W-band hybrid E-plane waveguide power divider and W-band array antenna

Abstract

The invention discloses a W-band hybrid E-plane waveguide power divider and a W-band array antenna, the power divider comprises an input port and four output ports, the power divider is in left and right mirror symmetry, the input port is arranged on a central axis in left and right mirror symmetry, a hollow waveguide structure of the input port is located at a lower layer, and the output port is located at a lower layer. The four output ports are arranged at four corners of the H shape in the same layer, and the hollow waveguide structures of the four output ports are located at the upper layer; the input port and the output port are connected through a branch waveguide body, and a stepped metal ridge structure is arranged in the branch waveguide body; the input port waveguide body and the branch waveguide body form a hollow-ridge transmission structure; and a ridge-hollow transmission structure is formed from the branch waveguide body to the four output port waveguide bodies. In-phase output of four ports of the E-plane T-junction power divider is achieved, on the basis that high consistency of signal amplitudes and phases of the four output ports is guaranteed, the E-plane T-junction power divider has the advantage of low insertion loss of a waveguide power divider, and the aperture utilization rate is increased.

Description

Technical Field

[0001] The present invention belongs to the field of millimeter-wave passive devices, and particularly relates to a W-band hybrid E-plane waveguide power divider and a W-band array antenna. Background Art

[0002] With the rapid development of wireless communication technology, people's demand for communication bandwidth has gradually increased. In order to cope with the application scenarios of new high-speed communication, communication technology is expanding to higher frequency bands. The W-band (75G - 110GHz) is an important electromagnetic wave window frequency band in the millimeter-wave and terahertz spectra. Because of its smaller antenna structure size, higher target resolution, and better communication security, it has important application value in systems such as high-resolution radars and precision guidance, and has become a research hotspot in recent years.

[0003] In the antenna design of the W-band, as a basic unit of the feeding network, the power divider plays a key role in power distribution, phase, and amplitude regulation. Due to the high frequency of electromagnetic waves in this band, the structure size is very small, and the attenuation of electromagnetic waves during path propagation is very strong, which causes great difficulties for the miniaturized design of the feeding network. This makes the design and research of power dividers in this band always the key content of antenna research.

[0004] Power dividers with waveguide systems are widely used in this band due to their characteristics such as low insertion loss and high power capacity. In terms of aperture, the H-plane waveguide power divider has a larger planar size, which is not conducive to the design of the feeding network in this frequency band. The E-plane waveguide power divider has a compact structure and can leave corresponding space for the radiation unit. For the traditional E-plane T-junction waveguide power divider structure, due to the structural symmetry and electric field distribution characteristics, there is a 180° phase difference between the two output ports. When using this traditional E-plane power divider as the basic feeding unit and then combining it into a large-size array, the phases of each output port will be different, and there will be large grating lobes in the antenna array, making it difficult for the E-plane waveguide power divider to be applied to large-scale planar array designs. In addition, when designing an array antenna to ensure the transmission efficiency, the main part of the power divider needs to be larger than the branch part. The main part and the branch part of the traditional power divider are on the same layer, which will increase the overall structure size of the power divider and result in low utilization rate of the antenna array aperture, all of which bring great difficulties to the miniaturized design of the W-band array antenna. Summary of the Invention

[0005] The purpose of the present invention is to overcome the defects of the prior art and provide a design method for a W-band hybrid E-plane waveguide power divider. By designing the conversion between the hollow waveguide structure and the ridge waveguide structure, the equal-amplitude and in-phase output of each port of the E-plane T-junction four-way power divider is realized, and through the hierarchical design of the input port and the output port, ideas are provided for the miniaturized design of the W-band waveguide antenna feeding network.

