Coupler and radio frequency chip

Abstract

Provided are a coupler and a radio frequency chip. The coupler comprises a first microstrip line, and a second microstrip line coupled to the first microstrip line, two ends of the first microstrip line being respectively provided with a radio frequency input port and an antenna output port, and two ends of the second microstrip line being respectively provided with an isolation port and a coupling output port. The coupler further comprises a first resonant circuit, a second resonant circuit and a first resistor, the first resonant circuit, the second resonant circuit and the first resistor being used for optimizing the isolation and directivity of the coupler. Compared with the prior art, the provided coupler has high isolation, good directivity and lower power fluctuation. On the basis of the original design of the coupler, resonant loops are directly added to to widen the frequency range. Using microstrip lines as basic structures involves low cost, and exhibits high isolation, high directivity and low power fluctuation in the case of low design complexity.

Description

Couplers and RF chips Technical Field

[0001] This utility model relates to the field of wireless communication technology, and in particular to a coupler and a radio frequency chip. Background Technology

[0002] The 2.4GHz band is one of the commonly used frequency bands in wireless communication systems, widely used in short-range wireless communication technologies such as WiFi, Bluetooth, and ZigBee. CPL couplers with integrated radio frequency technology play a crucial role in wireless communication systems. Integrating a CPL coupler into a 2.4GHz WiFi module enables bidirectional signal transmission and monitoring, improving system flexibility and reliability. Couplers can be used in various scenarios such as power distribution and signal monitoring, meeting the needs of WiFi modules in complex communication environments, and helping to improve signal transmission quality, reduce system interference, and increase communication efficiency.

[0003] However, existing CPL couplers have the following problems: bandwidth limitation. Although the couplers have wide bandwidth coverage, in some extreme high-frequency applications, RF integrated CPL couplers may still face bandwidth limitations and cannot fully meet the needs of high-frequency signal transmission. Higher cost. Due to the use of high-performance materials and advanced manufacturing processes, existing CPL couplers have relatively high production costs, which in turn drives up the market price. This can be a disadvantage for cost-sensitive applications. Design complexity. To achieve high performance, the design process of RF integrated CPL couplers is relatively complex, requiring designers to have deep expertise and extensive experience. This increases the design difficulty and cost of the product to some extent.

[0004] Therefore, there is an urgent need for a new coupler and RF chip to solve the above-mentioned technical problems.

[0005] Utility Model Content

[0006] This invention provides a coupler and an RF chip, aiming to solve the problems of high cost, complex structure and bandwidth limitation of existing couplers.

[0007] In a first aspect, this utility model provides a coupler comprising a first microstrip line and a second microstrip line coupled to the first microstrip line. The first microstrip line has a radio frequency input port and an antenna output port at its two ends, and the second microstrip line has an isolation port and a coupling output port at its two ends. The coupler further comprises a first resonant circuit, a second resonant circuit, and a first resistor. A first end of the first resonant circuit is connected to the second microstrip line, a second end of the first resonant circuit is connected to the isolation port, a first end of the first resistor is connected to the isolation port, and a second end of the first resistor is grounded. A first end of the second resonant circuit is connected to the coupling output port, and a second end of the second resonant circuit is connected to an external input port for receiving externally input radio frequency signals.

[0008] The first resonant circuit, the second resonant circuit, and the first resistor are used to optimize the isolation and directivity of the coupler.

[0009] Preferably, the first resonant circuit includes a first inductor and a first capacitor. The first end of the first inductor serves as the first end of the first resonant circuit, the second end of the first inductor is connected to the first end of the first capacitor, the first end of the first capacitor serves as the second end of the first resonant circuit, and the second end of the first capacitor is grounded.

[0010] Preferably, the second resonant circuit includes a second inductor and a second capacitor, the first end of the second capacitor serves as the second end of the second resonant circuit, the second end of the second capacitor is connected to the first end of the second inductor, and the second end of the second inductor serves as the first end of the second resonant circuit.

[0011] Preferably, the first microstrip line includes a first microstrip line segment connected to the radio frequency input port and a second microstrip line segment extending from the first microstrip line. The end of the second microstrip line segment away from the first microstrip line segment is connected to the antenna output port. The second microstrip line also includes a third microstrip line segment connected to the coupling output port and a fourth microstrip line segment extending from the third microstrip line segment. The end of the fourth microstrip line segment away from the third microstrip line segment is connected to the isolation port. The second microstrip line segment and the third microstrip line segment are parallel.

[0012] The width of the first microstrip line is 8um-10um, the width of the second microstrip line is 13um-15um, the width of the third microstrip line is 3um-6um, the width of the fourth microstrip line is 2um-6um, and the distance between the second microstrip line and the third microstrip line is 2um-4um.

[0013] Secondly, this utility model also provides a radio frequency chip, which includes a coupler as described in any of the above embodiments.

