Broadband digital phase shifter based on inductance sharing topology and equivalent band-pass network

Abstract

The invention discloses a broadband digital phase shifter based on an inductor sharing topology and an equivalent band-pass network, relates to the technical field of microwave integrated circuits, and is suitable for being applied to a Sub-GHz frequency band. The phase shifter comprises a phase shift circuit module and a driving circuit module, and the phase shift circuit module comprises six basic phase shift units including a fine phase shift unit and a coarse phase shift unit which cooperatively realize full-range multi-state phase shift. The fine phase shift unit adopts an inductor sharing topology, so that a phase shift path and a reference path share a circuit architecture, the design is simplified, and the chip layout is optimized; the coarse tuning phase shifting unit adopts an all-pass network as a reference path, a phase shifting path is an equivalent band-pass network formed by cascading a high-pass network and a low-pass network, and the 180-degree phase shifter adopts a double-inductor all-pass network to optimize amplitude-frequency response. And the driving circuit module outputs complementary voltage pairs through the level conversion circuit to drive the switching transistor to realize path switching. The antenna has the advantages of being compact in structure, stable in amplitude, excellent in radio frequency performance and high in adaptability.

Description

Technical Field

[0001] This invention relates to the field of microwave integrated circuit technology, and more specifically to a broadband digital phase shifter based on inductor-shared topology and equivalent bandpass network. Background Technology

[0002] Phase shifters are core components of phased array radar transceiver modules and beamforming systems, used to achieve precise control of signal phase. Key performance indicators of phase shifters include phase shift accuracy, operating bandwidth, insertion loss, return loss, and amplitude variation, which directly affect the performance of the entire system.

[0003] With the development of IoT technology, especially the popularization of civilian devices such as drones, the application of Sub-GHz frequency band (below 1GHz) in mobile communication and civilian devices is becoming increasingly widespread. This is because Sub-GHz signals have excellent propagation characteristics such as long transmission distance and strong diffraction ability. At the same time, monolithic microwave integrated circuits (MMICs) are developing towards miniaturization and digitalization. The high mobility and low loss advantages of GaAs technology make it an ideal choice for designing numerically controlled phase shifter chips based on this technology.

[0004] In existing technologies, phase shifters are mainly divided into two categories: active and passive. Active phase shifters are primarily based on vector modulation architecture (VMPS), but due to their complex control logic and large chip area, they are rarely used in engineering applications. Traditional fine phase shifters based on dual SPDT architecture have independent low-pass and band-pass networks, requiring not only a large number of switching transistors but also two independent inductors, resulting in a large area footprint and high manufacturing costs in low-frequency applications. Traditional coarse-tuning phase shifters based on all-pass and high-low-pass networks struggle to achieve low-amplitude changes in broadband applications because the superposition of all-pass and high-low-pass characteristics inevitably produces a tilted amplitude response. Therefore, traditional switch-selective phase shifters are difficult to implement effectively in low-frequency ultra-wideband applications.

[0005] To address the issues of large chip area, low phase shifting accuracy, and large amplitude fluctuations in phase shifters for low-frequency ultrawideband applications, DM Zaiden, JE Grandfield, “Compact and Wideband MMIC Phase Shifters Using Tunable Active Inductor-Loaded All-Pass Networks,” IEEE Trans. Microwave Theory Techn., vol. 66, no. 2, pp. 1047-1057, Feb. 2018, doi:10.1109 / TMTT.2017.2766061. A MMIC phase shifter architecture with adjustable active differential inductors and an all-pass network was proposed, providing a solution for S-band and L-band phased array systems. However, it is noted that this technology operates in the 1.5-3.0 GHz frequency band, with an RMS phase error of <9° and an RMS gain error of <1.5 dB. Its low phase shifting accuracy and large amplitude fluctuations make it difficult to promote in practical applications. Furthermore, its operating frequency band is still above 1 GHz, and its relative bandwidth is only 67%. In summary, current research on broadband digital phase shifters for the Sub-GHz band is limited, and there is a lack of effective technical solutions to simultaneously address multiple issues such as phase shifting accuracy, amplitude variation, chip area, and cost.

[0006] Therefore, there is an urgent need for a technical solution that balances narrow chip area, high phase shift accuracy, low amplitude fluctuation and wide operating bandwidth to solve the core technical bottlenecks faced by Sub-GHz band phase shifters and fill the technical gap in high-performance broadband digital phase shifters. Summary of the Invention

[0007] Based on the above-mentioned technical problems, this application discloses a broadband digital phase shifter based on inductor shared topology and equivalent bandpass network, including a phase shift circuit module and a drive circuit module.

[0008] The phase shift circuit module includes six basic phase shift units: a 5.625° phase shifter, an 11.25° phase shifter, a 22.5° phase shifter, a 45° phase shifter, a 90° phase shifter, and a 180° phase shifter. The 5.625° and 11.25° phase shifters are fine-tuning phase shift units, while the 22.5°, 45°, 90°, and 180° phase shifters are coarse-tuning phase shift units. These six basic phase shift units work together to achieve 64 phase shift states, with a phase shift step of 5.625°, covering a total phase shift range of 0°-360°.

[0009] The 5.625° phase shifter consists of an inductor L1, a capacitor C1, a capacitor C2, and four switching transistors M1-M4; the 11.25° phase shifter consists of an inductor L2, a capacitor C3, a capacitor C4, and four switching transistors M5-M8.

