Secondary quadrature coupler based on transformer

Abstract

The invention discloses a secondary orthogonal coupler based on a transformer, and belongs to the field of microwave radio frequency, the secondary orthogonal coupler comprises a primary orthogonal coupler and a secondary orthogonal coupler, the primary orthogonal coupler is composed of a single coupling piece, and the secondary orthogonal coupler is composed of two primary orthogonal couplers; a differential output port THRU + and a differential output port THRU-of the primary quadrature coupler are respectively connected with a signal input end IN + and a signal input end IN-of one coupling piece in the secondary quadrature coupler; and a differential output port CPL + / -of the first-stage orthogonal coupler is connected with a signal input end IN + / -of the other coupling piece in the second-stage orthogonal coupler. According to the invention, the two-stage quadrature coupler design is adopted, a compact layout structure is realized, high-precision differential quadrature signals can be generated at the same time, the bandwidth of the quadrature signals is greatly improved, and it is ensured that the amplitude difference of the quadrature signals is small in the broadband; and redundant transmission line connection is eliminated, so that the design difficulty is greatly reduced.

Description

Technical Field

[0001] The invention relates to the field of microwave radio frequency, in particular to a two-stage orthogonal coupler based on a transformer. Background Art

[0002] The field of integrated circuit chips is the core of modern information technology, among which radio frequency integrated circuits are the key technologies for the new generation of mobile communications, precision radars, aerospace and other application systems. For a long time, radio frequency millimeter wave technology has played a vital role in my country's national defense and civil construction, especially in the field of phased array radars. It has significant application advantages in long-range early warning radars, high-altitude protection radars, weather radar detection, and automobile collision avoidance. Phase shifters are core devices that control and change the phase of electromagnetic waves. They are key modules that affect the performance of phased arrays and are an important part of phased array systems. Among them, broadband phase shifters play a more prominent role in phased array radars, millimeter wave communication systems, etc. Among them, the Cartesian vector synthesis phase shifter scheme is the most widely used phase shifting scheme, which obtains a phase response with relative accuracy by modulating orthogonal signals of varying amplitudes.

[0003] For the Cartesian phase shifter, the four groups of orthogonal signals generated by the orthogonal signal generator determine its shifting accuracy. The principle is to divide the input signal into two pairs of mutually orthogonal differential signals, and then optimize and adjust the phase and amplitude of these two signals according to the shifting angle required by the phase shifter, and then synthesize the signals to obtain the required phase output signal. The orthogonal coupler plays an important role in the phased array phase shifter and directly affects the phase shifting accuracy. The traditional single-stage orthogonal coupler, whose THRU path is a high-pass network and CPL is a low-pass network, is bound to cause the orthogonal signal to pass through and the coupling end to present high and low pass results, resulting in too large an amplitude difference between the high and low pass of the orthogonal signal when the bandwidth is too large, which is not conducive to accurate phase shifting and amplitude control.

[0004] Due to its own architectural problems, the traditional transformer-based differential orthogonal coupler has its input port IN± and coupled output port CPL± on the same side, while the through output THRU± and the isolation port ISO± are on the other side. When using the traditional orthogonal coupler as a two-level architecture, a large number of transmission lines are required to connect the various ports, which consumes a large amount of chip area and introduces a large amount of transmission line loss, affecting the accuracy of the orthogonal coupler. Therefore, designing a broadband, miniaturized, and high-precision orthogonal coupler has important practical value. Summary of the invention

