Reconfigurable coupler and radio frequency integrated circuit equipment

Abstract

The invention discloses a reconfigurable coupler and radio frequency integrated circuit equipment, and belongs to the technical field of millimeter wave radio frequency integrated circuits. The reconfigurable coupler comprises a first input port, a second input port, a first output port, a second output port and a coupling circuit connecting the ports. The coupling circuit is configured to switch between at least two operating modes: a pass-through mode in which an output signal is in phase with a corresponding input signal; and an orthogonal mode in which the output signals of the two output ports have a relative phase difference of 90 degrees. The reconfigurable coupler adopting the topological structure provided by the invention can flexibly switch 0-degree and 90-degree phase modes in a single module, improves the system integration level and the mode flexibility, is compact in structure, and is suitable for various millimeter wave application scenes needing in-phase / orthogonal signal switching.

Description

Technical Field

[0001] The present disclosure relates to the technical field of millimeter-wave radio frequency integrated circuits, and in particular to a reconfigurable coupler and a radio frequency integrated circuit device. Background Art

[0002] In modern RF circuits and systems, quadrature signal generation is the foundation of many important applications. These include quadrature clock generation, quadrature baseband synthesis in image rejection receivers, input 90° phase compensation in Doherty power amplifiers, input-output coupling in balanced power amplifiers, and quadrature signal generation in vector summing phase shifters.

[0003] In system-level applications, dual-polarization antenna systems rely particularly on flexible control of signal phase. These systems can generate dual-polarization signals in direct-through mode to achieve channel reuse, while also utilizing H-polarization and V-polarization (horizontal / vertical polarization) signals to synthesize circularly polarized signals when their phases differ by 90°. Therefore, integrated circuit modules that can flexibly switch between 0° and 90° phase states are crucial for increasing system flexibility and reducing costs.

[0004] Traditional methods for implementing orthogonal signals mainly include: discrete 90° hybrids, Branch-line couplers, Lange couplers, and rectangular couplers. However, these traditional coupler structures can usually only provide a fixed 90° phase difference and cannot flexibly switch to the in-phase (0°) signal transmission mode. In application scenarios that need to support both orthogonal and in-phase transmission, traditional practices often require the use of two independent circuit paths, one for orthogonal signal transmission and the other for in-phase signal transmission. Path selection is then achieved through additional switching circuits, which not only increases system complexity but also significantly increases chip area and cost.

[0005] The rapid development of millimeter-wave communication systems is placing higher demands on RF front-end circuits with greater integration and flexibility. In multi-mode, multi-band millimeter-wave systems, achieving multi-function multiplexing within a limited chip area is particularly crucial. Currently, the industry lacks an integrated circuit solution that can flexibly switch between 0° and 90° phase states within a single structure.

[0006] On the other hand, existing tunable couplers primarily focus on adjusting the coupling ratio or operating frequency, with few designs capable of fundamentally switching operating modes. For example, some designs employ voltage-controlled capacitors or switched capacitors to achieve continuous adjustment of the coupling ratio, but these still maintain the fundamental quadrature coupling mode and are unable to switch to pass-through mode. Other designs achieve frequency reconfiguration by adjusting circuit parameters, but these similarly cannot alter the fundamental characteristics of the phase relationship.

[0007] Furthermore, at millimeter-wave frequencies, due to the short wavelengths and significant parasitic effects, traditional distributed coupler structures (such as microstrip line couplers) face the problem of being too large when implemented on integrated circuits. While lumped-element equivalent circuits can effectively reduce the area, increasing pattern reconstruction capabilities while maintaining good RF performance remains a pressing challenge.

[0008] Therefore, this field urgently needs a solution that can achieve flexible switching between 0° and 90° phase states in a single structure, which can not only meet the functional requirements of multi-mode operation, but also efficiently utilize chip area, reducing system complexity and cost while ensuring RF performance. Summary of the Invention

[0009] The disclosed embodiments provide a reconfigurable coupler capable of flexibly switching between 0° and 90° phase states in a single structure. The disclosed embodiments also provide a radio frequency integrated circuit device using the reconfigurable coupler.

