Broadband phase-shift circuit

Abstract

The present invention discloses a broadband phase-shift circuit comprising a first path and a second path. The second path includes a grounded inductor, which is added to the third-order all-pass network in the second path. This technical solution provides a larger phase lead, compensates for phase nonlinearity at low frequencies, and broadens the bandwidth. While reducing network losses, the circuit also features a simple structure and compact size, facilitating mass production and reducing production costs.

Description

Technical Field

[0001] The present invention relates to the field of radio frequency microwave integrated circuits, and in particular to a broadband phase shift circuit. Background Art

[0002] A microwave phase shifter is a microwave control circuit primarily used to control the phase of a microwave signal to meet system requirements. Phase shifters are widely used in numerous fields, including phased array radar, microwave communications, and satellite technology. In phased array radar systems, they are particularly crucial components in the T / R assembly, and their performance plays a crucial role in the overall radar system.

[0003] Currently, monolithic integrated phase shifter circuits that achieve large phase shifts mainly include transmission-type and reflection-type. Among them, reflection-type phase shifters can achieve a wider bandwidth, but the quarter-wavelength line occupies a large area, which is not conducive to chip miniaturization. Common structures of transmission-type phase shifters include all-pass network structures, especially broadband phase shifters based on magnetically coupled all-pass network structures. Their phase-shift path and reference path both use all-pass network structures. However, to achieve a larger phase shift, it is necessary to continuously cascade multiple all-pass network circuits, while increasing the inductance and capacitance values of the all-pass network in the phase-shifted state, which in turn leads to increased network loss and volume. Summary of the Invention

[0004] The present invention provides a new design concept for a broadband phase-shifting circuit, which aims to provide a larger leading phase by setting a grounding inductor in the reference path to compensate for the phase nonlinearity in the low-frequency band, widen the bandwidth, and thus reduce the loss and volume of the network.

[0005] Technical solution: The present invention provides a broadband phase-shift circuit, comprising: a first path, a second path, a first single-pole double-throw switch, and a second single-pole double-throw switch, wherein: the fixed end of the first single-pole double-throw switch is the input end of the broadband phase-shift circuit, the first movable end of the first single-pole double-throw switch is connected to the input end of the first path, and the second movable end of the first single-pole double-throw switch is connected to the input end of the second path; the fixed end of the second single-pole double-throw switch is the output end of the broadband phase-shift circuit, the first movable end of the second single-pole double-throw switch is connected to the output end of the first path, and the second movable end of the first single-pole double-throw switch is connected to the output end of the second path; the first path includes a first inductor, a second inductor, and a first grounding terminal. The first end of the first inductor and the first end of the second inductor serve as the input and output of the first path, respectively. The second end of the first inductor and the second end of the second inductor are connected to form a first ground connection point. The first end of the first grounded capacitor is connected to the first ground connection point, and the second end of the first grounded capacitor is grounded. The second path includes a third inductor, a fourth inductor, a second grounded capacitor, and a grounded inductor. The first end of the third inductor and the first end of the fourth inductor serve as the input and output of the second path, respectively. The second end of the third inductor and the second end of the fourth inductor are connected to form a second ground connection point. The first end of the second grounded capacitor is connected to the second ground connection point, and the second end of the second grounded capacitor is grounded. The grounded inductor and the second grounded capacitor are connected in series or in parallel.

[0006] In one embodiment, a capacitor is provided on the line between the first end of the first inductor and the first end of the second inductor. Furthermore, a capacitor may be provided on the line between the first end of the third inductor and the first end of the fourth inductor. Alternatively, an inductor may be provided on the line between the first end of the third inductor and the first end of the fourth inductor.

[0007] In another embodiment, an inductor is provided on the line between the first end of the first inductor and the first end of the second inductor. Furthermore, a capacitor may be provided on the line between the first end of the third inductor and the first end of the fourth inductor. Alternatively, an inductor may be provided on the line between the first end of the third inductor and the first end of the fourth inductor.

[0008] Furthermore, the first single-pole double-throw switch and the second single-pole double-throw switch may adopt a series tube switch structure, a parallel tube switch structure or a series-parallel tube switch structure.

