A directional coupler device for high power transmitter output power detection

Abstract

The application discloses a directional coupler device for high-power transmitter output power detection, which is composed of a first waveguide layer and a second waveguide layer; the first waveguide layer structure is composed of a main line waveguide, a first auxiliary line waveguide, a first rectangular coupling window, a second auxiliary line waveguide, a second rectangular coupling window, a third auxiliary line waveguide, a third rectangular coupling window, a fourth auxiliary line waveguide and a fourth rectangular coupling window; the second waveguide layer structure is composed of the main line waveguide, the first auxiliary line waveguide, the second auxiliary line waveguide, the third auxiliary line waveguide and the fourth auxiliary line waveguide; the first waveguide layer and the second waveguide layer of the application are split along the waveguide top surface from the first rectangular coupling window to the fourth rectangular coupling window to form a split waveguide; the application has a compact structure, reserves a waveguide-microstrip conversion circuit, can simplify the transition structure, and improves the system reliability while ensuring high power capacity and good isolation.

Description

Technical Field

[0001] This invention relates to the field of microwave technology, and more specifically, to a multi-channel directional coupler device and method for detecting the output power of a high-power transmitter. Background Technology

[0002] In high-frequency, high-power transmission systems, to protect the expensive high-frequency, high-power core power amplifier tubes from damage caused by reflected power surges due to overload or mismatch, and to simultaneously monitor their output efficiency and stability, directional couplers must be used for non-invasive sampling and monitoring of forward and reflected power. The directional coupler, through its coupling structure, non-invasively couples out minute amounts of radio frequency signals propagating along the forward and reverse directions from the main transmission line and separates them for output, thereby enabling real-time monitoring of output power and reflected power (used to calculate the standing wave ratio).

[0003] Current high-power transmission systems commonly employ discrete directional couplers based on waveguides, coaxial lines, or microstrip lines. As operating frequencies increase, the insertion loss of coaxial and microstrip line couplers deteriorates significantly, substantially impacting system output power. Furthermore, this deterioration increases coupler heat generation, leading to a significant reduction in power capacity. Therefore, waveguide-based directional couplers are the preferred choice for high-frequency, high-power transmission systems. However, due to limitations in their structure and interface, waveguide directional couplers often require multi-stage precision transition structures such as "waveguide-coaxial" and "coaxial-microstrip" when integrated into a system. These transition structures not only significantly increase system size and weight but also introduce problems such as high assembly complexity, difficulty in ensuring consistency, and increased costs due to multi-stage assembly. Therefore, there is an urgent need for a compact, multi-channel directional coupling device capable of bidirectional, multi-degree-of-coupling signal coupling and power detection, simplifying the transition structure while ensuring high power capacity and good isolation, and improving system reliability. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a directional coupler device and method for detecting the output power of high-power transmitters. This invention can solve the problems of large size and weight and complex transition structure of existing systems, and has strong engineering applicability. It is very promising for applications such as satellite communication and vehicle radar.

[0005] The objective of this invention is achieved through the following scheme: a directional coupler device for detecting the output power of a high-power transmitter, used to realize bidirectional, multi-coupling degree signal coupling and power detection, the device adopts a split waveguide structure, including a first waveguide layer and a second waveguide layer.

[0006] The first waveguide layer includes a main waveguide, a first secondary waveguide, a first rectangular coupling window, a second secondary waveguide, a second rectangular coupling window, a third secondary waveguide, a third rectangular coupling window, a fourth secondary waveguide, and a fourth rectangular coupling window. The first secondary waveguide, the first rectangular coupling window, the second secondary waveguide, and the second rectangular coupling window are parallel to the main waveguide and are distributed on both sides of the main waveguide's X-axis, close to the input end of the main waveguide. The third secondary waveguide, the third rectangular coupling window, the fourth secondary waveguide, and the fourth rectangular coupling window are parallel to the main waveguide and are distributed on both sides of the main waveguide's X-axis, close to the output end of the main waveguide. The second waveguide layer includes a main waveguide, a first sub-waveguide, a second sub-waveguide, a third sub-waveguide, and a fourth sub-waveguide. The first and second sub-waveguides are parallel to the main waveguide and are located on both sides of the main waveguide's X-axis, close to the input end of the main waveguide. The third and fourth sub-waveguides are parallel to the main waveguide and are located on both sides of the main waveguide's X-axis, close to the output end of the main waveguide. The first sub-waveguide includes a first bend and a second bend; the second sub-waveguide includes a third bend and a fourth bend; the third sub-waveguide includes a fifth bend and a sixth bend; and the fourth sub-waveguide includes a seventh bend and an eighth bend. The first, second, fifth, and sixth bends are distributed along the +Y axis, while the third, fourth, seventh, and eighth bends are distributed along the -Y axis.

