A waveguide - microstrip three - way power divider

Abstract

The present invention relates to the technical field of radio frequency and microwave circuits, and provides a waveguide-microstrip three-way power divider, which includes a first rectangular waveguide, a dielectric substrate, a first microstrip line and a pair of second microstrip lines; the first microstrip line is arranged on the upper surface of the dielectric substrate, and a strip-shaped microstrip probe is arranged at one end of the first microstrip line. The strip-shaped microstrip probe extends into the first rectangular waveguide and is located on one wide-side of the first rectangular waveguide, and the strip-shaped microstrip probe is coaxially arranged with the central connection line of a pair of wide sides of the bottom cross-section of the first rectangular waveguide; a coupling ring is arranged at one end of the second microstrip line. The coupling ring extends into the first rectangular waveguide and is located on the other side of the first rectangular waveguide, and a pair of coupling rings are symmetrically arranged with respect to the central connection line of a pair of wide sides of the bottom cross-section of the first rectangular waveguide; the present invention realizes the three-way output distribution of the input power, and has the advantages of good in-band matching and low insertion loss.

Description

Technical Field

[0001] The present invention relates to the technical field of radio frequency and microwave circuits, and particularly to a waveguide-microstrip three-way power divider. Background Art

[0002] A power divider is a multi-port microwave passive device that divides the power of an input signal into two or more output signals with equal or unequal power, and is widely used in electronic systems such as communication, radar, and electronic countermeasure.

[0003] Rectangular waveguides and microstrip lines are two commonly used circuit structure types in engineering. Rectangular waveguides have the characteristics of high power capacity and low insertion loss, while microstrip lines, as a planar circuit, are easy to integrate with microwave integrated circuits with other functions.

[0004] In the prior art, in the category of power dividers with rectangular waveguides as signal inputs and microstrip lines as signal outputs, implementation schemes using microstrip probes or coupling rings inserted inside the waveguide have the advantages of compact circuit structure, low insertion loss, and easy integration with other functional circuits at the back end of power distribution output. However, their power division types mainly use an electrical excitation method of inserting 1 microstrip probe at the center axis of each of the two wide sides of the rectangular waveguide and inserting 2 microstrip probes on the same-side wide side of the rectangular waveguide, or a magnetic excitation method of inserting 1 ring-shaped circuit at the center of each of the two narrow sides of the rectangular waveguide to achieve two-way equal-power distribution output of the input signal power, and still cannot meet the requirement of three-way output of the input power, nor the implementation requirement of a circuit structure that can be compatible with three-way equal-power or unequal-power output. Summary of the Invention

[0005] The present invention provides a waveguide-microstrip three-way power divider to solve the defect that it is difficult to achieve the three-way output requirement of the input power in the prior art of rectangular waveguide planar probe or planar ring type power dividers, and to realize a circuit structure that can be compatible with three-way equal-power or unequal-power output.

[0006] The present invention provides a waveguide-microstrip three-way power divider, comprising:

[0007] A first rectangular waveguide for inputting electromagnetic signals;

[0008] A dielectric substrate connected to the bottom cross-section of the first rectangular waveguide;

[0009] A first microstrip line disposed on the upper surface of the dielectric substrate. One end of the first microstrip line is provided with a strip-shaped microstrip probe, which extends into the first rectangular waveguide and is located on one wide side of the first rectangular waveguide, and the strip-shaped microstrip probe is coaxially arranged with the center connection line of a pair of wide sides of the bottom cross-section of the first rectangular waveguide;

[0010] A pair of second microstrip lines, one end of each second microstrip line is provided with a coupling loop, the coupling loop extends into the first rectangular waveguide and is located on the other wide side in the first rectangular waveguide, and a pair of the coupling loops are symmetrically arranged with respect to the central connection line of a pair of wide sides of the bottom cross-section of the first rectangular waveguide.

[0011] For the waveguide-microstrip three-way power divider provided by the present invention, both the strip-shaped microstrip probe and the coupling loop circuit are laid on a dielectric substrate.

