A broadband high-precision 180° phase shifter based on a broadband coupler structure

Abstract

The present invention relates to a broadband high-precision 180° phase shifter based on a broadband coupler structure. Aiming at the problem that the phase shifter unit of the high-low pass switching structure has poor phase shifting accuracy in the millimeter wave frequency band, has a small bandwidth, and the phase shifting accuracy is greatly affected by process deviation, the present invention adopts a millimeter wave broadband coupler structure to replace the high-pass network structure in the traditional high-low pass switching structure, which greatly improves the phase shifting accuracy and phase shifting bandwidth of the phase shifter. At the same time, the phase deviation is less affected by process changes, the circuit robustness of the phase shifter is increased, and the overall performance of the phase shifter is improved. The phase shifter unit is different from the inductor-capacitor high-pass network structure in the previous high-low pass switching structure, and makes full use of the electromagnetic coupling effect between metal layers and the stability of the wide metal layer. It has a clear design principle, a simple structure, and low cost.

Description

Technical Field

[0001] The present invention belongs to the field of silicon-based millimeter waves and relates to a broadband high-precision 180° phase shifter based on a broadband coupler structure, which can be applied to phased array radar systems, satellite communications, vehicle-mounted anti-collision radars, millimeter wave imaging and other technical fields. Background Art

[0002] Phased array technology is currently widely used in military and civilian fields. It can improve the signal-to-noise ratio of the phased array system by signal addition, and has the functions of beam forming and beam scanning. It has been a hot topic of research in recent years. The phase shift architecture of the phased array system can be divided into RF phase shift architecture, local oscillator phase shift architecture and digital phase shift architecture according to the location of the phase shifter in the system. Due to the advantages of small size and low power consumption of the RF phase shift architecture, combined with the technical advantages of low cost, low power consumption and small size of silicon-based processes, the silicon-based RF phase shift architecture can meet the technical requirements of civilian and military use. In the field of millimeter-wave phase shifters, as an important component of the phased array system, the performance of the phase shifter directly determines the performance of the entire phased array system.

[0003] As the operating frequency reaches the millimeter wave band and above, the operating bandwidth of the phase shifter is limited, the insertion loss is large, and the phase shift accuracy is significantly deteriorated. Due to the influence of process deviation, the geometric dimensions of passive components will be significantly affected. The parameter values ​​of the passive components used, such as inductors and capacitors, have significant errors, which will also have a great impact on the phase shift accuracy of the phase shifter. Switching phase shifters are widely used in millimeter wave phase shifter design. Among them, large-bit phase shifters (such as 180° phase shifters) often use high-low pass switching structures. This structure often has problems such as small operating bandwidth and sensitivity to processing technology changes in the millimeter wave frequency band, which makes it difficult to meet the design requirements of high-performance phase shifters. Summary of the invention

[0004] The purpose of the present invention is to provide a 180° phase shifter with a high-low-pass switching structure based on a broadband coupler to solve the problems existing in the high-low-pass switching structure phase shifter in the millimeter wave frequency band. The high-pass phase shifting part of the phase shifter adopts a broadband coupler structure composed of two layers of metal layers cross-coupled, and controls the RF signal to switch between the broadband coupler structure and the third-order low-pass filter network structure through a switching transistor to form a phase difference. This phase shifter structure greatly improves the phase shift bandwidth and phase shift accuracy, while increasing the robustness of the overall circuit.

[0005] A broadband high-precision 180° phase shifter based on a broadband coupler structure comprises a high-order high-pass filter network, a third-order low-pass filter network, and a plurality of switch transistors, wherein the switch transistors are connected in series between the broadband coupler and the third-order low-pass filter network structure.

[0006] The high-order high-pass filter network adopts a millimeter wave broadband coupler; the millimeter wave broadband coupler is a metal layer cross-coupling structure, adopts a multi-layer arrangement structure, and includes, from top to bottom, a first metal layer (6), a second metal layer (8), a third metal layer (10), a fourth metal layer (12), a fifth metal layer (14), a sixth metal layer (16), and a seventh metal layer (18); adjacent metal layers are connected by metal vias, and there is a distance between the first metal layer (6) and the second metal layer (8);

[0007] The first metal layer (6) is etched with a first coupling slit (5-1) in the middle to form two mutually coupled metal wires, specifically comprising a first metal wire (1) and a second metal wire (2); one end of the first metal wire (1) faces the first coupling slit (5-1), and the other end serves as an input / output port; one end of the second metal wire (2) faces the first coupling slit (5-1), and the other end serves as an input / output port; the first metal wire (1) comprises a first horizontal line (1-1), a first vertical line (1-2), a second horizontal line (1-3), and a second vertical line (1-4) which are sequentially connected in series. 4), and a third horizontal line (1-5); the second metal line (2) includes a fourth horizontal line (2-1), a third vertical line (2-2), a fifth horizontal line (2-3), a fourth vertical line (2-4), and a sixth horizontal line (2-5) connected in series in sequence; the first horizontal line (1-1), the first vertical line (1-2), the second horizontal line (1-3), the second vertical line (1-4), and the third horizontal line (1-5) are respectively arranged symmetrically with the fourth horizontal line (2-1), the third vertical line (2-2), the fifth horizontal line (2-3), the fourth vertical line (2-4), and the sixth horizontal line (2-5);

