阅读说明：本技术 一种矩形波导te10模到圆波导旋转te11模的模式转换器 (Mode converter from rectangular waveguide TE10 mode to circular waveguide rotating TE11 mode ) 是由 张勇 张博 代春玥 张铁笛 胡江 于 2021-09-01 设计创作，主要内容包括：本发明公开一种矩形波导TE10模到圆波导旋转TE11模的模式转换器,包括共面魔T结构、4路合成器、若干折弯波导、两个3dB耦合器和四个90°波导扭转器；共面魔T结构的两个输出端口分别经对应折弯波导弯折180°连接至对应3dB耦合器输入端；两个3dB耦合器关于4路合成器中心轴中心对称,直通端和耦合端分别经对应90°波导扭转器连接至4路合成器输入端；与同一个3dB耦合器相连的两个90°波导扭转器关于该3dB耦合器沿电磁信号传输方向的中心轴180°旋转对称；与不同3dB耦合器相连的两对90°波导扭转器关于4路合成器对称面平面对称。该模式转换器具有设计简便、模式纯度高、易于加工制作、转换效率高的优点。(The invention discloses a mode converter for converting a TE10 mode of a rectangular waveguide to a TE11 mode of a circular waveguide, which comprises a coplanar magic T structure, a 4-path synthesizer, a plurality of bent waveguides, two 3dB couplers and four 90-degree waveguide twisters, wherein the coplanar magic T structure is provided with a plurality of first waveguides and second waveguides; two output ports of the coplanar magic T structure are respectively bent by 180 degrees through corresponding bent waveguides and connected to the input ends of corresponding 3dB couplers; the two 3dB couplers are centrosymmetric about the central axis of the 4-path synthesizer, and the straight-through end and the coupling end are respectively connected to the input end of the 4-path synthesizer through corresponding 90-degree waveguide twisters; two 90-degree waveguide twisters connected with the same 3dB coupler are in 180-degree rotational symmetry with respect to the central axis of the 3dB coupler along the transmission direction of electromagnetic signals; two pairs of 90 waveguide twisters connected to different 3dB couplers are plane-symmetric about the 4-way combiner plane of symmetry. The mode converter has the advantages of simple design, high mode purity, easy processing and manufacture and high conversion efficiency.)

1. A mode converter from a rectangular waveguide TE10 mode to a circular waveguide rotating TE11 mode is characterized by comprising a coplanar magic T structure, a 4-path synthesizer, two bent waveguides, two 3dB couplers and four 90-degree waveguide twisters; two rectangular waveguide output ports of the coplanar magic T structure are respectively bent by 180 degrees through corresponding bent waveguides and connected to the input end of a corresponding 3dB coupler; the two 3dB couplers are in central symmetry about the central axis of the 4-path synthesizer, and the straight-through end and the coupling end of the two 3dB couplers are respectively connected to the input end of the 4-path synthesizer through corresponding 90-degree waveguide twisters; the twisting directions of two 90-degree waveguide twisters connected with the same 3dB coupler are consistent, and the twisting directions of two pairs of 90-degree waveguide twisters connected with different 3dB couplers are opposite.

2. The rectangular waveguide TE10 mode-to-circular waveguide rotated TE11 mode converter as claimed in claim 1, wherein said coplanar magic T structure is an E-plane splitter, and the difference of signal amplitudes of two rectangular waveguide output ports is less than 0.1dB, and the phase difference is 180 °.

3. The rectangular waveguide TE10 mode-to-circular waveguide rotated TE11 mode converter as claimed in claim 1, wherein said 3dB coupler is an E-plane coupler, and the difference of signal amplitude between the straight end and the coupling end is less than 0.5dB and the phase difference is 90 °.

4. The rectangular waveguide TE10 mode-to-circular waveguide rotation TE11 mode converter as claimed in claim 1, wherein 4 input ends of said 4-way combiner are all H-plane rectangular waveguides, the output ends are circular waveguides, and the radius of the circular waveguides is smaller than the cut-off wavelength of TE11 mode of the circular waveguides.

