CN117096568A - Arch three-branch waveguide directional coupler - Google Patents

Abstract

The invention discloses an arched three-branch waveguide directional coupler, which belongs to the field of electronic components, in particular to a waveguide coupler. The common 3 branch line coupler structure is relatively poor in coupling performance and relatively narrow in bandwidth, and the branch waveguide structure is used for improving the width of the narrowest coupling hole to the level of 0.2mm on the basis of realizing the same performance as that of the common 5 branch line coupler, so that the processing requirement is greatly reduced, and the cost is reduced. Meanwhile, the width of the narrowest coupling hole of the coupler is more than one time wider than that of the narrowest coupling hole of the coupler with the traditional 5 branch line structure, the processed metal branch structure is stronger and firmer, and the improved structure is less prone to deformation under the same stress condition in the long-term use process, so that the service life of the coupler is prolonged.

Description

Translated fromChinese

一种拱形三分支波导定向耦合器An arched three-branch waveguide directional coupler

技术领域Technical field

本发明属于电子元器件领域，特别是一种拱形三分支波导定向耦合器。The invention belongs to the field of electronic components, in particular to an arched three-branch waveguide directional coupler.

背景技术Background technique

太赫兹波通常是指频率在0.1~10THz范围内，波长在0.003~3mm之间的电磁波，是电场和磁场周期性变化相互耦合产生。按照频率的高低，可以将其排列在一个轴线上，类似于家谱，科学家称之为电磁波谱。太赫兹波左侧波长偏向长波方向，属于微波范围，适用于电子学理论；右侧波长偏向短波方向，属于红外线与可见光范围，适用于光子学理论。太赫兹波位于微波与红外之间的一段“尴尬”的电磁波谱过渡区域，兼具了宏观经典理论和微观量子理论，结合了光电子学、半导体学和材料学等多学科，是目前人们极力研究开发的一个领域。太赫兹波与其他频段的波相比，有着自身独特的特点，如高频率、短波长、大带宽、低光子能量、强穿透性和指纹谱性。这些特点使其在大气环境监测、通信、雷达、国家安全等领域具有重要应用价值，成为各国争抢的科学技术制高点。Terahertz waves usually refer to electromagnetic waves with frequencies in the range of 0.1~10THz and wavelengths in the range of 0.003~3mm. They are generated by the mutual coupling of periodic changes in the electric field and magnetic field. According to the frequency, they can be arranged on an axis, similar to a family tree, which scientists call the electromagnetic spectrum. The wavelength of the terahertz wave on the left side is biased towards the long wave direction, which belongs to the microwave range, and is suitable for electronic theory; the wavelength on the right side is biased towards the short wave direction, which belongs to the infrared and visible light range, and is suitable for photonics theory. Terahertz waves are located in an "awkward" transition region of the electromagnetic spectrum between microwaves and infrared. They combine macroscopic classical theory and microscopic quantum theory, and combine multiple disciplines such as optoelectronics, semiconductor science, and materials science. They are currently being studied very hard. an area of development. Compared with waves in other frequency bands, terahertz waves have their own unique characteristics, such as high frequency, short wavelength, large bandwidth, low photon energy, strong penetration and fingerprint spectrum. These characteristics make it have important application value in the fields of atmospheric environment monitoring, communications, radar, national security, etc., and have become the scientific and technological commanding heights that countries compete for.

定向耦合器是一个具有方向性的无源四端口电路，主要用于功率的分配，可以设计为任意功率分配比，在电子对抗、通信系统、雷达系统以及测试测量仪器中有着不可缺少的作用。在一些重要的测量仪器中如矢量网络分析仪、反射计等，定向耦合器也有着比较广泛的应用。The directional coupler is a directional passive four-port circuit. It is mainly used for power distribution and can be designed to any power distribution ratio. It plays an indispensable role in electronic countermeasures, communication systems, radar systems and test and measurement instruments. In some important measuring instruments such as vector network analyzers, reflectometers, etc., directional couplers are also widely used.

