Bidirectional low intermodulation attenuator and application thereof

Abstract

The invention discloses a bidirectional low intermodulation attenuator comprising a coupler which is provided with an input port, an output port, a coupling port and an isolation resistor port. The output port is connected with a first low-intermodulation load, the isolation resistor port is connected with a second low-intermodulation load, so that the input port and the coupling port are bidirectional interfaces without dividing input and output, and the two bidirectional interfaces are respectively used as an input port and an output port of the fixed attenuator. According to the invention, the output port and the isolation resistor port of the coupler are connected with the low-intermodulation cable assembly, so that the input port and the coupling port of the coupler are bidirectional interfaces without dividing input and output, the two bidirectional interfaces become the input port and the output port of the attenuator, and the whole attenuator does not divide input and output and can be used bidirectionally; the condition that maintenance is needed due to burning does not exist, and bidirectional low intermodulation and bidirectional high power are realized.

Description

Technical Field

[0001] The present invention relates to the field of attenuators, and in particular to a bidirectional low intermodulation attenuator and applications thereof. Background Art

[0002] In electromagnetic compatibility testing, attenuators with different parameters are often connected to the input of current probes, LISNs, receivers, spectrum analyzers and other equipment to adjust signal strength, improve impedance matching, protect test equipment, etc., thereby ensuring the accuracy and reliability of test results. While ensuring normal performance of attenuators, the intermodulation value was proposed very early. The intermodulation value will affect the high-quality transmission of the entire communication link. At the same time, the intermodulation value is also an important reference value for the quality of a product.

[0003] Some fixed attenuators on the market generally have 0.7~4GHz, 0.7~6GHz, etc. Such attenuators within a certain frequency band have a variety of different attenuation values, different intermodulation values, and the input and output ports are clearly marked. However, in daily long-term use, these attenuators with clearly marked input and output ports will inevitably confuse the input and output. Once the input and output are confused, the internal resistors will burn out, causing abnormal attenuation values, which will affect the performance of the attenuator and prevent it from being used normally.

[0004] Therefore, how to solve the above-mentioned deficiencies in the prior art has become a subject to be studied and solved by the present invention. Summary of the invention

[0005] The object of the present invention is to provide a bidirectional low intermodulation fixed attenuator which can be used in both directions without distinguishing between input and output.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is: A first aspect of the present invention provides a bidirectional low intermodulation attenuator, comprising a coupler having an input port, an output port, a coupling port and an isolation resistor port; The output port is connected to a first low intermodulation load, and the isolation resistor port is connected to a second low intermodulation load, so that the input port and the coupling port are bidirectional interfaces without input and output distinction, and the two bidirectional interfaces serve as the input port and output port of the fixed attenuator respectively.

[0007] Preferably, the first low intermodulation load adopts a low intermodulation cable assembly.

[0008] Preferably, the second low intermodulation load adopts a low intermodulation cable assembly.

[0009] Preferably, the coupling port is connected to the signal transmission line via a third low intermodulation load.

[0010] Preferably, the third low intermodulation load adopts a low intermodulation cable assembly.

[0011] Preferably, the bidirectional low intermodulation fixed attenuator also includes a box body, the coupler and each low intermodulation cable assembly are installed in the box body, the input port and the output end of the third low intermodulation load are two bidirectional interfaces, and the bidirectional interfaces are installed on the outer wall of the box body.

[0012] Further preferably, the box body comprises a box body with upper and lower openings and a cover plate detachably connected to the two openings, and outer walls of the two cover plates are provided with a plurality of heat sinks.

[0013] Further preferably, two groups of wire limiting ribs for limiting and arranging the first low intermodulation load and the second low intermodulation load are provided on the upper surface of the cover plate located below the box body.

[0014] Further preferably, the number of the wire limiting ribs in each group is multiple and they are distributed in a spiral or U-shaped pattern.

[0015] Further preferably, thermal conductive silicone grease layers are provided on upper and lower surfaces of the first low intermodulation load and the second low intermodulation load.

[0016] A second aspect of the present invention provides an application of a bidirectional low intermodulation attenuator, which is used in a signal transmission line of a wireless communication system, a satellite communication system, a radio and television transmission system, a radar system or a radio frequency signal test and measurement system.

[0017] The working principle and advantages of the present invention are as follows: The present invention connects a low intermodulation cable assembly to both the output port and the isolation resistor port of the coupler, so that the input port and the coupling port of the coupler are bidirectional interfaces without input and output distinction, and the two bidirectional interfaces become the input port and the output port of the attenuator. The entire attenuator has no input and output distinction and can be used bidirectionally, and bidirectional low intermodulation and bidirectional high power are achieved.

[0018] The attenuator of the present invention can be quickly wired when testing related communication equipment, and the device will not burn out instantly after being connected to a wrong input or output port during the test, thereby improving the test efficiency and reducing the maintenance rate of the device.