[0005] With regard to the above problems existing in the prior art, the object of the present invention is to provide a two-stage orthogonal coupler based on a transformer to solve the above problems raised in the background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions: A transformer-based two-stage orthogonal coupler includes a primary coupler and a secondary coupler, wherein the primary coupler includes a coupling element and the secondary coupler includes two coupling elements; The differential signal output terminal THRU+ of the primary coupler is connected to the signal input terminal IN+ of a coupling element in the secondary coupler, and the differential signal output terminal THRU- of the primary coupler is connected to the signal input terminal IN- of the same coupling element in the secondary coupler; The differential signal output terminal CPL+ of the primary coupler is connected to the signal input terminal IN+ of another coupling element in the secondary coupler, and the differential signal output terminal CPL- of the primary coupler is connected to the signal input terminal IN- of the same coupling element in the secondary coupler; The signal input terminal IN± of the primary coupler is the input terminal of the secondary orthogonal coupler, the differential signal output terminal THRU+, the differential signal output terminal THRU-, the differential signal output terminal CPL+, and the differential signal output terminal CPL- of the two coupling elements in the secondary coupler are respectively connected to each other, and the differential signal output terminal THRU± and the differential signal output terminal CPL± of the secondary coupler that are connected to each other are the output terminals of the secondary orthogonal coupler.

[0007] As a further solution of the present invention: the coupling component is provided with a main inductor L1, a main inductor L4, a secondary inductor L2, a secondary inductor L3, a coupling capacitor C1, a coupling capacitor C2, a coupling capacitor C3, a coupling capacitor C4 and an isolation resistor R1; One end of the main inductor L1 is connected to the signal input terminal IN+ of the coupling element, and the other end of the main inductor L1 is connected to the differential signal output terminal THRU+ of the coupling element; One end of the coupling capacitor C1 is connected to the signal input terminal IN+ of the coupling element, and the other end of the coupling capacitor C1 is simultaneously connected to one end of the secondary inductor L2 and the differential signal output terminal CPL+ of the coupling element, and the other end of the secondary inductor L2 is simultaneously connected to one end of the coupling capacitor C3 and one end of the isolation resistor R1, and the other end of the coupling capacitor C3 is connected to the differential signal output terminal THRU+ of the coupling element.

[0008] As a further solution of the present invention: one end of the main inductor L4 is connected to the signal input terminal IN- of the coupling element, and the other end of the main inductor L4 is connected to the differential signal output terminal THRU- of the coupling element; One end of the coupling capacitor C2 is connected to the signal input terminal IN- of the coupling element, and the other end of the coupling capacitor C2 is simultaneously connected to one end of the secondary inductor L3 and the differential signal output terminal CPL- of the coupling element, and the other end of the secondary inductor L3 is simultaneously connected to one end of the coupling capacitor C4 and the other end of the isolation resistor R1, and the other end of the coupling capacitor C4 is connected to the differential signal output terminal THRU- of the coupling element.

[0009] As a further solution of the present invention: the main inductor L1, the auxiliary inductor L2, the main inductor L4 and the auxiliary inductor L3 are arranged in upper and lower mirror symmetry.

[0010] As a further solution of the present invention: the two coupling members in the secondary coupler are symmetrically arranged up and down.

[0011] As a further solution of the present invention: the main inductor L1 and the main inductor L4 of the coupling component are inductors of the same model; the signal input terminal IN± of the coupling component is on the left side of the circuit, and the differential signal output terminal THRU±, the differential signal output terminal CPL± and the isolation terminal ISO± port of the coupling component are on the right side of the circuit.

[0012] As a further solution of the present invention: a main inductor, a secondary inductor and a connecting line in the coupling component constitute a coupled inductor, and the coupling component includes a coupled inductor graphic layer, a coupled capacitor graphic layer, a jumper connecting line, an isolation resistor graphic layer and an outer ring metal dummy.

[0013] As a further solution of the present invention: the coupled inductor graphic layer, the coupled capacitor graphic layer, and the isolation resistor graphic layer are all formed based on TSMC N65 process.

