitudinal side lengths of the rectangular waveguide tube ai and a conductor length Li are determined such that a conductor wavelength λ gi (i = 1 to 5) has a ratio shown in Equation 2 with the conductor length Li of each rectangular waveguide tube 11. The conductor wavelength λ gi is calculated in advance using Equation 1 via a free-space wavelength λ of a signal transmitted by the rectangular waveguide tube 11 and the longitudinal side length ai of the rectangular waveguide tube (i = 1 to 5, where the longitudinal side lengths a1 to a5 correspond to rectangular waveguide tubes 11a to 11e; the same applies below). Li=m×λ gi(m is a positive real number)
[0026] In the high-frequency device 1 constructed in this way, the conductor length Li of the rectangular waveguide tube 11 is set to m × λ gi, wherein the longitudinal side length of the rectangular waveguide tube 11 increases as the conductor length decreases.
[0027] In the high-frequency device 1 constructed in this way, the transmission line length L (L1 to L5) of each rectangular waveguide tube 11 can be arbitrarily adjusted, while maintaining a phase ratio between the high-frequency signals transmitted by each rectangular waveguide tube 11, since the longitudinal side length a (a1 to a5) of each rectangular waveguide tube 11 (11a to 11e) in the longitudinal direction (i.e., in the magnetic field direction) is adjusted accordingly. In particular, reducing the difference in transmission line lengths between the rectangular waveguide tubes 11 increases the degree of freedom in an arrangement of the rectangular waveguide tubes 11, while suppressing the deterioration of the propagation characteristics caused by temperature changes. (Second embodiment)
[0028] A second embodiment is described below.
[0029] The second embodiment differs from the first embodiment in that the through holes 12, the opposing areas 13, and the grooves 14 formed on the waveguide tube plate 10 have a different shape. Consequently, these differences will be discussed primarily below.
[0030] The through holes 12 (12a to 12e), which are opposite the rectangular areas 22 and 32 of the first substrate 20 and the second substrate 30, and the opposite areas 13 (13a to 13e) are, as in Fig. As shown in Figure 4, the through holes 12 and the opposing areas 13 are arranged on the outermost side. That is, the through holes 12 and the opposite areas 13 are formed with the same size as the cross-section of the rectangular waveguide tubes 11a and 11e, which have the shortest longitudinal side length a.
[0031] Furthermore, the grooves 14b to 14d, with the exception of grooves 14a and 14e, which form the rectangular waveguide tubes 11a and 11e, are designed such that sections of the inner wall taper (which in the Fig. 4 areas surrounded by the dashed ellipses), so that the longitudinal side lengths a of the rectangular waveguide tubes 11b to 11d change continuously in the direction of the through holes 12b to 12d and the opposite areas 13b to 13d.
[0032] Furthermore, the length of each region formed with the tapered shape is set to a value greater than or equal to λg / 3, where λg is the conductor wavelength in each rectangular waveguide tube 11.
[0033] In the high-frequency device 1 constructed in this way, the transmission loss caused by the fact that the longitudinal side length differs between the two end sections (input and output connection) of the rectangular waveguide tube 11 and the other areas can be significantly reduced.
[0034] In this context, the Fig. 7 a diagram showing the simulation results of a ratio between the length (cone length) of the inner wall formed by the tapered shape and a transmission loss. Fig. Figure 8 shows an exemplary illustration of a rectangular waveguide tube model used in the simulation.
[0035] The rectangular waveguide tube model transmits, as in Fig. Figure 8 shows high-frequency signals with a frequency of 76.5 GHz (free-space wavelength λ = 3.92 mm). A length h of the short side edge of the waveguide tube (P1 side in the Fig. 8) is 1 mm. One longitudinal side length Wg_b is 3 mm (i.e., the conductor wavelength λg is λg = 6.84 mm). One longitudinal side length Wg_a at the input and output terminals (P2 side in the Fig. 8) of the rectangular waveguide tube is 2.5 mm.
[0036] The one in Fig. Diagram 7 illustrates a case in which the cone length Wg_L is changed between a range of 0.5 mm (approximately 0.07 λ g) and 6.0 mm (approximately 0.88 λ g) and the transmission loss from P1 to P2 is determined.
[0037] As from the Fig. As can be seen in Figure 7, the transmission loss is sufficiently low (-0.005 dB or less) if the cone length Wg_L is greater than or equal to λ g / 3. (Other embodiments)
[0038] According to the embodiments described above, the rectangular waveguide tube 11 is formed from the grooves 14 formed on the waveguide tube plate 10 and the grooves 14 covered by the mass patterns 25 formed on the first substrate 20. However, the rectangular waveguide tube 11 can be, as in the embodiment described above, Fig. The high-frequency device 3 shown in Figure 5 is constructed using a waveguide plate 40, which is constructed from the through holes 41 formed in place of the slots 40 on a metallic plate with the same plate thickness as the short side edge of the rectangular waveguide tube 11, wherein the openings of the through holes 41 are covered on both sides by the ground patterns 25 and 35 formed on the first substrate 20 and the second substrate 30.
[0039] Furthermore, as in Fig. Figure 5 shows that matching devices 26 and 36 made of metallic patterns are arranged near the center of the rectangular areas 22 and 32 of the first substrate 20 and the second substrate 30. By providing the matching devices 26 and 36, the reflection of electromagnetic waves at the E-arc in the rectangular areas 26 and 36 can be controlled, and the transmission efficiency can be improved.
