A voltage controlled oscillator coupled array circuit and scalable phased array system

Abstract

This invention discloses a voltage-controlled oscillator (VCO) coupled array circuit and a scalable phased array system. The circuit comprises several cascaded VCO chips. Two transmission lines within each VCO chip achieve common-mode coupling between two cross-coupled VCOs. Two bonding lines between the VCO chips enable cascading connections and common-mode coupling between cross-coupled VCOs in preceding and following stages. This effectively suppresses phase noise in the VCO output signal and ensures accurate phase synchronization between VCOs. Furthermore, integrating two cross-coupled VCOs within a single VCO chip improves integration density and supports large-scale cross-chip expansion. Therefore, this invention can meet the performance requirements of large-scale scalable phased array systems and exhibits excellent scalability and system integration.

Description

Technical Field

[0001] This invention relates to the field of phased array technology, and in particular to a voltage-controlled oscillator coupled array circuit and a scalable phased array system. Background Technology

[0002] The working principle of phased array technology is to achieve coherent superposition and beam directionality of electromagnetic waves in a specified spatial direction by precisely controlling the amplitude and phase of each radiating element in the array. This allows phased array systems to effectively increase equivalent omnidirectional radiated power at the transmitting end and enhance spatial filtering capabilities at the receiving end. Combined with adaptive beamforming algorithms, interference suppression can also be achieved, thereby comprehensively improving the transmission efficiency and reliability of communication links. Based on these outstanding advantages, phased array systems have demonstrated irreplaceable core value in high-performance application scenarios such as 5G communication, satellite navigation, and advanced radar.

[0003] Phased array technology has long been primarily focused on the military field. Traditional active phased array systems rely on costly independent transceiver modules and require manual assembly. This results in complex manufacturing processes and high costs when constructing large-scale array systems, significantly limiting its adoption in civilian and other fields. In recent years, the rapid development of silicon-based millimeter-wave integrated circuit technology has greatly improved chip-level integration, effectively reducing the R&D and manufacturing costs of phased array systems and driving the gradual expansion of phased array technology into the civilian sector.

[0004] However, with the continuous increase in integration, the limitations of multi-channel single-chip solutions are gradually becoming apparent, failing to meet future development needs in terms of chip area utilization and system energy efficiency. In contrast, scalable phased array architecture, with its significant advantages in chip area utilization and energy efficiency, has become the core development direction for future high-performance, large-scale integrated phased array systems. In the implementation of scalable phased array systems, the core design challenge lies in how to achieve low phase noise while ensuring high-precision phase synchronization between radiating elements, which places extremely high demands on oscillator performance.

[0005] Therefore, in order to realize the implementation and development of large-scale scalable phased array systems, it is urgent to solve the problem of improving the oscillator performance in large-scale scalable phased array systems. Summary of the Invention

[0006] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a voltage-controlled oscillator (VCO) coupling array circuit. This circuit achieves common-mode coupling between two cross-coupled VCOs by using two transmission lines within the VCO chip, and achieves cascading connection of VCO chips and common-mode coupling between two cross-coupled VCOs between preceding and following VCO chips by using two bonding lines. This effectively suppresses phase noise in the VCO output signal and ensures accurate phase synchronization between VCOs. Furthermore, integrating two cross-coupled VCOs within a single VCO chip not only improves integration density but also supports large-scale cross-chip expansion.

[0007] This invention provides a voltage-controlled oscillator (VCO) coupling array circuit, which is composed of a plurality of cascaded VCO chips. Each VCO chip includes: a first cross-coupled VCO, a second cross-coupled VCO, a first transmission line, and a second transmission line. The first output port of the first cross-coupled VCO and the second output port of the second cross-coupled VCO are coupled through the first transmission line to form common-mode coupling; the second output port of the first cross-coupled VCO and the first output port of the second cross-coupled VCO are coupled through the second transmission line to form common-mode coupling.

[0008] Furthermore, the second output port of the second cross-coupled voltage-controlled oscillator in the preceding voltage-controlled oscillator chip is coupled to the first output port of the first cross-coupled voltage-controlled oscillator in the following voltage-controlled oscillator chip via a first bonding wire to form common-mode coupling; the first output port of the second cross-coupled voltage-controlled oscillator in the preceding voltage-controlled oscillator chip is coupled to the second output port of the first cross-coupled voltage-controlled oscillator in the following voltage-controlled oscillator chip via a second bonding wire to form common-mode coupling.