[0008] The second metal layer (8) is etched with a second coupling slot (5-2) in the middle to form two mutually coupled metal lines, specifically comprising a third metal line (3) and a fourth metal line (4); one end of the third metal line (3) faces the second coupling slot (5-2), and the other end serves as a ground port; one end of the fourth metal line (4) faces the second coupling slot (5-2), and the other end serves as a ground port; the third metal line (3) comprises a seventh horizontal line (3-1), a fifth vertical line (3-2), an eighth horizontal line (3-3) and a sixth vertical line (3-4); the fourth metal line (4) comprises a ninth horizontal line (4-1), a seventh vertical line (4-2), a tenth horizontal line (4-3) and an eighth vertical line (4-4) which are sequentially connected in series; the seventh horizontal line (3-1), the fifth vertical line (3-2), the eighth horizontal line (3-3) and the sixth vertical line (3-4) are respectively arranged axially symmetrically with the ninth horizontal line (4-1), the seventh vertical line (4-2), the tenth horizontal line (4-3) and the eighth vertical line (4-4);

[0009] The projections of the first horizontal line (1-1), the first vertical line (1-2), the second horizontal line (1-3), and the second vertical line (1-4) on the second metal layer (8) are respectively located on the seventh horizontal line (3-1), the fifth vertical line (3-2), the eighth horizontal line (3-3), and the sixth vertical line (3-4);

[0010] The projections of the fourth horizontal line (2-1), the third vertical line (2-2), the fifth horizontal line (2-3), and the fourth vertical line (2-4) on the second metal layer (8) are respectively located on the ninth horizontal line (4-1), the seventh vertical line (4-2), the tenth horizontal line (4-3), and the eighth vertical line (4-4);

[0011] The first metal wire (1) and the third metal wire (3) are connected through a first metal via (7) to form a first inductive joint metal layer; the second metal wire (2) and the fourth metal wire (4) are connected through the first metal via (7) to form a second inductive joint metal layer; inductive coupling is generated between the two joint inductive metal layers, which is equivalent to a transformer;

[0012] The first metal wire (1), the second metal wire (2), the third metal wire (3), and the fourth metal wire (4) are each equivalent to an inductor, and there is significant capacitive coupling between the first metal layer (6) and the second metal layer (8), thereby introducing an equivalent coupling capacitor;

[0013] The third metal layer (10), the fourth metal layer (12), the fifth metal layer (14), and the sixth metal layer (16) are located below the grounding ports of the first metal line (1) and the second metal line (2);

[0014] The seventh metal layer (18) is used as a grounding metal layer and has a hollowed-out structure in the middle. There is a gap between the edge of the hollowed-out part and the edges of the first metal layer (6) and the second metal layer (8) of the broadband coupler. The bottom surface of the seventh metal layer (18) is connected to GND.

[0015] Preferably, the end of the first horizontal line (1-1) facing the first coupling slot (5-1), the end of the fourth horizontal line (2-1) facing the first coupling slot (5-1), the end of the seventh horizontal line (3-1) facing the second coupling slot (5-2), and the end of the ninth horizontal line (4-1) facing the second coupling slot (5-2) are all provided with end extension lines;

[0016] More preferably, the end extension line is an integrally formed structure, comprising a straight metal line and a right-angled trapezoidal metal line; the outer side surface of the straight metal line is connected to the lower bottom edge of the right-angled trapezoidal metal line; the hypotenuse of the right-angled trapezoidal metal line faces the connected metal line, and the right-angled side faces the first coupling gap (5-1) or the second coupling gap (5-2);

[0017] Preferably, the first coupling slot (5-1) is a mirror image Z-shaped structure rotated counterclockwise by (90)°; the Z-shaped structure comprises a first vertical slot, a horizontal slot, and a second vertical slot, and the two ends of the horizontal slot are respectively arranged perpendicular to one end of the first vertical slot and one end of the second vertical slot; the second coupling slot (5-2) is a Z-shaped structure arranged in a mirror image with the first coupling slot (5-1);

[0018] Preferably, the lengths of the first metal wire (1), the second metal wire (2), the third metal wire (3), and the fourth metal wire (4) are all λ / 8; wherein λ is the wavelength corresponding to the central operating frequency of the phase shifter;

[0019] Preferably, the line widths of the first metal line (1), the second metal line (2), the third metal line (3) and the fourth metal line (4) are the same, which is w; the distance between the edge of the hollowed-out portion of the seventh metal layer (18) and the edges of the first metal layer (6) and the second metal layer (8) is 3w;

[0020] The multiple switch transistors include eight switch transistors Q1-Q8; the switch transistors Q1-Q4 are connected in series between the broadband coupler and the third-order low-pass filter network, the switch transistors Q5-Q6 are connected in parallel between the broadband coupler and the series switch transistors Q1-Q2 and grounded, and the switch transistors Q7-Q8 are connected in parallel between the third-order low-pass filter network and the series switch transistors Q3-Q4 and grounded; VC is a control voltage, which can switch the phase shifter between the phase shift state and the reference state by connecting a high level and a low level;

[0021] Preferably, the collector of the switching transistor Q1 and the collector of the switching transistor Q3 are connected as the input terminal IN, the emitter of the switching transistor Q1 is connected to the collector of the switching transistor Q5 and an input / output port of the millimeter-wave broadband coupler, and the base of the switching transistor Q1 is connected to the control voltage VC; the emitter of the switching transistor Q3 is connected to the collector of the switching transistor Q7 and an input / output port of the third-order low-pass structure, and the base of the switching transistor Q3 is connected to the control voltage The collector of the switching transistor Q2 and the collector of the switching transistor Q4 are connected as the output terminal OUT, the emitter of the switching transistor Q2 is connected to the collector of the switching transistor Q6 and another input / output port of the millimeter-wave broadband coupler, and the base of the switching transistor Q2 is connected to the control voltage VC; the emitter of the switching transistor Q4 is connected to the collector of the switching transistor Q8 and another input / output port of the third-order low-pass structure, and the base of the switching transistor Q4 is connected to the control voltage The base of the switching transistors Q5 and Q6 is connected to the control voltage The bases of the switch transistors Q7 and Q8 are connected to the control voltage VC. The emitters of the switch transistors Q5-Q8 are grounded;

