A low-phase-noise oscillator based on a multi-mode substrate integrated waveguide filter power divider

Abstract

This invention discloses a low-phase-noise oscillator based on a multimode substrate integrated waveguide filter power divider, comprising a multimode substrate integrated waveguide filter power divider, an amplification unit, and a loop phase-shifting microstrip line. The multimode substrate integrated waveguide filter power divider includes a substrate integrated waveguide circular cavity composed of a uniformly distributed array of metallized vias along the circumference, one input port, and two output ports. Inside the substrate integrated waveguide circular cavity, there are first-type metal perturbation vias located in the center and second-type metal perturbation vias located on both sides of the first-type metal perturbation vias. The input terminal of the multimode substrate integrated waveguide filter power divider is connected to the output terminal of the amplification unit through the loop phase-shifting microstrip line. One output terminal of the multimode substrate integrated waveguide filter is connected to the input terminal of the amplification unit through the loop phase-shifting microstrip line, and the other output terminal outputs a signal. This invention has a simple structure, small size, and effectively reduces phase noise.

Description

Technical Field

[0001] This invention belongs to the technical field of microwave and millimeter-wave substrate integrated waveguide active devices, specifically relating to a low phase noise oscillator based on a multimode substrate integrated waveguide filter power divider. Background Technology

[0002] As an essential component of communication and radar systems, the performance of oscillators has a significant impact on the entire system. 5G communication systems, while achieving massive data throughput through complex signal modulation, place even more stringent demands on oscillator phase noise. Furthermore, the massive hardware circuitry required by large-scale MIMO technology places even greater demands on the oscillator's circuit size. Therefore, how to simultaneously achieve miniaturization and low phase noise requires further research.

[0003] Substrate integrated waveguide (SIWB) technology is a novel waveguide device that has emerged in the last decade or so, characterized by low insertion loss, high quality factor, and high power capacity. Various passive and active SIWB devices, fabricated using PCB and LTCC processes, combine the advantages of traditional metal waveguides and planar circuits, offering unparalleled advantages in production cost and design complexity in the microwave and millimeter-wave bands. Passive devices designed using SIWB technology are widely used in oscillator design due to their high quality factor and ease of integration. Traditional miniaturized cavities can significantly reduce circuit size, but phase noise performance is affected; traditional multifunctional devices can simplify the oscillator circuit structure and provide good phase noise, but often require multiple cavities, resulting in excessive size.

[0004] With the rapid development of communication systems, especially 5G microwave and millimeter-wave communication systems and massive MIMO systems, higher requirements are placed on oscillators, demanding not only good phase noise performance but also larger circuit dimensions. Therefore, miniaturization and low phase noise are crucial research considerations for oscillator design. However, current technologies struggle to achieve both miniaturization and low phase noise simultaneously. Summary of the Invention

[0005] The purpose of this invention is to achieve miniaturization and low phase noise requirements for oscillators, and to provide a low phase noise oscillator based on a multi-mode substrate integrated waveguide filter power divider;

[0006] To achieve the above objectives, the present invention adopts the following technical solution: including: a multimode substrate integrated waveguide filter power divider, an amplification unit, a first loop phase-shifting microstrip line, and a second loop phase-shifting microstrip line;

[0007] The multimode substrate integrated waveguide filter power divider includes a first type of metal perturbation via, a second type of metal perturbation via, an input terminal, a first output terminal, a second output terminal, and a substrate integrated waveguide circular cavity composed of an array of metallized vias uniformly distributed along the circumference. Inside the substrate integrated waveguide circular cavity are a first type of metal via located in the middle and second type of metal perturbation vias located on both sides of the first type of metal via. The input terminal, the first output terminal, and the second output terminal are connected to the integrated waveguide circular cavity.

[0008] The input terminal is connected to the output terminal of the amplification unit through a second loop phase-shifting microstrip line, the first output terminal is connected to the input terminal of the amplification unit through a first loop phase-shifting microstrip line, and the multimode substrate integrated waveguide filter power divider outputs a signal through the second output terminal.

[0009] Furthermore, the first type of metal disturbance via can simultaneously shift the TM010 and TM110 modes to higher frequencies, and cause the TM010 and TM110 modes to converge to form a passband.

[0010] Furthermore, the second type of metal disturbance via is used for individual adjustment of the TM010 mode.

[0011] Furthermore, the first output terminal and the second output terminal are mirror-symmetrical.

[0012] Furthermore, the second type of metal disturbance through-holes located on both sides of the first type of metal through-hole are mirror-symmetrical.

[0013] Beneficial Effects: This invention discloses a low-phase-noise oscillator based on a multi-mode substrate integrated waveguide filter power divider. Compared to traditional oscillators, the circuit structure is simplified, eliminating the need for couplers, and the signal can be directly output from the multi-mode substrate integrated waveguide filter. Compared to oscillators based on miniaturized cavities, such as those using quarter-mode or eighth-mode structures as filtering and frequency-stabilizing units, its phase noise is significantly improved. Compared to oscillators based on traditional multifunctional devices as filtering and frequency-stabilizing units, its size is smaller, and the phase noise is not significantly degraded. Therefore, this invention can simultaneously achieve the characteristics of low phase noise and miniaturization. Attached Figure Description

[0014] Figure 1 This is a structural diagram of the oscillator in a specific embodiment of the present invention;

[0015] Figure 2 This is the output spectrum diagram of the oscillator in a specific embodiment of the present invention;

[0016] Figure 3 This is a phase noise diagram of the oscillator in a specific embodiment of the present invention.