[0009] Specifically, by switching the first single-pole double-throw switch circuit and the second single-pole double-throw switch circuit, the first path or the second path is selected as the transmission path.

[0010] Compared with the existing technology, the present invention has the following significant advantages: it provides a larger advanced phase, compensates for the phase nonlinearity in the low-frequency band, widens the bandwidth, and while reducing network losses, it has a simple structure and a small size, is convenient for mass production, saves production costs, and reverses the industry's fixed R&D ideas on expanding bandwidth. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 A schematic structural diagram of a broadband phase shift circuit provided by the present invention;

[0012] Figures 2 to 7 They are schematic structural diagrams of multiple embodiments of the broadband phase shift circuit provided by the present invention;

[0013] Figure 8 A schematic diagram of a structure in which a series-parallel MOS tube is used as a single-pole double-throw switch in a specific embodiment provided by the present invention;

[0014] Figure 9 A 90-degree phase shift simulation curve in the 4 to 20 GHz frequency band for the broadband phase shift circuit provided by the present invention;

[0015] Figure 10 The insertion loss simulation curve of a 90-degree phase shift in the 4 to 20 GHz frequency band for the broadband phase shift circuit provided by the present invention is shown;

[0016] Figure 11 The present invention provides a 90-degree phase-shifted input and output standing wave simulation curve for the broadband phase-shift circuit provided by the present invention in the 4 to 20 GHz frequency band. DETAILED DESCRIPTION

[0017] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0018] See Figure 1 , which is a schematic structural diagram of the broadband phase shift circuit provided by the present invention; see Figures 2 to 7 They are schematic structural diagrams of multiple embodiments of the broadband phase shift circuit provided by the present invention.

[0019] According to one aspect of the present invention, a broadband phase shift circuit is provided. Figure 1 A specific embodiment of a broadband phase shift circuit is shown. Figure 1 As shown, the broadband phase shift circuit includes a first path, a second path, a first single-pole double-throw switch SPDT1 and a second single-pole double-throw switch SPDT2.

[0020] Among them, the fixed end 1 of the first single-pole double-throw switch SPDT 1 is the input end of the broadband phase-shift circuit, the first movable end 2 of the first single-pole double-throw switch SPDT 1 is connected to the input end of the first path, and the second movable end 3 of the first single-pole double-throw switch SPDT 1 is connected to the input end of the second path.

[0021] The fixed end 1 of the second single-pole double-throw switch SPDT 2 is the output end of the broadband phase-shift circuit, the first movable end 2 of the second single-pole double-throw switch SPDT 2 is connected to the output end of the first path, and the second movable end 3 of the first single-pole double-throw switch SPDT 1 is connected to the output end of the second path.

[0022] The first path includes a first inductor L1, a second inductor L2, and a first grounded capacitor C2. A first end 1 of the first inductor L1 and a first end 1 of the second inductor L2 serve as an input and an output of the first path, respectively. A second end 2 of the first inductor L1 and a second end 2 of the second inductor L2 are connected to form a first ground connection point. A first end of the first grounded capacitor C2 is connected to the first ground connection point, and a second end of the first grounded capacitor C2 is grounded.

[0023] The second path includes a third inductor L3, a fourth inductor L4, a second grounding capacitor C4, and a grounding inductor L5. A first end 1 of the third inductor L3 and a first end 1 of the fourth inductor L4 serve as the input and output of the second path, respectively. A second end 2 of the third inductor L3 and a second end 2 of the fourth inductor L4 are connected to form a second ground connection point. A first end of the second grounding capacitor C4 is connected to the second grounding connection point, a second end of the second grounding capacitor C4 is grounded, and the grounding inductor L5 is connected in parallel with the second grounding capacitor C4.