[0006] In view of this, the present invention proposes a W-band hybrid E-plane waveguide power divider, which includes an input port and four output ports. The power divider is symmetric about the left-right mirror, and the input port is disposed on the central axis of the left-right mirror symmetry. The hollow waveguide structure of the input port is located in the lower layer, and the four output ports are arranged in the same layer at the four corners of the H shape. The hollow waveguide structures of the four output ports are located in the upper layer. The input port and the output ports are connected by branch waveguides, and a stepped metal ridge structure is provided in the branch waveguides. Among them, the input port waveguide and the branch waveguide form a hollow-ridge transmission structure; the branch waveguide to the four-way output port waveguide forms a ridge-hollow transmission structure.

[0007] Preferably, a matching slot structure is provided on the side of each output port close to the branch waveguide structure. The four matching slot structures are symmetrically distributed and are used to adjust the impedance matching of the transmission ports.

[0008] Preferably, the length and width of the matching slot affect the matching characteristics of the power divider, and the height of the matching slot is equal to the height of the output port waveguide.

[0009] Preferably, the power divider operates in the single-mode TE 10 mode, and the length of the input port waveguide, the height of the branch waveguide, and the height of the output port waveguide are all set between half a wavelength and one wavelength.

[0010] Preferably, the following constraint relationship is satisfied: within a set range, the width of the input port is greater than the width of the branch waveguide, and the width of the branch waveguide is greater than the width of the output port waveguide;

[0011] Under the constraint relationship, by adjusting the width of the input port, the width of the branch waveguide, and / or the width of the output port waveguide, the better the resonance effect at the center operating frequency point, and the better the matching effect of the corresponding ports.

[0012] Preferably, the stepped metal ridge structure provided in the branch waveguide is disposed at the center of the wide side of the branch and is used to adjust the transmission performance between the input port waveguide and the output port waveguide.

[0013] Preferably, the stepped metal ridge structure is a three-level step, where

[0014] The first-level stepped metal ridge is used for the transmission between the input port waveguide and the branch waveguide;

[0015] The second-level stepped metal ridge is used for the transmission of electromagnetic waves in the branch waveguide;

[0016] The third-level stepped metal ridge is used for the transmission between the branch waveguide and the output port waveguide.

[0017] Preferably, the width of the first-stage stepped metal ridge is slightly wider than that of the latter two-stage stepped metal ridges; the length slightly extends beyond the branch part; the height is greater than half of the height of the branch waveguide; the widths of the second-stage stepped metal ridge and the third-stage stepped metal ridge are equal, and the height of the second-stage stepped metal ridge is greater than that of the third-stage stepped metal ridge.

[0018] Preferably, the stepped metal ridge structure is made of aluminum.

[0019] On the other hand, the present invention also provides a W-band array antenna, which includes the W-band hybrid E-plane waveguide power divider described in any one of the above.

[0020] Compared with the prior art, the advantages of the present invention are as follows:

[0021] Phase correction: Different from the traditional four-way E-T power divider with different phases at each output port, the present invention adopts a "hollow-ridge-hollow" hybrid structure. By setting a stepped metal ridge structure at the branch position, the phase of the electromagnetic wave is accurately adjusted. This structure can effectively correct the phase, making the phases of the four output ports consistent, thus avoiding the generation of grating lobes and significantly improving the performance and directivity of the antenna array.

[0022] Enhanced structural compactness: In the traditional E-T power divider, the input port and the output port are on the same layer, resulting in a large planar size of the power divider, which is not conducive to the miniaturization design of the W-band array antenna. In the present invention, the hollow waveguide structure of the input port is arranged on the lower layer as the feeding port; the hollow waveguide structure of the output port is arranged on the upper layer, and the four output ports are arranged on the same layer. While effectively reducing the profile, the structure of the power divider is made more compact, effectively reducing the size of the power divider in the planar direction, further improving the space utilization rate, and being conducive to the miniaturization of the W-band array antenna. Description of the Drawings

[0023] Figure 1 is a three-dimensional structure diagram of the specific embodiment of the present invention;