[0009] According to a specific embodiment, in the voltage-controlled oscillator coupling array circuit provided by the present invention, when both the first transmission line and the second transmission line have signals passing through, they form electromagnetic coupling with each other to match the external impedance of the port; when both the first bonding line and the second bonding line have signals passing through, they form electromagnetic coupling with each other to match the external impedance of the port.

[0010] According to a specific embodiment, in the voltage-controlled oscillator coupling array circuit provided by the present invention, the first transmission line and the second transmission line have the same length and are arranged parallel to each other; the first bonding wire and the second bonding wire have the same length and are arranged parallel to each other.

[0011] According to a specific embodiment, in the voltage-controlled oscillator coupling array circuit provided by the present invention, both the first cross-coupled voltage-controlled oscillator and the second cross-coupled voltage-controlled oscillator are cross-coupled type C voltage-controlled oscillators.

[0012] Based on the same inventive concept, the present invention also provides a scalable phased array system, which uses the voltage-controlled oscillator coupled array circuit provided by the present invention to provide a local oscillator signal for the radio frequency front-end array.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0014] The voltage-controlled oscillator (VCO) coupling array circuit provided by this invention achieves common-mode coupling between two cross-coupled VCOs using two transmission lines within the VCO chip, and achieves cascading connection of VCO chips and common-mode coupling between two cross-coupled VCOs between successive VCO chips using two bonding lines. This effectively suppresses phase noise in the VCO output signal and ensures accurate phase synchronization between VCOs. Furthermore, integrating two cross-coupled VCOs within a single VCO chip not only improves integration density but also supports large-scale cross-chip expansion. Therefore, this invention can meet the performance requirements of large-scale scalable phased array systems and possesses excellent scalability and system integration. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the voltage-controlled oscillator coupled array circuit structure provided by the present invention;

[0016] Figure 2 A schematic diagram of the on-chip voltage-controlled oscillator coupling circuit structure in the voltage-controlled oscillator coupling array circuit provided by the present invention;

[0017] Figure 3 A schematic diagram of the inter-chip voltage-controlled oscillator coupling circuit structure in the voltage-controlled oscillator coupling array circuit provided by the present invention;

[0018] Figure 4 Simulation results of the frequency range of the voltage-controlled oscillator coupled array circuit (four voltage-controlled oscillator chips cascaded) provided by the present invention;

[0019] Figure 5 The simulation results of phase noise for the voltage-controlled oscillator coupled array circuit (four voltage-controlled oscillator chips cascaded) provided by the present invention;

[0020] Figure 6 The simulation results of phase error of the voltage-controlled oscillator coupled array circuit (four voltage-controlled oscillator chips cascaded) provided by the present invention;

[0021] Figure 7 This is a simplified module diagram of the scalable phased array system provided by the present invention. Detailed Implementation

[0022] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. However, this should not be construed as limiting the scope of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0023] like Figure 1 As shown, in one embodiment of the present invention, the voltage-controlled oscillator coupling array circuit 100 provided by the present invention is composed of four cascaded voltage-controlled oscillator chips 101-104. Those skilled in the art should know that the voltage-controlled oscillator coupling array circuit provided by the present invention supports large-scale expansion across chips and can adaptively adjust the number of voltage-controlled oscillator chips used according to actual needs.

[0024] Specifically, voltage-controlled oscillator (VCO) chips 101 and 102 are cascaded together via two bonding wires 121 and 122; VCO chips 102 and 103 are cascaded together via two bonding wires 231 and 232; and VCO chips 103 and 104 are cascaded together via two bonding wires 341 and 342. Simultaneously, VCO chips 101-104 are respectively provided with a set of constant voltage inputs V from an external source. B ~V B1 V B2 ~V B3 V B4 ~V B5 V B6 ~V B7 ; and the voltage-controlled oscillator chips 101~104 correspondingly output a set of oscillation signals V. out11 ~V out14 V out21 ~V out24 V out31 ~V out34 V out41 ~V out44 .