[0014] As a further solution of the present invention: the inward-rotating port of the coupled inductor graphic layer leads out an input side connecting line and an output side extending line through a jumper connecting line, the input side connecting line of the inward-rotating port of the coupled inductor graphic layer is connected to the coupling capacitor, and the output side extending line of the inward-rotating port of the coupled inductor graphic layer is connected to the differential signal output terminal CPL.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The present invention adopts a two-stage orthogonal coupler design, and the orthogonal signal from the first-stage coupler is corrected by the second-stage coupler. A single coupler adopts a new layout design, and a large number of transmission lines are not required. The couplers can be directly cascaded, and a compact layout structure is achieved while being able to generate high-precision differential orthogonal signals. Compared with traditional couplers, the coupler of the present invention greatly improves the bandwidth of the orthogonal signal and ensures that the amplitude difference of the orthogonal signal is small within the broadband. Compared with other types of two-stage orthogonal couplers, the present invention has a smaller size while ensuring broadband performance, eliminates redundant transmission line connections, greatly reduces the design difficulty, and has a broader application prospect. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The present invention is a connection diagram of a transformer-based two-stage orthogonal coupler disclosed in an embodiment.

[0017] Figure 2 The schematic circuit diagram of a single coupling element in a two-stage transformer-based orthogonal coupler disclosed in an embodiment is shown.

[0018] Figure 3 The figure is a schematic diagram of a graphic layer of a single coupling element in a two-stage orthogonal coupler based on a transformer disclosed in an embodiment.

[0019] Figure 4 The electromagnetic field simulation in a transformer-based two-stage orthogonal coupler disclosed in the embodiment is a diagram of the differential signal amplitude and phase data output by the coupler.

[0020] Figure 5 The diagram is a schematic diagram of a phase difference result in a transformer-based two-stage orthogonal coupler disclosed in an embodiment. DETAILED DESCRIPTION

[0021] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention; it is obvious that the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "provided with", "connected", and "connected" should be understood in a broad sense; for example, it can be a fixed connection, a detachable connection, or an integral connection, a mechanical connection, or an electrical connection, a direct connection, or an indirect connection through an intermediate medium, or the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0023] See also Figure 1-5 , a transformer-based two-stage orthogonal coupler, comprising a primary coupler and a secondary coupler, wherein the primary coupler comprises a coupling element and the secondary coupler comprises two coupling elements; The differential signal output terminal THRU+ of the primary coupler is connected to the signal input terminal IN+ of a coupling element in the secondary coupler, and the differential signal output terminal THRU- of the primary coupler is connected to the signal input terminal IN- of the same coupling element in the secondary coupler; The differential signal output terminal CPL+ of the primary coupler is connected to the signal input terminal IN+ of another coupling element in the secondary coupler, and the differential signal output terminal CPL- of the primary coupler is connected to the signal input terminal IN- of the same coupling element in the secondary coupler; The signal input terminal IN± of the primary coupler is the input terminal of the secondary orthogonal coupler, the differential signal output terminal THRU+, the differential signal output terminal THRU-, the differential signal output terminal CPL+, and the differential signal output terminal CPL- of the two coupling elements in the secondary coupler are respectively connected to each other, and the differential signal output terminal THRU± and the differential signal output terminal CPL± of the secondary coupler that are connected to each other are the output terminals of the secondary orthogonal coupler.

[0024] Figure 2 Detailed circuit diagram of a coupling component, wherein a main inductor L1, a main inductor L4, a secondary inductor L2, a secondary inductor L3, a coupling capacitor C1, a coupling capacitor C2, a coupling capacitor C3, a coupling capacitor C4 and an isolation resistor R1 are arranged inside the coupling component; One end of the main inductor L1 is connected to the signal input terminal IN+ of the coupling element, and the other end of the main inductor L1 is connected to the differential signal output terminal THRU+ of the coupling element; One end of the coupling capacitor C1 is connected to the signal input terminal IN+ of the coupling element, and the other end of the coupling capacitor C1 is simultaneously connected to one end of the secondary inductor L2 and the differential signal output terminal CPL+ of the coupling element, and the other end of the secondary inductor L2 is simultaneously connected to one end of the coupling capacitor C3 and one end of the isolation resistor R1, and the other end of the coupling capacitor C3 is connected to the differential signal output terminal THRU+ of the coupling element.