[0010] According to one embodiment of the present disclosure, a reconfigurable coupler is proposed, comprising:

[0011] a first input port, a second input port, a first output port, and a second output port;

[0012] a coupling circuit connecting the first input port, the second input port, the first output port, and the second output port;

[0013] The coupling circuit is configured to switch between at least two operating modes, the operating modes comprising a through mode and a quadrature mode, wherein:

[0014] In the pass-through mode, the output signal of the first output port is in phase with the input signal of the first input port, and the output signal of the second output port is in phase with the input signal of the second input port;

[0015] In the quadrature mode, when an input signal is applied to the first input port or the second input port, it is transmitted to the first output port and the second output port respectively, and the output signals of the first output port and the second output port have a relative phase difference of 90 degrees.

[0016] In some embodiments, the coupling circuit is implemented based on an LC equivalent structure of a 3dB coupler, including:

[0017] a first inductor, disposed between the first input port and the first output port;

[0018] a second inductor, disposed between the second input port and the second output port;

[0019] A first adjustable capacitor is connected between the first input port and the second output port;

[0020] a second adjustable capacitor connected between the second input port and the first output port;

[0021] The switching between the through mode and the orthogonal mode is achieved by controlling the capacitance values of the first adjustable capacitor and the second adjustable capacitor.

[0022] In some embodiments, the first adjustable capacitor and the second adjustable capacitor each include an N-bit capacitance switch array, where N is an integer greater than or equal to 1.

[0023] In some embodiments, when the capacitance values of the first adjustable capacitor and the second adjustable capacitor are both set to their minimum capacitance states, the coupling circuit operates in a pass-through mode;

[0024] When the capacitance values of the first adjustable capacitor and the second adjustable capacitor are both set to a non-minimum predetermined capacitance value state, the coupling circuit operates in an orthogonal mode.

[0025] In some embodiments, the first inductor and the second inductor are arranged in a figure-8 configuration to reduce mutual inductance between the first inductor and the second inductor.

[0026] In some embodiments, the coupling circuit includes:

[0027] A coupled transmission line structure comprising a first transmission line and a second transmission line coupled to each other;

[0028] a first set of switches comprising at least one first switch configured to selectively connect the first input port to the first transmission line, and at least one second switch configured to selectively connect the second input port to the second transmission line;

[0029] a second set of switches comprising at least one third switch configured to selectively establish a transmission path between the first input port and the first output port that bypasses the coupled transmission line structure, and at least one fourth switch configured to selectively establish a transmission path between the second input port and the second output port that bypasses the coupled transmission line structure;

[0030] The switching between the through mode and the orthogonal mode is achieved by controlling the switch states of the first group of switches and the second group of switches.

[0031] In some embodiments, when the at least one first switch and the at least one second switch in the first group of switches are both set to an open state, and the at least one third switch and the at least one fourth switch in the second group of switches are both set to a closed state, the coupling circuit operates in a pass-through mode;

[0032] When the at least one first switch and the at least one second switch in the first group of switches are both set to a closed state, and the at least one third switch and the at least one fourth switch in the second group of switches are both set to an open state, the coupling circuit operates in an orthogonal mode.

[0033] In some embodiments, the coupling circuit further comprises:

[0034] at least one first bypass capacitor connected in parallel to the at least one third switch in the second group of switches;

[0035] At least one second bypass capacitor is connected in parallel to the at least one fourth switch in the second group of switches.

[0036] In some embodiments, the coupling circuit further comprises:

[0037] At least one coupling capacitor is connected between the first transmission line and the second transmission line.

[0038] According to another embodiment of the present disclosure, a radio frequency integrated circuit device is provided. The device includes the reconfigurable coupler as described above.

[0039] This disclosure proposes a reconfigurable coupler and a radio frequency integrated circuit device including the reconfigurable coupler, which can effectively achieve flexible switching between two operating modes: straight-through (0°) and orthogonal (90°) within a single integrated circuit module. Compared to traditional solutions that use fixed-phase modules in conjunction with switching networks or require multiple independent modules, the present disclosure significantly improves the system's integration and mode switching flexibility through structural reuse. At the same time, the structure is compact, and the area occupied is generally comparable to that of a single traditional coupler. This greatly improves the resource utilization of the on-chip system, simplifies system design, and helps reduce overall cost and signal path loss. It is particularly suitable for millimeter-wave applications that require high integration and functional flexibility.