在太赫兹频段，由于微带耦合器微带线之间的干扰严重，而波导中耦合孔加工十分困难，分支波导定向耦合器成为了太赫兹频段耦合器的主要电路结构，具有各端口匹配、隔离度高、插入损耗小等优点，改善了三端口网络的不足，而且具有高功率容量的特性。分支波导定向耦合器的研究理论主要基于微带分支线耦合器的理论，但当耦合器工作频率上升至毫米波频段，分支波导的宽度不再远远小于主波导的窄边宽度，所引入的误差也越来越大。1956年，美国学者John Reed基于网络分析法和奇偶模分析法，提出了分支波导宽度与耦合器耦合度之间的理论关系：太赫兹波导耦合器的带宽会随着分支数量的增多而增加，但每个分支的宽度会相应变窄。根据研究，例如在220GHz频段的3dB耦合器，分支宽度的和为0.6mm，如果为目前常用的5分支结构，每个分支宽度0.12mm，目前已报道的太赫兹频段分支波导定向耦合器为了保证优良的性能大都采用多分5分支结构甚至6-9分支结构，若为5分支，每个分支宽度0.12mm，7分支时每个分支宽度不到0.1mm，这不仅对腔体加工提出了较高的要求，在加工过程中也极易出现弯曲甚至折断。由于其最窄耦合孔的宽度较窄，导致其对尺寸极其敏感，在实际加工中，若无法保证加工精度，会明显恶化耦合器的性能。同时，高精度的腔体加工要求也极大地增加了加工成本，并且窄分支线的存在又会导致耦合器的稳定性和使用寿命大打折扣。In the terahertz frequency band, due to the serious interference between the microstrip lines of the microstrip coupler and the difficulty in processing the coupling holes in the waveguide, the branch waveguide directional coupler has become the main circuit structure of the terahertz frequency band coupler, with the characteristics of each port matching, It has the advantages of high isolation and low insertion loss, which improves the shortcomings of the three-port network, and has the characteristics of high power capacity. The research theory of branch waveguide directional couplers is mainly based on the theory of microstrip branch line couplers. However, when the operating frequency of the coupler rises to the millimeter wave frequency band, the width of the branch waveguide is no longer much smaller than the narrow side width of the main waveguide. The introduced The errors are getting bigger and bigger. In 1956, American scholar John Reed proposed a theoretical relationship between branch waveguide width and coupler coupling based on network analysis and odd-even mode analysis: the bandwidth of a terahertz waveguide coupler will increase as the number of branches increases. But the width of each branch will be correspondingly narrower. According to research, for example, for a 3dB coupler in the 220GHz frequency band, the sum of branch widths is 0.6mm. If it is a commonly used 5-branch structure, each branch width is 0.12mm. The branch waveguide directional couplers that have been reported in the terahertz frequency band are to ensure Most of the excellent performance adopts multi-5 branch structure or even 6-9 branch structure. If it is 5 branches, the width of each branch is 0.12mm. When it is 7 branches, the width of each branch is less than 0.1mm. This not only puts forward higher requirements for cavity processing. requirements, it is also very easy to bend or even break during the processing. Due to the narrow width of its narrowest coupling hole, it is extremely sensitive to size. In actual processing, if the processing accuracy cannot be guaranteed, the performance of the coupler will be significantly deteriorated. At the same time, the high-precision cavity processing requirements also greatly increase the processing cost, and the existence of narrow branch lines will greatly reduce the stability and service life of the coupler.

发明内容Contents of the invention

为了解决分支线波导定向耦合器最窄分支加工困难、寿命短的问题，同时实现小型化，本发明提出了一种拱形三分支波导定向耦合器。In order to solve the problems of difficult processing and short service life of the narrowest branch of the branch line waveguide directional coupler, and at the same time achieve miniaturization, the present invention proposes an arched three-branch waveguide directional coupler.