5. The rectangular waveguide TE10 mode-to-circular waveguide rotation TE11 mode converter as claimed in claim 1, wherein the bent waveguide comprises a long inclined waveguide, a 150 ° arc bent waveguide and a short inclined waveguide connected in sequence to realize 180 ° bending.

6. The rectangular waveguide TE10 mode-to-circular waveguide rotated TE11 mode converter as claimed in claim 1, wherein a curved waveguide is disposed between the straight end of the 3dB coupler and the corresponding 90 ° waveguide twister, between the coupling end and the corresponding 90 ° waveguide twister, and between the 90 ° waveguide twister and the input end of the 4-way combiner.

Technical Field

The invention belongs to the technical field of millimeter wave and terahertz devices, and particularly relates to a mode converter from a rectangular waveguide TE10 mode to a circular waveguide rotating TE11 mode.

Background

In a modern communication transmitting system, a power amplifier determines the transmitting output power of the system, and further influences the working distance, the working efficiency and other indexes of the system. Although the traditional vacuum electronic device can output power of hundreds of watts, the traditional vacuum electronic device is gradually replaced by a solid semiconductor device due to the adverse factors of large volume, small bandwidth and high processing difficulty, and compared with the solid semiconductor device, the solid semiconductor device has the advantages of small volume, long service life, low working voltage, and capability of being processed and produced in batches. However, as the operating frequency increases, the output power of the solid-state semiconductor device gradually decreases. Particularly, in the millimeter wave high-end frequency band, the output power of a single solid-state semiconductor device is sometimes only tens of milliwatts, and the power of a plurality of solid-state semiconductor devices needs to be combined to increase the power level, so that the research on the radial power combining technology is hot.

The conventional radial power combining mode is a field distribution space symmetric mode, such as an axial TEM mode, a circular waveguide TM01 mode, a circular waveguide TE01 mode and the like. With the increase of the working frequency, the central conductor in the coaxial line is difficult to process, and the modes of the circular waveguides TM01, TE01 and the like are higher-order modes of the circular waveguides, so that main mode interference exists, and the synthesis efficiency is affected. For the above reasons, in recent years, it has been proposed to use a circular polarization mode for radial power synthesis, the circular polarization mode having a rotating field characteristic, and an electromagnetic signal can be uniformly output over time, thereby achieving equal power distribution. However, the circularly polarized mode cannot be directly obtained, and a mode converter is required. The existing circularly polarized TE11 mode converter is mainly used in microwave and millimeter wave low-end frequency bands, is large in structural size and relatively simple to process, but has serious processing problems in millimeter wave high-end and terahertz low-end frequency bands and cannot be directly applied. The existing circularly polarized mode converter for the high frequency band has a complex structure, large processing and assembling errors and serious energy leakage, so that a novel circularly polarized mode converter which can be applied to the technical field of millimeter waves and terahertz devices needs to be designed.

Disclosure of Invention

The invention aims to overcome the problems in the prior art, and provides a mode converter from a rectangular waveguide TE10 mode to a circular waveguide rotating TE11 mode, which has the advantages of simple design, high mode purity, easiness in processing and manufacturing and high conversion efficiency.

The technical scheme adopted by the invention is as follows:

a mode converter from a rectangular waveguide TE10 mode to a circular waveguide rotating TE11 mode is characterized by comprising a coplanar magic T structure, two bent waveguides, two 3dB couplers, four 90-degree waveguide twisters and a 4-path synthesizer; the coplanar magic T structure comprises a rectangular waveguide input port, a first rectangular waveguide output port, a second rectangular waveguide output port and an isolation port which adopts microstrip probe output, wherein the first rectangular waveguide output port and the second rectangular waveguide output port are respectively connected to the input end of a corresponding 3dB coupler through bending waveguides bent by 180 degrees correspondingly, the two 3dB couplers are centrosymmetric about the central axis of a 4-way synthesizer, and the straight end and the coupling end of the two 3dB couplers are respectively connected to the input end of the 4-way synthesizer through corresponding 90-degree waveguide twisters so as to realize the conversion of E-plane waveguide-H-plane waveguide; the twisting directions of two 90-degree waveguide twisters connected with the same 3dB coupler are consistent, and the twisting directions of two pairs of 90-degree waveguide twisters connected with different 3dB couplers are opposite.