[0040] This disclosure proposes two different implementation topologies, each with its own focus on optimizing performance. The solution based on the improved LC equivalent structure, by introducing an adjustable capacitor array, can compensate for the instantaneous bandwidth limitation in the orthogonal mode and better meet the phase accuracy requirements of broadband applications; at the same time, the use of an 8-shaped inductor layout is intended to reduce the mutual coupling between inductors, thereby improving the amplitude balance of the output signal in the orthogonal mode. The solution based on coupled transmission lines and switch groups uses switches to directly reconstruct the signal path, clearly realizing the switching between the two working modes. Practical results show that this solution has the potential to achieve wider working bandwidth, more compact chip area and more flexible layout.

[0041] Additional details and advantages of the present disclosure are described below. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the specification and, together with the description, serve to explain the principles of the specification.

[0043] FIG1( a ) shows a schematic diagram of the LC equivalent circuit structure of a conventional 3 dB coupler;

[0044] FIG1( b ) shows a schematic circuit diagram of a reconfigurable coupler according to an exemplary embodiment of the present disclosure;

[0045] FIG1( c ) shows a schematic diagram of a layout implementation based on the circuit principle of FIG1( b );

[0046] FIG2( a ) shows a schematic circuit diagram of another reconfigurable coupler according to an exemplary embodiment of the present disclosure;

[0047] FIG2( b ) shows a schematic diagram of a layout implementation based on the circuit principle of FIG2( a ). DETAILED DESCRIPTION

[0048] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numerals in different figures represent identical or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all possible embodiments consistent with the present disclosure. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present disclosure, as detailed in the appended claims.

[0049] The present disclosure proposes a reconfigurable coupler, comprising:

[0050] a first input port, a second input port, a first output port, and a second output port;

[0051] a coupling circuit connecting the first input port, the second input port, the first output port, and the second output port;

[0052] The coupling circuit is configured to switch between at least two operating modes, the operating modes comprising a through mode and a quadrature mode, wherein:

[0053] In the pass-through mode, the output signal of the first output port is in phase with the input signal of the first input port, and the output signal of the second output port is in phase with the input signal of the second input port;

[0054] In the quadrature mode, when an input signal is applied to the first input port or the second input port, it is transmitted to the first output port and the second output port respectively, and the output signals of the first output port and the second output port have a relative phase difference of 90 degrees.

[0055] According to an exemplary embodiment of the present disclosure, a reconfigurable coupler based on a lumped element LC equivalent structure is proposed. The design idea is to improve the traditional 3dB coupler LC equivalent circuit model shown in Figure 1(a). The model in Figure 1(a) includes a first input port ①, a second input port ②, a first output port ③, and a second output port ④, which is mainly composed of a first inductor L up (Connect ①-③), second inductor L down (Connect ②-④), and two fixed cross-coupling capacitors C M (Connect ①-④ and ②-③). The traditional structure has mutual inductance M and a fixed working mode.

[0056] Figures 1(b) and 1(c) illustrate the structure and implementation of a reconfigurable coupler according to an exemplary embodiment of the present disclosure. As shown in the circuit schematic diagram of Figure 1(b), the reconfigurable coupler also includes ports ①, ②, ③, ④ and a main path inductor L up(i.e. the first inductor, mainly connecting nodes ① and ③) and L down (i.e. the second inductor, mainly connecting nodes ② and ④). According to the design of the present disclosure, the fixed capacitor in Figure 1(a) is replaced with an adjustable capacitor. Specifically, the capacitors between connecting nodes ① and ④, and between connecting nodes ② and ③ are both set as adjustable capacitors C M In this example, these adjustable capacitors are preferably implemented by an N-bit switched capacitor array (N≥1), and their capacitance values can be precisely adjusted by external control.

[0057] By controlling the two adjustable capacitors C M The capacitance value can flexibly select the working mode of the coupler:

[0058] Through mode (common phase mode): When two adjustable capacitors C M When both are set to their minimum achievable capacitance, the coupling between nodes ①-④ and ②-③ is the weakest. up (①→③) and L down The (②→④) path transmission makes the output of port ③ in phase with the input of port ①, and the output of port 4 in phase with the input of port ②.

[0059] Quadrature mode: When two adjustable capacitors C M When both capacitors are set to predetermined, non-minimum values, the circuit behaves as a quadrature coupler. A signal applied to one input port produces signals of approximately equal amplitude and 90 degrees out of phase at both output ports. Adjustable capacitance also allows for performance tuning in quadrature mode, such as optimizing phase accuracy or bandwidth.