本发明技术方案为一种拱形三分支波导定向耦合器，该定向耦合器传输频率为170GHz到260GHz；该定向耦合器由两条长4mm宽0.546mm高1.092mm并列设置的矩形波导组成，这两条矩形波导的距离为0.4mm；这两条波导之间具有三个尺寸相同的拱形通道，第一条波导的两个端口分别定义为端口1和端口2，另一条波导中靠近端口1的端口定义为端口4，靠近端口2的端口定义为端口3；所述定向耦合器中端口1为输入端口，端口2为直通端口，端口3为耦合端口，端口4为隔离端口；直通端口与耦合端口输出信号有90°的相位差，隔离端口连接匹配负载；定向耦合器的长度方向为矩形波导的长边所在方向，两个矩形波导的高度加上拱形通道的高度为定向耦合器的高度，定向耦合器的宽度方向为矩形波导的宽度所在方向；三个拱形通道的宽度与矩形波导的宽度相同，拱形通道的高度即两个矩形波导之间的距离，三个拱形通道沿着矩形波导的长边依次设置，中间的拱形通道位于矩形波导长边的中点，另外两个拱形通道对称设置于中间拱形通道的两侧；所述拱形通道包括4个侧壁，与长度方向平行的两个侧壁之间的距离不变，该距离为矩形波导的宽度；与长度方向垂直的两个侧壁距离由大变小再变大，且变化过程对称，由长宽方向组成的平面截取的拱形通道截面为矩形；拱形通道与长度方向垂直的两个侧壁距离最长为0.35mm，最窄为0.3mm。The technical solution of the present invention is an arched three-branch waveguide directional coupler. The transmission frequency of the directional coupler is 170GHz to 260GHz. The directional coupler consists of two rectangular waveguides 4mm long, 0.546mm wide, 0.546mm high and 1.092mm high, arranged side by side. The distance between the two rectangular waveguides is 0.4mm; there are three arched channels of the same size between the two waveguides. The two ports of the first waveguide are defined as port 1 and port 2 respectively, and the other waveguide is close to port 1. The port is defined as port 4, and the port close to port 2 is defined as port 3; in the directional coupler, port 1 is the input port, port 2 is the pass-through port, port 3 is the coupling port, and port 4 is the isolation port; the pass-through port and The coupling port output signal has a phase difference of 90°, and the isolation port is connected to a matching load; the length direction of the directional coupler is the direction of the long side of the rectangular waveguide, and the height of the two rectangular waveguides plus the height of the arched channel is the length of the directional coupler. Height, the width direction of the directional coupler is the direction of the width of the rectangular waveguide; the width of the three arched channels is the same as the width of the rectangular waveguide, the height of the arched channel is the distance between the two rectangular waveguides, the three arched channels They are arranged sequentially along the long sides of the rectangular waveguide. The middle arched channel is located at the midpoint of the long side of the rectangular waveguide. The other two arched channels are symmetrically arranged on both sides of the middle arched channel; the arched channel includes 4 sides. wall, the distance between the two side walls parallel to the length direction remains unchanged, this distance is the width of the rectangular waveguide; the distance between the two side walls perpendicular to the length direction changes from large to small and then to large, and the change process is symmetrical, as The cross-section of the arched channel taken from the plane composed of the length and width directions is rectangular; the distance between the two side walls of the arched channel perpendicular to the length direction is 0.35mm at the longest and 0.3mm at the narrowest.

