A high-isolation in-phase power combiner based on ridge waveguide-microstrip line

Abstract

The present invention provides a high-isolation in-phase power combiner based on ridge waveguide-microstrip line. By symmetrically arranging two parallel groups of ridge waveguides on the wide side of a standard waveguide, the input power of the waveguide port is divided equally. Each group of ridge waveguides is composed of several ridges with different ridge heights to achieve impedance transformation. The output ends of the ridge waveguides are horizontally connected to two microstrip lines to achieve in-phase output. At the same time, a group of ridge waveguide structures are introduced in the longitudinal direction of the ridge waveguide so that the signals of the sub-ports converge at the other sub-port through different paths and cancel each other out, thereby achieving isolation between the sub-ports. An isolation resistor is set at the end of the ridge waveguide to absorb the energy flowing through the two sub-ports due to imbalance. The present invention solves the technical problems in the prior art that the isolation between the ports of the dual-probe transition combiner is poor, which affects the stability of the system when used for power amplifier combination, and the ordinary ridge waveguide transition is not easy to achieve power synthesis.

Description

Technical Field

[0001] The present invention relates to the field of radio frequency microwave technology, and in particular to a high-isolation in-phase power combiner based on a ridge waveguide-microstrip line. Background Art

[0002] Microstrip lines are a crucial transmission method in microwave and millimeter-wave integrated circuits (MICRs). However, many current MICR and millimeter-wave test systems and device interfaces utilize rectangular waveguides. Consequently, waveguide-to-microstrip converters are widely used in testing MICR and millimeter-wave monolithic integrated circuits and hybrid circuits, as well as in connecting waveguides to planar circuits, to ensure a well-matched transition between the two transmission lines. Waveguide-to-microstrip transition technology has become a key technology for system implementation and has been the subject of extensive research. Common waveguide-to-microstrip transition techniques include probe transition, ridge waveguide transition, and fin-line transition.

[0003] Microwave power combiners, as crucial passive components in modern microwave communications, radar, and electronic countermeasure systems, play a crucial role in microwave systems. Their function is to transfer power from multiple channels to a single channel for power summation. These devices are often used for power combining in high-power systems. Common microwave power combiners currently fall into various types: planar microstrip, SIW (substrate integrated waveguide), coaxial, and cavity. Waveguide-based power combiners, with their high power handling capacity and low insertion loss, have attracted widespread attention in microwave researchers. Therefore, power distribution technology using waveguide structures is a valuable research topic in microwave and millimeter-wave technology. In power combining circuits, MMIC (monolithic microwave integrated circuit) chips are typically used for power amplification. These MMIC chips need to be connected to microstrip lines, necessitating signal transition from the waveguide to the corresponding microstrip line. The commonly used waveguide-to-microstrip dual-probe transition achieves both waveguide-microstrip conversion and power combining, but the isolation between the output ports is poor. The theoretical isolation between the two channels is only 6dB, and in practice, it is even worse. When used as a power combiner, if one of the input ports is mismatched or multiple input ports are seriously unbalanced, it will cause a greater impact on each other, resulting in reduced system stability.

[0004] In the prior art, although the ordinary ridge waveguide transition has good transition performance like the probe transition, it cannot satisfy both the conversion of the waveguide microstrip and the power synthesis as the double-probe transition does. Summary of the Invention

[0005] In view of this, the present invention provides a high-isolation in-phase power combiner based on ridge waveguide-microstrip line, which solves the technical problems in the prior art that the isolation between the ports of the double-probe transition combiner is poor, affecting the stability of the system when used for power amplifier combination, and ordinary ridge waveguide transition is not easy to achieve power synthesis.

[0006] The embodiments of this specification provide the following technical solutions: a high-isolation in-phase power combiner based on a ridge waveguide-microstrip line, characterized in that the power combiner comprises: a waveguide cavity, a waveguide combining port is provided at one end of the waveguide cavity, a waveguide ridge with a gradient height is symmetrically provided inside the waveguide cavity along the length direction of the waveguide cavity, an isolation resistor is provided at the end of the waveguide ridge away from the waveguide combining port, and the isolation resistor is located between the lower surface of the waveguide cavity and the end of the waveguide ridge; a microstrip cavity, the microstrip cavity is provided on two side surfaces of the waveguide cavity, and includes a dielectric substrate, a microstrip line and a metal block, wherein the microstrip line is connected to the waveguide ridge, a metal block is provided at the connection, and the end of the microstrip cavity is a microstrip line branch port.