[0060] Referring to Figure 1(c), this example also calculates the inductance L up and L down In the traditional LC coupler, L up and L down The mutual inductance M between them may cause the amplitude imbalance of the output signal in the orthogonal mode. To overcome this problem, this example preferably adopts an optimized layout for the two inductors to reduce or eliminate the mutual inductance M. In a preferred layout implementation scheme as shown in Figure 1(c), the first inductor L up and the second inductor L down Both use an 8-shaped (Figure-8) layout structure. This special geometric shape can effectively offset the magnetic field coupling between the two inductors, thereby significantly improving the amplitude balance in the orthogonal mode. Figure 1 (c) also schematically shows this 8-shaped inductor and the adjustable capacitor C M And the relative layout relationship of ports ① to ④.

[0061] The above exemplary embodiment adopts an adjustable cross-coupling capacitor C M(such as N-bit switch capacitor array) to achieve flexible switching of working modes, and further by preferably adopting the low mutual inductance main path inductor L of the 8-shaped layout up and L down To improve the performance, a reconfigurable coupler that can flexibly switch between the through mode and the orthogonal mode is obtained, and the performance is significantly improved.

[0062] Another exemplary embodiment of the present disclosure proposes a reconfigurable coupler based on a coupled transmission line and a switch group, the structure and working principle of which can be seen in FIG. 2( a ) and FIG. 2( b ).

[0063] As shown in Figure 2(a), the reconfigurable coupler mainly comprises a coupled transmission line structure having a first transmission line and a second transmission line coupled to each other, and also comprises two groups of switches: a first group of switches and a second group of switches.

[0064] The first switch group includes at least one first switch S1 and at least one second switch S2. The first switch S1 is configured to selectively connect the first input port ① to the first transmission line. The second switch S2 is configured to selectively connect the second input port ② to the second transmission line.

[0065] The second switch group includes at least one third switch S3 and at least one fourth switch S4. The third switch S3 is configured to selectively establish a transmission path between the first input port ① and the first output port ③ that bypasses the coupled transmission line structure. The fourth switch S4 is configured to selectively establish a transmission path between the second input port ② and the second output port ④ that bypasses the coupled transmission line structure.

[0066] The reconfigurable coupler switches between two operating modes by controlling the states of the first set of switches (S1, S2) and the second set of switches (S3, S4):

[0067] Through mode (in-phase mode): In this mode, the first set of switches (S1, S2) is set to the open state, severing the connection between the input port and the coupled transmission line structure. Simultaneously, the second set of switches (S3, S4) is set to the closed state, establishing a bypass transmission path. Specifically, at least one third switch S3 is closed, connecting the first input port ① to the first output port ③, forming a bypass path; at least one fourth switch S4 is closed, connecting the second input port ② to the second output port ④, forming another bypass path. On these two paths, the signals primarily experience similar transmission delays, resulting in the output signals (ports ③, ④) being in phase with the corresponding input signals (ports ①, ②).

[0068] Quadrature Mode: In this mode, the first set of switches (S1, S2) is closed, connecting input ports ① and ② to the coupled transmission line structure, respectively. Simultaneously, the second set of switches (S3, S4) is open, eliminating the bypass path. Signals are transmitted and coupled via the coupled transmission line structure, operating as a quadrature coupler. The input signal applied to the first input port ① passes through the coupled transmission line structure, generating two output signals (i.e., quadrature signals) with identical amplitudes and 90-degree phase shifts at the first and second output ports ③ and ④, respectively.

[0069] Figure 2(b) shows a possible layout implementation diagram for the topology shown in Figure 2(a). The layout intuitively shows the coupled transmission lines (central area) and switches S1, S2, S3, and S4 used for mode switching. In addition, the layout also shows other components that may exist in an actual implementation: for example, a fixed bypass capacitor C2 in parallel with switches S3 and S4, and a fixed coupling capacitor C1 connected between the first and second transmission lines. It should be noted that although the schematic diagram of Figure 2(a) does not include these fixed capacitors, the layout of Figure 2(b) shows that they may exist as part of the actual chip implementation, possibly to improve the isolation of the switches (C2) or to enhance the coupling between the transmission lines (C1).

[0070] The present disclosure also proposes a radio frequency integrated circuit device using the above-mentioned reconfigurable coupler. Specific details and advantages thereof are described above.

[0071] The above exemplary embodiments based on coupled transmission lines and switch groups achieve mode switching through clear switching logic and can generally provide a wider operating bandwidth than solutions based on LC equivalent structures, while also having advantages in area and layout flexibility.