本发明采用一种基于拱形分支结构的波导耦合器结构，在传统的矩形分支线结构上额外铣出四个圆角，形成拱形，这种渐变结构可以有效降低波导不连续性引入的影响，提高耦合器工作带宽。普通3分支线耦合器结构由于耦合性能较差，带宽较窄而较少采用，而本发明的分支波导结构在实现与普通5分支线结构耦合器相同性能的基础上，将最窄耦合孔的宽度提升到0.2mm级，极大地降低了加工要求，降低了成本。同时，本发明耦合器最窄耦合孔的宽度与传统5分支线结构耦合器最窄耦合孔的宽度相比宽一倍以上，加工出的金属枝节结构更加结实牢固，这种改进型的结构在长期使用的过程中，在同样的应力情况下，更不容易发生形变，提升了耦合器的使用寿命。The present invention adopts a waveguide coupler structure based on an arched branch structure. Four additional rounded corners are milled out on the traditional rectangular branch line structure to form an arch. This gradient structure can effectively reduce the impact of waveguide discontinuity introduction. , improve the coupler operating bandwidth. Ordinary 3-branch line coupler structures are rarely used due to poor coupling performance and narrow bandwidth. However, on the basis of achieving the same performance as the ordinary 5-branch line structure coupler, the branch waveguide structure of the present invention has the narrowest coupling hole. The width is increased to 0.2mm, which greatly reduces processing requirements and costs. At the same time, the width of the narrowest coupling hole of the coupler of the present invention is more than twice as wide as the width of the narrowest coupling hole of the traditional five-branch structure coupler, and the processed metal branch structure is stronger and firmer. This improved structure is During long-term use, it is less likely to deform under the same stress, which increases the service life of the coupler.

附图说明Description of the drawings

图1为传统的五分支波导定向耦合器的典型结构。Figure 1 shows the typical structure of a traditional five-branch waveguide directional coupler.

图2为本发明拱形分支耦合器整体电路结构图。Figure 2 is an overall circuit structure diagram of the arched branch coupler of the present invention.

图3为本发明拱形分支耦合器整体仿真结果示意图。Figure 3 is a schematic diagram of the overall simulation results of the arched branch coupler of the present invention.

图4为本发明拱形三分支波导定向耦合器和传统五分支波导定向耦合器仿真结果对比图。Figure 4 is a comparison chart of the simulation results of the arched three-branch waveguide directional coupler of the present invention and the traditional five-branch waveguide directional coupler.

实施方式Implementation

如图1所示为现有技术中五分支波导定向耦合器的典型结构，根据分支线耦合器理论，两个主波导的间距和每个波导分支间的间距均为，其中/>为波导波长。将最外边的两个波导分支的宽度记为/>，其他分支的宽度等长，记为c。Figure 1 shows the typical structure of a five-branch waveguide directional coupler in the prior art. According to the branch line coupler theory, the spacing between the two main waveguides and the spacing between each waveguide branch are , of which/> is the waveguide wavelength. Let the width of the two outermost waveguide branches be expressed as/> , the other branches have the same width and length, denoted asc .