[0010] The 22.5° phase shifter includes a reference path, a phase shift path, and a switching network. The reference path is a full-pass network, and the phase shift path is an equivalent bandpass network. The full-pass network includes inductors L3 and L4 and capacitors C5 and C6. The equivalent bandpass network includes inductors L5, L6, and L7 and capacitors C7, C8, C9, and C10. 10 The switching network contains eight switching transistors M9-M 16 ;

[0011] The 45° phase shifter includes a reference path, a phase shift path, and a switching network. The reference path is a full-pass network, and the phase shift path is an equivalent bandpass network. The full-pass network includes inductors L8 and L9 and capacitor C. 11 C 12 The equivalent bandpass network includes inductance L 10 L 11 L 12 and capacitor C 13 C 14 C 15 C 16 The switching network contains eight switching transistors M 17 -M 24 ;

[0012] The 90° phase shifter includes a reference path, a phase shift path, and a switching network. The reference path is a full-pass network, and the phase shift path is an equivalent bandpass network. The full-pass network includes an inductor L. 13 L 14 and capacitor C 17 C 18 The equivalent bandpass network includes inductance L 15 L 16 L 17 and capacitor C 19 C 20 C 21 C 22 The switching network contains eight switching transistors M 25 -M 32 ;

[0013] The 180° phase shifter includes a reference path, a phase shift path, and a switching network. The reference path is a full-pass network, and the phase shift path is an equivalent bandpass network. The full-pass network includes an inductor L. 18 L 19 L 20 L 21 and capacitor C 23 C24 The equivalent bandpass network includes inductance L 22 L 23 L 24 and capacitor C 25 C 26 C 27 C 28 The switching network contains eight switching transistors M 33 -M 40 ;

[0014] The drive circuit module consists of a 6-bit input control signal interface and 6 level conversion circuits.

[0015] Preferably, both the 5.625° phase shifter and the 11.25° phase shifter adopt an inductor-shared topology; wherein in the inductor-shared topology of the 5.625° phase shifter, inductor L1 is split into two L1 / 2 connected in series, and capacitor C2 is split into two C2 / 2 connected in parallel; in the inductor-shared topology of the 11.25° phase shifter, inductor L2 is split into two L2 / 2 connected in series, and capacitor C4 is split into two C4 / 2 connected in parallel.

[0016] Preferably, the all-pass network used in the reference paths of the 22.5° phase shifter, 45° phase shifter, 90° phase shifter, and 180° phase shifter all consists of a specific connection structure composed of capacitors and inductors; wherein in the all-pass network of the 22.5° phase shifter, capacitors C5 and C6 are connected to inductor L3 in sequence; in the all-pass network of the 45° phase shifter, capacitors C9 and C6 are connected to inductor L3 in sequence. 10 Connected sequentially to inductor L6; in the all-pass network of the 90° phase shifter, capacitor C 13 C 14 Connected sequentially to inductor L9; in the all-pass network of the 180° phase shifter, capacitor C 17 C 18 With inductor L 12 L 13 Connect them sequentially.

[0017] Preferably, the equivalent bandpass networks used in the phase shift paths of the 22.5° phase shifter, 45° phase shifter, 90° phase shifter, and 180° phase shifter are all formed by cascading high-pass and low-pass networks; wherein in the equivalent bandpass network of the 22.5° phase shifter, capacitor C7 and inductor L5 are connected in series to form a high-pass network, and capacitor C8 and inductor L4 are connected in series to form a low-pass network, with the high-pass and low-pass networks connected end-to-end; in the equivalent bandpass network of the 45° phase shifter, capacitor C... 11 A high-pass network is formed by connecting it in series with inductor L8, and capacitor C 12 A low-pass network is formed by connecting it in series with inductor L7, and the high-pass network is connected end-to-end with the low-pass network; in the equivalent bandpass network of the 90° phase shifter, capacitor C 15 With inductor L11 The series connection forms a Qualcomm network, and the capacitor C 16 With inductor L 10 A series connection forms a low-pass network, and the high-pass network is connected end-to-end with the low-pass network; in the equivalent bandpass network of the 180° phase shifter, the capacitor C 19 With inductor L 15 The series connection forms a Qualcomm network, and the capacitor C 20 With inductor L 14 The high-pass network is connected in series to form a low-pass network, and the high-pass network is connected end to end with the low-pass network.

[0018] Preferably, in the 5.625° phase shifter, one end of capacitor C1 is connected to the signal input terminal, and the other end is connected to one end of inductor L1. The other end of inductor L1 is connected to the signal output terminal. The two ends of capacitor C2 are respectively connected to the two ends of inductor L1. Switching transistors M1 and M2 are connected in series and then in parallel across capacitor C2. Switching transistors M3 and M4 are connected in series and then in parallel across capacitor C2. In the 11.25° phase shifter, the connection method of each component is the same as that of the 5.625° phase shifter.

[0019] Preferably, in the all-pass network of the 22.5° phase shifter, one end of inductor L3 is connected to the signal input terminal, and the other end is connected to one end of capacitor C5. The other end of capacitor C5 is connected to one end of capacitor C6, and the other end of capacitor C6 is connected to the signal output terminal. The two ends of inductor L4 are respectively connected to the connection point of capacitors C5 and C6 and ground. In the equivalent bandpass network, one end of inductor L5 is connected to the signal input terminal, and the other end is connected to one end of capacitor C7. The other end of capacitor C7 is connected to one end of capacitor C8, and the other end of capacitor C8 is connected to the signal output terminal. The two ends of inductor L6 are respectively connected to the connection point of capacitors C7 and C8 and ground. The two ends of inductor L7 are respectively connected to the signal input terminal and ground. In the 45° phase shifter, 90° phase shifter, and 180° phase shifter, the component connection method of the all-pass network and the equivalent bandpass network is the same as that of the 22.5° phase shifter.