[0012] For the waveguide-microstrip three-way power divider provided by the present invention, it further includes a second rectangular waveguide, the second rectangular waveguide is short-circuited at the terminal and is connected to the lower surface of the dielectric substrate, and the cross-sectional dimensions of the second rectangular waveguide are the same as those of the first rectangular waveguide.

[0013] For the waveguide-microstrip three-way power divider provided by the present invention, isolation resistors are provided between the first microstrip line and any one of the second microstrip lines, and between a pair of the second microstrip lines.

[0014] For the waveguide-microstrip three-way power divider provided by the present invention, the first microstrip line further includes a first impedance transformation section and a first output section, one end of the first impedance transformation section is connected to the strip-shaped microstrip probe, and the other end of the first impedance transformation section is connected to the first output section.

[0015] For the waveguide-microstrip three-way power divider provided by the present invention, the second microstrip line further includes a second impedance transformation section and a second output section, one end of the second impedance transformation section is connected to the coupling loop, and the other end of the second impedance transformation section is connected to the second output section.

[0016] For the waveguide-microstrip three-way power divider provided by the present invention, the power divider circuit further includes three channel structures for the dielectric substrate carrying the strip-shaped microstrip probe and the coupling loop circuit to pass through the waveguide from the first rectangular waveguide, and the three channel structures are formed on the outer cavity wall of the first rectangular waveguide and are communicated with the inside of the first rectangular waveguide.

[0017] For the waveguide-microstrip three-way power divider provided by the present invention, the isolation resistor is assembled on the dielectric substrate in the groove of the outer cavity wall of the first rectangular waveguide.

[0018] For the waveguide-microstrip three-way power divider provided by the present invention, the first output section and the second output section are 50-ohm microstrip output lines.

[0019] For the waveguide-microstrip three-way power divider provided by the present invention, the dielectric substrate is made of Rogers5880 and has a thickness of 0.254 mm.

[0020] A waveguide-microstrip three-way power divider provided by the present invention is to design a strip microstrip probe on the central axis of one wide side of the first rectangular waveguide, and respectively set coupling rings on both sides symmetric about the central axis on the other wide side of the first rectangular waveguide. The strip microstrip probe and the coupling rings respectively lead out microstrip lines from the respective wide sides, and output the converted electromagnetic signals in three paths, so as to realize the functions of coupling and picking up the input power and power distribution in the rectangular waveguide; and by changing physical structure parameters such as the sizes of the probe and the two coupling rings and their relative positions, the use requirements of a three-way power divider with different output power division ratios between the three output channels can be realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0022] Figure 1 It is a three-dimensional structure schematic diagram of a waveguide-microstrip three-way power divider provided by an embodiment of the present invention;

[0023] Figure 2 It is a schematic diagram of the upper surface circuit on the dielectric substrate provided by an embodiment of the present invention;

[0024] Figure 3 It is a schematic diagram of the lower surface circuit on the dielectric substrate provided by an embodiment of the present invention;

[0025] Figure 4 It is a simulation result diagram of the input return loss and insertion loss of a waveguide-microstrip three-way power divider provided by an embodiment of the present invention;

[0026] Figure 5 It is a simulation result diagram of the output return loss of a waveguide-microstrip three-way power divider provided by an embodiment of the present invention;

[0027] Figure 6 It is a simulation result diagram of the isolation between the output ports of a waveguide-microstrip three-way power divider provided by an embodiment of the present invention;

[0028] Figure 7 It is a simulation result diagram of the phase consistency of the output ports of a waveguide-microstrip three-way power divider provided by an embodiment of the present invention.

[0029] REFERENCE SIGNS:

[0030] 1. First rectangular waveguide; 2. Dielectric substrate;

[0031] 3. First microstrip line; 31. Strip microstrip probe; 32. First impedance transformation section; 33. First output section;

[0032] 4. Second microstrip line; 41. Coupling loop; 42. Second impedance transformation section; 43. Second output section;

[0033] 5. Second rectangular waveguide; 6. Channel structure; 7. Isolation resistor; 8. Outer cavity wall groove; 9. Metal - free layer area; 10. Dielectric substrate copper - clad layer area. Detailed implementation manners

[0034] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below with reference to the accompanying drawings in the present invention. Apparently, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art without making creative efforts based on the embodiments in the present invention belong to the scope of protection of the present invention.