[0017] In the figure: 1. Multimode substrate integrated waveguide filter power divider; 2. Type I metal perturbation via; 3. Type II metal perturbation via; 4. Input terminal; 5. First output terminal; 6. Metallized via array; 7. First loop phase-shifting microstrip line; 8. Amplification unit; 9. First loop phase-shifting microstrip line; 10. First output terminal; 11. Substrate integrated waveguide circular cavity. Detailed Implementation

[0018] The invention will now be further explained with reference to the accompanying drawings.

[0019] like Figure 1 As shown, the present invention provides a low phase noise oscillator based on a multimode substrate integrated waveguide filter power divider, comprising: a multimode substrate integrated waveguide filter power divider 1, an amplification unit 8, a first loop phase-shifting microstrip line 7, and a second loop phase-shifting microstrip line 9;

[0020] The multimode substrate integrated waveguide filter power divider 1 includes a first type of metal perturbation via 2, a second type of metal perturbation via 3, an input terminal 4, a first output terminal 5, a second output terminal 10, and a substrate integrated waveguide circular cavity 11 composed of a uniformly distributed array of metallized vias 6 along the circumference. Inside the substrate integrated waveguide circular cavity 11, there is a first type of metal via 2 located in the middle and a second type of metal perturbation via 3 located on both sides of the first type of metal via 2. The input terminal 4, the first output terminal 5, and the second output terminal 10 are connected to the integrated waveguide circular cavity 11.

[0021] The input terminal 4 is connected to the output terminal of the amplification unit 8 through the second loop phase-shifting microstrip line 9, the first output terminal 5 is connected to the input terminal of the amplification unit 8 through the first loop phase-shifting microstrip line 7, and the multimode substrate integrated waveguide filter power divider 1 outputs a signal through the second output terminal 10.

[0022] The first type of metal disturbance via 2 is located at the center of the circular cavity of the substrate integrated waveguide, which simultaneously shifts the TM010 and TM110 modes to higher frequencies and causes the TM010 and TM110 modes to move closer together to form a passband.

[0023] The second type of metal disturbance via 3 is located on both sides of the first type of metal disturbance via 2, and is in a mirror symmetrical relationship. The TM010 mode can be adjusted individually by adjusting the distance of the second type of disturbance via 3 from the center of the circular cavity 11 of the substrate integrated waveguide.

[0024] The multimode substrate integrated waveguide filter power divider has an input terminal 4, a first output terminal 5, and a second output terminal 10. The input terminal 4, the first output terminal 5, and the second output terminal 10 are all 50 ohms, and the first output terminal 5 and the second output terminal 10 are mirror-symmetrical.

[0025] The output signal of the amplifier unit 8 is input from the input terminal 4 of the multimode substrate integrated waveguide filter power divider 1 and is divided into two equal-amplitude and in-phase signals. One signal returns to the input terminal of the amplifier unit 8 from the first output terminal 5, and the other signal is output from the second output terminal 10.

[0026] In this embodiment, the substrate-integrated waveguide circular cavity 11 consists of a dielectric substrate and two layers of metal sheets, which are respectively applied to the upper and lower ends of the dielectric substrate. The dielectric substrate has a relative permittivity of 2.2 and a dielectric thickness of 0.508 mm. The overall planar dimensions of the oscillator are 30 mm * 52 mm.

[0027] In this specific embodiment, the signal is input from the output terminal of the amplification unit 8 through the second loop phase-shifting microstrip line 9 to the input terminal 4 of the multimode substrate integrated waveguide filter power divider 1, which has a first metal disturbance via 2 and a second metal disturbance via 3. Then the signal is split into two paths. One path is fed back from the first output terminal 5 of the multimode substrate integrated waveguide filter power divider 1 through the first loop phase-shifting microstrip line 7 to the input terminal of the amplification unit 8 to form a loop. The other path is directly output from the second output terminal 10 of the multimode substrate integrated waveguide filter power divider 1.

[0028] Figure 2 and Figure 3 The figures show the spectrum and phase noise of the oscillator in this specific embodiment, respectively. The solid line represents the simulation result curve, and the dashed line represents the test result curve. The output frequency of the oscillator in this specific embodiment is 9.97 GHz, and the phase noise at a frequency 1 MHz off the center frequency is -139.6 dBc / Hz. The simulation and test results show good consistency, and low phase noise and miniaturization are achieved.

[0029] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A low-phase-noise oscillator based on a multi-mode substrate integrated waveguide filter power divider, characterized in that, include: Multimode substrate integrated waveguide filter power divider (1), amplification unit (8), first loop phase-shifting microstrip line (7) and second loop phase-shifting microstrip line (9); The multimode substrate integrated waveguide filter power divider (1) includes a first type of metal perturbation via (2), a second type of metal perturbation via (3), an input terminal (4), a first output terminal (5), a second output terminal (10), and a substrate integrated waveguide circular cavity (11) composed of a metallized via array (6) uniformly distributed along the circumference. Inside the substrate integrated waveguide circular cavity (11) are a first type of metal via (2) located in the middle and a second type of metal perturbation via (3) located on both sides of the first type of metal via (2). The input terminal (4), the first output terminal (5), and the second output terminal (10) are connected to the integrated waveguide circular cavity (11). The input terminal (4) is connected to the output terminal of the amplification unit (8) through the second loop phase-shifting microstrip line (9), the first output terminal (5) is connected to the input terminal of the amplification unit (8) through the first loop phase-shifting microstrip line (7), and the multimode substrate integrated waveguide filter power divider (1) outputs a signal through the second output terminal (10). The first type of metal disturbance via (2) is used to simultaneously shift the TM010 and TM110 modes to a higher frequency and make the TM010 and TM110 modes move closer together to form a passband; the second type of metal disturbance via (3) is used to adjust the TM010 mode individually; The first output terminal (5) and the second output terminal (10) are mirror images of each other; The second type of metal disturbance through-hole (3) located on both sides of the first type of metal through-hole (2) is mirror symmetrical.

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