[0072] Although this specification includes many specific implementation details, these should not be interpreted as limiting the scope of any invention or the scope of protection claimed, but are mainly used to describe the features of specific embodiments of specific inventions. Certain features described in multiple embodiments within this specification may also be implemented in combination in a single embodiment. On the other hand, the various features described in a single embodiment may also be implemented separately in multiple embodiments or in any suitable sub-combination. In addition, although features may work in certain combinations as described above and even initially claimed as such, one or more features from the claimed combination may be removed from the combination in some cases, and the claimed combination may point to a sub-combination or a variation of the sub-combination.

[0073] The above description is merely a preferred embodiment of one or more embodiments of this specification and is not intended to limit one or more embodiments of this specification. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of one or more embodiments of this specification shall be included in the scope of protection of one or more embodiments of this specification.

Claims

1. A reconfigurable coupler, characterized in that: include: a first input port, a second input port, a first output port, and a second output port; a coupling circuit connecting the first input port, the second input port, the first output port, and the second output port; The coupling circuit is configured to switch between at least two operating modes, the operating modes comprising a through mode and a quadrature mode, wherein: In the pass-through mode, the output signal of the first output port is in phase with the input signal of the first input port, and the output signal of the second output port is in phase with the input signal of the second input port; In the quadrature mode, when an input signal is applied to the first input port or the second input port, it is transmitted to the first output port and the second output port respectively, and the output signals of the first output port and the second output port have a relative phase difference of 90 degrees.

2. The reconfigurable coupler according to claim 1, wherein: The coupling circuit is implemented based on the LC equivalent structure of a 3dB coupler, and includes: a first inductor, disposed between the first input port and the first output port; a second inductor, disposed between the second input port and the second output port; A first adjustable capacitor is connected between the first input port and the second output port; a second adjustable capacitor connected between the second input port and the first output port; The switching between the through mode and the orthogonal mode is achieved by controlling the capacitance values of the first adjustable capacitor and the second adjustable capacitor.

3. The reconfigurable coupler according to claim 2, wherein: The first adjustable capacitor and the second adjustable capacitor each include an N-bit capacitance switch array, where N is an integer greater than or equal to 1.

4. The reconfigurable coupler according to claim 2, wherein: When the capacitance values of the first adjustable capacitor and the second adjustable capacitor are both set to their minimum capacitance values, the coupling circuit operates in a pass-through mode; When the capacitance values of the first adjustable capacitor and the second adjustable capacitor are both set to a non-minimum predetermined capacitance value state, the coupling circuit operates in an orthogonal mode.

5. The reconfigurable coupler according to claim 2, wherein: The first inductor and the second inductor adopt an 8-shaped layout structure to reduce the mutual inductance between the first inductor and the second inductor.

6. The reconfigurable coupler according to claim 1, wherein: The coupling circuit comprises: A coupled transmission line structure comprising a first transmission line and a second transmission line coupled to each other; a first set of switches comprising at least one first switch configured to selectively connect the first input port to the first transmission line, and at least one second switch configured to selectively connect the second input port to the second transmission line; a second set of switches comprising at least one third switch configured to selectively establish a transmission path between the first input port and the first output port that bypasses the coupled transmission line structure, and at least one fourth switch configured to selectively establish a transmission path between the second input port and the second output port that bypasses the coupled transmission line structure; The switching between the through mode and the orthogonal mode is achieved by controlling the switch states of the first group of switches and the second group of switches.

7. The reconfigurable coupler according to claim 6, wherein: When the at least one first switch and the at least one second switch in the first group of switches are both set to an open state, and the at least one third switch and the at least one fourth switch in the second group of switches are both set to a closed state, the coupling circuit operates in a pass-through mode; When the at least one first switch and the at least one second switch in the first group of switches are both set to a closed state, and the at least one third switch and the at least one fourth switch in the second group of switches are both set to an open state, the coupling circuit operates in an orthogonal mode.

8. The reconfigurable coupler according to claim 6, wherein: The coupling circuit further includes: at least one first bypass capacitor connected in parallel to the at least one third switch in the second group of switches; At least one second bypass capacitor is connected in parallel to the at least one fourth switch in the second group of switches.

9. The reconfigurable coupler according to claim 6, wherein: The coupling circuit further includes: At least one coupling capacitor is connected between the first transmission line and the second transmission line.

10. A radio frequency integrated circuit device, characterized in that: The device includes a reconfigurable coupler as described in any one of Claims 1 to 9.

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