A four-way power splitter filter with dielectric substrate loaded in waveguide

Abstract

The present invention provides a four-way power division filter with a dielectric substrate loaded in a waveguide, and relates to the technical field of radio frequency microwave circuits. The present invention comprises: a first rectangular waveguide, the signal transmission direction of which is arranged along a first direction; a dielectric substrate, which is assembled on the cross section of the end of the signal transmission direction of the first rectangular waveguide, and a pair of first circuits and a pair of second circuits are laid on the dielectric substrate. The present invention utilizes the first rectangular waveguide, the dielectric substrate circuit, and four second rectangular waveguides to realize a four-way power division filter circuit structure outputted from the narrow side and the wide side of the first rectangular waveguide, and can meet the use requirements of a four-way power division filter with different output powers between the four channels within a specific frequency band by changing the different physical structure dimensions of the first circuit and the second circuit.

Description

Technical Field

[0001] The invention relates to the technical field of radio frequency microwave circuits, and in particular to a four-way power division filter with a dielectric substrate loaded in a waveguide. Background Art

[0002] Power dividers and filters are both basic passive functional devices commonly used in various electromagnetic wave systems. The power divider can realize two-way or multi-way power distribution and synthesis of the input signal power, while the filter is a frequency selection device that can allow specific frequency components in the signal to pass through and greatly attenuate other frequency components. When the power divider and the bandpass filter are integrated into one component, the signal power distribution function within a specific frequency band can be realized at the same time.

[0003] The existing rectangular waveguide planar probe or planar ring type power divider has 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, its power division circuit structure mainly uses an electric excitation method of inserting one microstrip probe inward at the center of the two wide sides of the rectangular waveguide, or inserting two microstrip probes on the wide sides on the same side of the rectangular waveguide, or a magnetic excitation method of inserting a ring-shaped circuit inward at the center of the two narrow sides of the rectangular waveguide, to realize a two-way equal power distribution circuit structure of the input signal power, but does not realize a circuit structure of four-way equal power and unequal power distribution, resulting in limited use of four-way power division filters based on this type of power distribution circuit, which cannot meet the needs of actual engineering. Summary of the invention

[0004] In view of this, an embodiment of the present invention is dedicated to providing a four-way power division filter with a dielectric substrate loaded in a waveguide, so as to solve the problem in the prior art that the use of the power division filter is limited and cannot meet actual engineering needs.

[0005] The present invention provides a four-way power splitter filter with a dielectric substrate loaded in a waveguide, comprising:

[0006] A first rectangular waveguide, wherein a signal transmission direction is arranged along a first direction;

[0007] a dielectric substrate connected to a cross section of an end of the first rectangular waveguide in a signal transmission direction, wherein a pair of first circuits and a pair of second circuits are laid on the dielectric substrate, wherein the pair of first circuits are respectively arranged along a pair of narrow sides of the first rectangular waveguide, and the pair of second circuits are respectively arranged along a pair of wide sides of the first rectangular waveguide;

[0008] Four second rectangular waveguides are connected to the four side walls of the first rectangular waveguide, the signal transmission direction of the second rectangular waveguide is arranged along the second direction, the first direction is perpendicular to the second direction, and a pair of the first circuits and a pair of the second circuits are respectively arranged along the axial direction of the second rectangular waveguide.

[0009] In an optional embodiment, a third rectangular waveguide is further included, wherein a terminal of the third rectangular waveguide is short-circuited and connected to a surface of the dielectric substrate that is away from the first rectangular waveguide.

[0010] In an optional embodiment, the first circuit is composed of a metal semicircular ring circuit, a first impedance transformation circuit, a first microstrip bandpass filter circuit, and a first microstrip-waveguide transition conversion circuit.

[0011] In an optional embodiment, the semicircular ring circuit is arranged inside the first rectangular waveguide and located at the center of the two narrow sides. The straight line segment constituting the semicircular ring has a disconnected portion so that the semicircular ring circuit has two connecting portions, and the first impedance transformation circuit is connected to one of the connecting portions located at the center of the narrow side of the first rectangular waveguide.

[0012] In an optional embodiment, another of the connecting portions is connected to a quarter-wavelength open circuit.