[0024] In a specific implementation, the first inductor L1 and the second inductor L2 are intertwined according to the required coupling coefficient K1 and inductance values L1 and L2. After intertwining, their ends are connected, and the connection point is connected to one end of the first grounded capacitor C2. The other end of the first grounded capacitor C2 is grounded. The third inductor L3 and the fourth inductor L4 are intertwined according to the required coupling coefficient K2 and inductance values L3 and L4. After intertwining, their ends are connected, and the connection point is connected to one end of the second grounded capacitor C4. The other end of the second grounded capacitor C4 is grounded.

[0025] It is understood that by switching the first SPDT switch and the second SPDT switch, the first path or the second path can be selected as the transmission path. The output phase can be selected by switching the first path and the second path, thereby achieving broadband phase shifting.

[0026] In the prior art, when both the phase-shift path and the reference path use a full-pass network structure, a common approach to achieve greater phase shift is to continuously increase the inductance and / or capacitance values in the network, i.e., continuously add inductors and capacitors, which in turn increases the network's loss and volume. Without increasing the inductance and / or capacitance values, the phase shift is small, resulting in unsatisfactory results in practical applications. However, in the present invention, a grounded inductor is added to the reference path. Compared to phase-shifting solutions that use a full-pass network without adding a grounded inductor, the present invention further provides a greater phase lead (up to 90°), broadens the bandwidth, reduces the loss and volume of the overall phase-shifting circuit, and achieves a simple and compact structure, reducing the area by 1 / 3. Furthermore, due to the simplified structure, the circuit's performance is more stable, while also facilitating mass production and saving production costs.

[0027] In another embodiment, Figure 2 As shown, Figure 2 The embodiment shown is relative to Figure 1 The difference of the illustrated embodiment is that the grounding inductor L5 in the second path is connected in series with the second grounding capacitor C4.

[0028] In a specific embodiment, the grounding inductor L5 is connected in series with the second grounding capacitor C4. The second grounding capacitor C4 can be connected to the second ground connection point, and the grounding inductor L5 and the second grounding capacitor C4 are connected in series after being grounded by the grounding inductor L5. Alternatively, the grounding inductor L5 can be connected to the second ground connection point, and the second grounding capacitor C4 and the grounding inductor L5 are connected in series after being grounded by the second grounding capacitor C4.

[0029] In yet another embodiment, Figure 3 As shown, Figure 3 The embodiment shown is relative to Figure 1 The difference of the illustrated embodiment is that a capacitor C3 may be provided on the line between the first end 1 of the third inductor L3 and the first end 1 of the fourth inductor L4.

[0030] In another embodiment, Figure 4 As shown, Figure 4 The embodiment shown is relative to Figure 3 The difference between the illustrated embodiment is that a capacitor C1 may be provided on the line between the first end 1 of the first inductor L1 and the first end 1 of the second inductor L2.

[0031] It is understood that in other embodiments, Figure 4 The capacitor C1 shown can also be replaced by a capacitor.

[0032] In yet another embodiment, Figure 5 As shown, Figure 5 The embodiment shown is relative to Figure 1The difference between the illustrated embodiment is that an inductor L6 may be provided on the line between the first end 1 of the first inductor L1 and the first end 1 of the second inductor L2 .

[0033] In another embodiment, Figure 6 As shown, Figure 6 The embodiment shown is relative to Figure 5 The difference of the illustrated embodiment is that an inductor L7 may be provided on the line between the first end 1 of the third inductor L3 and the first end 1 of the fourth inductor L4.

[0034] In yet another embodiment, Figure 7 As shown, Figure 7 The embodiment shown is relative to Figure 1 The difference between the illustrated embodiment is that an inductor L6 may be provided on the line between the first end 1 of the first inductor L1 and the first end 1 of the second inductor L2, and a capacitor C3 may be provided on the line between the first end 1 of the third inductor L3 and the first end 1 of the fourth inductor L4.

[0035] Understandable, reference Figure 3-7 The embodiment shown, Figure 2 The embodiment shown can be modified accordingly. Figure 1 or Figure 2 Based on the illustrated embodiment, an inductor or a capacitor may be provided on the line between the first end 1 of the first inductor L1 and the first end 1 of the second inductor L2 and / or on the line between the first end 1 of the third inductor L3 and the first end 1 of the fourth inductor L4.