[0019] The attenuator of the present invention has strong versatility and can be applied to signal transmission lines in wireless communication systems, satellite communication systems, broadcast and television transmission systems, radar systems or radio frequency signal test and measurement systems, and has considerable advantages. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Attached Figure 1 is a structural block diagram of an embodiment of the present invention; Attached Figure 2A coupler circuit connection diagram of an embodiment of the present invention; Attached Figure 3 is an internal layout diagram of an attenuator according to an embodiment of the present invention; Attached Figure 4 It is a front view of the box body of an embodiment of the present invention; Attached Figure 5 Schematic diagram of experimental data of a nominal 20db bidirectional attenuator according to an embodiment of the present invention.

[0021] In the above figures: 1 coupler; 11 input port; 12 output port; 13 coupling port; 14 isolation resistor port; 15 first low intermodulation load; 16 second low intermodulation load; 17 third low intermodulation load; 2 box body; 21 box body; 22 cover plate; 23 heat sink; 24 wire limiting rib. DETAILED DESCRIPTION

[0022] The present invention will be further described below in conjunction with the accompanying drawings and embodiments: Embodiment: The present invention will be clearly described below with diagrams and detailed descriptions. After understanding the embodiments of the present invention, any person skilled in the art can make changes and modifications based on the techniques taught by the present invention without departing from the spirit and scope of the present invention.

[0023] The terms used herein are only for describing specific embodiments and are not intended to be limiting of the present invention. Singular forms such as "a", "this", "here", "this" and "the" as used herein also include plural forms.

[0024] The terms “first”, “second”, etc. used in this document do not specifically refer to an order or sequence, nor are they used to limit the present case. They are only used to distinguish components or operations described with the same technical terms.

[0025] As used herein, “connected” or “positioned” may refer to two or more components or devices being in direct physical contact with each other, or being in indirect physical contact with each other, or may refer to two or more components or devices operating or moving with each other.

[0026] The terms “include,” “including,” “have,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0027] The terms used in this document generally have the ordinary meaning of each term used in this field, in the context of the case and in the specific context, unless otherwise noted. Certain terms used to describe the present invention will be discussed below or elsewhere in this specification to provide additional guidance to those skilled in the art in describing the present invention.

[0028] The terms "front", "back", "up", "down", "left", "right", etc. used in this article are all directional terms. In this case, they are only used to illustrate the positional relationship between the various structures, and are not used to limit the protection plan of this case and the specific direction during actual implementation.

[0029] See attached Figure 1-4 In a first aspect, this embodiment provides a bidirectional low intermodulation attenuator, including a coupler 1 and a box body 2.

[0030] The coupler 1 has an input port 11, an output port 12, a coupling port 13 and an isolation resistor port 14; the output port 12 is connected to a first low intermodulation load 15, and the isolation resistor port 14 is connected to a second low intermodulation load 16, so that the input port 11 and the coupling port 13 are bidirectional interfaces without input and output distinction, and the two bidirectional interfaces serve as the input port and the output port of the fixed attenuator respectively, that is, the two bidirectional interfaces can be used as both input ports and output ports, and both ports achieve low intermodulation performance, which can improve the test efficiency and test effect in a specific usage environment.

[0031] Wherein, the first low intermodulation load 15 and the second low intermodulation load 16 both use low intermodulation cable assemblies. In order to achieve low intermodulation, especially when the intermodulation value is -150-165dBc, the first low intermodulation load 15 and the second low intermodulation load 16 generally use 20-30m low intermodulation cable assemblies. The principle is that the cable has loss per meter, and when the cable reaches a certain length, its loss can reach below -20dB in the entire frequency band.

[0032] The coupling port 13 is connected to the signal transmission line through a third low intermodulation load 17 , and the third low intermodulation load 17 can be a 100-200 mm low intermodulation cable assembly.

[0033] See attached Figure 3 The coupler 1 and each low intermodulation cable assembly are installed in the box body 2, and the input port 11 and the output end of the third low intermodulation load 17 are two bidirectional interfaces, which are installed on the outer wall of the box body 2 to facilitate connection with the signal transmission line.

[0034] The box body 2 includes a box body 21 with upper and lower openings and a cover plate 22 detachably connected to the two openings. The outer walls of the two cover plates 22 are each provided with a plurality of heat sinks 23 to help the cables and coupler 1 inside the box body 2 dissipate heat.

[0035] Since the first low intermodulation load 15 and the second low intermodulation load 16 generally use a 20-30m low intermodulation cable assembly, the cable length is relatively long, and the messy placement is not conducive to heat dissipation, and it is easy to cause safety problems such as insulation aging and breakdown over a long period of time. Therefore, two groups of wire limiting ribs 24 for limiting and arranging the first low intermodulation load 15 and the second low intermodulation load 16 are provided on the upper surface of the cover plate 22 located below the box body 21. There are multiple wire limiting ribs 24 in each group, and they are distributed in a spiral or round shape.

[0036] By means of the spiral or U-shaped conductor limiting ribs 24, the low intermodulation cable assembly can be arranged in close contact with the outer wall of the conductor limiting ribs 24, and the cable can be arranged into a spiral or U-shaped shape for heat dissipation.

[0037] In order to further accelerate the heat dissipation of the low intermodulation cable assembly, the upper and lower surfaces of the first low intermodulation load 15 and the second low intermodulation load 16 are provided with thermal grease layers. During the specific processing, an appropriate amount of thermal grease is applied to the upper and lower surfaces of the low intermodulation cable assembly.