[0020] Preferably, in the all-pass network of the 180° phase shifter, the inductor L 12 With inductor L 13 They are connected in series to form a fully passable network structure with two inductors connected in series. This two-inductor series structure is located at the signal input terminal of the fully passable network and the capacitor C. 17 between.

[0021] Preferably, the switching network of the 22.5° phase shifter, 45° phase shifter, 90° phase shifter, and 180° phase shifter achieves signal path switching by controlling the on and off states of each switching transistor; wherein in the switching network of the 22.5° phase shifter, switching transistors M9 and M... 10 The switching transistor M is connected to the input and output terminals of the all-through network, respectively. 15 M16 The switching transistor M is connected to the output of the all-pass network and the total output of the phase shifter, respectively. 11 M 12 The switching transistor M is connected to the input and output terminals of the equivalent bandpass network, respectively. 13 M 14 They are respectively connected to the output terminal of the equivalent bandpass network and the total output terminal of the phase shifter; the connection method of each switching transistor in the switching networks of the 45° phase shifter, 90° phase shifter and 180° phase shifter is the same as that of the switching network of the 22.5° phase shifter.

[0022] Preferably, the six level conversion circuits of the driving circuit module correspond to six basic phase shifting units. The input terminal of each level conversion circuit is connected to the corresponding pin of the 6-bit input control signal interface, and the output terminal is connected to the control terminal of the switching transistor in the corresponding basic phase shifting unit. Each level conversion circuit has a voltage conversion unit inside, which is used to convert the input 0V or +5V control signal into a complementary voltage pair of 0V and -5V.

[0023] Preferably, the switching transistors M1-M in the six basic phase-shifting units 40 All are depletion-type pHEMTs. The source of each switching transistor is grounded, the drain is connected to the capacitor or inductor in the corresponding phase-shifting unit, and the gate is connected to the output of the corresponding level conversion circuit in the drive circuit module.

[0024] Compared with the prior art, the technical solution of this application has the following technical effects:

[0025] This invention allows the phase shift path and the reference path to share a single circuit architecture through an inductor-shared topology. This eliminates the need to configure separate inductors and switching transistors for the two paths, simplifying the circuit design from a structural perspective. It also reduces the number of key components used inside the chip and avoids the area waste caused by the dispersed layout of components in the traditional dual SPDT architecture. This makes the overall chip layout more compact, effectively reducing the material cost and process complexity of chip manufacturing, and is more suitable for the integration requirements of miniaturized electronic devices.

[0026] This invention employs a combined topology of an equivalent bandpass network and an all-pass network to optimize amplitude stability during phase shifting. The equivalent bandpass network, composed of cascaded high-pass and low-pass networks, exhibits significantly better amplitude-frequency response flatness than a single high-pass or low-pass network, effectively mitigating the problem of excessive amplitude differences between paths in traditional topologies. Combined with the wideband impedance matching characteristics of the all-pass network, amplitude loss and fluctuations in signal transmission are further reduced. This design allows the phase shifter to output a more stable signal amplitude across a wide operating frequency band, avoiding the impact of amplitude fluctuations on the signal processing accuracy of downstream systems.

[0027] This invention improves the overall RF performance and environmental adaptability of the phase shifter through multi-dimensional circuit optimization. The introduction of a dual-inductor all-pass network in the 180° phase shifter precisely tunes the amplitude-frequency response, ensuring that the differential amplitude response of the all-pass network and the equivalent bandpass network maintains maximum flatness, further reducing phase error. At the same time, the overall circuit design fully considers the impact of temperature on performance, and can still operate stably over a wide temperature range, avoiding problems such as phase shift and sudden increase in insertion loss under extreme temperature conditions, thus providing a guarantee for the reliable application of the phase shifter under complex operating conditions.

[0028] This invention provides a more adaptable phase shifter solution for Sub-GHz band applications. It can achieve full-range phase shift control with only 6-bit digital signals, eliminating the need for complex control circuits and reducing the integration difficulty with devices such as the Internet of Things and drones. At the same time, the circuit architecture has flexible adjustment space, which can simplify or expand the number of phase shifting units according to actual needs, adapting to application scenarios with different accuracy, cost and area requirements, and providing strong support for the implementation of technologies such as Sub-GHz band phased array radar and beamforming systems.

[0029] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the preferred embodiments of this application are described in detail below with reference to the accompanying drawings.

[0030] The above and other objects, advantages and features of this application will become more apparent to those skilled in the art from the following detailed description of specific embodiments in conjunction with the accompanying drawings. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In all drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0032] Based on the description of the figures and their corresponding technical content in the document, the titles of the figures are as follows:

[0033] Figure 1 This is an overall topology block diagram of the broadband digital phase shifter based on inductor-shared topology and equivalent bandpass network of the present invention;

[0034] Figure 2This is a block diagram of a 6-phase shifter circuit for a broadband digital phase shifter based on an inductor-shared topology and an equivalent bandpass network, as described in this invention.

