CN110752422A - Compact high-purity circular waveguide TE02Mode exciter - Google Patents
Compact high-purity circular waveguide TE02Mode exciter Download PDFInfo
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- CN110752422A CN110752422A CN201910998670.XA CN201910998670A CN110752422A CN 110752422 A CN110752422 A CN 110752422A CN 201910998670 A CN201910998670 A CN 201910998670A CN 110752422 A CN110752422 A CN 110752422A
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
- H01P1/00—Auxiliary devices
- H01P1/16—Auxiliary devices for mode selection, e.g. mode suppression or mode promotion; for mode conversion
Abstract
The invention discloses a compact high-purity circular waveguide TE02Mode exciter belongs to microwave millimeter wave technical field. The mode converter comprises a rectangular waveguide power distribution network, a cross waveguide and a cross waveguide-circular waveguide transition structure which are connected in sequence. TE10The mode outputs four paths of TE with equal amplitude and same phase through a rectangular waveguide power distribution network10Signal, four-way TE10Injecting signals into the cross waveguide from the connection positions of the four included angles of the cross waveguide, and exciting a circle of rotationally symmetrical field in the inner ring of the cross waveguide; the field of the inner ring diffuses towards the outer ring and excites the field rotating in the opposite direction, thereby exciting TE in the cross waveguide44A mode; TE44The mode is converted into TE in the circular waveguide through a cross waveguide-circular waveguide transition structure02And (6) outputting the mode. The invention by using a cross waveguide TE44The mode is used as an intermediary mode, the internal power distribution network is greatly simplified, and the rectangular waveguide TE is effectively realized10Mode-to-circular waveguide TE02Mode conversion, and can suppress parasitic signals efficientlyAnd generating a generating mode.
Description
Technical Field
The invention belongs to the technical field of microwave and millimeter waves, and particularly relates to a circular waveguide TE02A mode exciter.
Background
The gyrotron traveling wave tube is a microwave millimeter wave amplifier with the characteristics of high power, wide frequency band and high gain, and has great application value in the aspects of plasma heating, millimeter wave radar, electronic countermeasure and the like. Due to the circular waveguide TE0nThe mode has the characteristics of extremely low wall loss, symmetric field and no polarization, and is a common working mode of the gyrotron traveling wave tube. In the development process of the gyrotron traveling wave tube, low-power testing needs to be carried out on a high-frequency assembly, an output structure and a transition section, and devices meeting the indexes can be assembled into a finished product through a subsequent process. In addition, the high-power output signal of the gyrotron traveling wave tube can be converted into a Gaussian-like mode through a transmission link formed by a series of devices such as a waveguide turning structure, a mode converter and a filter and then is transmitted to the feed source port. These devices must undergo low power testing to test their performance before high power testing can be performed. Therefore, various specific mode exciters are required to simulate the working mode of the gyrotron, so that each part of the device and the subsequent transmission link which form the gyrotron can be tested. Circular waveguide TE01Mode exciters have been extensively studied, however with respect to higher order TEs0nThe mode exciters are less studied. Development of higher order TE0nThe mode exciter is an important link for developing high-performance and high-power millimeter wave traveling wave tube parts and transmission devices thereof.
TE according to the excitation pattern02The mode exciter can be realized in two modes of direct connection and edge coupling. The use of Yaojinlei and the like proposes a direct connection type HE04Confocal waveguide exciters (YeleiYao, Jianxunwang, Guo liu, et al., "HE 04mode oscillators with float transmission and high modulation for confocal gyro-TWAs," IEEE Transactions on Electron Devices, vol.65, No.6, Jun.2018). Due to confocal waveguide HE04Mode and circular waveguide TE02Height of modeDegree of similarity, HE04The mode may be followed by HE04-TE02The transition section forms a circular waveguide TE02Mode(s). To excite HE04Mode, TE using rectangular waveguide by YaoYelei et al40The mode is used as an intermediate mode, and TE is excited in a rectangular waveguide40Mode, then converted to HE in confocal waveguide by transition structure04Mode(s). However, the transition structure from rectangular waveguide to confocal waveguide or circular waveguide in the excitation structure will result in partial TE40Coupled to TE21And TE41Mode, resulting in reduced output mode purity. In addition, increasing the length of the transition structure reduces parasitic TE21And TE41The effect of the content of the pattern is not significant. Chang et al propose a TE using edge coupling02Mode actuators (T.H.Chang, B.Y.Shew, C.Y.Wu, and N.C.Chen, "X-ray diagnosis and measurement of a terahertz mode converter," Review of scientific Instruments, vol.81, No.05, pp.4701, May.2010.). To suppress the spurious mode TE41Chang et al adopts three-level Y-type power division to inject rectangular waveguide TE10TE with mode converted into eight paths of equal amplitude and same phase10The signals are then injected into the circular waveguide by means of sidewall coupling, thereby producing the circular waveguide TE02Mode(s). However, the three-stage power division network adopted by the structure is complicated and circuitous, high processing precision is required, and the structure causes high ohmic loss.