[0007] Furthermore, the first rectangular coupling window is located on the common plane of the first sub-waveguide and the main waveguide; the second rectangular coupling window is located on the common plane of the second sub-waveguide and the main waveguide; the third rectangular coupling window is located on the common plane of the third sub-waveguide and the main waveguide; and the fourth rectangular coupling window is located on the common plane of the fourth sub-waveguide and the main waveguide. Furthermore, the first rectangular coupling window of the first waveguide layer includes five rectangular slots. The height of each rectangular slot in the Z-axis direction is 1 mm, the depth in the Y-axis direction is 0.5 mm, the slot widths in the X-axis direction are 0.8 mm, 1.35 mm, 1.4 mm, 1.35 mm and 0.8 mm respectively, and the slot spacing in the X-axis direction is 1.68 mm, 2 mm, 2 mm and 1.68 mm respectively. Furthermore, the second rectangular coupling window of the first waveguide layer includes five rectangular slots. The height of each rectangular slot in the Z-axis direction is 1 mm, the depth in the Y-axis direction is 0.7 mm, the slot widths in the X-axis direction are 0.8 mm, 1.35 mm, 1.4 mm, 1.35 mm and 0.8 mm respectively, and the slot spacing in the X-axis direction is 1.68 mm, 2 mm, 2 mm and 1.68 mm respectively. Furthermore, the third rectangular coupling window of the first waveguide layer includes five rectangular slots. The height of each rectangular slot in the Z-axis direction is 1 mm, the depth in the Y-axis direction is 0.7 mm, the slot widths in the X-axis direction are 0.55 mm, 0.95 mm, 1 mm, 0.95 mm and 0.55 mm respectively, and the slot spacing in the X-axis direction is 1.5 mm, 1.75 mm, 1.75 mm and 1.5 mm respectively. Furthermore, the fourth rectangular coupling window of the first waveguide layer includes five rectangular slots. The height of each rectangular slot in the Z-axis direction is 1 mm, the depth in the Y-axis direction is 0.7 mm, the slot widths in the X-axis direction are 0.55 mm, 0.95 mm, 1 mm, 0.95 mm and 0.55 mm respectively, and the slot spacing in the X-axis direction is 1.5 mm, 1.75 mm, 1.75 mm and 1.5 mm respectively. Furthermore, the first waveguide layer and the second waveguide layer split along the top surface of the waveguide from the first rectangular coupling window to the fourth rectangular coupling window to form a split waveguide; Furthermore, the center distance between the first rectangular coupling window and the fourth rectangular coupling window is 0.99 mm from the top surface of the first waveguide layer, the waveguide depth of the first waveguide layer is 1.49 mm, and the waveguide depth of the second waveguide layer is 3.29 mm. Furthermore, the first and fourth bend ends are each provided with a microstrip probe reserved port; the second, third, fifth, and seventh bend ends are each provided with an isolation port for connecting the absorbing material wedge load; and the sixth and eighth bend ends are each provided with a coupling output port.

[0008] Furthermore, the first sub-waveguide is used to couple the reflected signal with a coupling degree of 35dB; the second sub-waveguide is used to couple the output signal with a coupling degree of 40dB; the third sub-waveguide is used to monitor the output signal with a coupling degree of 50dB; and the fourth sub-waveguide is used to forward the output signal with a coupling degree of 50dB. Compared with the prior art, the advantages and beneficial effects of the present invention are as follows: 1. The present invention adopts an unequal split waveguide scheme, which effectively simplifies the processing technology and can be processed using a traditional CNC center.