[0022] The third-order low-pass filter network adopts a traditional low-pass LCL network structure;

[0023] Another object of the present invention is to provide a control method for a broadband high-precision 180° phase shifter based on a broadband coupler structure, specifically:

[0024] When the control voltage VC is set to a high potential, the switch transistors Q1, Q2, Q7, and Q8 are turned on, which are equivalent to on-resistance, and the switch transistors Q3, Q4, Q5, and Q6 are turned off, which are equivalent to off-capacitance; at the working center frequency of the 180° phase shifter, the RF signal is input from the input terminal IN through the switch transistor Q1 into the input terminal of the millimeter-wave broadband coupler (i.e., the high-order high-pass filter network), and then generates a 90° phase advance through the millimeter-wave broadband coupler, and finally outputs from the output terminal OUT through the switch transistor Q2 from the output terminal of the millimeter-wave broadband coupler. At this time, the 180° phase shifter is in a phase shift state;

[0025] When the control voltage VC is set to a low potential, the switch transistors Q3, Q4, Q5, and Q6 are turned on, which are equivalent to on-resistance, and the switch transistors Q1, Q2, Q7, and Q8 are turned off, which are equivalent to off-capacitance; at the working center frequency of the 180° phase shifter, the RF signal is input from the input terminal IN through the switch transistor Q3 into the input terminal of the third-order low-pass filter network, and then generates a 90° phase lag through the third-order low-pass filter network, and finally outputs from the output terminal OUT through the switch transistor Q4 from the output terminal of the third-order low-pass filter network. At this time, the 180° phase shifter is in a reference state;

[0026] By switching the high and low levels of the control voltage VC, the 180° phase shifter switches between a phase shift state and a reference state. The phase shift state causes the RF signal to generate a 90° phase advance at the center frequency, and the reference state causes the RF signal to generate a 90° phase lag at the center frequency. There is a 180° phase difference between the two working states.

[0027] The phase difference achieved between the input and output ports of the third-order low-pass filter network is expressed as follows:

[0028]

[0029] The phase difference achieved between the input and output ports of the millimeter-wave broadband coupler is expressed as:

[0030]

[0031] According to formulas (1)-(2), the phase difference between the millimeter wave broadband coupler and the third-order low-pass filter network is expressed as:

[0032]

[0033] Where X n , B n represents the normalized impedance of the inductive metal layer and the admittance of the MIM capacitor in the third-order low-pass filter network; B1 represents the equivalent admittance of the first metal wire (1) and the second metal wire (2), and B2 represents the equivalent admittance of the third metal wire (3) and the fourth metal wire (4).

[0034] When the 180° phase shifter is in the phase shift state, the switch transistors Q7 and Q8 are equivalent to on-resistances connected to GND; when the 180° phase shifter is in the reference state, the switch transistors Q5 and Q6 are equivalent to on-resistances connected to GND; better isolation is provided when switching between the phase shift state and the reference state;

[0035] The 180° phase shifter is different from the traditional high-pass and low-pass structures, in which the high-pass filter network adopts the above-mentioned millimeter-wave broadband coupler as a high-order filter network, which can achieve a larger bandwidth and higher phase shifting accuracy than the traditional structure, and has better circuit robustness.

[0036] The present invention has the following advantages:

[0037] (1) The millimeter wave broadband coupler of the present invention adopts a structure in which the first metal layer and the second metal layer are cross-coupled and used as a high-order high-pass network structure, and its phase and amplitude have a large bandwidth in the millimeter wave frequency band.

[0038] (2) The broadband, high-precision 180° phase shifter of the present invention is different from the previous high-low pass switching 180° phase shifter structure. The high-pass part adopts the above-mentioned millimeter wave broadband coupler structure, which increases the phase shifting accuracy and bandwidth, and at the same time increases the robustness of the phase shifter circuit. The design principle of this phase shifter structure is clear and the structure is simple, which has important scientific research and practical value for millimeter wave phased array systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1is a top view of the broadband, high-precision 180° phase shifter of the present invention;

[0040] Figure 2 It is a schematic diagram of the three-dimensional structure of the millimeter wave broadband coupler of the present invention;

[0041] Figure 3 is a top view of the ground metal layer (seventh metal layer) of the millimeter wave broadband coupler of the present invention;

[0042] Figure 4 It is a top view of the first metal wire 1 and the second metal wire 2 (first metal layer) of the millimeter wave broadband coupler of the present invention;

[0043] Figure 5 It is a top view of the third metal wire 3 and the fourth metal wire 4 (the second metal layer) of the millimeter wave broadband coupler of the present invention;

[0044] Figure 6 It is a schematic structural diagram of the cross-connection between the first metal layer and the second metal layer of the millimeter wave broadband coupler of the present invention;

[0045] Figure 7 is a left side view of the millimeter wave broadband coupler of the present invention;

[0046] Figure 8 It is a schematic diagram of the three-dimensional structure of the third-order low-pass filter network of the broadband, high-precision 180° phase shifter of the present invention;