[0024] Figure 2 is a top view of the structure of the specific embodiment of the present invention;

[0025] Figure 3 is a front view of the structure of the specific embodiment of the present invention;

[0026] Figure 4 is an electric field vector distribution diagram of the "hollow-ridge" power division structure from the input port to the branch part designed by the present invention;

[0027] Figure 5 is an electric field vector distribution diagram of the "ridge-hollow" power division structure from the branch part to the output port designed by the present invention;

[0028] Figure 6 is the electric field vector distribution diagram of each port of the whole invention;

[0029] Figure 7 is the schematic diagram of the electric field transmission of the whole invention;

[0030] Figure 8 is the S-parameter curve graph of the specific implementation mode of the invention in the range of 86 GHz to 95 GHz;

[0031] Figure 9 is the phase curve graph of the specific implementation mode of the invention in the range of 86 GHz to 95 GHz.

[0032] Reference Signs

[0033] Port1. Input port Port2, Port3, Port4, Port5. Output ports

[0034] 1. First-stage metal ridge 2. Second-stage metal ridge 3. Third-stage metal ridge

[0035] 4. Branch waveguide structure 5. Matching slot structure 6. First-stage waveguide extension

[0036] 7. The electric field vector diverges along the metal ridge

[0037] 8. The electric field vector converges along the metal ridge

[0038] 9. In-phase distribution of the electric field vector Specific Implementation Mode

[0039] To achieve the above content, the present invention adopts the following technical solutions:

[0040] A W-band hybrid E-plane waveguide power divider, characterized in that the structure is left-right mirror symmetric, and includes a hollow waveguide structure of the input port, branches, and output ports, a stepped metal ridge structure arranged at the branch position of the waveguide power divider, and a matching slot structure arranged at the output port position of the waveguide power divider.

[0041] Further, the hybrid structure of the power divider is described:

[0042] The hollow waveguide structure of the input port is located in the lower layer and serves as the feeding port of the power divider;

[0043] The hollow waveguide structure of the output port is located in the upper layer, and the four output ports are arranged in the same layer and in an "H" shape;

[0044] The input port in the lower layer is connected to the output ports in the upper layer through the waveguide at the branch position, and a stepped metal ridge structure is arranged in the waveguide at the branch position;

[0045] The lower-layer input-port waveguide and the branch waveguide form a "hollow - ridge" transmission structure; the branch waveguide and the upper-layer four-way output-port waveguide form a "ridge - hollow" transmission structure; this "hollow - ridge - hollow" transmission structure is called the hybrid structure of this power divider.

[0046] Among them, to ensure single-mode transmission of the waveguide power divider, the operating mode of this waveguide power divider is set to single-mode TE 10 mode, and the lengths of the input-port waveguides, the heights of the branches and the output-port waveguides need to be set to values between half a wavelength and one wavelength.

[0047] To enable the four-way output ports to be designed on the same layer, the waveguide heights of the branches and the output ports are equal.

[0048] The stepped metal ridge structure is located at the center of the wide side of the branch, and is used to adjust the transmission performance between the input-port waveguide and the output-port waveguide.

[0049] The stepped metal ridge structure is provided with a total of three levels of steps. Among them, the first-level stepped metal ridge structure is used for the transmission between the input-port waveguide and the branch waveguide; the second-level stepped metal ridge structure is used for the transmission of electromagnetic waves in the branch waveguide; the third-level stepped metal ridge is used for the transmission between the branch waveguide and the output-port waveguide.

[0050] Furthermore, the width of the first-level stepped metal ridge structure is slightly wider than the widths of the latter two levels of stepped metal ridges; the length slightly extends beyond the branch part; the height is greater than half of the height of the branch waveguide.

[0051] Furthermore, the widths of the second-level and third-level stepped metal ridge structures are equal, but the height of the third-level step is less than that of the second-level step.

[0052] The matching slot structure is symmetrically distributed on one side of the four-way output ports, and is used to adjust the impedance matching of the transmission ports.