Further, the twisting directions are consistent, i.e. 180 ° rotational symmetry about the central axis of the 3dB coupler in the transmission direction of electromagnetic signals; the twisting directions are opposite, namely symmetrical about the plane of symmetry of the 4-way combiner, and two 90-degree waveguide twisters connected with the same 3dB coupler are used as a pair.

Furthermore, the coplanar magic T structure is an E-surface power divider, the signal amplitude difference between the first rectangular waveguide output port and the second rectangular waveguide output port is less than 0.1dB, the phase difference is 180 degrees, and no signal is output from the isolation port.

Furthermore, the 3dB coupler is an E-plane coupler, the signal amplitude difference between the straight-through end and the coupling end is less than 0.5dB, and the phase difference is 90 degrees.

Furthermore, 4 input ends of the 4-path synthesizer are all H-plane rectangular waveguides, an output end of the 4-path synthesizer is a circular waveguide, and the radius of the circular waveguide is smaller than the cut-off wavelength of the TE11 mode of the circular waveguide.

Furthermore, the bent waveguide comprises a long inclined waveguide, a 150-degree arc bent waveguide and a short inclined waveguide which are connected in sequence, and 180-degree bending is realized.

Further, arc-shaped bent waveguides are arranged between the straight-through end of the 3dB coupler and the corresponding 90-degree waveguide twister, between the coupling end and the corresponding 90-degree waveguide twister, and between the 90-degree waveguide twister and the input end of the 4-path synthesizer.

The principle of the mode converter from the TE10 mode of the rectangular waveguide to the TE11 mode of the circular waveguide is as follows: when two polarization degenerate modes with the phase difference of +/-90 degrees work simultaneously, a circular polarization mode with rotating field characteristics can be synthesized through vector superposition, and the synthesis conditions are related to power distribution and phase adjustment structures. The specific conversion process of the mode converter of the invention is as follows: the rectangular waveguide TE10 mode electromagnetic signals are input from a rectangular waveguide input port of the coplanar magic T structure, divided into two paths of electromagnetic signals with the signal amplitude difference smaller than 0.1dB and the phase difference of 180 degrees, respectively output from a first rectangular waveguide output port and a second rectangular waveguide output port, respectively input to an input end of a corresponding 3dB coupler through bending waveguides and bending by 180 degrees, respectively, a straight-through end and a coupling end of the 3dB coupler output two paths of electromagnetic signals with the signal amplitude difference smaller than 0.5dB and the phase difference of 90 degrees, respectively adjust the amplitude and the phase of the signals through a 90-degree waveguide twister to meet the synthesis conditions of a rotary TE11 mode, transmit the signals to a 4-path synthesizer, and are converted into the circular waveguide rotary TE11 mode electromagnetic signals, so that the mode conversion from the rectangular waveguide TE10 mode to the circular waveguide rotary TE11 mode is realized.

The invention has the beneficial effects that:

the invention provides a mode converter from a rectangular waveguide TE10 mode to a circular waveguide rotation TE11 mode, realizes mode conversion from the rectangular waveguide TE10 mode to the circular waveguide rotation TE11 mode, can be applied to the technical field of millimeter wave and terahertz devices, and has the advantages of simple design, high mode purity, easiness in processing and manufacturing and high conversion efficiency; moreover, the signal power distribution and phase shift circuits are distributed on the same layer by designing a plurality of bent waveguides, so that the processing and assembling difficulty is low and the realization is easy; each power distribution structure is a four-port device, full matching can be achieved, port isolation is high, amplitude and phase errors are small, and conversion loss is low.