[0025] One end of the main inductor L4 is connected to the signal input terminal IN- of the coupling element, and the other end of the main inductor L4 is connected to the differential signal output terminal THRU- of the coupling element; One end of the coupling capacitor C2 is connected to the signal input terminal IN- of the coupling element, and the other end of the coupling capacitor C2 is simultaneously connected to one end of the secondary inductor L3 and the differential signal output terminal CPL- of the coupling element, and the other end of the secondary inductor L3 is simultaneously connected to one end of the coupling capacitor C4 and the other end of the isolation resistor R1, and the other end of the coupling capacitor C4 is connected to the differential signal output terminal THRU- of the coupling element.

[0026] The main inductor L1, the auxiliary inductor L2, the main inductor L4 and the auxiliary inductor L3 are arranged in vertical mirror symmetry. The two coupling components in the secondary coupler are arranged in vertical symmetry.

[0027] The main inductor L1 and the main inductor L4 of the coupling element are inductors of the same model; the signal input terminal IN± of the coupling element is on the left side of the circuit, and the differential signal output terminal THRU±, the differential signal output terminal CPL± and the isolation terminal ISO± port of the coupling element are on the right side of the circuit.

[0028] Figure 3Specifically, it is a schematic diagram of the graphic layer of the coupling component. A main inductor, a secondary inductor and a connecting line in the coupling component form a coupled inductor, and the coupling component includes a coupled inductor graphic layer, a coupled capacitor graphic layer, a jumper connecting line, an isolation resistor graphic layer and an outer ring metal dummy.

[0029] The coupled inductor graphic layer, the coupled capacitor graphic layer, and the isolation resistor graphic layer are all formed based on TSMC N65 process.

[0030] The two inductor main parts of a single coupling component are fully fitted and exactly the same size. The signal input end is on the left side of the circuit, and the signal output end (THRU±, CPL±) and isolation end (ISO±) port are on the right side of the circuit, which is conducive to cascading.

[0031] Furthermore, a jumper connection line is used to increase the secondary inductance of a single transformer by half a turn, and the coupling capacitor interface is led to the input coupling end, and CPL± is led to the output side to form a fully bonded transformer.

[0032] Furthermore, the output of the first-stage coupler is connected to the four inputs of the second-stage coupler using a transmission line, and the same coupler is used to perform low-pass correction on the high-pass signal of the first-stage output, and high-pass correction on the low-pass signal of the first-stage output, and the eight groups of signals of the second-stage output are combined in pairs with the same phase to generate four groups of orthogonal signals.

[0033] The CPL of a single coupler leads the interface to the same side as the THRU through a jumper transmission line, connects the output of the first-stage coupler to the four inputs of the second-stage coupler using a transmission line, uses the same coupler to perform low-pass correction on the high-pass signal of the first-stage output, and high-pass correction on the low-pass signal of the first-stage output, and combines the eight groups of signals of the second-stage output in pairs with the same phase to generate four groups of orthogonal signals.

[0034] The board diagram of the coupling device includes a transformer graphic layer, a coupling capacitor graphic layer, a jumper wire, an isolation resistor graphic layer, and an outer ring metal dummy. The coupler layer is based on TSMC N65 process. The coupler graphic layer includes a square spiral inductor and a connecting wire. The M1 and M2 layers are used as the outer ring metal dummy, and the metal layer M2 is used as the reference ground.

[0035] Furthermore, the inwardly rotating port of the coupled inductor is connected to the coupled output port through a jumper connecting line, so that the coupled inductor is increased by half a turn relative to the straight-through inductor, and the inwardly rotating port is led out and extends to the input side and the output side respectively, the input side is connected to the interface of the input coupling capacitor, and the output side is connected to the coupled output port.

[0036] The above settings produce the following effects: The present invention reconstructs the layout and style of the coupler, uses the AP layer metal to lead out the inwardly rotating port of the M9 layer coupling inductor, and then connects it through the M9 layer metal, so that the coupling inductor is increased by half a circle; after the inwardly rotating port is led out, it extends to the input and output respectively, and the coupling capacitor port is led to the input coupling end, and the coupling output port is led to the output side, forming a fully laminated transformer.