[0047] Fig. 9 It is a left view of the third-order low-pass filter network of the broadband, high-precision 180° phase shifter of the present invention;

[0048] Fig.10 It is a simplified equivalent circuit diagram of the broadband, high-precision 180° phase shifter of the present invention;

[0049] Fig.11 It is a simulation diagram of the phase difference between two ports of the millimeter wave broadband coupler of the present invention;

[0050] Fig.12 It is a two-port S parameter simulation diagram of the millimeter wave broadband coupler of the present invention;

[0051] Fig.13 It is a phase simulation comparison diagram of the broadband, high-precision 180° phase shifter of the present invention and the traditional high-low pass switching structure 180° phase shifter;

[0052] Fig.14 This is a simulation diagram of the phase change of the traditional high-low pass switching structure of the 180° phase shifter with the process;

[0053] Fig.15 It is a simulation diagram of the phase change of the broadband, high-precision 180° phase shifter structure of the present invention with the process.

[0054] Markings in the figure:

[0055] 1. First metal wire; 2. Second metal wire; 3. Third metal wire; 4. Fourth metal wire; 5-1. First coupling gap; 5-2. Second coupling gap; 6. First metal layer; 7. First metal via; 8. Second metal layer; 9. Second metal via; 10. Third metal layer; 11. Third metal via; 12. Fourth metal layer; 13. Fourth metal via; 14. Fifth metal layer; 15. Fifth metal via; 16. Sixth metal layer; 17. Sixth metal via; 18. Seventh metal layer; 19. First metal layer of zigzag line inductance; 20. MIM capacitor; 21. Metal via; 22. Upper metal of MIM capacitor; 23. Lower metal of MIM capacitor. DETAILED DESCRIPTION

[0056] The present invention is further analyzed below in conjunction with specific embodiments.

[0057] like Figure 1 As shown, the millimeter-wave broadband coupler and the broadband, high-precision 180° phase shifter are composed of a broadband coupler, a third-order low-pass filter network and switch transistors Q1-Q8. The collector of the switch transistor Q1 and the collector of the switch transistor Q3 are connected as input ports, the emitter of the switch transistor Q1 is connected to the collector of the switch transistor Q5 and an input-output port of the millimeter-wave broadband coupler, and the base of the switch transistor Q1 is connected to the control voltage VC; the emitter of the switch transistor Q3 is connected to the collector of the switch transistor Q7 and an input-output port of the third-order low-pass structure, and the base of the switch transistor Q3 is connected to the control voltage The collector of the switching transistor Q2 and the collector of the switching transistor Q4 are connected as the output port, the emitter of the switching transistor Q2 is connected to the collector of the switching transistor Q6 and another input / output port of the millimeter-wave broadband coupler, and the base of the switching transistor Q2 is connected to the control voltage VC; the emitter of the switching transistor Q4 is connected to the collector of the switching transistor Q8 and another input / output port of the third-order low-pass structure, and the base of the switching transistor Q4 is connected to the control voltage The base of the switching transistors Q5 and Q6 is connected to the control voltage The bases of the switching transistors Q7 and Q8 are connected to the control voltage VC, and the emitters of the switching transistors Q5-Q8 are grounded;

[0058] like Figure 2 , 7As shown, the millimeter wave broadband coupler is a multi-layer arrangement structure, which includes, from top to bottom, a first metal layer 6, a second metal layer 8, a third metal layer 10, a fourth metal layer 12, a fifth metal layer 14, a sixth metal layer 16, and a seventh metal layer 18; the end extension line of the first metal layer 6 and the end extension line of the second metal layer 8 are connected through a first metal via 7; the second metal layer 8 and the third metal layer 10 are connected through a second metal via 9; the third metal layer 10 and the fourth metal layer 12 are connected through a third metal via 11; the fourth metal layer 12 and the fifth metal layer 14 are connected through a fourth metal via 13; the fifth metal layer 14 and the sixth metal layer 16 are connected through a fifth metal via 15; the sixth metal layer 16 and the seventh metal layer 18 are connected through a sixth metal via 17;

[0059] like Figure 3 As shown, the millimeter wave broadband coupler ground metal layer (the seventh metal layer 18) adopts a structure with a hollow middle, and the bottom surface of the metal layer is connected to GND;

[0060] like Figure 4 As shown, the first metal layer 6 is etched with a first coupling slot 5-1 in the middle to form two mutually coupled metal lines, specifically including a first metal line 1 and a second metal line 2; one end of the first metal line 1 faces the first coupling slot 5-1, and the other end serves as an input / output port; one end of the second metal line 2 faces the first coupling slot 5-1, and the other end serves as an input / output port; the first metal line 1 includes a first horizontal line 1-1, a first vertical line 1-2, a second horizontal line 1-3, The second vertical line 1-4, the third horizontal line 1-5; the second metal line 2 includes a fourth horizontal line 2-1, a third vertical line 2-2, a fifth horizontal line 2-3, a fourth vertical line 2-4, and a sixth horizontal line 2-5 connected in series in sequence; the first horizontal line 1-1, the first vertical line 1-2, the second horizontal line 1-3, the second vertical line 1-4, and the third horizontal line 1-5 are respectively arranged symmetrically with the fourth horizontal line 2-1, the third vertical line 2-2, the fifth horizontal line 2-3, the fourth vertical line 2-4, and the sixth horizontal line 2-5;