[0009] 2. The present invention has a compact structure and a reserved waveguide-to-microstrip conversion circuit, which simplifies the transition structure and improves system reliability while ensuring high power capacity and good isolation.

[0010] 3. This invention achieves standing wave protection through a multi-channel design with different coupling degrees and a simple operational circuit.

[0011] 4. The operating frequency of this invention is 40GHz-60GHz, and different coupling degrees of 35dB, 40dB and 50dB can be achieved within this frequency range. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of a directional coupler device for detecting the output power of a high-power transmitter according to the present invention.

[0013] Figure 2 This is a schematic diagram of the first waveguide layer structure of a directional coupler device for detecting the output power of a high-power transmitter according to the present invention.

[0014] Figure 3 This is a schematic diagram of the second waveguide layer structure of a directional coupler device for detecting the output power of a high-power transmitter according to the present invention.

[0015] Figure 4 This is a schematic diagram of the structure of the first to fourth rectangular coupling windows of the present invention.

[0016] Figure 5 This is a port schematic diagram of a directional coupler device for detecting the output power of a high-power transmitter according to the present invention.

[0017] Figure 6 This is a schematic diagram of the S-parameter curves of the coupling channel 1 based on the first sub-waveguide of the present invention.

[0018] Figure 7 This is a schematic diagram of the S-parameter curves of the coupling channel 2 based on the second sub-waveguide of the present invention.

[0019] Figure 8 This is a schematic diagram of the S-parameter curves of coupling channels 3 and 4 based on the third and fourth sub-waveguides of the present invention.

[0020] Wherein, 1 is the first waveguide layer; 2 is the second waveguide layer; 3 is the main waveguide; 4 is the first sub-waveguide; 5 is the second sub-waveguide; 6 is the third sub-waveguide; 7 is the fourth sub-waveguide; 8 is the first rectangular coupling window; 9 is the second rectangular coupling window; 10 is the third rectangular coupling window; 11 is the fourth rectangular coupling window; 12 is the first bend end; 13 is the second bend end; 14 is the third bend end; 15 is the fourth bend end; 16 is the fifth bend end; 17 is the sixth bend end; 18 is the seventh bend end; 19 is the eighth bend end; 20 is the reserved port for the microstrip probe; 21 is the coupling output port; 22 is the isolation port; 23 is the input port; and 24 is the output port. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and thoroughly described below with reference to the accompanying drawings. The described embodiments are merely some embodiments of the present invention.

[0022] This invention proposes a multi-channel directional coupler device for detecting the output power of a high-power transmitter, the overall structure of which is shown in the figure below. Figure 1 As shown, it consists of a first waveguide layer 1 and a second waveguide layer 2.

[0023] The structure of the first waveguide layer 1 is shown in the figure below. Figure 2 As shown, it consists of a main waveguide 3, a first secondary waveguide 4, a first rectangular coupling window 8, a second secondary waveguide 5, a second rectangular coupling window 9, a third secondary waveguide 6, a third rectangular coupling window 10, a fourth secondary waveguide 7, and a fourth rectangular coupling window 11. The dimensions of the first waveguide layer 1 are 65mm × 48.6mm × 13.4mm, and its outer material can be 6061 aluminum alloy, with air filling inside.

[0024] The structure of the second waveguide layer 2 is shown in the figure below. Figure 3 As shown, it consists of a main waveguide 3, a first secondary waveguide 4, a second secondary waveguide 5, a third secondary waveguide 6, and a fourth secondary waveguide 7. The second waveguide layer 2 has dimensions of 65mm × 48.6mm × 15.2mm, and its outer material can be 6061 aluminum alloy, while its interior is filled with air.

[0025] The main waveguide 3 in the first waveguide layer 1 and the second waveguide layer 2 have the same size. They are both WR19 standard rectangular waveguides with a cross-sectional size of 4.775mm × 2.388mm and a length of 65mm.