Disclosure of Invention
Against the existing TE in the background art02The invention provides a compact high-purity TE (transverse electric) transducer and solves the problems of high stray mode, complex structure and the like of a mode exciter02Mode exciter technical scheme.
The technical scheme of the invention is as follows: compact high-purity TE02The mode exciter comprises a rectangular waveguide power distribution network, a cross waveguide and a cross waveguide-circular waveguide transition structure which are sequentially connected.
The rectangular waveguide power distribution network converts rectangular waveguide input into four paths of output rectangular waveguide output which are symmetrically distributed at intervals of 90 degrees in the direction, and the four paths of output rectangular waveguides are respectively inserted into the cross waveguides from four included angles of the cross waveguides.
The rectangular waveguide power distribution network is composed of an input waveguide, a two-stage Y-shaped waveguide power distribution structure, a two-stage waveguide transition section, a two-stage waveguide turning structure and an output rectangular waveguide. The input waveguide is a standard rectangular waveguide and is connected with a first-stage Y-shaped waveguide power dividing structure. Two output ends of the first-stage Y-shaped waveguide power dividing structure are respectively provided with a first-stage waveguide transition section, and two waveguide power dividing branches are gradually changed into standard waveguide output. And through a subsequent first-stage waveguide turning structure, completing 180-degree turning of two output ports of the first-stage Y-shaped waveguide power dividing structure, and respectively connecting the two output ports with the input end of the second-stage Y-shaped waveguide power dividing structure. The output end of the second-stage Y-shaped waveguide power dividing structure is connected with a section of uniform waveguide and realizes 135-degree turning through the second-stage waveguide turning structure, and waveguide outputs which are symmetrically distributed at intervals of 90 degrees in four directions are obtained. The four-path waveguide output passes through the second-stage waveguide transition section connected in the rear to be converted into four-path output rectangular waveguides of the power distribution network.
The cross waveguide is composed of two rectangular waveguides which are perpendicular to each other, in order to enable the injected signals to be transmitted in a single direction in the cross waveguide, one end of the cross waveguide is closed, and the other end of the cross waveguide is connected with a cross waveguide-circular waveguide transition structure. In order to reduce reflection, the closed end of the cross waveguide is lower than the bottom of the four output ports of the rectangular waveguide power distribution network.
The cross waveguide-circular waveguide transition structure is a waveguide structure with gradually changed section calibers, the input end face is connected with the cross waveguide, and the output end face is connected with the circular waveguide. In the cross waveguide-circular waveguide transition structure, two side edges of the cross waveguide are close to each other, and finally are overlapped at an output port. Four paths of metal diaphragms which are symmetrically distributed and are spaced by 90 degrees are inserted into the outer side of the cross waveguide-circular waveguide transition structure to inhibit a parasitic mode.
The operating principle of the mode converter is as follows:
when the electromagnetic wave is TE10The mode enters the rectangular waveguide power distribution network from the input port, and is symmetrically distributed at intervals of 90 degrees in four directions after passing through the two-stage Y-shaped waveguide power distribution structureThe waveguide outputs four paths of TE with equal amplitude and same phase10A signal. Generated four-way TE10Injecting a mode into the cross waveguide from the connection position of two mutually vertical rectangular waveguides forming the cross waveguide, and exciting a circle of rotationally symmetrical field in the inner ring of the cross waveguide; the field of the inner ring of the cross waveguide diffuses towards the outer ring and excites a field rotating in the reverse direction, thereby exciting TE in the cross waveguide44Mode(s). Due to TE10The mode is injected into the cross waveguide at the junction of two rectangular waveguides perpendicular to each other, so that only four TE paths are required10The signal and preceding-stage power division network only needs two-stage Y-shaped waveguide power division structure cascade connection, so that a complex structure is avoided, and the processing difficulty is reduced. Simultaneous, four-way TE10The signal injection is located slightly above the closed end of the cross waveguide, effectively reducing reflections. TE excited in a cross waveguide44The mode is converted into TE in the circular waveguide through a cross waveguide-circular waveguide transition structure02Mode(s). Four metal diaphragms symmetrically arranged in the cross waveguide-circular waveguide transition structure can effectively inhibit TE of the cross waveguide44Mode-to-circular waveguide TE41And the conversion of the mode improves the purity of the output mode.