[0007] Furthermore, the waveguide ridge is composed of a transverse waveguide ridge and a longitudinal waveguide ridge. The two transverse waveguide ridges are arranged along the width direction of the waveguide cavity, and the two symmetrically arranged longitudinal waveguide ridges are arranged along the length direction of the waveguide cavity. Each of the waveguide ridges is composed of multiple ridges with different ridge heights, and the height of the multiple longitudinal waveguide ridges increases in the direction away from the waveguide port. The two symmetrically arranged longitudinal waveguide ridges are respectively connected to the two transverse waveguide ridges.

[0008] Furthermore, the length of each section of the longitudinal waveguide ridge is a quarter of the wavelength, and the ridge widths of each section of the longitudinal waveguide ridge are the same but the ridge heights are different.

[0009] Furthermore, the number of sections of the longitudinal waveguide ridges is determined according to the design bandwidth requirement and design frequency of the power combiner.

[0010] Furthermore, the impedance of each section of the longitudinal waveguide ridge is different.

[0011] Furthermore, when the power combiner is in use, the two microstrip line branch ports are respectively connected to two microstrip circuit amplifiers, and after power combination, the power is output through the waveguide combining port.

[0012] Furthermore, the two microstrip circuit amplifiers are in phase.

[0013] Compared with the prior art, the beneficial effects that can be achieved by at least one of the above-mentioned technical solutions adopted in the embodiments of this specification include at least the following: The present invention provides a high-isolation in-phase power combiner based on ridge waveguide-microstrip line, which divides the input power of the waveguide port equally by symmetrically arranging two parallel groups of ridge waveguides on the wide side of the standard waveguide. Each group of ridge waveguides is composed of several ridges with different ridge heights to achieve impedance transformation, and transform the standard waveguide impedance of several hundred ohms into two impedances close to the microstrip line. The output ends of the ridge waveguides are horizontally connected to the two microstrip lines to achieve in-phase output. At the same time, a group of ridge waveguide structures are introduced in the longitudinal direction of the ridge waveguide, so that the signals of the sub-ports are gathered at the other sub-port through different paths and the energy cancels each other out, thereby achieving isolation between the sub-ports. An absorption load (isolation resistor) is set at the end of the ridge waveguide to absorb the energy flowing through the two sub-ports due to unbalanced flow. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0015] Figure 1 This is a side view of the structure of a high-isolation in-phase power combiner based on a ridge waveguide-microstrip line according to an embodiment of the present invention;

[0016] Figure 2 This is a top view of the structure of a high-isolation in-phase power combiner based on a ridge waveguide-microstrip line according to an embodiment of the present invention;

[0017] Figure 3 This is a front view of the structure of a high-isolation in-phase power combiner based on a ridge waveguide-microstrip line according to an embodiment of the present invention;

[0018] Figure 4 1 is a standing wave curve diagram of a waveguide combiner port according to an embodiment of the present invention;

[0019] Figure 5 is an insertion loss curve diagram of an embodiment of the present invention;

[0020] Figure 6 is a standing wave curve diagram of a microstrip port according to an embodiment of the present invention;

[0021] Figure 7 is an isolation curve diagram of an embodiment of the present invention;

[0022] Figure 8 Schematic diagram of the phase relationship between two microstrip ports in an embodiment of the present invention.

[0023] Reference numerals in the figure: 1. waveguide cavity; 2. microstrip cavity; 3. waveguide ridge; 4. dielectric substrate; 5. microstrip line; 6. isolation resistor; 7. metal block; 8. waveguide combining port; 9. microstrip line dividing port. DETAILED DESCRIPTION

[0024] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0025] The following describes the embodiments of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, in the absence of conflict, the features in the following embodiments and embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of this application.