[0035] Figure 3 This invention relates to the inductor-shared topology of the fine phase-shifting unit in a broadband digital phase-shifter circuit based on inductor-shared topology and equivalent bandpass network.

[0036] Figure 4 This invention relates to the circuit architecture of the coarse-tuning phase-shifting unit in a broadband digital phase-shifter based on an inductor-shared topology and an equivalent bandpass network.

[0037] Figure 5 This invention provides the all-pass network-reference path in the coarse-tuning phase-shifting unit of a broadband digital phase-shifter circuit based on inductor shared topology and equivalent bandpass network.

[0038] Figure 6 This invention relates to the equivalent all-pass network-phase-shifting path in the coarse-tuning phase-shifting unit of a broadband digital phase shifter based on inductor shared topology and equivalent bandpass network.

[0039] Figure 7 This is a chip photograph of the completed fabrication of the broadband digital phase shifter based on inductor shared topology and equivalent bandpass network of the present invention.

[0040] Figure 8 The test results of the broadband digital phase shifter based on inductor shared topology and equivalent bandpass network of this invention - basic state;

[0041] Figure 9 Test results of the broadband digital phase shifter based on inductor-shared topology and equivalent bandpass network of this invention - full state;

[0042] Figure 10 The phase-shifting performance test results of the broadband digital phase shifter based on inductor-shared topology and equivalent bandpass network of this invention are presented in full state. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. In the following description, specific details such as specific configurations and components are provided merely to help fully understand the embodiments of this application. Therefore, those skilled in the art should understand that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of this application. In addition, for clarity and brevity, descriptions of known functions and structures are omitted in the embodiments.

[0044] It should be understood that the phrase "an embodiment" or "this embodiment" throughout the specification means that a specific feature, structure, or characteristic related to the embodiment is included in at least one embodiment of this application. Therefore, "an embodiment" or "this embodiment" appearing throughout the specification does not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments.

[0045] Furthermore, reference numerals and / or letters may be repeated in different examples within this application. Such repetition is for the purpose of simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or settings discussed.

[0046] In this article, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, B exists alone, and A and B exist simultaneously. The term " / and" in this article describes another type of relationship between related objects, indicating that two relationships can exist. For example, A / and B can mean: A exists alone, and A and B exist alone. In addition, the character " / " in this article generally indicates that the related objects before and after it are in an "or" relationship.

[0047] In this article, the term "at least one" is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, "at least one of A and B" can mean: A exists alone, A and B exist simultaneously, or B exists alone.

[0048] It should also be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion.

[0049] Example 1

[0050] This embodiment mainly describes a broadband digital phase shifter based on an inductor-shared topology and an equivalent bandpass network, such as... Figure 1 As shown, it includes a phase shift circuit module and a drive circuit module;

[0051] The phase shift circuit module includes a fine phase shift unit and a coarse phase shift unit, such as... Figure 2 As shown, the fine phase shifting unit includes a 5.625° phase shifter and an 11.25° phase shifter. The fine phase shifting unit adopts an inductor-shared topology, with the phase shifting path and the reference path sharing the same circuit topology. This reduces the number of inductors and switching transistors, significantly reducing the chip area and manufacturing costs.

[0052] The 5.625° phase shifter consists of an inductor L1, a capacitor C1, a capacitor C2, and four switching transistors M1-M4; the 11.25° phase shifter consists of an inductor L2, a capacitor C3, a capacitor C4, and four switching transistors M5-M8.

[0053] Phase shift circuit module, such as Figure 2 As shown, the coarse-adjustment phase-shifting unit includes 22.5°, 45°, 90°, and 180° phase shifters. The coarse-adjustment phase-shifting unit employs a combined topology of an all-pass network (reference path) and an equivalent bandpass network (phase-shifting path), minimizing the amplitude difference between the phase-shifting path and the reference path. The equivalent bandpass network is formed by cascading high-pass and low-pass networks, and its amplitude-frequency response flatness is superior to that of a single high-pass or low-pass network. The phase-shifting accuracy and amplitude fluctuation of the phase shifter are mainly determined by the large-scale phase-shifting unit. An inductor L is introduced in the 180° phase shifter. 12 This forms a dual-inductor all-pass network structure. The amplitude-frequency response of the all-pass network is then tuned to ensure that the differential amplitude response between the all-pass network and the equivalent bandpass network maintains maximum flatness within the operating bandwidth, further suppressing amplitude fluctuations.

[0054] The 22.5° phase shifter includes a reference path, a phase shift path, and a switching network. The reference path is a full-pass network, and the phase shift path is an equivalent bandpass network. The full-pass network includes inductors L3 and L4 and capacitors C5 and C6. The equivalent bandpass network includes inductors L5, L6, and L7 and capacitors C7, C8, C9, and C10. 10 The switching network contains eight switching transistors M9-M 16 ;

[0055] The 45° phase shifter includes a reference path, a phase shift path, and a switching network. The reference path is a full-pass network, and the phase shift path is an equivalent bandpass network. The full-pass network includes inductors L8 and L9 and capacitor C. 11 C 12 The equivalent bandpass network includes inductance L 10 L 11 L 12 and capacitor C 13 C 14 C 15 C 16 The switching network contains eight switching transistors M 17 -M 24 ;

[0056] The 90° phase shifter includes a reference path, a phase shift path, and a switching network. The reference path is a full-pass network, and the phase shift path is an equivalent bandpass network. The full-pass network includes an inductor L. 13 L 14 and capacitor C 17 C 18 The equivalent bandpass network includes inductance L15 L 16 L 17 and capacitor C 19 C 20 C 21 C 22 The switching network contains eight switching transistors M 25 -M 32 ;