[0037] The structure of the present invention changes the layout of the traditional coupler input port and the coupled output port on the same side, and leads the coupled output port to the output side through a jumper metal line, so that the coupled output port and the straight-through output port are on the same side, which greatly reduces the length of the jumper transmission line and integrates the connecting transmission line into its own inductance. The orthogonal coupler of the traditional structure needs to use a large number of transmission lines on the periphery of the coupler to transfer the CPL port and the THRU port to the same side, which will introduce a lot of loss and interference.

[0038] Under TSMC's N65 process, the thickness of the M9 layer coupled inductor and the M8 layer through inductor are different. When the inductor sizes are exactly the same and fully bonded, the inductance values ​​of the two inductors will differ too much. The inductance value of the M9 layer metal is smaller than that of the M8 layer metal, which affects the symmetry of the coupler.

[0039] The present invention ingeniously uses the transmission line to increase the coupling inductance by half a circle, thereby increasing the inductance value of the coupling inductance, which just compensates for the defect, so that the main parts of the two inductors are fully fitted and a high coupling coefficient is achieved.

[0040] The layers of the balun inductor of a single coupler in this design include the main inductors L1 and L4 formed by M8 metal, and the secondary inductors L2 and L3 formed by M9 metal. In addition, it also includes the main inductor jumper wire M7 and the secondary inductor jumper wire AP.

[0041] Combination Figure 4 Compared with the traditional differential two-stage orthogonal coupler, this design can output high-precision differential orthogonal signals while having a smaller size. The advantage of this structure is that by changing the style of a single orthogonal coupler, all its output ends are on the right and all its input ends are on the left. When cascading, they are directly connected without the need for additional routing, reducing area loss and routing crosstalk.

[0042] Combination Figure 5 The characteristic impedance of the signal ports of this design is 50 ohms, with the left side being the differential input port and the right side being the differential output ports THRU± and CPL±. The phase difference between THRU and CPL is 90 degrees, the phase difference between THRU (CPL) itself is 180 degrees, and the amplitude difference of the four groups of signals is less than 0.4dB within 12-20GHz, and the phase error is less than ±1°.

[0043] This example is manufactured using TSMC's 65nm process. The size of the differential two-stage orthogonal coupler is .

[0044] The present invention adopts a two-stage orthogonal coupler design, and the orthogonal signal from the first-stage coupler is corrected by the second-stage coupler. A single coupler adopts a new layout design, and a large number of transmission lines are not required. The couplers can be directly cascaded, and a compact layout structure is achieved while being able to generate high-precision differential orthogonal signals. Compared with traditional couplers, the coupler of the present invention greatly improves the bandwidth of the orthogonal signal and ensures that the amplitude difference of the orthogonal signal is small within the broadband. Compared with other types of two-stage orthogonal couplers, the present invention has a smaller size while ensuring broadband performance, eliminates redundant transmission line connections, greatly reduces the design difficulty, and has a broader application prospect.

[0045] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive from any point of view. The scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention, and any reference numerals in the claims should not be considered as limiting the claims involved.

[0046] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A transformer-based two-stage orthogonal coupler, characterized in that: It includes a primary coupler and a secondary coupler, wherein the primary coupler includes a coupling piece and the secondary coupler includes two coupling pieces; The differential signal output terminal THRU+ of the primary coupler is connected to the signal input terminal IN+ of a coupling element in the secondary coupler, and the differential signal output terminal THRU- of the primary coupler is connected to the signal input terminal IN- of the same coupling element in the secondary coupler; The differential signal output terminal CPL+ of the primary coupler is connected to the signal input terminal IN+ of another coupling element in the secondary coupler, and the differential signal output terminal CPL- of the primary coupler is connected to the signal input terminal IN- of the same coupling element in the secondary coupler; The signal input terminal IN± of the primary coupler is the input terminal of the secondary orthogonal coupler, the differential signal output terminal THRU+, the differential signal output terminal THRU-, the differential signal output terminal CPL+, and the differential signal output terminal CPL- of the two coupling elements in the secondary coupler are respectively connected to each other, and the differential signal output terminal THRU± and the differential signal output terminal CPL± of the secondary coupler that are connected to each other are the output terminals of the secondary orthogonal coupler.