[0040] According to the embodiments described above, the high-frequency devices 1 and 3 are constructed from the first substrate 20 and the second substrate 30, which are attached to both surfaces of the waveguide tube plate 10. However, as in the embodiments described above, the high-frequency devices 1 and 3 can be constructed from the first substrate 20 and the second substrate 30, which are attached to both surfaces of the waveguide tube plate 10. Fig. 6A and Fig. In the high-frequency devices 5 and 7 shown in Figure 6B, at least either the first substrate 20 or the second substrate 30 is attached to the waveguide tube plates (substrate) 50 and 60, which are made up of metallic plates on which the through holes 51 and 61 are formed in areas equal to the rectangular areas 22 and 32.
[0041] The one in Fig. The high-frequency device 5 shown in Figure 6A is the high-frequency device 1 according to the first embodiment, in which the waveguide tube plate 50 is attached instead of the first substrate 20. The one shown in the Fig. The high-frequency device 7 shown in Figure 6B is the high-frequency device 3 of the other embodiment, in which the waveguide tube plates 50 and 60 are attached instead of the first substrate 20 and the second substrate 30.
[0042] According to the embodiments described above, a single-layer resin-based substrate is used as the first substrate 20 and the second substrate 30. However, a multi-layer resin-based substrate can also be used.
Claims
[1] High-frequency device (1; 3; 5) with: - several rectangular waveguide tubes (11a-11e) for transmitting high-frequency signals, wherein the several rectangular waveguide tubes (11a-11e) have different lengths in their longitudinal direction, the lengths being adapted such that high-frequency signals are transmitted in the several rectangular waveguide tubes (11a-11e) in such a way that a phase ratio among the high-frequency signals at the input terminals of the several rectangular waveguide tubes (11a-11e) is maintained at the output terminals of the several rectangular waveguide tubes (11a-11e), wherein - each of the several rectangular waveguide tubes (11a-11e) has a waveguide passage, wherein the waveguide passages corresponding to the several rectangular waveguide tubes (11a-11e) are formed separately on the same plane, - each of the several rectangular waveguide tubes (11a-11e) has a rectangular cross-section that is cut perpendicular to the longitudinal direction of the waveguide tube, - the rectangular cross-section has a long side edge and a short side edge, - a length of the long side edge and a length of the short side edge are defined as a long side length (a1-a5) and as a short side length, respectively, characterized by , that - each of the longitudinal side lengths (a1-a5) of the multiple rectangular waveguide tubes (11a-11e) is determined on the basis of a conductor length of each rectangular waveguide tube such that the longitudinal side length (11a-11e) increases with decreasing conductor length in order to allow a conductor wavelength of the high-frequency signal in the waveguide tube to be shorter, and by each of the multiple rectangular waveguide tubes (11a-11e) having: - a metallic plate (10; 40; 50) on which grooves (14a-14e) are formed, having a depth corresponding to the short side length and a width corresponding to the long side length (a1-a5); and - a substrate (20) attached to the metallic plate (10) on a surface on which grooves (14a-14e) are formed, and having a mass pattern (25) at a position which covers the entire grooves (14a-14e), except for sections of a connecting surface to the metallic plate (10; 40; 50) in which the input terminals and the output terminals of the rectangular waveguide tubes are formed. [2] High-frequency device (1:3:5) according to claim 1, characterized by , that - the longitudinal side lengths (a1-a5) at the input terminals and the output terminals of the several rectangular waveguide tubes (11a-11e) are all formed such that they have the same length; and - the several rectangular waveguide tubes (11a-11e) have at least one waveguide tube having a section of an inner wall in which the longitudinal side length of the inner wall differs between the input port and the output port and other sections, wherein the inner wall of the waveguide tube has a tapered shape such that the longitudinal side length changes continuously in the direction of the input port and the output port. [3] High-frequency device (1; 3; 5) according to claim 2, characterized by , that the section of the inner wall with the tapered shape has a length in the longitudinal direction of the waveguide tube that is greater than or equal to λ g / 3, where λ g describes a conductor wavelength of the rectangular waveguide. [4] High-frequency device (1; 3; 5) according to claim 1, characterized by , that - through holes (41) are formed on the metallic plate (40), the metallic plate (40) has a plate thickness corresponding to the short side length, wherein a width of the through holes (41) is equivalent to the long side length (a1-a5); and - a pair of substrates (20, 30) which are attached to both surfaces of the metallic plate (40) and have mass patterns (25, 35) which cover the entire through-holes (41), except for sections of the connecting surfaces to the metallic plate (40) in which the input terminals and output terminals of the rectangular waveguide tubes are formed. [5] High-frequency device (5) according to claim 1 or 4, characterized by , that the substrate (50) is formed from a metallic plate on which through holes (51) are formed in sections in which the inlet ports and the outlet ports are formed. [6] High-frequency device (1) according to claim 1 or 4, characterized by , that the substrate (20) is composed of a single-layer or multi-layer resin substrate onto which the mass pattern (25) is printed. [7] High-frequency device (1) according to claim 6, characterized by , that - the substrate (20) has formation-free areas (22) where the mass pattern (25) is not formed, in sections where the input terminals and the output terminals are formed; and - Adaptive devices (26, 36), which serve as metallic patterns, are arranged in the formation-free areas (22).