[0013] In an optional embodiment, the second circuit is composed of a metal strip probe, a second impedance transformation circuit, a second microstrip bandpass filter circuit, and a second microstrip-waveguide transition conversion circuit.

[0014] In an optional embodiment, the metal strip probe is arranged inside the first rectangular waveguide and located at the center of the two wide sides. After the metal strip probe passes through the first rectangular waveguide, it is connected to the second impedance transformation circuit.

[0015] In an optional embodiment, the first impedance transformation circuit and the first microstrip bandpass filter circuit are placed inside the first substrate circuit channel and the first microstrip circuit shielding metal cavity on the side wall of the narrow side of the first rectangular waveguide.

[0016] In an optional embodiment, the first microstrip-waveguide transition conversion circuit is a gradient ridge fin line transition circuit, which is placed at the center of the E-surface of the second rectangular waveguide.

[0017] In an optional embodiment, the second impedance transformation circuit and the second microstrip bandpass filter circuit are placed inside the second substrate circuit channel and the second microstrip circuit shielding metal cavity on the side wall of the wide side of the first rectangular waveguide.

[0018] In an optional embodiment, the second microstrip-waveguide transition conversion circuit is a gradient ridge fin line transition circuit, which is placed at the center of the E-surface of the second rectangular waveguide.

[0019] The embodiments of the present disclosure provide a four-way power-dividing filter with a dielectric substrate loaded in a waveguide. The four-way power-dividing filter circuit structure with outputs on the narrow side and the wide side of the first rectangular waveguide is realized by using a first rectangular waveguide, a dielectric substrate circuit, and four second rectangular waveguides in coordination. The different physical structure dimensions between the first circuit and the second circuit can be changed to meet the use requirements of a four-way power-dividing filter with different output powers between the four channels within a specific frequency band. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The figure shows a three-dimensional structure diagram of a four-way power splitter filter with a dielectric substrate loaded in a waveguide;

[0021] Figure 2 Shown is a schematic diagram of the front circuit on the dielectric substrate of the power splitter filter;

[0022] Figure 3 Shown is a schematic diagram of the back side circuit on the dielectric substrate of the power splitter filter;

[0023] Figure 4 FIG. 4 is a diagram showing the simulation results of the input echo and insertion loss of the four-way power divider of this embodiment;

[0024] Figure 5 Shown is a diagram showing the simulation results of the isolation between the output ports of the waveguide-microstrip four-way power divider of this embodiment.

[0025] Reference numerals

[0026] 1. First rectangular waveguide; 2. Second rectangular waveguide; 3. Dielectric substrate; 4. First circuit; 401. Semicircular ring circuit; 402. First impedance transformation circuit; 403. First microstrip bandpass filter circuit; 404. First microstrip-waveguide transition conversion circuit; 405. Disconnection portion; 406. Quarter-waveguide wavelength open line; 407. First substrate circuit channel; 408. First microstrip circuit shielded metal cavity; 5. Second circuit; 501. Metal strip probe; 502. Second impedance transformation circuit; 503. Second microstrip bandpass filter circuit; 504. Second microstrip-waveguide transition conversion circuit; 505. Second substrate circuit channel; 506. Second microstrip circuit shielded metal cavity; 6. Third rectangular waveguide; 7. No copper-clad area at the same size joint between the dielectric substrate circuit and the third rectangular waveguide; 8. Dielectric substrate copper-clad layer. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] Power dividers (hereinafter referred to as power dividers) and filters are both basic passive functional devices commonly used in various electromagnetic wave systems. The power divider can realize two-way or multi-way power distribution and synthesis of the input signal power, while the filter is a frequency selection device that allows specific frequency components in the signal to pass through and greatly attenuates other frequency components. After integrating the power divider and the bandpass filter into one component, the function of signal power distribution within a specific frequency band can be realized at the same time. This type of power divider filter with filtering response has a wide range of applications in wireless multi-band communication systems in terms of improving antenna carrier-to-noise performance.

[0029] Rectangular waveguides have the characteristics of high power capacity and low insertion loss, and are a common type of circuit application structure in engineering. Existing waveguide power dividers such as E-plane T-branch, H-plane T-branch, waveguide magic T, H-plane waveguide crack bridge, etc., have some problems in use, such as working bandwidth, unequal power distribution, multi-equal power distribution, and structural complexity.