[0014] Compared with existing technologies, the coupler proposed in this invention includes a first microstrip line and a second microstrip line coupled to the first microstrip line. The first microstrip line has an RF input port and an antenna output port at its two ends, respectively, and the second microstrip line has an isolation port and a coupling output port at its two ends, respectively. The coupler also includes a first resonant circuit, a second resonant circuit, and a first resistor. The first end of the first resonant circuit is connected to the second microstrip line, and the second end of the first resonant circuit is connected to the isolation port. The first end of the first resistor is connected to the isolation port, and the second end of the first resistor is grounded. The first end of the second resonant circuit is connected to the coupling output port, and the second end of the second resonant circuit is connected to the external input port. The first resonant circuit, the second resonant circuit, and the first resistor are used to optimize the isolation and directivity of the coupler. Thus, the coupler proposed in this invention has high isolation, good directivity, and low power fluctuation. It directly adds a resonant circuit to the original coupler design to broaden the frequency range. Using a microstrip line as the basic structure, it achieves high isolation, high directivity, and low power fluctuation with low cost and design complexity. Attached Figure Description

[0015] The present invention will now be described in detail with reference to the accompanying drawings. The above and other aspects of the present invention will become clearer and easier to understand through the detailed description in conjunction with the following drawings. In the drawings:

[0016] Figure 1 is a schematic diagram of the circuit structure of the coupler provided in an embodiment of this utility model.

[0017] Figure 2 is a schematic diagram of the operating frequency range of the coupler provided in the embodiment of this utility model.

[0018] Figure 3 is a schematic diagram of the difference between the antenna output port power and the coupling output port power of the coupler provided in the embodiment of this utility model. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0020] Example 1

[0021] Please refer to Figures 1-3. In one aspect, this utility model provides a coupler, which is a bidirectional coupler. The coupler includes a first microstrip line and a second microstrip line coupled to the first microstrip line. The two ends of the first microstrip line are respectively provided with a radio frequency input port and an antenna output port. The two ends of the second microstrip line are respectively provided with an isolation port and a coupling output port. The coupler also includes a first resonant circuit 1, a second resonant circuit 2, and a first resistor R1. The first end of the first resonant circuit 1 is connected to the second microstrip line, and the second end of the first resonant circuit 1 is connected to the isolation port. The first end of the first resistor R1 is connected to the isolation port, and the second end of the first resistor R1 is grounded. The first end of the second resonant circuit 2 is connected to the coupling output port, and the second end of the second resonant circuit 2 is connected to an external input port for receiving externally input radio frequency signals.

[0022] The first resonant circuit 1, the second resonant circuit 2, and the first resistor R1 are used together to optimize the isolation and directivity of the coupler.

[0023] Specifically, the first resistor R1 is 50Ω and is used to absorb unwanted signal energy. The first resonant circuit 1 is set at the isolation port to form a resonant circuit, and the second resonant circuit 2 is set at the coupling output port to form a resonant circuit, which effectively increases the resonant circuit of the coupler and widens the frequency range.

[0024] The first microstrip line is used to transmit radio frequency signals, and the second microstrip line realizes signal coupling and distribution. The first microstrip line includes a first segment microstrip line connected to the radio frequency input port and a second segment microstrip line extended from the first segment microstrip line. The end of the second segment microstrip line away from the first segment microstrip line is connected to the antenna output port. The second microstrip line includes a third segment microstrip line connected to the coupling output port and a fourth segment microstrip line extended from the third segment microstrip line. The end of the fourth segment microstrip line away from the third segment microstrip line is connected to the isolation port. The second segment microstrip line and the third segment microstrip line are parallel.

[0025] The first microstrip line has a width W1 of 8µm-10µm, exemplarily 10µm. The second microstrip line has a width W2 of 13µm-15µm, with a 3.2µm thick copper microstrip line serving as the dominant waveguide, placed on an oxide semiconductor material; exemplarily W2 is 15µm. The third microstrip line has a width W3 of 3µm-6µm, and the fourth microstrip line has a width W4 of 2µm-6µm. The distance S1 between the second and third microstrip lines is 2µm-4µm, exemplarily 3µm. The coplanar coupling length between the first and second microstrip lines is 176.33µm. The coupling coefficient of the coupler can be controlled by adjusting the coupling distance and coupling length between the second and first microstrip lines. By designing the widths and coupling distances of different segments of the first and second microstrip lines, a balance between coupling and isolation is achieved, effectively ensuring the normal operation of the coupler.

[0026] The first and second microstrip lines are made of copper as the conductor material due to its excellent conductivity and processing performance. The substrate material for both microstrip lines is oxide semiconductor with a dielectric constant of 4.1 to ensure efficient and high-quality signal transmission. The resistors and capacitors in the couplers are high-precision, high-stability surface-mount components.