[0053] Furthermore, the length and width of the matching slot affect the matching characteristics of the power divider, and its height is equal to the height of the output-port waveguide.

[0054] The principle of the technical solution of the present invention is as follows:

[0055] Symmetry design: The power divider adopts left-right mirror symmetry. The input port is located in the lower layer as the feeding port, and the four-way output ports are arranged on the same layer in an "H" shape on the upper layer. This symmetrical structure ensures that signals are evenly distributed to each output port along the same path. Especially for the design of W-band high-frequency array antennas, the symmetrical structure of the feeding network can ensure the consistency of the output signal amplitude.

[0056] Hybrid Structure Design: The "hollow - ridge - hollow" hybrid structure enables smooth transition and efficient transmission of signals in different waveguide sections. Among them, due to the electric field transmission characteristics, the "hollow - ridge" structure makes the electric field distribution phases at both ends of the branch sections opposite (the electric field of one end of the branch converges along the metal ridge, while the electric field of the other end of the branch diverges along the metal ridge); while the "ridge - hollow" structure makes the electric field distribution phases at the two output ports the same, so that the four output ports of the E - plane T - junction waveguide power divider have the same phase.

[0057] Single - mode Transmission Design: The power divider operates in the single - mode TE 10 mode. The length of the waveguide body at the input port, the branch, and the height of the waveguide body at the output port are all set between half a wavelength and one wavelength to ensure that only the TE 10 mode is transmitted in the waveguide, avoiding multimode interference and ensuring the stability and reliability of signal transmission.

[0058] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0059] Embodiment 1

[0060] Embodiment 1 of the present invention provides a W - band hybrid E - plane waveguide power divider, as shown in Figure 1 and Figure 2 . This structure is symmetric about the left - right mirror image and includes an input port (such as Port 1 in Figure 1 ), a branch waveguide body structure (such as label 4 in Figure 2 ), a hollow waveguide body structure of the output port (such as Port2 - Port5 in Figure 1 ), a stepped metal ridge structure arranged at the branch position of the waveguide power divider (such as labels 1, 2, 3 in Figure 1 ), and a matching slot structure arranged at the output port position of the waveguide power divider (such as label 5 in Figure 2 ).

[0061] The following formula is used to analyze and calculate the waveguide dimensions of each section of the power divider:

[0062]

[0063] Among them, λ c is the cut - off wavelength of the waveguide, k c is the cut - off wave number of the waveguide, m and n respectively represent the number of half - waves on different coordinate axes, and a and b are the cross - sectional dimensions of the rectangular waveguide. It can be seen from the formula that the cut - off wavelength of different modes of the rectangular waveguide depends on the cross - sectional dimensions. When the rectangular waveguide operates in the dominant mode TE 10 mode, its cut - off wavelength is 2a; when it operates in the adjacent higher - order mode TE 20 mode, its cut - off wavelength is a.

[0064] In one embodiment, the center operating frequency of the power divider is 90 GHz, and the calculated operating wavelength is λ≈3.33 mm. To make the waveguide operate in the single-mode TE 10 , according to the single-mode operating condition: a<λ<2a, so the length l IN of the waveguide at the input port, the height h of the branch and the output port waveguides are all set between half a wavelength and one wavelength. Among them, l IN = 1.8 mm, h = 2.08 mm.

[0065] Satisfy the following constraint relationship: within the set range, the width of the input port is greater than the width of the branch waveguide, and the width of the branch waveguide is greater than the width of the output port waveguide; under the above constraint relationship, adjust the width of the input port, the width of the branch waveguide and / or the width of the output port waveguide, so that the resonance effect at the center operating frequency point is better, and the matching effect of the corresponding ports is better.