[0025] Furthermore, such as Figure 2 As shown, the specific internal structure of the voltage-controlled oscillator chip used in the voltage-controlled oscillator coupling array circuit provided by the present invention is as follows:

[0026] The voltage-controlled oscillator chip 200 includes: a first cross-coupled voltage-controlled oscillator 201, a second cross-coupled voltage-controlled oscillator 202, a first transmission line TL1, and a second transmission line TL2; wherein, the first output port (V...) of the first cross-coupled voltage-controlled oscillator 201... out1The output port) and the second output port (V) of the second cross-coupled voltage-controlled oscillator 202 out4 The output port is coupled through the first transmission line TL1 to form common-mode coupling; the second output port (V) of the first cross-coupled voltage-controlled oscillator 201 is connected in phase. out2 The output port) and the first output port (V) of the second cross-coupled voltage-controlled oscillator 202 out3 The output port is coupled through the second transmission line TL2 to form common-mode coupling; in other words, the first output port (V) of the first cross-coupled voltage-controlled oscillator 201 is coupled through the second transmission line TL2 to form common-mode coupling. out1 The output port is coupled to one end of the first transmission line TL1, and the second output port (V) of the second cross-coupled voltage-controlled oscillator 202 is connected to one end of the first transmission line TL1. out4 The output port is coupled to the other end of the first transmission line TL1. When V out1 Output port and V out4 When the output port outputs an oscillation signal, a V signal can be generated through the first transmission line TL1. out1 Output port and V out4 Common-mode coupling between output ports; similarly, the second output port (V) of the first cross-coupled voltage-controlled oscillator 201 out2 The output port is coupled to one end of the second transmission line TL2, and the first output port (V) of the second cross-coupled voltage-controlled oscillator 202 is connected to one end of the second transmission line TL2. out3 The output port is coupled to the other end of the second transmission line TL2. When V out2 Output port and V out3 When the oscillation signal is output from the output port, it can form V through the second transmission line TL2. out2 Output port and V out3 Common-mode coupling between output ports. Furthermore, when V... out1 Output port, V out2 Output port, V out3 Output port and V out4 When the output port outputs an oscillation signal, both the first transmission line TL1 and the second transmission line TL2 have signals passing through. In this way, the first transmission line TL1 and the second transmission line TL2 can form electromagnetic coupling with each other, which can better match the external impedance of the port.

[0027] In practical implementation, considering that common-mode coupling is due to the intermediate node of the coupling structure exhibiting AC open-circuit characteristics with respect to the fundamental frequency, the open-circuit characteristic of the intermediate point increases the equivalent parallel impedance of the resonant cavity, maintaining a high quality factor (Q value) resonant environment and reducing phase noise; therefore, in the voltage-controlled oscillator coupling array circuit provided by this invention, the first cross-coupled voltage-controlled oscillator 201 and the second cross-coupled voltage-controlled oscillator 202 in the voltage-controlled oscillator chip 200 are both cross-coupled Class C voltage-controlled oscillators. Thus, the output frequency is controlled through the Class C voltage-controlled oscillator, ensuring that the coupling channel between the first transmission line TL1 and the second transmission line TL2 operates in common-mode coupling mode. Figure 2 As shown, the cross-coupled Class C voltage-controlled oscillator in the voltage-controlled oscillator chip 200 adopts a differential symmetrical structure, mainly including an LC resonant unit, a cross-coupled negative resistance transistor pair, and a Class C bias circuit. The base and collector of the cross-coupled negative resistance transistor pair (i.e., transistor Q1 and transistor Q2, or transistor Q3 and transistor Q4) are cross-coupled to the two differential output terminals of the LC resonant unit, providing negative resistance to the resonant circuit to compensate for energy loss. The Class C bias circuit, through the gate bias resistor and DC blocking capacitor, sets the cross-coupled negative resistance transistor pair to a DC bias below the conduction threshold, so that it only conducts in the peak range of the oscillation signal, operating in Class C mode. The tail current source provides a stable operating current for the circuit, while the external voltage-controlled tuning unit is connected to the LC resonant unit, and the oscillation frequency is adjusted by changing the equivalent capacitance through external control voltage.