[0038] When the above-mentioned attenuator is actually used, it can be tested and used alone, or it can be installed in the relevant RF unit for use. When the attenuator is connected to the signal transmission line, no matter its input port and output port are connected in a positive or negative way, when the signal is input to the attenuator, an attenuated signal will be output, and both the positive and negative signals are low intermodulation signals with accurate attenuation values. In addition, the attenuator worked normally during the test without burning.

[0039] This implementation provides experimental data of a nominal 20db bidirectional attenuator, see Figure 5 The data on the left and right of the figure are two sets of attenuation data of the bidirectional attenuator. It can be seen from the two sets of data that no matter whether the bidirectional attenuator is connected forwardly or reversely, when the signal is input to the attenuator, an attenuated signal will be output.

[0040] In practical applications, the length of the low intermodulation cable assembly can be adjusted according to requirements to obtain bidirectional attenuators with various attenuations.

[0041] A second aspect of this embodiment provides an application of a bidirectional low intermodulation attenuator, which is used in signal transmission lines of wireless communication systems, satellite communication systems, radio and television transmission systems, radar systems or radio frequency signal test and measurement systems.

[0042] When the low intermodulation attenuator of this embodiment is connected to the signal transmission line of a wireless communication system, in the wireless communication system, especially between the base station antenna and the signal amplifier, the low intermodulation attenuator can effectively reduce the intermodulation distortion caused by strong signal interference, thereby improving the performance and stability of the communication system.

[0043] When the low intermodulation attenuator of this embodiment is connected to the signal transmission line of a satellite communication system, in the satellite communication system, the low intermodulation attenuator can improve the sensitivity and usage capacity of the system, while reducing the distortion rate and ensuring the quality of signal transmission.

[0044] When the low intermodulation attenuator of this embodiment is connected to the signal transmission line of a radio and television transmission system, in the radio and television transmission system, the low intermodulation attenuator can reduce the interference of interference sources on the signal and improve the quality and stability of the signal.

[0045] When the low intermodulation attenuator of this embodiment is connected to the signal transmission line of the radar system, in the radar system, the low intermodulation attenuator is used to reduce the power level of the signal, achieve level balance and dynamic range expansion of the signal chain, and provide impedance matching to ensure the accuracy and stability of the radar system.

[0046] When the low intermodulation attenuator of this embodiment is connected to the signal transmission line of the electromagnetic compatibility test and measurement system, in the field of electromagnetic compatibility test and measurement, the low intermodulation attenuator is used to calibrate and test radio frequency signals to ensure the accuracy and reliability of the measurement.

[0047] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A bidirectional low intermodulation attenuator, characterized in that: A coupler is included, the coupler having an input port, an output port, a coupling port, and an isolation resistor port; The output port is connected to a first low intermodulation load, and the isolation resistor port is connected to a second low intermodulation load, so that the input port and the coupling port are bidirectional interfaces without input and output distinction, and the two bidirectional interfaces serve as the input port and output port of the fixed attenuator respectively.

2. A bidirectional low intermodulation attenuator according to claim 1, characterized in that: The first low intermodulation load adopts a low intermodulation cable assembly.

3. A bidirectional low intermodulation attenuator according to claim 2, characterized in that: The second low intermodulation load uses a low intermodulation cable assembly.

4. A bidirectional low intermodulation attenuator according to claim 3, characterized in that: The coupling port is connected to the signal transmission line through a third low intermodulation load.

5. A bidirectional low intermodulation attenuator according to claim 4, characterized in that: The third low intermodulation load adopts a low intermodulation cable assembly.

6. A bidirectional low intermodulation attenuator according to claim 4, characterized in that: It also includes a box body, in which the coupler and each low intermodulation cable assembly are installed, and the input port and the output end of the third low intermodulation load are two bidirectional interfaces, which are installed on the outer wall of the box body.

7. A bidirectional low intermodulation attenuator according to claim 6, characterized in that: The box body comprises a box body with upper and lower openings and a cover plate detachably connected to the two openings, and the outer walls of the two cover plates are both provided with a plurality of heat sinks.

8. A bidirectional low intermodulation attenuator according to claim 7, characterized in that: Two groups of wire limiting ribs for limiting and arranging the first low intermodulation load and the second low intermodulation load are provided on the upper surface of the cover plate located below the box body.

9. A bidirectional low intermodulation attenuator according to claim 8, characterized in that: Each group of the conductor limiting ribs has a plurality of conductor limiting ribs, which are distributed in a spiral or U-shaped pattern.

10. A bidirectional low intermodulation attenuator according to claim 9, characterized in that: Thermal conductive silicone grease layers are provided on upper and lower surfaces of the first low intermodulation load and the second low intermodulation load.

11. An application of the bidirectional low intermodulation attenuator according to any one of claims 1 to 10, characterized in that: The bidirectional low intermodulation attenuator is used in the signal transmission lines of wireless communication systems, satellite communication systems, radio and television transmission systems, radar systems or radio frequency signal test and measurement systems.

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