[0061] like Figure 5As shown, the second metal layer 8 is etched with a second coupling gap 5-2 in the middle to form two sections of mutually coupled metal wires, specifically including a third metal wire 3 and a fourth metal wire 4; one end of the third metal wire 3 faces the second coupling gap 5-2, and the other end serves as a ground port; one end of the fourth metal wire 4 faces the second coupling gap 5-2, and the other end serves as a ground port; the third metal wire 3 includes a seventh horizontal line 3-1, a fifth vertical line 3-2, an eighth horizontal line 3-3, and a sixth vertical line 3-4 connected in series in sequence; the fourth metal wire 4 includes a ninth horizontal line 4-1, a seventh vertical line 4-2, a tenth horizontal line 4-3, and an eighth vertical line 4-4 connected in series in sequence; the seventh horizontal line 3-1, the fifth vertical line 3-2, the eighth horizontal line 3-3, and the sixth vertical line 3-4 are respectively axially symmetrically arranged with the ninth horizontal line 4-1, the seventh vertical line 4-2, the tenth horizontal line 4-3, and the eighth vertical line 4-4;

[0062] like Figure 2 As shown, the projections of the first horizontal line 1-1, the first vertical line 1-2, the second horizontal line 1-3, and the second vertical line 1-4 falling on the second metal layer 8 are respectively located on the seventh horizontal line 3-1, the fifth vertical line 3-2, the eighth horizontal line 3-3, and the sixth vertical line 3-4; the projections of the fourth horizontal line 2-1, the third vertical line 2-2, the fifth horizontal line 2-3, and the fourth vertical line 2-4 falling on the second metal layer 8 are respectively located on the ninth horizontal line 4-1, the seventh vertical line 4-2, the tenth horizontal line 4-3, and the eighth vertical line 4-4;

[0063] like Figure 6 As shown, the first metal layer 6 and the second metal layer 8 of the millimeter wave broadband coupler are cross-connected, the first metal wire 1 is connected to the fourth metal wire 4 through the first metal via 7, the second metal wire 2 is connected to the third metal wire 3 through the first metal via 7, and a gap with a horizontal length of ls and a vertical length of Ws is left between the first metal wire 1 and the second metal wire 2, and between the third metal wire 3 and the fourth metal wire 4;

[0064] like Figure 8 , 9As shown, the broadband, high-precision 180° phase shifter low-pass network structure adopts a traditional third-order low-pass filter network. This structure is a multi-layer arrangement structure, including 7 metal layers arranged up and down, wherein the bottom metal layer is used as a ground metal layer, and adjacent metal layers are connected by metal vias. The top metal layer is a symmetrical zigzag metal layer that constitutes the inductive first metal layer 19, and is connected to the MIM capacitor 20 through a metal via 21. The MIM capacitor is composed of a symmetrical metal layer (MIM capacitor upper metal 22, MIM capacitor lower metal 23), and a gap is left in the middle of the MIM capacitor metal layer. The upper metal of the MIM capacitor is connected to the inductive metal layer through a metal via, and the lower metal of the MIM capacitor is connected to the bottom metal layer through a metal via through 4 metal layers.

[0065] Working principle:

[0066] When the broadband coupler is working, the lower end ports of the first metal wire 1 and the second metal wire 2 serve as the input and output ports of the signal respectively; the lower end ports of the third metal wire 3 and the fourth metal wire 4 are connected to the ground through the metal layer and the metal via. Within the working frequency band, the broadband coupler of the present invention can be equivalent to a high-order high-pass filter network. Since the first metal layer and the second metal layer have different widths and lengths and have different inductance values, the coupling capacitance between the two metal layers will also change, which also affects the coupling coefficient of the equivalent transformer. Since the length of the metal layer is λ / 8, the working center frequency and phase range of the millimeter wave broadband coupler can be changed by adjusting the width of the first metal layer and the second metal layer and the length of the horizontal and vertical lines of the first metal wire 1, the second metal wire 2, the third metal wire 3 and the fourth metal wire 4. At the same time, since the width of the metal layer is wider, the performance of the broadband coupler is less affected by process errors.

[0067] The broadband coupler is used in high-low pass switching phase shifters. By combining the broadband coupler (i.e., high-order high-pass filter network) and the third-order low-pass filter network, a broadband, high-precision 180° phase shifter can be realized. Fig.10 As shown in the figure, it is a simplified equivalent circuit of the broadband, high-precision 180° phase shifter of the present invention. The first metal layer 1 and the second metal layer 2 in the broadband coupler are equivalent to inductors, and the electromagnetic field coupling effect of the two metal layers in the vertical direction is equivalent to capacitors. The coupling effect of the first metal line 1 and the second metal line 2 in the horizontal direction adopts the coupling coefficient K 12 The coupling effect between the third metal line 3 and the fourth metal line 4 in the horizontal direction is represented by the coupling coefficient K 34 Indicates that the first metal layer 19 of the zigzag line in the third-order low-pass filter network is also equivalent to an inductor.

[0068] like Fig.10As shown, X1 represents the normalized impedance of the coupling capacitance between the first metal layer 6 and the second metal layer 8 in the broadband coupler. n , B n Indicates the normalized impedance of the inductive metal layer and the admittance of the MIM capacitor in the third-order low-pass filter network. B1 represents the equivalent admittance of the first metal wire 1 and the second metal wire 2, and B2 represents the equivalent admittance of the third metal wire 3 and the fourth metal wire 4.