[0030] The hybrid power divider realized by designing a microstrip probe or a coupling ring on a dielectric substrate inserted inside the waveguide has the advantages of compact circuit structure, low insertion loss, and easy integration with other functional circuits at the back end of the power distribution output. However, the existing power division circuit structures mainly use an electric excitation method of inserting one microstrip probe at the center of each of the two wide sides of the rectangular waveguide, or inserting two microstrip probes on the wide sides on the same side of the rectangular waveguide, or a magnetic excitation method of inserting one ring-shaped circuit at the center of each of the two narrow sides of the rectangular waveguide to achieve two-way equal power distribution of the input power, but do not achieve four-way power distribution of the input signal power, let alone four-way unequal power distribution of the input power. Under certain design conditions, two-way equal power distribution obviously cannot meet the needs of engineering use.

[0031] For the above problems, refer to Figure 1-Figure 3 An embodiment of the present invention provides a four-way power division filter with a dielectric substrate loaded in a waveguide, comprising: a first rectangular waveguide 1, wherein the signal transmission direction is arranged along a first direction, and the first direction refers to the vertical direction in space, that is, the length direction of the first rectangular waveguide 1 is arranged vertically to ensure that the signal transmission direction of the first rectangular waveguide 1 is set vertically.

[0032] The two surfaces of the first rectangular waveguide 1 used for signal transmission direction are defined as the input surface and the output surface. Among the other four surfaces of the first rectangular waveguide 1 except the input surface and the output surface, the surface with relatively small area is defined as the narrow side, and the surface with relatively large area is defined as the wide side. The dielectric substrate 3 is mounted on the cross section at the end of the signal transmission direction of the first rectangular waveguide 1, that is, it is mounted on the output surface of the first rectangular waveguide 1.

[0033] In addition, a pair of first circuits 4 and a pair of second circuits 5 are laid on the dielectric substrate 3. The semicircular ring circuits 401 of the pair of first circuits 4 are respectively inserted vertically into a pair of narrow sides from the center of the narrow side of the first rectangular waveguide 1, and the metal strip probes 501 of the pair of second circuits 5 are respectively inserted vertically into a pair of wide sides from the center of the wide side of the first rectangular waveguide 1, so as to realize the coupled power division output of the input signal power in the first rectangular waveguide 1.

[0034] A pair of first circuits 4 and a pair of second circuits 5 on the dielectric substrate 3 are respectively arranged in a signal transmission direction perpendicular to the narrow side wall and the wide side wall of the first rectangular waveguide 1. The four second rectangular waveguides 2 are respectively connected to the rear ends of the first microstrip circuit shielding metal cavity 408 and the second microstrip circuit shielding metal cavity 506 connected to the first rectangular waveguide 1 via two side walls. The signal transmission direction of the second rectangular waveguides 2 is arranged along the second direction, and the first direction is arranged perpendicular to the second direction.

[0035] In a pair of first circuits 4, a first impedance conversion circuit 402 and a first microstrip bandpass filter circuit 403 cascaded at the rear end of a semicircular ring circuit 401 are placed inside a first substrate circuit channel 407 and a first microstrip circuit shielding metal cavity 408 where the first rectangular waveguide 1 passes through the side wall. In a pair of second circuits 5, a second impedance conversion circuit 502 and a second microstrip bandpass filter circuit 503 cascaded at the rear end of a metal strip probe 501 are placed inside a second substrate circuit channel 505 and a second microstrip circuit shielding metal cavity 506 where the first rectangular waveguide 1 passes through the side wall.

[0036] In a pair of first circuits 4, a first microstrip-waveguide transition conversion circuit 404 in a gradient-to-ridge fin line manner cascaded at the rear end of the first microstrip bandpass filter circuit 403 is placed at the center of the E-plane inside the second rectangular waveguide 2. In a pair of second circuits 5, a second microstrip-waveguide transition conversion circuit 504 in a gradient-to-ridge fin line manner cascaded at the rear end of the second microstrip bandpass filter circuit 503 is placed at the center of the E-plane inside the second rectangular waveguide 2.