[0027] In this embodiment, the first resonant circuit 1 includes a first inductor L1 and a first capacitor C1. The first end of the first inductor L1 serves as the first terminal of the first resonant circuit 1, and the second end of the first inductor L1 is connected to the first terminal of the first capacitor C1. The first terminal of the first capacitor C1 serves as the second terminal of the first resonant circuit 1, and the second terminal of the first capacitor C1 is grounded. Specifically, the first capacitor C1 has a value of 1.5pF, and the first inductor L1 has a value of 1.3nH.

[0028] In this embodiment, the second resonant circuit 2 includes a second inductor L2 and a second capacitor C2. The first terminal of the second capacitor C2 serves as the second terminal of the second resonant circuit 2, and the second terminal of the second capacitor C2 is connected to the first terminal of the second inductor L2. The second terminal of the second inductor L2 serves as the first terminal of the second resonant circuit 2. Specifically, the second capacitor C2 has a value of 1.2 pF, and the second inductor L2 has a value of 1.8 nH.

[0029] Compared with existing technologies, the coupler proposed in this invention includes a first microstrip line and a second microstrip line coupled to the first microstrip line. The first microstrip line has an RF input port and an antenna output port at its two ends, respectively, and the second microstrip line has an isolation port and a coupling output port at its two ends, respectively. The coupler also includes a first resonant circuit, a second resonant circuit, and a first resistor. The first end of the first resonant circuit is connected to the second microstrip line, and the second end of the first resonant circuit is connected to the isolation port. The first end of the first resistor is connected to the isolation port, and the second end of the first resistor is grounded. The first end of the second resonant circuit is connected to the coupling output port, and the second end of the second resonant circuit is connected to the external input port. The first resonant circuit, the second resonant circuit, and the first resistor are used to optimize the isolation and directivity of the coupler. Thus, the coupler proposed in this invention has high isolation, good directivity, and low power fluctuation. It directly adds a resonant circuit to the original coupler design to broaden the frequency range. Using a microstrip line as the basic structure, it achieves high isolation, high directivity, and low power fluctuation with low cost and design complexity.

[0030] Example 2

[0031] Secondly, this utility model also provides a radio frequency (RF) chip, which includes a coupler as described in any of the above embodiments. The RF chip achieves the same technical effects as the coupler described in the above embodiments, and will not be repeated here.

[0032] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0033] The embodiments of the present utility model have been described above with reference to the accompanying drawings. The disclosed embodiments are merely preferred embodiments of the present utility model. However, the present utility model is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many equivalent changes under the guidance of the present utility model without departing from the spirit and scope of the claims. All such changes are within the protection scope of the present utility model.

Claims

1. A coupler, the coupler comprising a first microstrip line and a second microstrip line coupled to the first microstrip line, wherein the first microstrip line has a radio frequency input port and an antenna output port respectively at its two ends, and the second microstrip line has an isolation port and a coupling output port respectively at its two ends; characterized in that, The coupler further includes a first resonant circuit, a second resonant circuit, and a first resistor; a first end of the first resonant circuit is connected to the second microstrip line, a second end of the first resonant circuit is connected to the isolation port, a first end of the first resistor is connected to the isolation port, and a second end of the first resistor is grounded; a first end of the second resonant circuit is connected to the coupling output port, and a second end of the second resonant circuit is connected to an external input port for receiving externally input radio frequency signals; The first resonant circuit, the second resonant circuit, and the first resistor are used together to optimize the isolation and directivity of the coupler.

2. The coupler as claimed in claim 1, characterized in that, The first resonant circuit includes a first inductor and a first capacitor. The first end of the first inductor serves as the first end of the first resonant circuit. The second end of the first inductor is connected to the first end of the first capacitor. The first end of the first capacitor serves as the second end of the first resonant circuit. The second end of the first capacitor is grounded.

3. The coupler as described in claim 1, characterized in that, The second resonant circuit includes a second inductor and a second capacitor; the first end of the second capacitor serves as the second end of the second resonant circuit, and the second end of the second capacitor is connected to the first end of the second inductor, which serves as the first end of the second resonant circuit.

4. The coupler as claimed in claim 1, characterized in that, The first microstrip line includes a first segment of microstrip line connected to the radio frequency input port and a second segment of microstrip line extending from the first segment of microstrip line. The end of the second segment of microstrip line away from the first segment of microstrip line is connected to the antenna output port. The second microstrip line also includes a third segment of microstrip line connected to the coupling output port and a fourth segment of microstrip line extending from the third segment of microstrip line. The end of the fourth segment of microstrip line away from the third segment of microstrip line is connected to the isolation port. The second segment of microstrip line and the third segment of microstrip line are parallel. The width of the first microstrip line is 8um-10um, the width of the second microstrip line is 13um-15um, the width of the third microstrip line is 3um-6um, the width of the fourth microstrip line is 2um-6um, and the distance between the second microstrip line and the third microstrip line is 2um-4um.

5. A radio frequency chip, characterized in that, The radio frequency chip includes a coupler as described in any one of claims 1-4.

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