如图2所示为本发明拱形分支耦合器整体电路结构图；该定向耦合器由两条长4mm宽0.546mm高1.092mm并列设置的矩形波导组成，这两条矩形波导的距离为0.4mm；这两条波导之间具有三个尺寸相同的拱形通道，第一条波导的两个端口分别定义为端口1和端口2，另一条波导中靠近端口1的端口定义为端口4，靠近端口2的端口定义为端口3；所述定向耦合器中端口1为输入端口，端口2为直通端口，端口3为耦合端口，端口4为隔离端口；直通端口与耦合端口输出信号有90°的相位差，隔离端口连接匹配负载；定向耦合器的长度方向为矩形波导的长边所在方向，两个矩形波导的高度加上拱形通道的高度为定向耦合器的高度，定向耦合器的宽度方向为矩形波导的宽度所在方向；三个拱形通道的宽度与矩形波导的宽度相同，拱形通道的高度即两个矩形波导之间的距离，三个拱形通道沿着矩形波导的长边依次设置，中间的拱形通道位于矩形波导长边的中点，另外两个拱形通道对称设置于中间拱形通道的两侧；所述拱形通道包括4个侧壁，与长度方向平行的两个侧壁之间的距离不变，该距离为矩形波导的宽度；与长度方向垂直的两个侧壁距离由大变小再变大，且变化过程对称，由长宽方向组成的平面截取的拱形通道截面为矩形；拱形通道与长度方向垂直的两个侧壁距离最长为0.35mm，最窄为0.3mm。Figure 2 shows the overall circuit structure diagram of the arched branch coupler of the present invention; the directional coupler is composed of two rectangular waveguides 4mm long, 0.546mm wide, 1.092mm high and arranged side by side. The distance between the two rectangular waveguides is 0.4mm. ; There are three arched channels of the same size between these two waveguides. The two ports of the first waveguide are defined as port 1 and port 2 respectively. The port close to port 1 in the other waveguide is defined as port 4, and the port close to port 1 is defined as port 4. The port of 2 is defined as port 3; in the directional coupler, port 1 is the input port, port 2 is the through port, port 3 is the coupling port, and port 4 is the isolation port; the output signals of the through port and the coupling port have a phase of 90° difference, the isolation port is connected to the matching load; the length direction of the directional coupler is the direction of the long side of the rectangular waveguide, the height of the two rectangular waveguides plus the height of the arched channel is the height of the directional coupler, and the width direction of the directional coupler is The direction of the width of the rectangular waveguide; the width of the three arched channels is the same as the width of the rectangular waveguide, and the height of the arched channel is the distance between the two rectangular waveguides. The three arched channels are arranged sequentially along the long sides of the rectangular waveguide. , the middle arched channel is located at the midpoint of the long side of the rectangular waveguide, and the other two arched channels are symmetrically arranged on both sides of the middle arched channel; the arched channel includes 4 side walls, two parallel to the length direction The distance between the side walls remains unchanged, which is the width of the rectangular waveguide; the distance between the two side walls perpendicular to the length direction changes from large to small and then large, and the change process is symmetrical. The arch is intercepted by a plane composed of the length and width directions. The cross-section of the arched channel is rectangular; the distance between the two side walls perpendicular to the length direction of the arched channel is 0.35mm at the longest and 0.3mm at the narrowest.

本发明220GHz拱形三分支耦合器的仿真结果如图3所示。从图中看出，从190-230GHz频段，回波损耗和隔离度均优于15dB，相位不平坦度优于3°，性能优异。The simulation results of the 220GHz arched three-branch coupler of the present invention are shown in Figure 3. It can be seen from the figure that from the 190-230GHz frequency band, the return loss and isolation are better than 15dB, the phase unevenness is better than 3°, and the performance is excellent.

在220GHz频段，传统五分支波导定向耦合器的最窄分支宽度为0.12mm，采用数控精密机械加工技术加工时，需要直径为0.1mm铣刀加工，且加工精度需求为5μm；本发明三分支波导定向耦合器最窄分支宽度为0.2mm，同样加工方式下，仅需要直径为0.2mm铣刀即可加工，且加工精度需求仅为10μm。同时，当两种结构的耦合器均采用E面剖分结构进行加工时，传统五分支波导定向耦合器的最窄分支的深宽比为4.55（0.546mm/0.12mm），而拱形三分支波导定向耦合器最窄分支的深宽比为2.73（0.546mm/0.2mm）。根据文献P. J. Sobis,J. Stake, A. Emrich. A 170 GHz 45° hybrid for submillimeter wave sidebandseparating subharmonic mixers[J]. IEEE Microwave and Wireless ComponentsLetters, 2008, 18(10): 680-682的研究，结构深宽比超过3时，就会对加工工具造成一定影响，加工难度也会相应提高。In the 220GHz frequency band, the narrowest branch width of the traditional five-branch waveguide directional coupler is 0.12mm. When processed using CNC precision machining technology, a milling cutter with a diameter of 0.1mm is required, and the machining accuracy requirement is 5 μm; the three-branch waveguide of the present invention The narrowest branch width of the directional coupler is 0.2mm. Under the same processing method, only a milling cutter with a diameter of 0.2mm can be processed, and the processing accuracy requirement is only 10μm. At the same time, when the couplers of both structures are processed using the E-plane split structure, the aspect ratio of the narrowest branch of the traditional five-branch waveguide directional coupler is 4.55 (0.546mm/0.12mm), while the arched three-branch The aspect ratio of the narrowest branch of the waveguide directional coupler is 2.73 (0.546mm/0.2mm). According to the research in the literature P. J. Sobis,J. Stake, A. Emrich. A 170 GHz 45° hybrid for submillimeter wave sidebandseparating subharmonic mixers[J]. IEEE Microwave and Wireless ComponentsLetters, 2008, 18(10): 680-682, the structure is deep When the width ratio exceeds 3, it will have a certain impact on the processing tools, and the processing difficulty will increase accordingly.