The invention has the following beneficial effects:
the invention by using a cross waveguide TE44The mode is used as an intermediary mode, so that the internal power distribution network can be greatly simplified, and the rectangular waveguide TE is effectively realized10Mode-to-circular waveguide TE02Mode conversion, and generation of spurious modes can be suppressed efficiently. The invention has the advantages of high purity, high efficiency and wide frequency band. Meanwhile, the converter is simple and compact in structure, easy to process and assemble and good in engineering practicability.
Drawings
FIG. 1 is a schematic view of the overall structure of the present invention;
FIG. 2 is a schematic diagram of the power distribution network and the cross waveguide structure according to the present invention;
FIG. 3 is a schematic diagram of a cross waveguide-circular waveguide transition structure according to the present invention;
FIG. 4 shows the reflection condition of the input port and the output port TE of the present invention02The content of the pattern;
fig. 5 shows the content and distribution of the output port parasitic mode of the present invention.
The reference numbers illustrate: 1-1 is an input standard rectangular waveguide; 1-2 is a first-stage Y-shaped waveguide power dividing structure; 1-3 is a first-stage waveguide transition section; 1-4 is a first-stage waveguide turning structure; 1-5 is a first-stage waveguide connecting section; 1-6 is a second-stage Y-shaped waveguide power dividing structure; 1-7 are second-stage waveguide connecting sections; 8 is a second-stage waveguide turning structure; 1-9 is a second-stage waveguide transition section; 2-1 is a cross waveguide; 2-2 is a cross waveguide signal injection port; 3-1 is a cross waveguide-circular waveguide transition structure; 3-2 is a metal membrane; 3-3 is an output circular waveguide.
Detailed Description
Based on the above theory and design points, a circular waveguide TE working in the Ka band is designed02The invention will be further explained in more detail with reference to the drawings, but the scope of protection of the invention is not limited to this embodiment.
As shown in FIG. 1, the present invention is a compact high purity circular waveguide TE02The mode exciter comprises a rectangular waveguide power distribution network, a cross waveguide and a cross waveguide-circular waveguide transition structure which are sequentially connected. Four output ports of the rectangular waveguide power distribution network are injected into the cross waveguide from the connection position of two mutually perpendicular rectangular waveguides forming the cross waveguide; the cross waveguide-circular waveguide transition structure realizes circular waveguide output. The structure is as follows:
the front-stage input standard rectangular waveguide 1-1 model of the rectangular waveguide power distribution network is BJ320(7.112mm 3.556 mm). The output of the first-stage Y-shaped waveguide power dividing structure 1-2 is two paths of 7.112mm by 1.778mm rectangular waveguides, and the first-stage Y-shaped waveguide power dividing structure 1-3 with the length of 38mm is transited into 7.112mm by 3.556mm rectangular waveguides; and then the first-stage waveguide turning structure 1-4 realizes 180-degree turning and is connected to the second-stage Y-shaped waveguide power dividing structure 1-6. The first-stage waveguide turning structure 1-4 comprises two first-stage waveguide elbows and a middle first-stage waveguide connecting section 1-5, wherein the turning radii of the two waveguide elbows are both 7.15mm, the bending angle is 90 degrees, and the length of the first-stage waveguide connecting section 1-5 is 20 mm. And the output signal of the second-stage Y-shaped waveguide power dividing structure sequentially passes through a second-stage waveguide connecting section 1-7 with the length of 20mm, a second-stage waveguide turning structure 1-8 with the turning radius of 3.54mm and the bending angle of 135 degrees and a second-stage waveguide transition section 1-9 with the length of 25mm to reach the cross waveguide signal injection port 2-2.
The cross waveguide 2-1 is formed by two mutually perpendicular rectangular waveguides of 24.8mm 5mm 30 mm. The signal injection port 2-2 of the cross waveguide is a rectangular port of 7.112mm by 5mm, and the direction of the rectangular port is 45 degrees different from that of the two rectangular waveguides forming the cross waveguide 2-1. The bottom of the signal injection port 2-2 is located 1mm above the bottom of the cross waveguide 2-1. The output port of the cross waveguide 2-1 is connected with a cross waveguide-circular waveguide transition structure 3-1 to be transited into circular waveguide output.