[0057] The 180° phase shifter includes a reference path, a phase shift path, and a switching network. The reference path is a full-pass network, and the phase shift path is an equivalent bandpass network. The full-pass network includes an inductor L. 18 L 19 L 20 L 21 and capacitor C 23 C 24 The equivalent bandpass network includes inductance L 22 L 23 L 24 and capacitor C 25 C 26 C 27 C 28 The switching network contains eight switching transistors M 33 -M 40 ;

[0058] The drive circuit module includes a 6-bit input control signal interface and 6 level conversion circuits. The 6-bit input control signal is a 0V or +5V voltage signal. The 6 level conversion circuits output complementary 0V and -5V voltage pairs to directly drive the depletion-mode pHEMT switching transistor. The 6-bit control signal corresponds to 6 basic phase shift units, realizing 64 phase shift states with a phase shift step of 5.625° and a total phase shift range of 0° - 360°.

[0059] The circuit parameters of the fine phase-shifting unit are shown below:

[0060] In the 5.625° phase shifter:

[0061] In the 11.25° phase shifter:

[0062] Circuit parameters of the coarse-tuning phase-shifting unit:

[0063] In the 22.5° phase shifter:

[0064] In the 45° phase shifter:

[0065] In the 90° phase shifter:

[0066] In the 180° phase shifter:

[0067] The phase shift circuit includes 6 basic phase shift units. Each phase shift unit includes a phase shift path and a reference path. The phase difference between the two paths is the phase shift amount of the unit. According to the principle of placing the phase shift units with good standing wave performance at both ends and the phase shift units with slightly worse standing wave performance in the middle, the cascading order from input to output is: 90° phase shifter, 5.625° phase shifter, 180° phase shifter, 45° phase shifter, 11.25° phase shifter, and 22.5° phase shifter.

[0068] The 5.625° and 11.25° phase shifters in the fine phase shift unit use the same circuit structure, such as... Figure 3 As shown, Figure 3 (a) is an inductor-shared circuit architecture. Figure 3 (b) is the bandpass network reference path when M1-M4 are turned off. Figure 3 (c) is the low-pass network-phase shift path when M1-M4 are on; taking a 5.625° phase shifter as an example, it includes inductor L1, capacitor C1, capacitor C2 and four switching transistors M1-M4. When M1-M4 are off, the circuit is equivalent to a bandpass network as the reference path; when M1-M4 are on, the circuit is equivalent to a low-pass network as the phase shift path; the phase shift path and the reference path share the first inductor L1; the 11.25° phase shifter includes inductor L2, capacitor C3, capacitor C4 and four switching transistors M5-M8. When M5-M8 are off, the circuit is equivalent to a bandpass network as the reference path; when M5-M8 are on, the circuit is equivalent to a low-pass network as the phase shift path; the phase shift path and the reference path share the second inductor L2.

[0069] This invention employs an inductor-sharing topology in a fine phase shifter, reducing the number of switching transistors by 50%. Simultaneously, the phase shift path and reference path reuse the same circuit architecture, sharing inductors. Each fine phase shifter uses one less inductor, resulting in a total reduction of two inductors. In low-frequency applications, inductors occupy a large area; this invention effectively reduces chip costs. Including ESD protection, pads, and driver circuitry, the total area is only 4.9 × 3.0 mm². Figure 7 As shown.

[0070] The coarse-tuning phase shifter reference path adopts an all-through network topology, such as... Figure 4 As shown, the components in the circuit have been renumbered, and the equivalent circuit of the all-pass network is as follows. Figure 5 As shown, the all-through network circuit is as follows: Figure 5As shown in (a), the parity-mode equivalent circuit of the all-pass network is as follows: Figure 5 As shown in (b), the odd-mode equivalent circuit is as follows: Figure 5 As shown in (c), the even-mode equivalent circuit is as follows: Figure 5 As shown in (d), based on the analysis method of symmetrical circuits, the S-parameters can be obtained as follows:

[0071]

[0072]

[0073] From (1) and (2), we can see that when When, then S 11 =0, independent of frequency, indicating that the all-pass network can achieve impedance matching over a wide bandwidth. At this point, |S 21 |=1 indicates that the all-pass network is a lossless system, which can reduce the reference state insertion loss of the phase shifter and maximize the working efficiency of the phase shifter.

[0074] The phase shift path of the coarse-adjustment phase shifter adopts an equivalent bandpass network topology formed by cascading high-pass and low-pass networks, such as... Figure 6 As shown, the components in the circuit have been renumbered. L4 and C6 form a low-pass network, and C5 and L6 form a high-pass network. The low-pass network and the high-pass network are cascaded to form an equivalent bandpass characteristic, which reduces the amplitude fluctuation by 60% compared to a single high-pass or low-pass network.

[0075] The 180° phase shifter is the main source of amplitude fluctuation and requires special optimization. A dual-inductor all-pass network is used, and all components in the circuit have been renumbered. An inductor L2 = 30nH is added to the traditional all-pass network. L2 and L3 are connected in series and located at the input of the all-pass network. The introduction of L2 changes the amplitude-frequency response curve of the all-pass network, making it closer to the amplitude-frequency response of the equivalent bandpass network. The differential amplitude of the two paths maintains maximum flatness within the operating bandwidth. Without optimization, the amplitude fluctuation of the 180° phase shifter is ±1.2dB. After optimization, the amplitude fluctuation is reduced to ±0.6dB, an improvement of 50%.

