Bidirectional coupler and radio frequency chip

Abstract

The utility model provides a bidirectional coupler and a radio frequency chip. The bidirectional coupler comprises a main circuit, a coupling circuit which is located at one side of the main circuit and is coupled with the main circuit, and an input port which is formed by bending and extending one end of the main circuit towards a direction far away from the coupling circuit, the antenna port is formed by bending and extending the other end of the main circuit towards a direction far away from the coupling circuit, the coupling port and the isolation port are respectively formed at two ends of the coupling circuit, the first end of the adjustable resistor is connected to the isolation port, and the first end of the adjustable capacitor is connected to the isolation port. According to the bidirectional coupler, high isolation can be realized, stable performance can be maintained by means of high flatness of a full frequency band even if impedance mismatch is caused by temperature change, and meanwhile, the size and the cost of the bidirectional coupler can be reduced.

Description

Technical Field

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

[0002] With the development of communication technology, radio frequency power amplifiers have played an increasingly important role in communication systems. The transmitter module is a part of the radio frequency power amplifier. The transmitter module not only has a very high degree of integration, but also integrates a power amplifier, a multi-throw radio frequency switch, and a coupler.

[0003] In the transmitting module, the coupler receives the power energy from the linear power amplifier and feeds it back to the transceiver system of the electronic device. The transceiver system of the electronic device uses the feedback signal from the coupler to calibrate the power of the linear power amplifier in order to obtain accurate transmission power.

[0004] To meet the requirements of two-wire signal transmission, bidirectional couplers were developed. They are designed to process high-frequency signals, and their operating frequency range typically reaches the GHz level. In order to ensure the quality and efficiency of signal transmission, bidirectional couplers also need to ensure low insertion loss and high coupling efficiency in their design.

[0005] While existing bidirectional couplers can operate in high-frequency ranges, they require additional resonant matching to suppress specific frequencies to achieve high isolation at those frequencies. Although this method can forcibly improve the isolation of the bidirectional coupler, the fixed bandwidth limitation of the resonant matching leads to insufficient bandwidth, restricting the application of bidirectional couplers in high-frequency ranges. At the same time, bidirectional couplers require more tuning matching, and their frequency band has resonant pits, making their performance overly dependent on impedance matching. If they operate in extreme temperatures, their performance will be affected by impedance mismatch caused by temperature changes, resulting in unstable signal transmission. In addition, the size of bidirectional couplers is still relatively large, which cannot meet the needs of small electronic devices. Utility Model Content

[0006] To address the shortcomings of the existing technologies, this invention proposes a new bidirectional coupler and RF chip to solve the problems of insufficient bandwidth, temperature-dependent performance, and relatively large size of existing bidirectional couplers, which cannot meet the needs of small electronic devices.

[0007] To address the aforementioned technical problems, in a first aspect, this utility model provides a bidirectional coupler, comprising a main line, a coupling line located on one side of the main line and coupled to the main line, an input port formed by bending and extending from one end of the main line away from the coupling line, an antenna port formed by bending and extending from the other end of the main line away from the coupling line, a coupling port and an isolation port respectively formed at both ends of the coupling line, an adjustable resistor with its first end connected to the isolation port, and an adjustable capacitor with its first end connected to the isolation port. The coupling port is located near the input port and spaced apart from the input port, the isolation port is located near the antenna port and spaced apart from the antenna port, the second end of the adjustable resistor is grounded, and the second end of the adjustable capacitor is connected to the second end of the adjustable resistor.

[0008] The length of the main line and the length of the coupling line are both 100-240um. The total width of the main line and the coupling line is 10-25um. The width of the coupling line is 3-10um. The width of the input port is 8-25um. The width of the antenna port is 8-35um. The extension length of the input port and the extension length of the isolation port are both 3-20um. The distance between the coupling port and the input port is 3-8um.

[0009] Preferably, the resistance value of the adjustable resistor is adjustable in the range of 30-50Ω; the capacitance value of the adjustable capacitor is adjustable in the range of 0.2-0.6pF.

[0010] Preferably, the length of the main line and the length of the coupling line are both 197 μm.

[0011] Preferably, the total width of the main line and the coupling line is 25µm, the width of the coupling line is 10µm, the width of the input port is 10µm, the width of the antenna port is 32.8µm, the extension length of the input port and the extension length of the isolation port are both 15.5µm, and the distance between the coupling port and the input port is 5µm.

[0012] Secondly, this utility model provides a radio frequency chip, which includes the bidirectional coupler described above.