[0035] Next, with reference to Figures 1 to 7 a waveguide - microstrip three - way power divider provided in the embodiments of the present invention will be described.

[0036] A waveguide - microstrip three - way power divider provided in this embodiment, as Figures 1 - 3 shown, includes: a first rectangular waveguide 1, a dielectric substrate 2, a first microstrip line 3 and a pair of second microstrip lines 4.

[0037] Among them, the first rectangular waveguide 1 is used to input electromagnetic signals. The length direction of the first rectangular waveguide 1 is arranged vertically. The two surfaces of the first rectangular waveguide 1 for the signal transmission direction are defined as the input surface and the output surface. Among the other four surfaces around the first rectangular waveguide 1, the surface with a relatively small area is defined as the narrow - side, and the surface with a relatively large area is defined as the wide - side.

[0038] The dielectric substrate 2 is connected to the bottom cross - section of the first rectangular waveguide 1, that is, connected to the output surface of the first rectangular waveguide 1. The first microstrip line 3 is arranged on the upper surface of the dielectric substrate 2. One end of the first microstrip line 3 is provided with a strip microstrip probe 31. The strip microstrip probe 31 extends into the first rectangular waveguide 1 from the center position of the wide - side of the first rectangular waveguide 1 and is located on one wide - side in the first rectangular waveguide 1.

[0039] One end of the second microstrip line 4 is provided with a coupling loop 41. The coupling loop 41 extends into the first rectangular waveguide 1 and is located on the other wide - side in the first rectangular waveguide 1. And a pair of coupling loops 41 are symmetrically arranged with respect to the center connection line of the pair of wide - sides of the first rectangular waveguide 1. The first microstrip line 3 and the pair of second microstrip lines 4 are both used to output the electromagnetic signals input by the first rectangular waveguide 1 after coupling and power division.

[0040] As can be seen from the above solution, the present invention is ingeniously designed, with a compact structure, which is convenient for circuit implementation and engineering installation. Specifically, a strip microstrip probe 31 is designed on the central axis of one wide side of the first rectangular waveguide 1, and coupling rings 41 are respectively arranged on both sides symmetric about the central axis of the other wide side of the first rectangular waveguide 1. The strip microstrip probe 31 and the coupling rings 41 respectively lead out microstrip lines from their respective wide sides, thus realizing the function of coupling and picking up the input power from within the rectangular waveguide and splitting the input electromagnetic signal power into three paths for output.

[0041] As Figure 2 shown, the electric field direction of the strip microstrip probe 31 is consistent with that of the main mode TE 10 mode of the rectangular waveguide; the annular surface of the coupling ring 41 is perpendicular to the longitudinal magnetic field component of the main mode TE 10 mode of the rectangular waveguide. With such a setting, it can ensure that the input electromagnetic signal power is coupled and split for output.

[0042] It should be noted that by changing the structural dimensions of the strip microstrip probe 31 and the coupling rings 41 on the dielectric substrate 2, as well as their relative positions inserted into the first rectangular waveguide 1, the usage requirements of a three-way power divider with different output power splitting ratios between the three output channels can be achieved. Furthermore, based on this circuit structure, other circuits can be further integrated on the dielectric substrate 2 to design and implement circuit components with more functions, enabling it to have a wider application in microwave and millimeter-wave circuits and systems.

[0043] In this embodiment, it further includes a second rectangular waveguide 5 with a shorted end. The waveguide width and height dimensions of the second rectangular waveguide 5 are the same as those of the first rectangular waveguide 1. It is placed on the back of the dielectric substrate 2, and the waveguide opening of the second rectangular waveguide 5 is accurately docked with the waveguide opening of the first rectangular waveguide 1. The first rectangular waveguide 1, the dielectric substrate 2, and the second rectangular waveguide 5 are tightly connected and assembled together.