[0066] The width w IN of the input port of the waveguide power divider = 0.6 mm, the width w1 of the branch waveguide = 0.7 mm, and the width w OUT of the output port waveguide = 0.44 mm. The widths of the above parts affect the matching performance of the waveguide power divider. Through experimental analysis, within a certain range, the width w IN of the input port, the width w1 of the branch waveguide, and the width w OUT of the output port waveguide gradually increase step by step, and the resonance effect at the center operating frequency point is better, that is, the matching effect of each port of the power divider is better.

[0067] In one embodiment, the stepped metal ridge structure at the branch position of the waveguide power divider is made of aluminum, and the stepped metal ridge structure is located at the center of the wide side of the branch. A total of three steps are set for the stepped metal ridge structure. In one embodiment, the following dimensions are adopted:

[0068] The first-level stepped metal ridge structure is used for the transmission between the input port waveguide and the branch waveguide. Through a metal step with a width of w R1 = 0.39 mm, a length of l R1 = 0.44 mm, and a height of h R1 = 1.21 mm, the matching between the hollow waveguide and the ridge waveguide section is realized. Among them, the first-level stepped metal ridge structure extends slightly beyond the port w Δ = 0.04 mm, as shown in Figure 3 label 6, to realize the guided transmission of electromagnetic waves along the metal ridge structure.

[0069] The second-level stepped metal ridge structure is located inside the branch waveguide. The width w R2 = 0.27 mm, the length l R1 = 1.02 mm, and the height h R2= 1.51 mm. Its height is higher than that of the first-level step, which is to reduce the cut-off frequency of the transmission branch waveguide section and improve the bandwidth of the overall power divider. Through experimental analysis, when the height of the second-level metal ridge satisfies 0.85h ≤ h R2 <h, it can ensure that in this frequency band, good transmission performance can be achieved in the branch part.

[0070] The third-level stepped metal ridge is used for the matching between the branch waveguide and the output port waveguide. Its width is the same as that of the second-level metal ridge w R2 , and the height h R3 = 1.14 mm, which is lower than the height of the second-level metal ridge.

[0071] Figure 4 、 Figure 5 shows the distribution diagram of the electric field vector under the stepped metal ridge structure. Among them, the electric field vector makes a phase correction under the metal ridge structure. Between the hollow waveguide at the input port and the branch waveguide, the metal ridge causes an edge effect, which can be equivalent to the perturbation of the field distribution caused by the discontinuity of the transmission line, resulting in different distributions of the electric field vector on both sides. The electric field of one side branch converges along the metal ridge (such as the mark 8 in Figure 4 ), and the electric field of the other side branch diverges along the metal ridge (such as the mark 7 in Figure 4 ). Figure 5 The mark 9 in

[0072] is the in-phase distribution of the electric field vector. Figure 6 、 Figure 7 .

[0073] The matching slot structure is mirror-distributed at the four output ports, with a length m = 0.38 mm, a width n = 0.28 mm, and the same height as the output port height h. Its main function is to adjust the impedance matching within the working frequency band.

[0074] Figure 8 shows the insertion loss and reflection coefficient curves of the present invention when operating at 86 GHz to 95 GHz. The reflection coefficient S 11 < -24 dB at the center operating frequency point of 90 GHz, and S 11 < -10 dB at 86.5 GHz to 94.1 GHz. The maximum additional insertion loss within the passband is 0.62 dB, having low insertion loss performance; the maximum difference in the output power of the four paths of the power divider at the same frequency point is 0.058 dB, having good amplitude consistency.

[0075] Figure 9The phase diagram of the present invention when operating at 86 GHz to 95 GHz is given. In the passband of 86.5 GHz to 94.1 GHz, the maximum difference between the four output signals at the same frequency point is 0.83°, showing good phase consistency.