[0037] In some embodiments, reference Figure 1 , Figure 3, and also includes a third rectangular waveguide 6 with a short-circuited terminal. The third rectangular waveguide 6 has the same waveguide width and narrow side dimensions as the first rectangular waveguide 1 and is placed on the back of the dielectric substrate 3 circuit. The back circuit of the dielectric substrate 3 at the junction with the third rectangular waveguide of the same size is a copper-free area 7. The waveguide port of the third rectangular waveguide 6 is precisely docked with the waveguide port of the first rectangular waveguide 1, and the first rectangular waveguide 1, the dielectric substrate 3 and the third rectangular waveguide 6 are tightly connected and assembled together.

[0038] The third rectangular waveguide 6 with a short circuit at the terminal belongs to a partial circuit structure for realizing a four-way coupled power division output device. By optimizing the distance between the dielectric substrate 3 and the short circuit surface of the third rectangular waveguide 6, the best power division performance can be obtained.

[0039] In some embodiments, reference Figure 2 The straight line segment constituting the semicircular ring has a disconnected portion 405, one of which is located at the center of the narrow side of the first rectangular waveguide 1, and is directly connected to the first impedance conversion circuit 402, the first microstrip bandpass filter circuit 403, and the first microstrip-waveguide transition conversion circuit 404 at the rear end for output, and the other breakpoint is connected to a quarter-waveguide wavelength open line 406 to achieve equivalent grounding.

[0040] It should be understood that the first rectangular waveguide 1 planar probe or planar ring type power divider, due to the main mode electromagnetic field structure in the waveguide, determines that the planar ring inserted into the waveguide has the characteristic of being able to output from both the wide side and the narrow side of the waveguide after coupling, while the planar probe inserted into the waveguide can only be output from the wide side of the waveguide after coupling. Therefore, under the condition of a reasonable circuit layout structure, multi-channel power division output can be achieved.

[0041] By changing the different physical structural dimensions of the two metal semicircular ring circuits 401 and the two metal strip probes 501 on the dielectric substrate 3 in the first rectangular waveguide 1, the use requirements of a four-power division filter with the same output power or different output powers between four output channels can be met.

[0042] Furthermore, based on the above circuit structure, other circuit structures are further integrated on the dielectric substrate 3 to form circuit components with different functions.

[0043] In a specific embodiment of this embodiment, refer to Figure 2 , which is a four-way power division filter loaded with millimeter wave guide E-surface dielectric. The dielectric substrate 3 used is made of Rogers5880 with a thickness of 0.254 mm.

[0044] An input signal with a center frequency of 33.9 GHz is fed into the first rectangular waveguide 1 at the input end. A dielectric substrate 3 is placed on the cross section of the first rectangular waveguide 1 at a transmission distance from the input surface of the first rectangular waveguide 1. Two metal strip probes 501 and two metal semicircular ring circuits 401 located in the first rectangular waveguide 1 are respectively arranged on the dielectric substrate 3. The length and width of the two metal strip probes 501 are 1.116 and 0.68 mm respectively. The inner radius, outer radius and the circular radius of the two metal semicircular ring circuits 401 are The center distances are 1.065mm, 1.265mm, and 5mm respectively. Two metal strip probes 501 and two metal semicircular ring circuits 401 are respectively led out from the two wide sides and the two narrow sides to the outside of the first rectangular waveguide 1 and are respectively connected to the first impedance transformation circuit 402, the first microstrip bandpass filter circuit 403, the first microstrip-waveguide transition conversion circuit 404, the second impedance transformation circuit 502, the second microstrip bandpass filter circuit 503, and the second microstrip-waveguide transition conversion circuit 504 at the rear end to achieve power transmission of the required specific passband frequency band signal.

[0045] Reference Figure 4 , which is the input echo and insertion loss curve of the four-way millimeter wave power splitter filter of this embodiment. In the figure, due to the symmetry of the circuit structure, only S is given. 21 With S 31 Results. As can be seen from the figure, within the passband frequency range of 33.3-34.5GHz, the insertion loss of the probe output is about 6.39dB, the insertion loss of the magnetic ring output is about 6.07dB, and the average insertion loss of the four channels is 6.3dB; the input return loss in the passband is greater than 20dB; in the frequency band below 31.5 GHz and above 35.7 GHz, the insertion loss of each output channel is greater than 20dB. It can be seen that the four-channel millimeter wave power splitter filter has good input impedance matching and good transmission characteristics.