[0036] In various specific embodiments of the present invention, coupling capacitors or coupling inductors are added to the coupled inductor network as design variables, thereby achieving greater coupling strength and increasing design flexibility.

[0037] In a specific embodiment of the present invention, the first single-pole double-throw switch SPDT 1 and the second single-pole double-throw switch SPDT 2 can adopt a series tube switch structure, a parallel tube switch structure or a series-parallel tube switch structure. Figure 8 , which is a structural diagram of a specific embodiment provided by the present invention using series-parallel MOS tubes as single-pole double-throw switches.

[0038] In a specific implementation, the switch tubes M1 to M8 can be FET tubes or MOS tubes as appropriate.

[0039] Any one of the above embodiments is selected to simulate the results. The simulation results are as follows: Figure 9-11 As shown, Figure 9 As shown in Figure 1, within the 5 to 20 GHz frequency band, the phase shift accuracy of this broadband phase shifter is very high, and the phase shift error of a 90-degree phase shift is less than ±1°. Figure 10As shown in Figure 2, the insertion loss is less than 2.7dB in the 5 to 20GHz band; Figure 11 As shown, in the 5 to 20 GHz frequency band, the input and output standing waves in the base state and the input and output standing waves in the phase-shifted state are better than 1.4.

Claims

1. A broadband phase shift circuit, characterized in that: include: A first path, a second path, a first single-pole double-throw switch, and a second single-pole double-throw switch, wherein: The fixed end of the first single-pole double-throw switch is the input end of the broadband phase-shift circuit, the first movable end of the first single-pole double-throw switch is connected to the input end of the first path, and the second movable end of the first single-pole double-throw switch is connected to the input end of the second path; The fixed end of the second single-pole double-throw switch is the output end of the broadband phase-shift circuit, the first movable end of the second single-pole double-throw switch is connected to the output end of the first path, and the second movable end of the first single-pole double-throw switch is connected to the output end of the second path; The first path includes a first inductor, a second inductor, and a first grounded capacitor, wherein a first end of the first inductor and a first end of the second inductor serve as an input end and an output end of the first path, respectively; a second end of the first inductor and a second end of the second inductor are connected to form a first ground connection point; a first end of the first grounded capacitor is connected to the first ground connection point; and a second end of the first grounded capacitor is grounded; The second path includes a third inductor, a fourth inductor, a second grounding capacitor, and a grounding inductor. The first end of the third inductor and the first end of the fourth inductor serve as the input end and the output end of the second path, respectively. The second end of the third inductor and the second end of the fourth inductor are connected to form a second grounding connection point. The first end of the second grounding capacitor is connected to the second grounding connection point. The second end of the second grounding capacitor is grounded. The grounding inductor and the second grounding capacitor are connected in series or in parallel.

2. The broadband phase shift circuit according to claim 1, wherein: A capacitor is provided on a line between the first end of the first inductor and the first end of the second inductor.

3. The broadband phase shift circuit according to claim 2, characterized in that: A capacitor is provided on the line between the first end of the third inductor and the first end of the fourth inductor.

4. The broadband phase shift circuit according to claim 2, wherein: An inductor is provided on a line between the first end of the third inductor and the first end of the fourth inductor.

5. The broadband phase shift circuit according to claim 1, wherein: An inductor is provided on a line between the first end of the first inductor and the first end of the second inductor.

6. The broadband phase shift circuit according to claim 5, characterized in that: A capacitor is provided on the line between the first end of the third inductor and the first end of the fourth inductor.

7. The broadband phase shift circuit according to claim 5, characterized in that: An inductor is provided on a line between the first end of the third inductor and the first end of the fourth inductor.

8. The broadband phase shift circuit according to claim 1, wherein: The first single-pole double-throw switch and the second single-pole double-throw switch adopt a series tube switch structure, a parallel tube switch structure or a series-parallel tube switch structure.

9. The broadband phase shift circuit according to claim 8, characterized in that: By switching the first single-pole double-throw switch circuit and the second single-pole double-throw switch circuit, the first path or the second path is selected as the transmission path.

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