[0076] The drive circuit module includes a 6-bit input control signal interface and 6 level conversion circuits; each phase shift unit is equipped with one level conversion circuit, for a total of 6; the input control signal is 0V or +5V (TTL level), from the FPGA or microcontroller, and the output complementary voltage pair is 0V and -5V to directly drive the gate of the depletion-type pHEMT. The power supply is VDD = 0V, VEE = -5V, and the conversion delay is less than 20ns.

[0077] The control logic consists of 6 control signals (Control 1-6) corresponding to 6 phase shifting units, as shown in the table below.

[0078] The phase shift state code has a total of 64 states, with a phase shift step of 5.625°. The relationship between the control code and the phase shift amount is as follows:

[0079] Based on the above, a specific test implementation method is provided, which is as follows:

[0080] The process implementation includes:

[0081] Manufacturing process: 0.15μm GaAs pHEMT process, number of metal layers: 3, dielectric layer: SiN

[0082] Chip layout: Total area: 4.9mm × 3.0mm = 14.7mm², Input / output pads: 0.3mm² each, ESD protection circuit: 0.5mm², Driver circuit: 2.0mm², Phase shift circuit: 11.9mm².

[0083] Passive components are used to implement the following: Inductor: a spiral inductor with a line width of 10μm and 3-8 turns; Capacitor: a MIM capacitor with a dielectric thickness of 0.2μm; Resistor: a thin film resistor with a sheet resistance of 50Ω / □.

[0084] The test results are as follows:

[0085] Test conditions: Test equipment: Agilent PNA-X network analyzer; Test method: on-wafer; Probe station: Cascade Microtech; Power supply voltage: VEE = -5V; Control voltage: +5V / 0V (input), 0V / -5V (after conversion); Temperatures: -55°C, +25°C, +85°C.

[0086] S-parameter test results: Input return loss (S) 11 )like Figure 9 As shown in (a), Figure 9 (a) Input return loss S11, better than -14dB across the entire frequency band, output return loss (S 22 )like Figure 9 As shown in (b), the impedance matching performance is better than -13dB across the entire frequency band. Figure 9 (c) is the original Smith chart of the input standing wave. Figure 9 (d) is the Smith chart of the output standing wave; insertion loss (S 21 ),like Figure 9 As shown in (e), the full-band loss is less than -9dB, and the variation range of the 64 phase shift states is 7.0-8.8dB. The variation of the reference state insertion loss under three temperature conditions is as follows. Figure 9As shown in (f), Figure 9 (f) represents the insertion loss under three temperature conditions (-55℃, +25℃, +85℃) in the reference state. The insertion loss increases by about 1dB under high temperature conditions and decreases by about 1dB under low temperature conditions, showing good temperature stability.

[0087] Phase shift performance test results: The phase of the 64-state output signal is as follows Figure 10 As shown in (a), the quantized phase shift value is as follows Figure 10 As shown in (b), the theoretical phase shift step is 5.625°, the actual measurement is 5.5° - 5.8°, and the phase shift error is as follows: Figure 10 As shown in (c), the phase shift error is <±6°, and the amplitude fluctuation is as follows: Figure 10 As shown in (d), the amplitude variations of the 64 phase-shifting states are all within ±0.8 dB, exhibiting good amplitude stability. The RMS phase error and RMS amplitude error under the three-temperature conditions are as follows: Figure 10 As shown in (e), the RMS phase error is <3.3°, the root mean square amplitude error is <0.4dB, and the RMS phase error variation under three temperature conditions is less than 1.7°, while the RMS amplitude error variation is <0.2dB, demonstrating high phase shift accuracy and temperature stability, and low amplitude fluctuation. The phase shift effect of the fundamental state at room temperature is as follows: Figure 8 As shown.

[0088] Linearity test results: P-1dB (input 1dB compression point) Figure 10 As shown in (f), the full-band impedance is greater than 21.5dBm, and the IIP3 (input third-order intermodulation point @350MHz) is 32dBm (estimated).

[0089] In one preferred embodiment, a simplified 4-phase shifter comprises only 4 phase shifting units:

[0090] The phase shifting unit consists of: a 22.5° phase shifter, a 45° phase shifter, a 90° phase shifter, and a 180° phase shifter.

[0091] Performance specifications: Phase shift step: 22.5°, Total number of states: 16 (2 4 RMS phase error: <5°, RMS amplitude error: <0.6dB, chip area: 3.5mm × 2.5mm (actual measurement results)

[0092] Application scenarios: Applications with low phase shift accuracy requirements, cost-sensitive applications, and applications with limited chip area.

[0093] In one preferred embodiment, the extended 7-phase shifter includes 7 phase shifting units, including: a 2.8125° phase shifter (fine unit, inductor-shared topology), a 5.625° phase shifter (fine unit, inductor-shared topology), an 11.25° phase shifter (fine unit, inductor-shared topology), a 22.5° phase shifter (coarse adjustment unit, equivalent bandpass network), a 45° phase shifter (coarse adjustment unit, equivalent bandpass network), a 90° phase shifter (coarse adjustment unit, equivalent bandpass network), and a 180° phase shifter (coarse adjustment unit, dual-inductor optimized).