Drawings

Fig. 1 is a schematic three-dimensional perspective view of a mode converter of a rectangular waveguide TE10 mode to a circular waveguide rotation TE11 mode provided in embodiment 1 of the present invention;

FIG. 2 is a plan view of a mode converter of rectangular waveguide TE10 mode to circular waveguide rotated TE11 mode provided in embodiment 1 of the present invention;

fig. 3 is a perspective view of a back-to-back connection structure of a mode converter applied to a WR-4 waveguide band according to embodiment 1 of the present invention;

fig. 4 is a plan view of a back-to-back connection structure of a mode converter applied to a WR-4 waveguide band according to embodiment 1 of the present invention;

fig. 5 is an electric field distribution diagram of a back-to-back connection structure of a mode converter applied to a WR-4 waveguide frequency band according to embodiment 1 of the present invention;

fig. 6 is a diagram of simulation results of S11 and S21 of the mode converter applied to a back-to-back connection structure of a WR-4 waveguide band according to embodiment 1 of the present invention.

The reference numerals are explained below:

1: a coplanar magic T structure; 2: a long angled waveguide; 3: 150 degree arc bend waveguide; 4: a short angled waveguide; 5: a 3dB coupler; 6: 45-degree arc bending waveguide; 7: a 90 ° waveguide twister; 8: 90-degree arc bend waveguide; 9: a 4-way synthesizer.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be further described with reference to the following embodiments and the accompanying drawings. The present embodiments are illustrative, and the claims hereof are not to be limited to only such embodiments.

Example 1:

the present embodiment provides a mode converter from a rectangular waveguide TE10 mode with a center frequency of 220GHz to a circular waveguide rotation TE11 mode, and the structure is shown in fig. 1 and fig. 2, and includes a coplanar magic T structure 1, two bending waveguides, two 3dB couplers 5, four 45 ° arc curved waveguides 6, four 90 ° waveguide twisters 7, four 90 ° arc curved waveguides 8, and a 4-way combiner 9.

The coplanar magic T structure 1 comprises a rectangular waveguide input port, a first rectangular waveguide output port, a second rectangular waveguide output port and an isolation port which adopts microstrip probe output, wherein the first rectangular waveguide output port and the second rectangular waveguide output port are respectively connected to the input end of a corresponding 3dB coupler 5 by bending a corresponding bending waveguide by 180 degrees, and the bending waveguide consists of a long inclined waveguide 2, a 150-degree arc bent waveguide 3 and a short inclined waveguide 4 which are sequentially connected; the signal amplitudes of the first rectangular waveguide output port and the second rectangular waveguide output port are both higher than-3.02 dB, the signal amplitude difference is less than 0.1dB, the phase difference is 180 degrees, the interference between an input echo and the two output ports is lower than-20 dB, and no signal is output from the isolation port; the first rectangular waveguide output port and the second rectangular waveguide output port are connected with the corresponding long inclined waveguide 2 through 30-degree arc bent waveguides with the inner and outer radiuses of a circular ring being 0.65mm +/-b/2 (wherein b is the length of the narrow side of the rectangular waveguide for transmitting the TE10 mode of the rectangular waveguide); the lengths of the two long inclined waveguides 2 are both 8 mm; the inner and outer radiuses of the circular rings of the two 150-degree arc curved waveguides 3 are both 0.65mm +/-b/2; the lengths of the two short inclined waveguides 4 are both 2mm, the input ports of the two short inclined waveguides 4 are both positioned on the central line between the main waveguide and the auxiliary waveguide of the 3dB coupler 5, and the output ports are connected with the input ends of the corresponding 3dB couplers 5.