[0026] like Figure 1 and Figure 2 As shown, an embodiment of the present invention provides a high-isolation in-phase power combiner based on a ridge waveguide-microstrip line, characterized in that the power combiner includes:

[0027] A waveguide cavity 1 is provided with a waveguide combining port 8 at one end of the waveguide cavity 1. A waveguide ridge 3 with a gradually varying height is symmetrically provided inside the waveguide cavity 1 along the length direction of the waveguide cavity 1. An isolation resistor 6 is provided at the end of the waveguide ridge 3 away from the waveguide combining port 8. The isolation resistor 6 is located between the lower surface of the waveguide cavity 1 and the end of the waveguide ridge 3.

[0028] The microstrip cavity 2 is arranged on two sides of the waveguide cavity 1, and includes a dielectric substrate 4, a microstrip line 5 and a metal block 7, wherein the microstrip line 5 is connected to the waveguide ridge 3, and a metal block 7 is provided at the connection. The end of the microstrip cavity 2 is a microstrip line branch port 9.

[0029] Further, such as Figure 2 and Figure 3 As shown, the waveguide ridge 3 is composed of a transverse waveguide ridge 3 and a longitudinal waveguide ridge 3. The two transverse waveguide ridges 3 are arranged along the width direction of the waveguide cavity 1, and the two symmetrically arranged longitudinal waveguide ridges 3 are arranged along the length direction of the waveguide cavity 1. Each of the waveguide ridges is composed of multiple ridges with different ridge heights, and the height of the multiple longitudinal waveguide ridges 3 increases in the direction away from the waveguide port 8. The two symmetrically arranged longitudinal waveguide ridges 3 are respectively connected to the two transverse waveguide ridges 3.

[0030] Preferably, the length of the waveguide ridge 3 in the longitudinal direction of each section is a quarter of the wavelength, and the ridge widths of the waveguide ridge 3 in the longitudinal direction of each section are the same but the ridge heights are different.

[0031] Furthermore, the number of sections of the longitudinal waveguide ridge 3 is determined according to the design bandwidth requirement and design frequency of the power combiner.

[0032] Furthermore, the impedance of each section of the longitudinal waveguide ridge 3 is different.

[0033] Furthermore, when the power combiner is in use, the two microstrip line branch ports 9 are respectively connected to two microstrip circuit amplifiers, and the power is output through the waveguide combining port 8 after power combination.

[0034] Preferably, the two microstrip circuit amplifiers are in phase.

[0035] Specifically, the power combiner provided by the embodiments of the present invention comprises two major components: a waveguide cavity and a microstrip circuit cavity. One end of the waveguide cavity 1 can be considered a standard waveguide. Several waveguide ridges 3 with constant width and varying heights are symmetrically machined along the waveguide's broadside. This divides the input power at the waveguide port equally, forming several ridge waveguide sections with varying impedances. Each ridge waveguide section is approximately one-quarter wavelength long, thereby achieving impedance transformation from the high impedance of a standard waveguide to the low impedance of a ridge waveguide. To facilitate connection with a low-impedance microstrip circuit, a ridge waveguide structure is still present at the rear end of the ridge waveguide's connection to the microstrip circuit. An isolation resistor 6 is provided at the end of the ridge waveguide to absorb the unbalanced energy flowing through the two microstrip line split ports 9. The microstrip cavity 2 is divided into two sections, located on either side of the waveguide. A dielectric substrate 4 and a microstrip line 5 are arranged within the cavity. The microstrip line is connected to the waveguide ridge 3, and a metal block 7 ensures a reliable connection between the microstrip line and the ridge. By introducing a set of ridge waveguide structures along the longitudinal direction of the ridge waveguide, the signals at the branch ports, passing through different paths, converge at the other branch ports and cancel each other out, thus achieving isolation between the branch ports. When the power combiner is in use, the microstrip line branch port 9 is connected to two microstrip circuit amplifiers, each of which must be in phase. After power is combined, the two amplifiers are output through the waveguide combiner port 8.

[0036] Furthermore, Figure 4 、 Figure 5 、 Figure 6 、 Figure 7 、 Figure 8 Schematic diagram of simulation results of a high-isolation in-phase power combiner based on ridge waveguide-microstrip line provided by an embodiment of the present invention. Figure 4 It is the standing wave of the waveguide combiner port; Figure 5 is the insertion loss diagram; Figure 6 is the standing wave diagram of the microstrip port; Figure 7 It is the isolation curve diagram; Figure 8The phase relationship diagram of the two microstrip ports is shown in Figure 2. The simulation results show that the power combiner structure achieves in-phase power division and has good isolation performance and port standing wave performance.