[0028] Furthermore, such as Figure 3 As shown, with Figure 1 Taking the cascaded connection between voltage-controlled oscillator (VCO) chip 102 and VCO chip 103 as an example, VCO chip 102 serves as the front-stage VCO chip, and VCO chip 103 serves as the rear-stage VCO chip. Simultaneously, each of the two output ports of the first cross-coupled VCO 102a and the two output ports of the second cross-coupled VCO 102b of VCO chip 102 has a solder pad connected to it. Similarly, each of the two output ports of the first cross-coupled VCO 103a and the two cross-coupled VCO 103b of VCO chip 103 has a solder pad connected to it. In this way, large-scale cross-chip expansion and common-mode coupling between cross-chip VCOs can be achieved through two bonding wires, thereby ensuring the accuracy of phase synchronization of oscillation signals between chips.

[0029] Specifically, the second cross-coupled voltage-controlled oscillator 102b in the voltage-controlled oscillator chip 102 has its second output port (V out24 The pads leading out from the output port are connected to the first cross-coupled voltage-controlled oscillator 103a in the voltage-controlled oscillator chip 103, and its first output port (Vout31 The pads from the output port are coupled together via bonding wire 231. When V out24 Output port and V out31 When the output port outputs an oscillation signal, it can form a V through the bonding wire 231. out24 Output port and V out31 Common-mode coupling between output ports; the second cross-coupled voltage-controlled oscillator 102b in the voltage-controlled oscillator chip 102 has its first output port (V out23 The pads leading out from the output port are connected to the second output port (V) of the first cross-coupled voltage-controlled oscillator 103a in the voltage-controlled oscillator chip 103. out32 The pads from the output port are coupled via bonding wires 232. When V out23 Output port and V out32 When the output port outputs an oscillation signal, it can form a V through the bonding wire 232. out23 Output port and V out32 Common-mode coupling between output ports.

[0030] Furthermore, when V out23 Output port, V out24 Output port, V out31 Output port and V out32 When the output port outputs an oscillation signal, both bonding wires 231 and 232 can pass through the signal, thus forming electromagnetic coupling between them, which can better match the external impedance of the port.

[0031] Therefore, the voltage-controlled oscillator (VCO) coupling array circuit provided by this invention effectively suppresses phase noise in the VCO output signal and ensures the accuracy of phase synchronization between VCOs by using two transmission lines within the VCO chip to achieve common-mode coupling between two cross-coupled VCOs, and by using two bonding lines between VCO chips to achieve cascading connections between VCO chips and common-mode coupling between two cross-coupled VCOs between preceding and following stage VCO chips. Furthermore, by integrating two cross-coupled VCOs into a single VCO chip, it not only improves integration density but also supports large-scale cross-chip expansion. Therefore, this invention can meet the performance requirements of large-scale scalable phased array systems and possesses excellent scalability and system integration.

[0032] In another specific embodiment, considering the consistency of the external impedance of the differential ports of the two cross-coupled voltage-controlled oscillators in the voltage-controlled oscillator chip, the two transmission lines in the voltage-controlled oscillator chip are arranged in parallel and have the same length. In this way, the amplitude and phase of the differential signal output by the voltage-controlled oscillator can be guaranteed to be consistent.

[0033] Furthermore, by precisely designing the characteristic impedance and physical length of the transmission line, efficient energy exchange and precise phase synchronization between two cross-coupled voltage-controlled oscillators (VCOs) within the VCO chip can be achieved. Simultaneously, the transmission line structure possesses excellent high-frequency signal transmission characteristics, effectively maintaining signal integrity, reducing transmission loss and reflection interference, and improving the system's reliability at high frequencies. Thus, compared to traditional solutions using lumped elements or weakly coupled structures, employing a transmission line coupling structure within the VCO chip provides stronger coupling strength, thereby ensuring the collaborative operation capability between VCO chips in a large-scale array.

[0034] Similarly, since the pad positions in the voltage-controlled oscillator (VCO) chip package structure are fixed, aligning the pad positions of the preceding and following VCO chips during cascading assembly, and configuring the bonding machine's operating parameters, ensures that the two bonding wires between the two cascaded VCO chips are of equal length and parallel to each other. This guarantees the consistency of the external impedance of the differential ports of the cross-coupled VCO chips, thereby ensuring the consistency of the amplitude and phase of the differential signal output by the VCO. Preferably, the bonding wires used in the cascading assembly of VCO chips in this invention are gold wires.