The bottom of the cross waveguide-circular waveguide transition structure 3-1 is the same as the cross waveguide in size, the output port is the same as the circular waveguide 3-3 in size, and the circular waveguide 3-3 is 12.4mm in radius and 60mm in length. The cross waveguide-circular waveguide transition structure 3-1 is gradually changed along the axial direction, and the long sides of the two rectangular waveguides forming the cross waveguide are close to each other and finally overlapped. 4 metal diaphragms 3-2 with the length of 37mm, the width of 1.2mm and the depth of 2.2mm are symmetrically inserted from the outer side of the cross waveguide-circular waveguide transition structure 3-1, and the metal diaphragms are 45 degrees apart from the four signal injection ports.
The Ka-waveband compact high-purity circular waveguide TE can be completed through the steps02Designing a mode exciter, and then establishing a three-dimensional model through simulation software for simulation verification.
FIG. 4 shows TE obtained by simulation02Reflection situation of input port and output port TE of mode exciter02Conversion efficiency of the mode. In the range of 28GHz-34GHz, the input port reflection is less than-10 dB, and the output port TE02The content is more than 87% (-0.6 dB); after the frequency exceeds 34GHz, the reflection is obviously increased and TE is output02The content of the pattern decreases. Shows that the invention can realize the circular waveguide TE in a wide frequency band02Efficient excitation of the modes.
FIG. 5 shows TE obtained by simulation02Mode exciter output port spurious mode profiles. Main parasiticMode is TE01Mode, TE41Mode TM41Mode(s). The content of the three parasitic modes in the range of 28GHz-37.5GHz is less than-15 dB. Shows that the invention can excite high-purity circular waveguide TE in a wide frequency band02Mode(s).
Claims (3)
1. Compact high-purity circular waveguide TE02The mode exciter comprises a rectangular waveguide power distribution network, a cross waveguide and a cross waveguide-circular waveguide transition structure which are sequentially connected;
the rectangular waveguide power distribution network converts rectangular waveguide input into four paths of output rectangular waveguide output which are symmetrically distributed at intervals of 90 degrees in the direction, and the four paths of output rectangular waveguides are respectively inserted into the cross waveguides from four included angles of the cross waveguides;
the cross waveguide is composed of two rectangular waveguides which are vertical to each other, one end of the cross waveguide is closed, the other end of the cross waveguide is connected with a cross waveguide-round waveguide transition structure, and signals injected from the rectangular waveguide power distribution network are transmitted in a single direction in the cross waveguide;
the cross waveguide-circular waveguide transition structure is a waveguide structure with gradually changed section calibers, the input end surface is connected with the cross waveguide, and the output end surface is connected with the circular waveguide; in the cross waveguide-circular waveguide transition structure, two side edges of the cross waveguide are close to each other, and finally are overlapped at an output port; four paths of metal diaphragms which are symmetrically distributed and are spaced by 90 degrees are inserted into the outer side of the cross waveguide-circular waveguide transition structure to inhibit a parasitic mode.
2. A compact high purity circular waveguide TE as claimed in claim 102The mode exciter is characterized in that the rectangular waveguide power dividing network consists of an input waveguide, a two-stage Y-shaped waveguide power dividing structure, a two-stage waveguide transition section, a two-stage waveguide turning structure and an output rectangular waveguide; the input waveguide is a standard rectangular waveguide and is connected with a first-stage Y-shaped waveguide power dividing structure. Two output ends of the first-stage Y-shaped waveguide power dividing structure are respectively provided with a first-stage waveguide transition section, and two waveguide power dividing branches are gradually changed into standard waveguide output; through the subsequent first stageThe waveguide turning structure is used for turning two output ports of the first-stage Y-shaped waveguide power dividing structure by 180 degrees and is respectively connected with the input end of the second-stage Y-shaped waveguide power dividing structure; the output end of the second-stage Y-shaped waveguide power dividing structure is connected with a section of uniform waveguide and realizes 135-degree turning through a second-stage waveguide turning structure, and waveguide outputs which are symmetrically distributed at intervals of 90 degrees in four directions are obtained; the four-path waveguide output passes through the second-stage waveguide transition section connected in the rear to be converted into four-path output rectangular waveguides of the power distribution network.
3. A compact high purity circular waveguide TE as claimed in claim 102The mode exciter is characterized in that the closed end of the cross waveguide is lower than the bottom of the four output ports of the rectangular waveguide power dividing network in order to reduce reflection.
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| CN111969288A (en) * | 2020-07-09 | 2020-11-20 | 电子科技大学 | Oblique multipath synthesis gyrotron traveling wave tube TE02Mode input coupler |
| CN115458881A (en) * | 2022-09-29 | 2022-12-09 | 电子科技大学 | Compact rectangular waveguide-circular waveguide mode converter |
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Cited By (2)
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