2. A transformer-based two-stage orthogonal coupler according to claim 1, characterized in that: The coupling component is provided with a main inductor L1, a main inductor L4, a secondary inductor L2, a secondary inductor L3, a coupling capacitor C1, a coupling capacitor C2, a coupling capacitor C3, a coupling capacitor C4 and an isolation resistor R1; One end of the main inductor L1 is connected to the signal input terminal IN+ of the coupling element, and the other end of the main inductor L1 is connected to the differential signal output terminal THRU+ of the coupling element; One end of the coupling capacitor C1 is connected to the signal input terminal IN+ of the coupling element, and the other end of the coupling capacitor C1 is simultaneously connected to one end of the secondary inductor L2 and the differential signal output terminal CPL+ of the coupling element, and the other end of the secondary inductor L2 is simultaneously connected to one end of the coupling capacitor C3 and one end of the isolation resistor R1, and the other end of the coupling capacitor C3 is connected to the differential signal output terminal THRU+ of the coupling element.

3. A transformer-based two-stage orthogonal coupler according to claim 2, characterized in that: One end of the main inductor L4 is connected to the signal input terminal IN- of the coupling element, and the other end of the main inductor L4 is connected to the differential signal output terminal THRU- of the coupling element; One end of the coupling capacitor C2 is connected to the signal input terminal IN- of the coupling element, and the other end of the coupling capacitor C2 is simultaneously connected to one end of the secondary inductor L3 and the differential signal output terminal CPL- of the coupling element, and the other end of the secondary inductor L3 is simultaneously connected to one end of the coupling capacitor C4 and the other end of the isolation resistor R1, and the other end of the coupling capacitor C4 is connected to the differential signal output terminal THRU- of the coupling element.

4. The transformer-based two-stage orthogonal coupler according to claim 3, characterized in that: The main inductor L1, the auxiliary inductor L2, the main inductor L4 and the auxiliary inductor L3 are arranged in upper and lower mirror symmetry.

5. The transformer-based two-stage orthogonal coupler according to claim 4, characterized in that: The two coupling members in the secondary coupler are arranged symmetrically up and down.

6. The transformer-based two-stage orthogonal coupler according to claim 5, characterized in that: The main inductor L1 and the main inductor L4 of the coupling element are inductors of the same model; the signal input terminal IN± of the coupling element is on the left side of the circuit, and the differential signal output terminal THRU±, the differential signal output terminal CPL± and the isolation terminal ISO± port of the coupling element are on the right side of the circuit.

7. The transformer-based two-stage orthogonal coupler according to claim 6, characterized in that: A main inductor, a secondary inductor and a connecting line in the coupling component form a coupled inductor. The coupling component includes a coupled inductor graphic layer, a coupled capacitor graphic layer, a jumper connecting line, an isolation resistor graphic layer and an outer ring metal dummy.

8. The transformer-based two-stage orthogonal coupler according to claim 7, characterized in that: The coupled inductor graphic layer, the coupled capacitor graphic layer, and the isolation resistor graphic layer are all formed based on TSMC N65 process.

9. The transformer-based two-stage orthogonal coupler according to claim 8, characterized in that: The inward-rotating port of the coupled inductor graphic layer leads out an input side connecting line and an output side extending line through a jumper connecting line. The input side connecting line of the inward-rotating port of the coupled inductor graphic layer is connected to the coupling capacitor, and the output side extending line of the inward-rotating port of the coupled inductor graphic layer is connected to the differential signal output terminal CPL.

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