[0076] The present invention uses a hybrid structure of ridge waveguide and hollow waveguide to achieve in-phase output of the four ports of the E-plane T-junction power divider. On the basis of ensuring strong amplitude and phase consistency of the signals at the four output ports, it also has the advantage of low insertion loss of the waveguide power divider. At the same time, a hierarchical design of the input port and the output port is proposed, avoiding the main problem that the traditional E-plane T-junction power divider is not easy to miniaturize in the W-band. Moreover, the concept of the transition structure of the present invention can also be used in other frequency bands or other cavity power dividers.

[0077] Embodiment 2

[0078] Embodiment 2 of the present invention provides a W-band array antenna, which includes the W-band hybrid E-plane waveguide power divider of Embodiment 1.

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the embodiments, those of ordinary skill in the art should understand that any modification or equivalent replacement of the technical solutions of the present invention does not depart from the spirit and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A W-band hybrid E-plane waveguide power divider, comprising an input port and four output ports, characterized in that, The power divider is left-right mirror symmetric. The input port is arranged on the central axis of the left-right mirror symmetry. The hollow waveguide structure of the input port is located in the lower layer. The four output ports are arranged in the same layer at the four corners of the H shape. The hollow waveguide structures of the four output ports are located in the upper layer. The input port and the output ports are connected by branch waveguides, and a stepped metal ridge structure is arranged in the branch waveguides. Among them, the input port waveguide and the branch waveguide form a hollow-ridge transmission structure; the branch waveguide to the four-way output port waveguides forms a ridge-hollow transmission structure.

2. The W-band hybrid E-plane waveguide power divider according to claim 1, wherein A matching slot structure is arranged on the side of each output port close to the branch waveguide structure. The four matching slot structures are symmetrically distributed and are used to adjust the impedance matching of the transmission ports.

3. The W-band hybrid E-plane waveguide power divider according to claim 2, wherein The length and width of the matching slot affect the matching characteristics of the power divider. The height of the matching slot is equal to the height of the output port waveguide.

4. The W-band hybrid E-plane waveguide power divider according to claim 1, characterized in that, The power divider operates in the single-mode TE 10 mode. The lengths of the input-port waveguide, the heights of the branch waveguides, and the heights of the output-port waveguides are all set between half a wavelength and one wavelength.

5. The W-band hybrid E-plane waveguide power divider according to claim 1, characterized in that, The following constraint relationship is satisfied: within a set range, the width of the input port is greater than the width of the branch waveguide, and the width of the branch waveguide is greater than the width of the output port waveguide. Under the constraint relationship, adjust the width of the input port, the width of the branch waveguide, and / or the width of the output port waveguide, so that the better the resonance effect at the central operating frequency point, the better the matching effect of the corresponding ports.

6. The W-band hybrid E-plane waveguide power divider according to claim 1, characterized in that The stepped metal ridge structure arranged in the branch waveguide is arranged at the center of the wide side of the branch and is used to adjust the transmission performance between the input port waveguide and the output port waveguide.

7. The W-band hybrid E-plane waveguide power divider according to claim 6, characterized in that, The stepped metal ridge structure is a three-level step. Among them, The first-level stepped metal ridge is used for the transmission between the input port waveguide and the branch waveguide. The second-level stepped metal ridge is used for the transmission of electromagnetic waves in the branch waveguide. The third-level stepped metal ridge is used for the transmission between the branch waveguide and the output port waveguide.

8. The W-band hybrid E-plane waveguide power divider according to claim 7, characterized in that, The width of the first-level stepped metal ridge is slightly wider than the widths of the latter two-level stepped metal ridges; the length slightly extends beyond the branch part; the height is greater than half of the height of the branch waveguide. The widths of the second-level stepped metal ridge and the third-level stepped metal ridge are equal, and the height of the second-level stepped metal ridge is greater than the height of the third-level stepped metal ridge.

9. The W-band hybrid E-plane waveguide power divider according to claim 1, wherein The stepped metal ridge structure is made of metal aluminum.

10. A W-band array antenna, characterized in that The antenna includes the W-band hybrid E-plane waveguide power divider according to any one of claims 1-8.

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