[0037] In summary, the high-isolation in-phase power combiner based on ridge waveguide-microstrip line provided in the embodiments of the present application can achieve the following technical effects compared with the prior art:

[0038] 1. Compared with ordinary ridge waveguide transition, this method not only completes the waveguide-to-microstrip transition but also realizes the power distribution / synthesis of two paths. Compared with the ordinary waveguide-to-microstrip dual-probe transition, in addition to satisfying the waveguide-microstrip conversion and power distribution / synthesis, it is easy to achieve isolation between paths and improve port standing waves, facilitate the connection between modules and system integration, and reduce the instability of the system caused by imbalance between paths or even damage to one path during multi-path system integration.

[0039] 2. This structure directly realizes power distribution / synthesis while achieving good isolation during the waveguide-microstrip conversion process. Compared with designing a microstrip power combiner with good isolation performance and then designing a waveguide-microstrip converter for cascade connection, the structure is more compact and conducive to the miniaturization design of the system.

[0040] 3. This structure connects a power resistor to the isolation port as an absorbing load. The resistor can be fixed to the cavity wall, and its position can be adjusted by the length of the waveguide ridge. Compared with the isolation resistor in a Wilkinson power divider, it is easier to assemble and dissipate heat. This invention can be applied in the RF microwave field for waveguide-microstrip transitions and power distribution / combination.

[0041] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A high-isolation in-phase power combiner based on ridge waveguide-microstrip line, characterized in that: The power combiner comprises: A waveguide cavity (1), wherein a waveguide combining port (8) is provided at one end of the waveguide cavity (1), a waveguide ridge (3) with a gradient height is symmetrically provided inside the waveguide cavity (1) along the length direction of the waveguide cavity (1), an isolation resistor (6) is provided at the end of the waveguide ridge (3) away from the waveguide combining port (8), and the isolation resistor (6) is located between the lower surface of the waveguide cavity (1) and the end of the waveguide ridge (3); A microstrip cavity (2), the microstrip cavity (2) being arranged on two sides of the waveguide cavity (1), comprising a dielectric substrate (4), a microstrip line (5) and a metal block (7), wherein the microstrip line (5) is connected to the waveguide ridge (3), a metal block (7) is provided at the connection, and the end of the microstrip cavity (2) is a microstrip line branch port (9); The waveguide ridge (3) is composed of a transverse waveguide ridge (3) and a longitudinal waveguide ridge (3), the two transverse waveguide ridges (3) being arranged along the width direction of the waveguide cavity (1), and the two symmetrically arranged longitudinal waveguide ridges (3) being arranged along the length direction of the waveguide cavity (1), each of which is composed of multiple sections of ridges with different ridge heights, and the heights of the multiple sections of longitudinal waveguide ridges (3) increasing in a direction away from the waveguide combining port (8), and the two symmetrically arranged longitudinal waveguide ridges (3) being connected to the two transverse waveguide ridges (3) respectively.

2. A high-isolation in-phase power combiner based on ridge waveguide-microstrip line according to claim 1, characterized in that: The length of the longitudinal waveguide ridge (3) of each section is a quarter of the wavelength, and the ridge widths of the longitudinal waveguide ridges (3) of each section are the same but the ridge heights are different.

3. The high-isolation in-phase power combiner based on ridge waveguide-microstrip line according to claim 2, characterized in that: The number of sections of the longitudinal waveguide ridge (3) is determined according to the design bandwidth requirement and design frequency of the power combiner.

4. The high-isolation in-phase power combiner based on ridge waveguide-microstrip line according to claim 3, characterized in that: The impedance of the longitudinal waveguide ridge (3) of each section is different.

5. The high-isolation in-phase power combiner based on ridge waveguide-microstrip line according to claim 1, characterized in that: When the power combiner is in use, the two microstrip line branch ports (9) are respectively connected to two microstrip circuit amplifiers, and after power synthesis, power is output through the waveguide combining port (8).

6. The high-isolation in-phase power combiner based on ridge waveguide-microstrip line according to claim 5, characterized in that: The two microstrip circuit amplifiers are in phase.

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