[0044] The second rectangular waveguide 5 with a shorted end belongs to a partial circuit structure of the device for realizing three-way coupled power splitting output. By optimizing the distance between the dielectric substrate 2 and the shorted surface of the second rectangular waveguide 5, the best power splitting output performance can be obtained.

[0045] As Figure 3 shown, the middle region of the lower surface of the dielectric substrate 2 is a metal-free layer region 9 with the same size as the second rectangular waveguide, and the surrounding is a copper-clad layer region 10 of the dielectric substrate.

[0046] Furthermore, isolation resistors 7 are arranged between the first microstrip line 3 and any second microstrip line 4, as well as between a pair of second microstrip lines 4. With such a setting, good isolation characteristics can be ensured between the three output power distribution channels.

[0047] In this embodiment, the first microstrip line 3 further includes a first impedance transformation section 32 and a first output section 33. The first output section 33 is a 50-ohm microstrip output line. One end of the first impedance transformation section 32 is connected to the strip-shaped microstrip probe 31, and the other end of the first impedance transformation section 32 is connected to the first output section 33.

[0048] As Figure 2 shown, the second microstrip line 4 further includes a second impedance transformation section 42 and a second output section 43. The second output section 43 is a 50-ohm microstrip output line. One end of the second impedance transformation section 42 is connected to the coupling loop 41, and the other end of the second impedance transformation section 42 is connected to the second output section 43.

[0049] In this embodiment, the power divider circuit structure further includes three channel structures 6 of a dielectric substrate carrying the strip-shaped microstrip probe 31 and the coupling loop 41 passing through the waveguide from the first rectangular waveguide 1. The three channel structures 6 are formed on the outer cavity wall of the first rectangular waveguide 1 and communicate with the inside of the first rectangular waveguide 1.

[0050] In this embodiment, the isolation resistor 7 is assembled on the dielectric substrate 2 in the groove 8 on the outer cavity wall of the first rectangular waveguide 1.

[0051] In some embodiments, the thickness of the dielectric substrate 2 is 0.254 mm, and the material can be selected as Rogers5880.

[0052] In a specific embodiment, a millimeter-wave waveguide-microstrip three-way power divider is provided. The three-dimensional structure of the three-way power divider circuit and the dielectric substrate circuit are respectively as Figures 1 - 3 shown.

[0053] An input signal with a center frequency of 33.25 GHz is fed into the first rectangular waveguide 1 through the input surface, and the dielectric substrate 2 is connected to the output surface. A strip-shaped microstrip probe and two coupling loops located in the first rectangular waveguide 1 are respectively arranged on the dielectric substrate 2. Among them, the length and width of the strip-shaped microstrip probe located at the center position of the waveguide wide side are 1.401 and 0.469 mm respectively, and the outer radius, the width of the circular metal strip, and the center distance of the two coupling loops located on the other wide side of the waveguide are 0.6 mm, 0.1 mm, and 3.7 mm respectively. The strip-shaped microstrip probe and the two coupling loops respectively lead out microstrip lines from their respective wide sides, completing the functions of coupling and picking up the input power and three-way power distribution from the rectangular waveguide. Between the pairwise adjacent channels of the three-way power output channels, patch resistors are respectively welded to improve the isolation degree index between adjacent output channels.

[0054] Figure 4It is the curve of the input return loss and insertion loss of the three-way millimeter-wave power divider of this embodiment. As can be seen from the figure, in the frequency range of 26.5 - 40 GHz, the average insertion loss is -0.78 dB, and at the center frequency, the insertion loss can reach -0.46 dB; in the frequency range of 26.5 - 40 GHz, the input return loss is greater than 15 dB, and in the frequency range of 28 - 35 GHz, the input return loss is greater than 20 dB. It can be seen that the three-way millimeter-wave power divider has good input impedance matching and good transmission coefficient.