[0026] The first sub-waveguide 4 in the first waveguide layer 1 and the second waveguide layer 2 adopts the WR19 standard rectangular waveguide with a cross-sectional dimension of 4.775mm×2.388mm. The waveguide length outside the first bend end 12 is 13.4mm. Through the probe-to-microstrip circuit, the waveguide length between the first bend end 12 and the second bend end 13 is 18mm, which is the area where the rectangular coupling window is located. The waveguide length outside the second bend end 13 is 14.4mm, which is the area where the absorbing material wedge load is placed.

[0027] The second sub-waveguide 5 in the first waveguide layer 1 and the second waveguide layer 2 adopts the WR19 standard rectangular waveguide with a cross-sectional dimension of 4.775mm×2.388mm. The waveguide length outside the third bend end 14 is 14.2mm, which is the area for placing the wedge load of the absorbing material. The waveguide length between the third bend end 14 and the fourth bend end 15 is 18mm, which is the area where the rectangular coupling window is located. The waveguide length outside the fourth bend end 15 is 13.2mm, which serves as the reserved port 20 for the microstrip probe through the probe-to-microstrip circuit.

[0028] The third sub-waveguide 6 and the fourth sub-waveguide 7 in the first waveguide layer 1 and the second waveguide layer 2 are symmetrical along the X-axis and adopt the WR19 standard rectangular waveguide with a cross-sectional dimension of 4.775mm × 2.388mm. The outer waveguide lengths of the fifth bend end 16 and the seventh bend end 18 are both 13.7mm, which is the area for placing the absorbing material wedge load. The waveguide lengths between the fifth bend end 16 and the sixth bend end 17, and between the seventh bend end 18 and the eighth bend end 19 are both 14mm, which is the area where the rectangular coupling window is located. The outer waveguide lengths of the sixth bend end 17 and the eighth bend end 19 are 21.2mm, which is the direct coupling output port 21.

[0029] The first rectangular coupling window 8 is located on the common plane of the first secondary waveguide 4 and the main waveguide 3; the second rectangular coupling window 9 is located on the common plane of the second secondary waveguide 5 and the main waveguide 3; the third rectangular coupling window 10 is located on the common plane of the third secondary waveguide 6 and the main waveguide 3; and the fourth rectangular coupling window 11 is located on the common plane of the fourth secondary waveguide 7 and the main waveguide 3. A schematic diagram of the four rectangular windows is shown below. Figure 4 As shown.

[0030] The first rectangular coupling window 8 of the first waveguide layer 1 includes five rectangular slots. The height of each rectangular slot in the Z-axis direction is 1 mm, the depth in the Y-axis direction is 0.5 mm, the slot widths in the X-axis direction are 0.8 mm, 1.35 mm, 1.4 mm, 1.35 mm and 0.8 mm respectively, and the slot spacing in the X-axis direction is 1.68 mm, 2 mm, 2 mm and 1.68 mm respectively. The second rectangular coupling window 9 of the first waveguide layer 1 includes five rectangular slots. The height of each rectangular slot in the Z-axis direction is 1 mm, the depth in the Y-axis direction is 0.7 mm, the slot widths in the X-axis direction are 0.8 mm, 1.35 mm, 1.4 mm, 1.35 mm and 0.8 mm respectively, and the slot spacing in the X-axis direction is 1.68 mm, 2 mm, 2 mm and 1.68 mm respectively.

[0031] The third rectangular coupling window 10 of the first waveguide layer 1 includes five rectangular slots. The height of each rectangular slot in the Z-axis direction is 1 mm, the depth in the Y-axis direction is 0.7 mm, the slot widths in the X-axis direction are 0.55 mm, 0.95 mm, 1 mm, 0.95 mm and 0.55 mm respectively, and the slot spacing in the X-axis direction is 1.5 mm, 1.75 mm, 1.75 mm and 1.5 mm respectively.

[0032] The fourth rectangular coupling window 11 of the first waveguide layer 1 includes five rectangular slots. The height of each rectangular slot in the Z-axis direction is 1 mm, the depth in the Y-axis direction is 0.7 mm, the slot widths in the X-axis direction are 0.55 mm, 0.95 mm, 1 mm, 0.95 mm and 0.55 mm respectively, and the slot spacing in the X-axis direction is 1.5 mm, 1.75 mm, 1.75 mm and 1.5 mm respectively.