[0069] The phase difference achieved between the input and output ports of the third-order low-pass filter network is expressed as follows:

[0070]

[0071] The phase difference achieved between the input and output ports of the millimeter-wave broadband coupler is expressed as:

[0072]

[0073] According to formulas (1)-(2), the phase difference between the millimeter wave broadband coupler and the third-order low-pass filter network is expressed as:

[0074]

[0075] The broadband, high-precision 180° phase shifter of the present invention can optimize the appropriate phase difference, operating frequency, operating bandwidth, and phase shift accuracy by adjusting the parameters in the attached figure. The specific contents are as follows:

[0076] like Figure 4 , 5 As shown, the parameters X1, B1, and B2 can be tuned by adjusting the width w of the first metal line 1, the second metal line 2, the third metal line 3, and the fourth metal line 4 in the broadband coupler structure, and the lengths of the horizontal lines and vertical lines of the first metal line 1, the second metal line 2, the third metal line 3, and the fourth metal line 4. Figure 6 As shown, the length and width of the gap at the connection part of the first metal layer and the second metal layer in the broadband coupler structure can be adjusted. s 、w s ) for parameter K 12 , K 34 Tuning, such as Figure 8 As shown, the parameter X can be controlled by adjusting the lengths (w4, l4, c, d) of the first metal layer of the meander line in the third-order low-pass filter network. n Tuning is performed by adjusting the size of the MIM capacitor to adjust the parameter B n The present invention adjusts and optimizes the above parameters to obtain X1, B1, B2, X n ,B nThe optimal parameter value achieves a 90° phase advance in the millimeter-wave coupler (high-order high-pass filter network) within the millimeter-wave broadband range, and a 90° phase lag in the third-order low-pass filter network, thereby realizing a broadband, high-precision 180° phase shifter.

[0077] Table 1 Specific structural geometric parameters of the broadband, high-precision 180° phase shifter of the present invention

[0078]

[0079]

[0080] Where t1 is the thickness of the seventh metal layer, t2 is the thickness of the first metal layer, t3 is the thickness of the second metal layer, h1 is the height between the second metal layer and the seventh metal layer, h2 is the height from the first metal layer to the upper metal layer of the MIM capacitor, a is the length of the seventh metal layer in the broadband coupler, b is the width of the seventh metal layer in the broadband coupler, l1 is the length of the hollowed-out portion in the seventh metal layer, w1 is the width of the hollowed-out portion in the seventh metal layer, l2 is the total length of the broadband coupler, w2 is the total width of the broadband coupler, and w is the first metal layer in the broadband coupler. The width of the metal layer 6 and the second metal layer 8, l5 is the left-right spacing between the first metal line 1 and the second metal line 2 of the broadband coupler, l6 is the length of the second horizontal line 1-5 of the first metal line 1 of the broadband coupler, w5 is the length of the second vertical line 1-4 in the first metal line 1 of the broadband coupler, l3 is the total length of the second metal layer in the broadband coupler, w3 is the total width of the second metal layer in the broadband coupler, l5 is the left-right spacing between the third metal line 3 and the fourth metal line 4 of the broadband coupler, w6 is the length of the sixth vertical line 3-4 in the third metal line 3, l s is the gap length at the connection between the first metal layer and the second metal layer, w s is the gap width at the connecting part of the first metal layer and the second metal layer, l4 is the total length of the inductive metal (first metal layer) in the third-order low-pass filtering network of the 180° phase shifter, w4 is the total width of the inductive metal (first metal layer) in the third-order low-pass filtering network of the 180° phase shifter, c is the upper and lower spacing of the metal lines of the inductive metal (first metal layer) in the third-order low-pass filtering network of the 180° phase shifter, and d is the left and right spacing of the metal lines of the inductive metal (first metal layer) in the third-order low-pass filtering network of the 180° phase shifter.

[0081] Fig.11 This is a phase characteristic curve diagram of the millimeter wave broadband coupler simulated in the present invention. It can be seen that a phase range of 18°-99° can be generated within a frequency range of 70-120 GHz, and can be used as a high-pass network part of a high-low pass switching structure. Fig.12The S parameter characteristic curve of the millimeter wave broadband coupler simulation of the present invention is shown in Figure 1. It can be seen that the insertion loss of the millimeter wave broadband coupler of the present invention is 2dB-4dB, and the return loss of the two ports is less than 18dB, which has excellent low insertion loss and high return loss performance. Fig.13 This is a simulation comparison diagram of the broadband, high-precision 180° phase shifter of the present invention and the traditional 180° phase shifter. It can be seen that the phase difference of the broadband, high-precision 180° phase shifter of the present invention in the range of 90GHz-100GHz is 179°±0.5°, and the phase difference of the traditional 180° phase shifter structure is 181°±4°. Therefore, the broadband, high-precision 180° phase shifter of the present invention has good phase shifting accuracy and a large bandwidth. Fig.14 , 15 They are respectively simulation diagrams of the phase changes caused by the process deviation of the traditional 180° phase shifter high-low pass switching structure and the broadband, high-precision 180° phase shifter structure of the present invention. In the three-dimensional electromagnetic field model, the process error (Scale of L / C ±5%, 10%) during processing is simulated by scaling the size of the inductor and capacitor by ±5%, ±10%. It can be seen that the traditional 180° phase shifter high-low pass switching structure has a phase change of 37° in the range of 90GHz-100GHz, and the broadband, high-precision 180° phase shifter of the present invention has a phase change of 27° in the range of 90GHz-100GHz, and the phase-frequency performance is improved by 27%. In summary, the phase of the broadband, high-precision 180° phase shifter proposed by the present invention is less affected by process deviations and has good circuit robustness.