[0046] Reference Figure 5 , is a curve of isolation between the output ports of the four-way millimeter wave power splitter filter of this embodiment. In the figure, due to the symmetry of the circuit structure, only S is given. 32 , S 42 , S 52 With S 53 Results. It can be seen from the figure that within the passband frequency range of 33.3-34.5 GHz, the isolation between the output ends of each channel is greater than 8.87 dB. It can be seen that the four-channel millimeter wave power splitter filter has certain isolation characteristics within the passband.

[0047] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A four-way power splitter filter with a dielectric substrate loaded in a waveguide, characterized in that: include: A first rectangular waveguide (1), wherein a signal transmission direction is arranged along a first direction; A dielectric substrate (3) connected to a cross section at an end of the first rectangular waveguide (1) in a signal transmission direction, a pair of first circuits (4) and a pair of second circuits (5) being laid on the dielectric substrate (3), the pair of first circuits (4) being arranged along a pair of narrow sides of the first rectangular waveguide (1), and the pair of second circuits (5) being arranged along a pair of wide sides of the first rectangular waveguide (1); Four second rectangular waveguides (2) are connected to four side walls of the first rectangular waveguide (1); the signal transmission direction of the second rectangular waveguides (2) is arranged along a second direction; the first direction is arranged perpendicular to the second direction; and a pair of the first circuits (4) and a pair of the second circuits (5) are arranged along the axial direction of the second rectangular waveguides (2); The first circuit (4) is composed of a metal semicircular ring circuit (401), a first impedance conversion circuit (402), a first microstrip bandpass filter circuit (403), and a first microstrip-waveguide transition conversion circuit (404); The semicircular ring circuit (401) is arranged inside the first rectangular waveguide (1) and is located at the center of the two narrow sides, and the straight line segment forming the semicircular ring has a disconnection portion (405), so that the semicircular ring circuit (401) has two connection portions, and the first impedance conversion circuit (402) is connected to one of the connection portions located at the center of the narrow side of the first rectangular waveguide (1); The second circuit (5) is composed of a metal strip probe (501), a second impedance conversion circuit (502), a second microstrip bandpass filter circuit (503), and a second microstrip-waveguide transition conversion circuit (504); The metal strip probe (501) is arranged inside the first rectangular waveguide (1) and is located at the center of two wide sides; after the metal strip probe (501) passes through the first rectangular waveguide (1), it is connected to the second impedance conversion circuit (502); The first impedance conversion circuit (402) and the first microstrip bandpass filter circuit (403) are placed inside the first substrate circuit channel (407) and the first microstrip circuit shielding metal cavity (408) on the narrow side wall of the first rectangular waveguide (1); The second impedance conversion circuit (502) and the second microstrip bandpass filter circuit (503) are placed inside the second substrate circuit channel (505) and the second microstrip circuit shielding metal cavity (506) on the side wall of the wide side of the first rectangular waveguide (1); The four second rectangular waveguides (2) are respectively connected to the first rectangular waveguide (1) via two side walls to the rear ends of the first microstrip circuit shielding metal cavity (408) and the second microstrip circuit shielding metal cavity (506) connected via two side walls.

2. The four-way power splitter filter with dielectric substrate loaded in waveguide according to claim 1, characterized in that: It also comprises a third rectangular waveguide (6), the terminal of the third rectangular waveguide (6) being short-circuited and connected to a surface of the dielectric substrate (3) away from the first rectangular waveguide (1).

3. The four-way power splitter filter with dielectric substrate loaded in waveguide according to claim 1, characterized in that: Another of the connecting parts is connected to a quarter-wavelength open line (406).

4. The four-way power splitter filter with dielectric substrate loaded in waveguide according to claim 1, characterized in that: The first microstrip-waveguide transition conversion circuit (404) is a gradient ridge fin line transition circuit, and is placed at the center of the E surface of the second rectangular waveguide (2).

5. The four-way power splitter filter with dielectric substrate loaded in waveguide according to claim 1, characterized in that: The second microstrip-waveguide transition conversion circuit (504) is a gradient ridge fin line transition circuit, and is placed at the center of the E surface of the second rectangular waveguide (2).

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