[0033] The second waveguide layer 2 has a microstrip probe reserved port 20 at its first bend end 12 and fourth bend end 15; an isolation port 22 at its second bend end 13, third bend end 14, fifth bend end 16 and seventh bend end 18, for connecting to the absorbing material wedge loads 1-4; and a coupling output port 21 at its sixth bend end 17 and eighth bend end 19. Figure 5 As shown, the coupler includes one main waveguide and four secondary waveguides, for a total of 10 ports. Among them, four isolation ports 22 are internal ports, which are achieved by loading a wedge load of absorbing material. Two microstrip probe reserved ports 20 are also internal ports. There are four external ports, namely one input port 23, two coupling output ports 21, and one output port 24.

[0034] Figure 6 This is the S-parameter curve of the coupling channel based on the first sub-waveguide 4 in this invention, where S11 represents the return loss of channel 1, S21 represents the insertion loss of channel 2, S41 represents the coupling degree of channel 1, and S31 represents the isolation degree of channel 1. Figure 6 It can be seen that the coupler of this channel operates in the frequency range of 40GHz to 60GHz. The insertion loss S21 at the center frequency of 50GHz is relatively ideal, the return loss S11 is about 48dB, the coupling S41 is about 34dB, and the isolation S31 is about 52dB.

[0035] Figure 7 This is the S-parameter curve of the coupling channel based on the second sub-waveguide 5 in this invention, where S11 represents the return loss of channel 1, S21 represents the insertion loss of channel 2, S41 represents the coupling degree of channel 1, and S31 represents the isolation degree of channel 1. Figure 6 It can be seen that the coupler of this channel operates in the frequency range of 40GHz to 60GHz. The insertion loss S21 at the center frequency of 50GHz is relatively ideal, the return loss S11 is about 46dB, the coupling S41 is about 39dB, and the isolation S31 is about 53dB.

[0036] Figure 8These are the S-parameter curves of the coupling channels based on the third sub-waveguide 6 and the fourth sub-waveguide 7 in this invention, where S11 represents the return loss of channel 1, S21 represents the insertion loss of channel 2, S41 represents the coupling degree of channel 1, and S31 represents the isolation degree of channel 1. Figure 6 It can be seen that the coupler of this channel operates in the frequency range of 40GHz to 60GHz. The insertion loss S21 at the center frequency of 50GHz is relatively ideal, the return loss S11 is about 50dB, the coupling S41 is about 48dB, and the isolation S31 is about 62dB.

[0037] In summary, the above-described embodiments are merely examples of the present invention and are not intended to limit the scope of protection of the present invention. It should be noted that those skilled in the art can make several equivalent modifications and substitutions based on the content disclosed in the present invention, such as changing the waveguide type, waveguide size, external material, number of sub-waveguides, number of rectangular coupling windows, size of rectangular coupling windows, number of ports, and port type. These equivalent modifications and substitutions, as well as adjustments to the frequency range, should also be considered within the scope of protection of the present invention.

Claims

1. A directional coupler device for detecting the output power of a high-power transmitter, characterized in that: A split waveguide structure is adopted, including a first waveguide layer and a second waveguide layer. The first waveguide layer and the second waveguide layer are split along the top surface of the waveguide from the first rectangular coupling window to the fourth rectangular coupling window to form a split waveguide. The first waveguide layer includes a main waveguide, a first secondary waveguide, a first rectangular coupling window, a second secondary waveguide, a second rectangular coupling window, a third secondary waveguide, a third rectangular coupling window, a fourth secondary waveguide, and a fourth rectangular coupling window. The first secondary waveguide, the first rectangular coupling window, the second secondary waveguide, and the second rectangular coupling window are parallel to the first main waveguide and are distributed on both sides of the first main waveguide along the X-axis, close to the input end of the first main waveguide. The third secondary waveguide, the third rectangular coupling window, the fourth secondary waveguide, and the fourth rectangular coupling window are parallel to the first main waveguide and are distributed on both sides of the first main waveguide along the X-axis, close to the output end of the first main waveguide. The second waveguide layer includes a main waveguide, a first sub-waveguide, a second sub-waveguide, a third sub-waveguide, and a fourth sub-waveguide. The first and second sub-waveguides are parallel to the main waveguide and are located on both sides of the main waveguide's X-axis, close to the input end of the main waveguide. The third and fourth sub-waveguides are parallel to the main waveguide and are located on both sides of the main waveguide's X-axis, close to the output end of the main waveguide. The first secondary waveguide is used to couple the reflected signal, with a coupling degree of 35dB; the second secondary waveguide is used to couple the output signal, with a coupling degree of 40dB.