[0082] Although the specific embodiments of the present invention are described above in conjunction with the accompanying drawings, it should be understood by those skilled in the art that these are only examples and that various modifications or variations may be made to these embodiments without departing from the principles and essence of the present invention. The scope of the present invention is limited only by the attached claims.

Claims

1. A broadband high-precision 180° phase shifter based on a broadband coupler structure, comprising a high-order high-pass filter network, a third-order low-pass filter network, and a plurality of switch transistors, wherein the switch transistors are connected in series between the broadband coupler and the third-order low-pass filter network structure; characterized in that: The high-order high-pass filter network adopts a millimeter wave broadband coupler; the millimeter wave broadband coupler is a metal layer cross-coupling structure, adopts a multi-layer arrangement structure, and includes, from top to bottom, a first metal layer (6), a second metal layer (8), a third metal layer (10), a fourth metal layer (12), a fifth metal layer (14), a sixth metal layer (16), and a seventh metal layer (18); adjacent metal layers are connected by metal vias, and there is a distance between the first metal layer (6) and the second metal layer (8); The first metal layer (6) is etched with a first coupling slit (5-1) in the middle to form two mutually coupled metal wires, specifically comprising a first metal wire (1) and a second metal wire (2); one end of the first metal wire (1) faces the first coupling slit (5-1), and the other end serves as an input / output port; one end of the second metal wire (2) faces the first coupling slit (5-1), and the other end serves as an input / output port; the first metal wire (1) comprises a first horizontal line (1-1), a first vertical line (1-2), a second horizontal line (1-3), and a second vertical line (1-4) which are sequentially connected in series. 4), and a third horizontal line (1-5); the second metal line (2) includes a fourth horizontal line (2-1), a third vertical line (2-2), a fifth horizontal line (2-3), a fourth vertical line (2-4), and a sixth horizontal line (2-5) connected in series in sequence; the first horizontal line (1-1), the first vertical line (1-2), the second horizontal line (1-3), the second vertical line (1-4), and the third horizontal line (1-5) are respectively arranged symmetrically with the fourth horizontal line (2-1), the third vertical line (2-2), the fifth horizontal line (2-3), the fourth vertical line (2-4), and the sixth horizontal line (2-5); The second metal layer (8) is etched with a second coupling slot (5-2) in the middle to form two mutually coupled metal lines, specifically comprising a third metal line (3) and a fourth metal line (4); one end of the third metal line (3) faces the second coupling slot (5-2), and the other end serves as a ground port; one end of the fourth metal line (4) faces the second coupling slot (5-2), and the other end serves as a ground port; the third metal line (3) comprises a seventh horizontal line (3-1), a fifth vertical line (3-2), an eighth horizontal line (3-3) and a sixth vertical line (3-4); the fourth metal line (4) comprises a ninth horizontal line (4-1), a seventh vertical line (4-2), a tenth horizontal line (4-3) and an eighth vertical line (4-4) which are sequentially connected in series; the seventh horizontal line (3-1), the fifth vertical line (3-2), the eighth horizontal line (3-3) and the sixth vertical line (3-4) are respectively arranged axially symmetrically with the ninth horizontal line (4-1), the seventh vertical line (4-2), the tenth horizontal line (4-3) and the eighth vertical line (4-4); The projections of the first horizontal line (1-1), the first vertical line (1-2), the second horizontal line (1-3), and the second vertical line (1-4) on the second metal layer (8) are respectively located on the seventh horizontal line (3-1), the fifth vertical line (3-2), the eighth horizontal line (3-3), and the sixth vertical line (3-4); The projections of the fourth horizontal line (2-1), the third vertical line (2-2), the fifth horizontal line (2-3), and the fourth vertical line (2-4) on the second metal layer (8) are respectively located on the ninth horizontal line (4-1), the seventh vertical line (4-2), the tenth horizontal line (4-3), and the eighth vertical line (4-4); The first metal wire (1) and the third metal wire (3) are connected through a first metal via (7) to form a first inductive joint metal layer; the second metal wire (2) and the fourth metal wire (4) are connected through the first metal via (7) to form a second inductive joint metal layer; inductive coupling is generated between the two joint inductive metal layers, which is equivalent to a transformer; The first metal wire (1), the second metal wire (2), the third metal wire (3), and the fourth metal wire (4) are each equivalent to an inductor, and there is significant capacitive coupling between the first metal layer (6) and the second metal layer (8), thereby introducing an equivalent coupling capacitor; The third metal layer (10), the fourth metal layer (12), the fifth metal layer (14), and the sixth metal layer (16) are located below the grounding ports of the first metal line (1) and the second metal line (2); The seventh metal layer (18) is used as a grounding metal layer and has a hollowed-out structure in the middle. There is a gap between the edge of the hollowed-out part and the edges of the first metal layer (6) and the second metal layer (8) of the broadband coupler. The bottom surface of the seventh metal layer (18) is connected to GND. The multiple switching transistors include eight switching transistors Q1-Q8; the switching transistors Q1-Q4 are connected in series between the broadband coupler and the third-order low-pass filter network, the switching transistors Q5-Q6 are connected in parallel between the broadband coupler and the series switching transistors Q1-Q2, and the switching transistors Q7-Q8 are connected in parallel between the third-order low-pass filter network and the series switching transistors Q3-Q4; VC is a control voltage, which can make the phase shifter switch between the two phase states of phase shift state and reference state by connecting high level and low level.

2. A broadband high-precision 180° phase shifter based on a broadband coupler structure according to claim 1, characterized in that The end of the first horizontal line (1-1) facing the first coupling slot (5-1), the end of the fourth horizontal line (2-1) facing the first coupling slot (5-1), the end of the seventh horizontal line (3-1) facing the second coupling slot (5-2), and the end of the ninth horizontal line (4-1) facing the second coupling slot (5-2) are all provided with end extension lines.