[0094] The performance metrics (simulation results) are: phase shift step: 2.8125°, total number of states: 128 (2 7 RMS phase error: <2°, RMS amplitude error: <0.3dB, chip area: 5.5mm × 3.5mm, application scenarios: high-precision phased array radar, precision beamforming system.

[0095] One preferred embodiment of this application is the specific implementation of different processes;

[0096] 0.25μm GaAs process: The transistor gate width is increased to 300μm, the on-resistance is about 5Ω, the insertion loss is increased by 0.5-1dB, and the chip area is increased by about 20%.

[0097] 0.5μm GaAs process: transistor gate width increases to 500μm, on-resistance is about 8Ω, insertion loss increases by 1-1.5dB, chip area increases by about 40%, and cost decreases by about 30%.

[0098] SiGe process: can achieve high integration, can integrate control circuits, and has lower cost, but its high-frequency performance is slightly worse.

[0099] CMOS SOI process: highest integration, system-on-a-chip (SoC), low cost, but limited RF performance.

[0100] This embodiment details how, by using an inductor-shared topology, the phase shifting path and reference path of the fine phase shifter share a single circuit topology. By introducing an equivalent bandpass network formed by cascading high-pass and low-pass networks into the phase shifting path of the coarse phase shifter, and combining it with the reference path composed of an all-pass network, it achieves small phase shift amplitude fluctuations with a relative bandwidth greater than 80%. It features low operating frequency, wide relative bandwidth, high phase shift accuracy, and small amplitude variation, and the chip area is also very compact, making it very suitable for phased array applications and beamforming systems in the Sub-GHz band.

[0101] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. For those skilled in the art, the present invention can have various modifications and variations. Any changes, modifications, substitutions, integrations, and parameter changes made to these embodiments within the spirit and principles of the present invention, without departing from the principles and spirit of the present invention, through conventional substitutions or to achieve the same function, fall within the scope of protection of the present invention.

Claims

1. Wideband digital phase shifter based on inductance sharing topology and equivalent bandpass network, characterized in that, The phase shift circuit module and the driving circuit module are included; The phase shift circuit module includes six basic phase shift units, which are a 5.625° phase shifter, an 11.25° phase shifter, a 22.5° phase shifter, a 45° phase shifter, a 90° phase shifter and a 180° phase shifter, wherein the 5.625° phase shifter and the 11.25° phase shifter are fine phase shift units, and the 22.5° phase shifter, the 45° phase shifter, the 90° phase shifter and the 180° phase shifter are coarse phase shift units; the six basic phase shift units work together to realize 64 phase shift states, the phase shift step is 5.625°, and the total phase shift range covers 0°-360°; The 5.625° phase shifter is composed of an inductor L1, a capacitor C1, a capacitor C2 and four switch transistors M1-M4; and the 11.25° phase shifter is composed of an inductor L2, a capacitor C3, a capacitor C4 and four switch transistors M5-M8. The 22.5° phase shifter comprises a reference path, a phase shift path and a switch network, the reference path is an all-pass network, the phase shift path is an equivalent band-pass network, the all-pass network comprises inductors L3, L4 and capacitors C5, C6, the equivalent band-pass network comprises inductors L5, L6, L7 and capacitors C7, C8, C9, C 10 10, the switch network comprises eight switch transistors M9-M 16 18. The 45° phase shifter comprises a reference path, a phase shift path and a switch network, the reference path is an all-pass network, the phase shift path is an equivalent band-pass network, the all-pass network comprises inductors L8, L9 and capacitors C 11 , 12 , the equivalent band-pass network comprises inductors L 10 , L 11 , L 12 and capacitors C 13 , C 14 , C 15 , C 16 , and the switch network comprises eight switch transistors M 17 -M 24 ; The 90° phase shifter comprises a reference path, a phase shift path and a switch network, the reference path is an all-pass network, the phase shift path is an equivalent band-pass network, the all-pass network comprises inductors L 13 , L 14 and capacitors C 17 , C 18 , the equivalent band-pass network comprises inductors L 15 , L 16 , L 17 and capacitors C 19 , C 20 , C 21 , C 22 , and the switch network comprises eight switch transistors M 25 -M 32 ; The 180° phase shifter comprises a reference path, a phase shift path and a switch network, the reference path is an all-pass network, the phase shift path is an equivalent band-pass network, the all-pass network comprises inductors L 18 、 19 、 20 、 21 and capacitors C 23 、 24 、 22 、 23 、 24 、 25 、 26 、 27 、 28 , the switch network comprises eight switch transistors M 33 -M 40 ; The driving circuit module is composed of a 6-bit input control signal interface and six level conversion circuits.

2. The wideband digital phase shifter of claim 1, wherein, The 5.625° phase shifter and the 11.25° phase shifter both adopt an inductance sharing topology structure; in the inductance sharing topology structure of the 5.625° phase shifter, the inductor L1 is split into two L1 / 2 and connected in series, and the capacitor C2 is split into two C2 / 2 and connected in parallel; in the inductance sharing topology structure of the 11.25° phase shifter, the inductor L2 is split into two L2 / 2 and connected in series, and the capacitor C4 is split into two C4 / 2 and connected in parallel.