The two 3dB couplers 5 are in central symmetry about the central axis of the 4-path synthesizer 9, the input end (isolation end) of one 3dB coupler 5 is correspondingly the isolation end (input end) of the other 3dB coupler 5, and the straight end and the coupling end are respectively connected to the input end of the 4-path synthesizer 9 through the corresponding 45-degree arc curved waveguide 6, 90-degree waveguide twister 7 and 90-degree arc curved waveguide 8 so as to realize the conversion of E-plane waveguide-H-plane waveguide; the signal amplitude of the straight-through end and the coupling end of the two 3dB couplers 5 is 3 +/-0.2 dB, the signal amplitude difference is less than 0.5dB, the phase difference is 90 degrees, and the output of the input echo and isolation end is lower than-25 dB; the inner and outer radiuses of the circular ring of the 45-degree arc curved waveguide 6 are both 1.2mm +/-b/2; the inner and outer radiuses of the ring of the 90-degree arc curved waveguide 8 are both 1mm +/-a/2 (wherein a is the length of the wide side of the rectangular waveguide for transmitting the TE10 mode of the rectangular waveguide);

the input echo of the 90-degree waveguide twister 7 is lower than-30 dB; the twisting directions of two 90-degree waveguide twisters 7 connected with the same 3dB coupler 5 are consistent, namely, the two 90-degree waveguide twisters are in 180-degree rotational symmetry with respect to the central axis of the 3dB coupler 5 along the transmission direction of the electromagnetic signals; the two pairs of 90 waveguide twisters 7 connected with different 3dB couplers 5 have opposite twisting directions, namely, the two pairs of 90 waveguide twisters 7 connected with the same 3dB coupler 5 are symmetrical about the plane of symmetry of the 4-way combiner 9.

The input echo of the 4-path synthesizer 9 is lower than-20 dB, and the radius of the circular waveguide is selected to be 0.5mm according to the transmission condition of the circular waveguide master mode.

In this embodiment, the coplanar magic T structure 1, the 3dB coupler 5, the 90 ° waveguide twister 7, and the 4-way combiner 9 are connected in sequence by using a bent waveguide, a 45 ° arc bent waveguide 6, and a 90 ° arc bent waveguide 8, and the central axes of the structures for transmitting the rectangular waveguide TE10 mode are ensured to be on the same horizontal plane, so as to facilitate the E-plane splitting manufacturing. In order to prevent the serious performance deterioration caused by the cascade connection of the unit circuits, the bending angles, the radii and the cutting angles of the bent waveguides, the 45-degree arc bent waveguides 6 and the 90-degree arc bent waveguides 8 need to be accurately optimized.

In order to verify the indexes of the mode converters provided in this embodiment, such as insertion loss and return loss, the two mode converters are connected back to obtain a back-to-back connection structure as shown in fig. 3 and 4, and the back-to-back connection structure is applied to the WR-4 waveguide frequency band, the electric field distribution diagram of the back-to-back connection structure is shown in fig. 5, so that the TE10 mode input by the rectangular waveguide is known, and the circular polarization TE11 mode with the rotating field characteristic is synthesized after passing through the coplanar magic T structure 1, the 3dB coupler 5, the 90 ° waveguide twister 7 and the 4-way synthesizer 9, thereby realizing the mode conversion from the rectangular waveguide to the circular waveguide.

The back-to-back connection structure is subjected to S11 and S21 simulation of a WR-4 waveguide frequency band, and the results are shown in FIG. 6, and it can be seen that the insertion loss at 195-245 GHz is better than 0.2dB, the return loss is better than 15dB, and the relative bandwidth is 23%.

In summary, the mode converter from the rectangular waveguide TE10 mode to the circular waveguide rotation TE11 mode provided in this embodiment realizes low-loss mode conversion from the rectangular waveguide TE10 mode to the circular waveguide rotation TE11 mode, and has the advantages of simple design, high mode purity, easy processing and manufacturing, less energy leakage, and low conversion loss.