[0013] Compared with existing technologies, the bidirectional coupler in this invention reduces signal transmission losses by optimizing the structure of the main line. The coupling line, through adjustable capacitors and its coupling design with the main line, maximizes its coupling efficiency. The impedance transformation section formed by adjustable resistors and capacitors between the main line and the coupling line ensures that the impedance observed from the coupling line is consistent with the impedance observed from the coupling port side, thereby improving the coupling efficiency of the bidirectional coupler and reducing transmission losses. Furthermore, considering the size limitations of the main line, coupling line, input port, and antenna port, the bidirectional coupler eliminates the need for resonant matching to suppress specific frequency points to achieve high isolation at a specific frequency, directly ensuring high isolation at the antenna port. The high isolation between the bidirectional coupler and the coupling port allows for applications in a higher frequency range and reduces the degradation of receiver sensitivity caused by antenna winding noise and high-order harmonics. Furthermore, due to these limitations, the bidirectional coupler requires minimal tuning and matching, and has no resonant pits within its frequency band. Therefore, its performance is not overly dependent on impedance control. Thanks to its high flatness across the entire frequency band, it maintains stable performance even with impedance mismatch caused by temperature changes, preventing signal transmission instability. In addition, the bidirectional coupler only requires adjustable resistors and capacitors at the isolation port; no matching is needed at other ports, especially inductors. This significantly reduces the size and cost of the bidirectional coupler, making it suitable for miniaturized electronic devices. Attached Figure Description

[0014] 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:

[0015] Figure 1 This is a schematic diagram of the structure of a bidirectional coupler provided in an embodiment of the present invention;

[0016] Figure 2 Performance indicators of isolation, coupling, and directivity of the bidirectional coupler provided in this embodiment of the utility model;

[0017] Figure 3 A power fluctuation diagram of a bidirectional coupler provided in an embodiment of this utility model.

[0018] Among them, 100 is a bidirectional coupler; 1 is the main line; 2 is the coupling line; 3 is the input port; 4 is the antenna port; 5 is the coupling port; 6 is the isolation port; 7 is the adjustable resistor; and 8 is the adjustable capacitor. Detailed Implementation

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and foregoing drawings of this application, are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or foregoing drawings of this application are used to distinguish different objects, not to describe a particular order.

[0020] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0021] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0022] Example 1

[0023] This utility model embodiment provides a bidirectional coupler 100, such as Figure 1 As shown, it includes a main line 1, a coupling line 2 located on one side of the main line 1 and coupled to the main line 1, an input port 3 formed by bending and extending from one end of the main line 1 away from the coupling line 2, an antenna port 4 formed by bending and extending from the other end of the main line 1 away from the coupling line 2, a coupling port 5 and an isolation port 6 formed at both ends of the coupling line 2, an adjustable resistor 7 with its first end connected to the isolation port 6, and an adjustable capacitor 8 with its first end connected to the isolation port 6. The coupling port 5 is close to the input port 3 and spaced apart from the input port 3, and the isolation port 6 is close to the antenna port 4 and spaced apart from the antenna port 4. The second end of the adjustable resistor 7 is grounded, and the second end of the adjustable capacitor 8 is connected to the second end of the adjustable resistor 7.

[0024] In this embodiment, the bidirectional coupler 100 is a CPL bidirectional coupler.

[0025] The lengths of the main line 1 and the coupling line 2 are both 100-240µm; the length of the main line 1 is the straight-line length from the input port 3 to the antenna port 4, and the length of the coupling line 2 does not include the bump pad.

[0026] Preferably, the length of the main line 1 and the length of the coupling line 2 are both 197 μm.

[0027] The total width of the main line 1 and the coupling line 2 is S1 = 10-25 μm, the width of the coupling line 2 is S2 = 3-10 μm, the width of the input port 3 is S3 = 8-25 μm, the width of the antenna port 4 is S4 = 8-35 μm, the extension length of the input port 3 and the extension length of the isolation port 6 are both S5 = 3-20 μm, and the distance between the coupling port 5 and the input port 3 is S6 = 3-8 μm.

[0028] Preferably, the total width of the main line 1 and the coupling line 2 is 25 μm, the width of the coupling line 2 is 10 μm, the width of the input port 3 is 10 μm, the width of the antenna port 4 is 32.8 μm, the extension length of the input port 3 and the extension length of the isolation port 6 are both 15.5 μm, and the distance between the coupling port 5 and the input port 3 is 5 μm.

[0029] The adjustable resistor 7 has a resistance range of 30-50Ω; the adjustable capacitor has a capacitance range of 0.2-0.6pF. Since the bidirectional coupler 100 is used to implement its function on a substrate or other carrier, different trace designs on the carrier result in different internal design configurations for the bidirectional coupler 100. Therefore, in this embodiment, the internal adjustable resistor 7 and adjustable capacitor 8 of the bidirectional coupler 100 have a controllable range.

[0030] In the bidirectional coupler 100 of this embodiment, the main line 1 is used to transmit the main radio frequency signal. Its structure is optimized to reduce signal loss during transmission. The coupling line 2, through the adjustable capacitor 8 and coupling with the main line 1, can achieve signal coupling output. The design of the coupling line 2 can ensure that its coupling efficiency with the main line 1 is maximized. The connection between the main line 1 and the coupling line 2 through the impedance transformation section formed by the adjustable resistor 7 and the adjustable capacitor 8 can ensure that the impedance observed from the coupling line 2 is consistent with the impedance observed from the coupling port 5 side, thereby improving the coupling efficiency of the bidirectional coupler 100 and reducing transmission loss. The input port 3 is used to provide output power to the output port of the connected power amplifier. The antenna port 4 is used to connect the antenna to transmit or receive wireless signals. The coupling port 5 is used to monitor the operating status of the bidirectional coupler 100, such as signal strength, VSWR, etc. The isolation port 6 is used to provide an additional isolation path to reduce signal interference between the antenna port 4 and the coupling port 5.