[0055] Figure 5 It is the curve of the output return loss of the three-way millimeter-wave power divider of this embodiment. As can be seen from the figure, in the frequency range of 26.5 - 40 GHz, the output return loss is greater than 3 dB. It can be seen that the three-way millimeter-wave power divider has certain output impedance matching.

[0056] Figure 6 It is the curve of the isolation between the output ports of the three-way millimeter-wave power divider of this embodiment. As can be seen from the figure, in the frequency range of 31.8 - 38.4 GHz, the isolation between the output ports is greater than 12 dB, and in the frequency range of 34 - 38 GHz, the output isolation is greater than 15 dB. It can be seen that the three-way millimeter-wave power divider has high isolation characteristics and a relatively wide operating bandwidth.

[0057] Figure 7 It is the curve of the phase consistency of the output ports of the three-way millimeter-wave power divider of this embodiment. As can be seen from the figure, in the frequency range of 26.5 - 40 GHz, the two output ports on the same side of the wide side of the waveguide of the power divider have high phase consistency.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A waveguide-microstrip three-way power divider, characterized in that: include: A first rectangular waveguide (1) for inputting an electromagnetic signal; A dielectric substrate (2) connected to the bottom cross section of the first rectangular waveguide (1); A first microstrip line (3) is arranged on the upper surface of the dielectric substrate (2); a strip microstrip probe (31) is arranged at one end of the first microstrip line (3); the strip microstrip probe (31) extends into the first rectangular waveguide (1) and is located on a wide side of the first rectangular waveguide (1); and the strip microstrip probe (31) is coaxially arranged with a center line connecting a pair of wide sides of a cross section at the bottom end of the first rectangular waveguide (1); the first microstrip line (3) further comprises a first impedance transformation section (32) and a first output section (33); one end of the first impedance transformation section (32) is connected to the strip microstrip probe (31), and the other end of the first impedance transformation section (32) is connected to the first output section (33); A pair of second microstrip lines (4), one end of the second microstrip lines (4) being provided with a coupling loop (41), the coupling loop (41) extending into the first rectangular waveguide (1) and being located on the other wide side of the first rectangular waveguide (1), and the pair of coupling loops (41) being symmetrically arranged about a center line connecting a pair of wide sides of a cross section at the bottom end of the first rectangular waveguide (1); the second microstrip lines (4) further comprising a second impedance transformation section (42) and a second output section (43), one end of the second impedance transformation section (42) being connected to the coupling loop (41), and the other end of the second impedance transformation section (42) being connected to the second output section (43); an isolation resistor (7) being provided between the first microstrip line (3) and any one of the second microstrip lines (4), and between a pair of the second microstrip lines (4); the isolation resistor (7) being mounted on the dielectric substrate (2) in the outer cavity wall groove (8) of the first rectangular waveguide (1); It also comprises a second rectangular waveguide (5), the terminal of the second rectangular waveguide (5) is short-circuited and connected to the lower surface of the dielectric substrate (2), and the cross-sectional dimensions of the second rectangular waveguide (5) are the same as the cross-sectional dimensions of the first rectangular waveguide (1).

2. The waveguide-microstrip three-way power divider according to claim 1, characterized in that: The strip microstrip probe (31) and the coupling loop (41) circuit are both laid on a dielectric substrate (2).

3. The waveguide-microstrip three-way power divider according to claim 1, characterized in that: The power divider circuit also includes three channel structures (6) passing through the waveguide from the first rectangular waveguide (1) through a dielectric substrate carrying the strip microstrip probe (31) and the coupling ring (41); the three channel structures (6) are formed on the outer cavity wall of the first rectangular waveguide (1) and are in communication with the interior of the first rectangular waveguide (1).

4. The waveguide-microstrip three-way power divider according to claim 1, characterized in that: The first output section (33) and the second output section (43) are 50-ohm microstrip output lines.

5. The waveguide-microstrip three-way power divider according to claim 1, characterized in that: The dielectric substrate (2) is made of Rogers 5880 and has a thickness of 0.254 mm.

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