与传统矩形分支耦合器性能对比，与传统五分支波导定向耦合器进行对比，优化后的五分支波导定向耦合器的仿真结果如图4所示，可以看出，除了中心频率有些差异，耦合器性能基本一致，幅度不平坦度均小于0.3dB，均具有良好的功率平分性能。但传统五分支耦合器的电路尺寸为2.3mm，拱形三分支耦合器的电路尺寸仅为1.5mm，尺寸减小了53%。综上所述，改进型三分支波导定向耦合器具有尺寸小、带宽宽、易加工的优势。Comparing the performance of the traditional rectangular branch coupler and the traditional five-branch waveguide directional coupler, the simulation results of the optimized five-branch waveguide directional coupler are shown in Figure 4. It can be seen that, except for some differences in the center frequency, the coupler The performance is basically the same, the amplitude unevenness is less than 0.3dB, and both have good power equalization performance. However, the circuit size of the traditional five-branch coupler is 2.3mm, and the circuit size of the arched three-branch coupler is only 1.5mm, which is a 53% reduction in size. In summary, the improved three-branch waveguide directional coupler has the advantages of small size, wide bandwidth, and easy processing.

Claims (1)

1. An arched three-branch waveguide directional coupler, characterized in that the directional coupler has a transmission frequency of 170GHz to 260GHz; the directional coupler consists of two rectangular waveguides which are 4mm long and 0.546mm wide and 1.092mm high and are arranged in parallel, and the distance between the two rectangular waveguides is 0.4mm; three arched channels with the same size are arranged between the two waveguides, wherein two ports of the first waveguide are respectively defined as a port 1 and a port 2, a port close to the port 1 in the other waveguide is defined as a port 4, and a port close to the port 2 is defined as a port 3; the port 1 in the directional coupler is an input port, the port 2 is a through port, the port 3 is a coupling port, and the port 4 is an isolation port; the direct port and the coupling port output signals have a phase difference of 90 degrees, and the isolation port is connected with a matched load; the length direction of the directional coupler is the direction of the long side of the rectangular waveguide, the height of the two rectangular waveguides plus the height of the arched channel is the height of the directional coupler, and the width direction of the directional coupler is the direction of the width of the rectangular waveguide; the width of the three arched channels is the same as that of the rectangular waveguide, the height of the arched channels is the distance between the two rectangular waveguides, the three arched channels are sequentially arranged along the long sides of the rectangular waveguide, the middle arched channel is positioned at the middle point of the long sides of the rectangular waveguide, and the other two arched channels are symmetrically arranged at the two sides of the middle arched channel; the arched channel comprises 4 side walls, and the distance between the two side walls parallel to the length direction is unchanged, and is the width of the rectangular waveguide; the distance between the two side walls perpendicular to the length direction is changed from large to small and then is changed into large, the change process is symmetrical, and the section of the arched channel which is cut by the plane consisting of the length direction and the width direction is rectangular; the distance between the two side walls of the arched channel perpendicular to the length direction is 0.35mm at the longest and 0.3mm at the narrowest.