[0035] To further verify the operating performance of the voltage-controlled oscillator coupled array circuit provided by the present invention, by performing tests on... Figure 1 The voltage-controlled oscillator (VCO) coupled array circuit, consisting of four cascaded VCO chips, is simulated for frequency range, phase noise, and phase error.

[0036] like Figure 4 As shown, with the base voltage constant at 1V, a wide frequency tuning range from 11.8GHz to 13.8GHz is achieved through continuous adjustment using control codes; furthermore, as... Figure 5 As shown, at 12.8 GHz, the phase noise is below -117 dBc / Hz, and the quality factor reaches 181 dBc / Hz; moreover, as Figure 6 As shown, under the condition of four voltage-controlled oscillator chips cascaded, the phase difference of each voltage-controlled oscillator unit (a cross-coupled voltage-controlled oscillator includes two voltage-controlled oscillator units) is precisely controlled within 1°.

[0037] In another embodiment, the present invention also provides a scalable phased array system, such as Figure 7As shown, this scalable phased array system typically includes components such as an antenna array, a frequency multiplier, a mixer, and an amplifier. Specifically, the scalable phased array system uses the voltage-controlled oscillator coupled array circuit provided by this invention to provide a local oscillator signal to the RF front-end array. The voltage-controlled oscillator array provides a local oscillator output with a frequency of 11.8 GHz to 13.8 GHz, which first passes through a driver amplifier to a nine-fold frequency multiplier to generate a signal with a frequency of 106.2 GHz to 124.2 GHz, then through a mixer to generate an RF signal with a frequency of 212.4 GHz to 248.4 GHz, and finally through an amplifier to amplify the signal for antenna radiation.

[0038] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A voltage-controlled oscillator (VCO) coupling array circuit, comprising a plurality of cascaded VCO chips, characterized in that: The voltage-controlled oscillator chip includes: a first cross-coupled voltage-controlled oscillator, a second cross-coupled voltage-controlled oscillator, a first transmission line, and a second transmission line; wherein, the first output port of the first cross-coupled voltage-controlled oscillator and the second output port of the second cross-coupled voltage-controlled oscillator are coupled through the first transmission line to form common-mode coupling; the second output port of the first cross-coupled voltage-controlled oscillator and the first output port of the second cross-coupled voltage-controlled oscillator are coupled through the second transmission line to form common-mode coupling. Furthermore, the second output port of the second cross-coupled voltage-controlled oscillator in the preceding voltage-controlled oscillator chip is coupled to the first output port of the first cross-coupled voltage-controlled oscillator in the following voltage-controlled oscillator chip via a first bonding wire to form common-mode coupling; the first output port of the second cross-coupled voltage-controlled oscillator in the preceding voltage-controlled oscillator chip is coupled to the second output port of the first cross-coupled voltage-controlled oscillator in the following voltage-controlled oscillator chip via a second bonding wire to form common-mode coupling.

2. The voltage-controlled oscillator coupled array circuit as described in claim 1, characterized in that, When both the first transmission line and the second transmission line have signals passing through them, they form electromagnetic coupling with each other to match the external impedance of the port; when both the first bonding wire and the second bonding wire have signals passing through them, they form electromagnetic coupling with each other to match the external impedance of the port.

3. The voltage-controlled oscillator coupled array circuit as described in claim 2, characterized in that, The first transmission line and the second transmission line are of the same length and are arranged parallel to each other; the first bonding wire and the second bonding wire are of the same length and are arranged parallel to each other.

4. The voltage-controlled oscillator coupled array circuit as described in claim 1, characterized in that, Both the first cross-coupled voltage-controlled oscillator and the second cross-coupled voltage-controlled oscillator are cross-coupled type C voltage-controlled oscillators.

5. A scalable phased array system, characterized in that, The voltage-controlled oscillator coupled array circuit as described in any one of claims 1 to 4 is used to provide the local oscillator signal for the radio frequency front-end array.

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