3. The wideband digital phase shifter of claim 1, wherein, The all-pass networks adopted by the reference paths of the 22.5° phase shifter, 45° phase shifter, 90° phase shifter and 180° phase shifter are composed of capacitors and inductors in specific connection structures; in the all-pass network of the 22.5° phase shifter, the capacitors C5, C6 and the inductor L3 are connected in sequence; in the all-pass network of the 45° phase shifter, the capacitors C9, C 10 and the inductor L6 are connected in sequence; in the all-pass network of the 90° phase shifter, the capacitors C 13 , C 14 and the inductors L9 are connected in sequence; in the all-pass network of the 180° phase shifter, the capacitors C 17 , C 18 and the inductors L 12 , L 13 are connected in sequence.

4. The wideband digital phase shifter of claim 3, wherein, The equivalent band-pass networks adopted by the phase shift paths of the 22.5° phase shifter, 45° phase shifter, 90° phase shifter and 180° phase shifter are all formed by cascading high-pass networks and low-pass networks; wherein in the equivalent band-pass network of the 22.5° phase shifter, the capacitor C7 and the inductor L5 are connected in series to form a high-pass network, the capacitor C8 and the inductor L4 are connected in series to form a low-pass network, and the high-pass network and the low-pass network are connected in head-to-tail manner; in the equivalent band-pass network of the 45° phase shifter, the capacitor C 11 and the inductor L8 are connected in series to form a high-pass network, the capacitor C 12 and the inductor L7 are connected in series to form a low-pass network, and the high-pass network and the low-pass network are connected in head-to-tail manner; in the equivalent band-pass network of the 90° phase shifter, the capacitor C 15 and the inductor L 11 are connected in series to form a high-pass network, the capacitor C 16 and the inductor L 10 are connected in series to form a low-pass network, and the high-pass network and the low-pass network are connected in head-to-tail manner; in the equivalent band-pass network of the 180° phase shifter, the capacitor C 19 and the inductor L 15 are connected in series to form a high-pass network, the capacitor C 20 and the inductor L 14 are connected in series to form a low-pass network, and the high-pass network and the low-pass network are connected in head-to-tail manner.

5. The wideband digital phase shifter of claim 1, wherein, In the 5.625° phase shifter, one end of the capacitor C1 is connected to a signal input end, the other end is connected to one end of the inductor L1, the other end of the inductor L1 is connected to a signal output end, and the two ends of the capacitor C2 are respectively connected to the two ends of the inductor L1; the switch transistors M1 and M2 are connected in series and then connected in parallel to the two ends of the capacitor C2, and the switch transistors M3 and M4 are connected in series and then connected in parallel to the two ends of the capacitor C2; in the 11.25° phase shifter, the connection modes of the elements are consistent with those of the 5.625° phase shifter.

6. The wideband digital phase shifter of claim 1, wherein, In the all-pass network of the 22.5° phase shifter, one end of the inductor L3 is connected to a signal input end, the other end is connected to one end of the capacitor C5, the other end of the capacitor C5 is connected to one end of the capacitor C6, the other end of the capacitor C6 is connected to a signal output end, and the two ends of the inductor L4 are respectively connected to the connection points of the capacitor C5 and the capacitor C6 and the ground; in the equivalent band-pass network, one end of the inductor L5 is connected to a signal input end, the other end is connected to one end of the capacitor C7, the other end of the capacitor C7 is connected to one end of the capacitor C8, the other end of the capacitor C8 is connected to a signal output end, the two ends of the inductor L6 are respectively connected to the connection points of the capacitor C7 and the capacitor C8 and the ground, and the two ends of the inductor L7 are respectively connected to the signal input end and the ground; in the 45° phase shifter, the 90° phase shifter and the 180° phase shifter, the element connection modes of the all-pass network and the equivalent band-pass network are consistent with those of the 22.5° phase shifter.

7. The wideband digital phase shifter of claim 1, wherein, In the all-pass network of the 180° phase shifter, the inductor L 12 is connected in series with the inductor L 13 to form a double inductor series all-pass network structure, which is located between the signal input end of the all-pass network and the capacitor C 17 .

8. The wideband digital phase shifter of claim 1, wherein, The switch networks of the 22.5° phase shifter, 45° phase shifter, 90° phase shifter and 180° phase shifter realize signal path switching by controlling the on and off states of the switch transistors; in the switch network of the 22.5° phase shifter, switch transistors M9, M 10 are connected to the input end and output end of the all-pass network respectively, switch transistors M 15 , M 16 are connected to the output end of the all-pass network and the total output end of the phase shifter respectively, switch transistors M 11 , M 12 are connected to the input end and output end of the equivalent band-pass network respectively, switch transistors M 13 , M 14 are connected to the output end of the equivalent band-pass network and the total output end of the phase shifter respectively; in the switch networks of the 45° phase shifter, 90° phase shifter and 180° phase shifter, the connection modes of the switch transistors are consistent with those of the switch network of the 22.5° phase shifter.

9. The wideband digital phase shifter of claim 1, wherein, The 6 level conversion circuits of the driving circuit module correspond to 6 basic phase shift units, the input end of each level conversion circuit is connected with the corresponding pin of the 6-bit input control signal interface, and the output end is connected with the control end of the switch transistor in the corresponding basic phase shift unit; a voltage conversion unit is arranged in each level conversion circuit, which is used for converting the input 0V or +5V control signal into a complementary voltage pair of 0V and -5V.

10. The wideband digital phase shifter of claim 9, wherein, The switching transistors M1-M 40 are all depletion-mode pHEMTs, the source of each switching transistor is grounded, the drain is connected with the capacitor or inductor in the corresponding phase-shifting unit, and the gate is connected with the output terminal of the corresponding level conversion circuit in the driving circuit module.

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