2. The directional coupler device for detecting the output power of a high-power transmitter according to claim 1, characterized in that: The first sub-waveguide includes a first bend and a second bend; the second sub-waveguide includes a third bend and a fourth bend; the third sub-waveguide includes a fifth bend and a sixth bend; and the fourth sub-waveguide includes a seventh bend and an eighth bend. The first, second, fifth, and sixth bends are distributed along the +Y axis, while the third, fourth, seventh, and eighth bends are distributed along the -Y axis.

3. The directional coupler device for detecting the output power of a high-power transmitter according to claim 1, characterized in that: The first rectangular coupling window is located on the common plane of the first sub-waveguide and the main waveguide; the second rectangular coupling window is located on the common plane of the second sub-waveguide and the main waveguide; the third rectangular coupling window is located on the common plane of the third sub-waveguide and the main waveguide; and the fourth rectangular coupling window is located on the common plane of the fourth sub-waveguide and the main waveguide.

4. A directional coupler device for detecting the output power of a high-power transmitter according to any one of claims 1-3, characterized in that: The first rectangular coupling window has five rectangular slots. The height of each slot in the Z-axis direction is 1 mm, the depth in the Y-axis direction is 0.5 mm, the slot widths in the X-axis direction are 0.8 mm, 1.35 mm, 1.4 mm, 1.35 mm and 0.8 mm respectively, and the slot spacing in the X-axis direction is 1.68 mm, 2 mm, 2 mm and 1.68 mm respectively. The second rectangular coupling window includes five rectangular slots. The height of each slot in the Z-axis direction is 1 mm, the depth in the Y-axis direction is 0.7 mm, the slot widths in the X-axis direction are 0.8 mm, 1.35 mm, 1.4 mm, 1.35 mm and 0.8 mm respectively, and the slot spacing in the X-axis direction is 1.68 mm, 2 mm, 2 mm and 1.68 mm respectively. The third rectangular coupling window includes five rectangular slots. The height of each slot in the Z-axis direction is 1 mm, the depth in the Y-axis direction is 0.7 mm, the slot widths in the X-axis direction are 0.55 mm, 0.95 mm, 1 mm, 0.95 mm and 0.55 mm respectively, and the slot spacing in the X-axis direction is 1.5 mm, 1.75 mm, 1.75 mm and 1.5 mm respectively. The fourth rectangular coupling window includes five rectangular slots. The height of each slot in the Z-axis direction is 1 mm, the depth in the Y-axis direction is 0.7 mm, the slot widths in the X-axis direction are 0.55 mm, 0.95 mm, 1 mm, 0.95 mm and 0.55 mm respectively, and the slot spacing in the X-axis direction is 1.5 mm, 1.75 mm, 1.75 mm and 1.5 mm respectively.

5. A directional coupler device for detecting the output power of a high-power transmitter according to any one of claims 1-3, characterized in that: The center distance between the first and fourth rectangular coupling windows is 0.99 mm from the top surface of the first waveguide layer. The waveguide depth of the first waveguide layer is 1.49 mm, and the waveguide depth of the second waveguide layer is 3.29 mm.

6. A directional coupler device for detecting the output power of a high-power transmitter according to any one of claims 1-3, characterized in that: The first and fourth bend ends each have a reserved port for a microstrip probe; the second, third, fifth, and seventh bend ends each have an isolation port for connecting a wedge load of absorbing material; the sixth and eighth bend ends each have a coupling output port.

7. A directional coupler device for detecting the output power of a high-power transmitter according to any one of claims 1-3, characterized in that: The third secondary waveguide is used to monitor the output signal, with a coupling of 50dB; the fourth secondary waveguide is used to relay the output signal, with a coupling of 50dB.

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