[0031] In this embodiment, the bidirectional coupler 100 only needs to be configured with an adjustable resistor 7 and grounded at the isolation port 6 to achieve high isolation.

[0032] In this embodiment, the performance indicators of isolation, coupling, and directivity of the bidirectional coupler 100 are as follows: Figure 2 As shown; in this embodiment, the power fluctuation of the bidirectional coupler 100 is as follows: Figure 3 As shown, the power fluctuation is extremely low, with a maximum of ±0.49.

[0033] The bidirectional coupler 100 in this embodiment employs advanced microfabrication techniques, such as photolithography, to fabricate the various parts of the bidirectional coupler 100, thereby ensuring the accuracy and consistency of the design.

[0034] Compared with existing technologies, the bidirectional coupler 100 in this embodiment reduces signal transmission losses by optimizing the structure of the main line 1. The coupling line 2, through the adjustable capacitor 8 and its coupling design with the main line 1, ensures maximum coupling efficiency with the main line 1. The impedance transformation section formed by the adjustable resistor 7 and the adjustable capacitor 8 between the main line 1 and the coupling line 2 ensures that the impedance observed from the coupling line 2 is consistent with the impedance observed from the coupling port 5 side, thereby improving the coupling efficiency of the bidirectional coupler 100 and reducing transmission losses. Considering the size limitations of the main line 1, coupling line 2, input port 3, and antenna port 4, the bidirectional coupler 100 does not require additional resonant matching to suppress specific frequency points to achieve high isolation at a specific frequency, directly ensuring high isolation at that frequency. The isolation between line port 4 and coupling port 5 enables the bidirectional coupler 100 to be used in a higher frequency range and reduces the degradation of receiver sensitivity caused by antenna winding noise and high-order harmonics. At the same time, due to the above limitations, the bidirectional coupler 100 does not require much tuning matching. It has no resonant pits in its frequency band, so its performance is not overly dependent on impedance control. With its high flatness across the entire frequency band, it can maintain stable performance even if impedance mismatch caused by temperature changes, without causing signal transmission instability. In addition, the bidirectional coupler 100 only requires the addition of an adjustable resistor 7 and an adjustable capacitor 8 at the isolation port 6. No matching is required at other ports, especially the inductor, which greatly reduces the size and cost of the bidirectional coupler 100, making it able to meet the needs of miniaturized electronic devices.

[0035] Example 2

[0036] This embodiment provides a radio frequency (RF) chip, which includes the bidirectional coupler 100 described in Embodiment 1 above. Since the RF chip in this embodiment includes the bidirectional coupler 100 described in Embodiment 1, it can achieve the same technical effects as the bidirectional coupler 100 described in Embodiment 1, and will not be elaborated further here.

[0037] It should be noted that the various embodiments described above with reference to the accompanying drawings are only illustrative of the present invention and not intended to limit its scope. Those skilled in the art should understand that any modifications or equivalent substitutions made to the present invention without departing from its spirit and scope should be covered within the scope of the present invention. Furthermore, unless the context otherwise requires, singular terms include plural forms, and vice versa. Additionally, unless specifically stated otherwise, all or part of any embodiment may be used in conjunction with all or part of any other embodiment.

Claims

1. A bidirectional coupler, characterized in that, The bidirectional coupler includes a main line, a coupling line located on one side of the main line and coupled to the main line, an input port formed by bending and extending from one end of the main line away from the coupling line, an antenna port formed by bending and extending from the other end of the main line away from the coupling line, a coupling port and an isolation port formed at both ends of the coupling line, an adjustable resistor with its first end connected to the isolation port, and an adjustable capacitor with its first end connected to the isolation port. The coupling port is close to the input port and spaced apart from the input port, the isolation port is close to the antenna port and spaced apart from the antenna port, the second end of the adjustable resistor is grounded, and the second end of the adjustable capacitor is connected to the second end of the adjustable resistor. The length of the main line and the length of the coupling line are both 100-240um. The total width of the main line and the coupling line is 10-25um. The width of the coupling line is 3-10um. The width of the input port is 8-25um. The width of the antenna port is 8-35um. The extension length of the input port and the extension length of the isolation port are both 3-20um. The distance between the coupling port and the input port is 3-8um.

2. The bidirectional coupler as described in claim 1, characterized in that, The adjustable resistor has a resistance range of 30-50Ω; the adjustable capacitor has a capacitance range of 0.2-0.6pF.

3. The bidirectional coupler as described in claim 2, characterized in that, The length of both the main line and the coupling line is 197µm.

4. The bidirectional coupler as described in claim 3, characterized in that, The total width of the main line and the coupling line is 25µm, the width of the coupling line is 10µm, the width of the input port is 10µm, the width of the antenna port is 32.8µm, the extension length of the input port and the extension length of the isolation port are both 15.5µm, and the distance between the coupling port and the input port is 5µm.

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

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