3. A broadband high-precision 180° phase shifter based on a broadband coupler structure according to claim 2, characterized in that The end extension line is an integrally formed structure, comprising a straight metal line and a right-angled trapezoidal metal line; the outer side surface of the straight metal line is connected to the lower base of the right-angled trapezoidal metal line; the hypotenuse of the right-angled trapezoidal metal line faces the connected metal line, and the right-angle side faces the first coupling gap (5-1) or the second coupling gap (5-2).

4. A broadband high-precision 180° phase shifter based on a broadband coupler structure according to claim 1, characterized in that The first coupling slot (5-1) is a mirror image Z-shaped structure after being rotated counterclockwise by (90) degrees; the Z-shaped structure comprises a first vertical slot, a horizontal slot, and a second vertical slot, and the two ends of the horizontal slot are respectively arranged perpendicularly to one end of the first vertical slot and one end of the second vertical slot; the second coupling slot (5-2) is a Z-shaped structure arranged in a mirror image with the first coupling slot (5-1).

5. A broadband high-precision 180° phase shifter based on a broadband coupler structure according to claim 1, characterized in that The lengths of the first metal wire (1), the second metal wire (2), the third metal wire (3) and the fourth metal wire (4) are all λ / 8, wherein λ is the wavelength corresponding to the central operating frequency of the phase shifter.

6. A broadband high-precision 180° phase shifter based on a broadband coupler structure according to claim 1 or 5, characterized in that The line widths of the first metal line (1), the second metal line (2), the third metal line (3) and the fourth metal line (4) are the same, all being w; and the distance between the edge of the hollowed-out portion of the seventh metal layer (18) and the edges of the first metal layer (6) and the second metal layer (8) is 3w.

7. A broadband high-precision 180° phase shifter based on a broadband coupler structure according to claim 1, characterized in that The collector of the switching transistor Q1 and the collector of the switching transistor Q3 are connected as the input terminal IN, the emitter of the switching transistor Q1 is connected to the collector of the switching transistor Q5 and an input / output port of the millimeter-wave broadband coupler, and the base of the switching transistor Q1 is connected to the control voltage VC; the emitter of the switching transistor Q3 is connected to the collector of the switching transistor Q7 and an input / output port of the third-order low-pass structure, and the base of the switching transistor Q3 is connected to the control voltage The collector of the switching transistor Q2 and the collector of the switching transistor Q4 are connected as the output terminal OUT, the emitter of the switching transistor Q2 is connected to the collector of the switching transistor Q6 and another input / output port of the millimeter-wave broadband coupler, and the base of the switching transistor Q2 is connected to the control voltage VC; the emitter of the switching transistor Q4 is connected to the collector of the switching transistor Q8 and another input / output port of the third-order low-pass structure, and the base of the switching transistor Q4 is connected to the control voltage The base of the switching transistors Q5 and Q6 is connected to the control voltage The bases of the switching transistors Q7 and Q8 are connected to the control voltage VC; the emitters of the switching transistors Q5-Q8 are grounded.

8. The control method of a broadband high-precision 180° phase shifter based on a broadband coupler structure as claimed in claim 7, characterized in that The method is specifically: When the control voltage VC is set to a high potential, the switching transistors Q1, Q2, Q7, and Q8 are turned on, which are equivalent to on-resistance, and the switching transistors Q3, Q4, Q5, and Q6 are turned off, which are equivalent to off-capacitance; at the working center frequency of the 180° phase shifter, the RF signal is input from the input terminal IN through the switching transistor Q1 into the input terminal of the millimeter-wave broadband coupler, and then generates a 90° phase advance through the millimeter-wave broadband coupler, and finally outputs from the output terminal OUT through the switching transistor Q2 from the output terminal of the millimeter-wave broadband coupler. At this time, the 180° phase shifter is in a phase shift state; When the control voltage VC is set to a low potential, the switch transistors Q3, Q4, Q5, and Q6 are turned on, which are equivalent to on-resistance, and the switch transistors Q1, Q2, Q7, and Q8 are turned off, which are equivalent to off-capacitance; at the working center frequency of the 180° phase shifter, the RF signal is input from the input terminal IN through the switch transistor Q3 into the input terminal of the third-order low-pass filter network, and then generates a 90° phase lag through the third-order low-pass filter network, and finally outputs from the output terminal OUT through the switch transistor Q4 from the output terminal of the third-order low-pass filter network. At this time, the 180° phase shifter is in a reference state; By switching the high and low levels of the control voltage VC, the 180° phase shifter switches between a phase shift state and a reference state. The phase shift state causes the RF signal to generate a 90° phase advance at the center frequency, and the reference state causes the RF signal to generate a 90° phase lag at the center frequency. There is a 180° phase difference between the two working states. The phase difference achieved between the input and output ports of the third-order low-pass filter network is expressed as follows: The phase difference achieved between the input and output ports of the millimeter-wave broadband coupler is expressed as: According to formulas (1)-(2), the phase difference between the millimeter wave broadband coupler and the third-order low-pass filter network is expressed as: Where X n , B n represents the normalized impedance of the inductive metal layer and the admittance of the MIM capacitor in the third-order low-pass filter network; B1 represents the equivalent admittance of the first metal wire (1) and the second metal wire (2), and B2 represents the equivalent admittance of the third metal wire (3) and the fourth metal wire (4).

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