Radar array device and method based on on-chip antenna-pulse source integration

Abstract

The invention discloses a radar array device and method based on on-chip antenna-pulse source integration, and relates to the technical field of antennae, and the device comprises an excitation structure which is composed of a photoconductive switch, generates a high-frequency pulse current through laser excitation, and is used for exciting an array antenna; the transmission structure adopts a low-loss GSG coplanar waveguide to transmit high-frequency current to the array antenna and is used for low-loss transmission; the acquisition structure consists of a photoconductive switch, receives the electromagnetic signal from the array antenna, converts the electromagnetic signal into a current signal, and is used for signal acquisition and transmission; the radiation structure consists of array passive antennas and is used for mutual conversion between electromagnetic waves and current; according to the invention, electromagnetic waves can be effectively excited and collected, the bandwidth can be expanded to millimeter waves or even higher frequency bands, and compared with the prior art, the antenna has the characteristics of higher signal-to-noise ratio, lower power consumption and smaller size; the receiving sensitivity and the transmission efficiency of the electromagnetic signal are improved, and the transmission loss is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of antennas, and specifically to a radar array device and method based on the integration of an on-chip antenna and a pulse source. Background Art

[0002] As a classic passive device, an antenna can realize the mutual conversion between a guided high-frequency alternating current and a space-radiated electromagnetic wave, and has been widely used in various fields. With the advent of the big data era, people's demand for high-speed data transmission has been increasing day by day, and the frequency band of wireless communication has gradually increased. At present, there are already mature passive antenna design solutions in the industry, which support the design of passive antennas in the millimeter wave band. However, contradictorily, due to the leakage effect generated under size miniaturization, the operating frequency of the electrical pulse source is limited to below 110 GHz. Doubling the frequency of low-frequency signals will greatly attenuate the excitation power, unable to meet the actual use requirements. Without the support of a high-frequency pulse source, the high-frequency passive antenna is like a castle in the air, thus restricting the development of high-frequency wireless communication. Therefore, new high-frequency electromagnetic wave emitting devices have been widely studied, such as photoconductive antennas, spin terahertz devices, photodiode antennas, etc. These new devices do not require external alternating current source excitation compared with traditional passive antennas, so they break through the frequency limitation of the current pulse source. These devices use the photoelectric conversion characteristics of the substrate material to autonomously generate alternating current under the excitation of a laser, and then form electromagnetic wave radiation. And the latest research shows that these devices can generate electromagnetic wave radiation at terahertz frequencies.

[0003] However, at present, such devices also face many problems, such as 1. Difficulty in increasing power. 2. Limited modulation methods. 3. Low sampling sensitivity. etc. Therefore, the specific form of the next-generation millimeter wave transceiver system still needs to be further explored. Here, this paper proposes a device design that integrates an array of high-frequency pulse sources and a millimeter wave array antenna. By integrating a photoelectric pulse source that can generate electrical pulses above 110 GHz and a passive antenna on the same chip, the radiation and reception of high-frequency electromagnetic waves are realized, and it is expected to be applied to wireless communication and radar ranging systems.

[0004] Currently, radiation antenna devices are divided into two categories: active devices and passive devices, and their respective advantages and disadvantages are as follows: Passive devices: Advantages: Mature design solutions, many modulation means; Disadvantages: Limited by the frequency bottleneck of electrical pulses at 110 GHz; Active devices: Advantages: The frequency can break through the limitation of the electrical pulse source; Disadvantages: Limited radiation power, few modulation means, low sampling sensitivity as a receiving module, and difficulty in integrating the transceiver function.

[0005] From the comparison of the above two types of devices, it can be seen that by utilizing the response of specific materials to laser irradiation, high-frequency alternating current can be generated, whose frequency can break through the limitations of traditional electrical pulse sources, which coincides with the requirements of passive antenna devices. However, there will be huge losses in the electrical signal transmission between heterogeneous devices, especially for high-frequency signals. A large amount of losses makes the devices unable to meet the power requirements for actual use. Therefore, on-chip integration has become a relatively good solution. However, such optoelectronic materials are often semiconductors or conductors, which often have large dielectric losses or leakage effects.

[0006] Existing high-frequency electromagnetic wave emitting devices, such as photoconductive antennas, spin terahertz devices, etc., although they can break through the frequency limitations of traditional electrical pulse sources, still have many deficiencies in terms of power improvement, modulation methods, and receiving functions. Therefore, special designs need to be carried out according to the material characteristics during device design. Here, we used the simulation design software HFSS to complete the design of the integrated pulse source and passive antenna, and realized the radiation and receiving functions of high-frequency electromagnetic waves. Summary of the Invention

[0007] The present invention provides a radar array device and method based on on-chip antenna-pulse source integration. The goal of this application is to construct an optoelectronic material ultrafast integrated antenna array with high efficiency, low loss, and high integration, to achieve high-frequency millimeter-wave communication, high-precision radar detection, and ultra-high-speed optoelectronic detection, so as to solve the problems in the background technology.

[0008] To achieve the above object, the present invention provides the following technical solution: A radar array device based on on-chip antenna-pulse source integration, including a radiation structure, a collection structure, a transmission structure, and an excitation structure; The radiation structure is composed of an array of passive antennas and is used for the mutual conversion of electromagnetic waves and current; The collection structure is composed of photoconductive switches, receives electromagnetic signals from the array antenna and converts them into current signals, and is used for signal collection and transmission; The transmission structure uses a low-loss GSG coplanar waveguide to transmit high-frequency current to the array antenna and is used for low-loss transmission; The excitation structure is composed of photoconductive switches, generates high-frequency pulsed current through laser excitation, and is used to excite the array antenna.

[0009] Further, the radiation structure is composed of multiple passive antennas, and the number can be adjusted according to application requirements.

[0010] Further, the excitation structure is a gap electrode on a photoconductive substrate. By providing a DC bias voltage from the lower end, when the photoconductive substrate material between the electrode gaps is irradiated by laser, picosecond electrical pulses are excited upward to feed the array antenna.

[0011] Furthermore, the output power is increased by increasing the number of excitation structures, and a matching transmission structure needs to be designed for the coupling structure of multiple excitation structures for transmission.

[0012] Furthermore, the transmission structure is optimized by electromagnetic simulation to match the transmission of electromagnetic waves with different frequencies and powers.

[0013] Furthermore, the low-loss GSG coplanar waveguide used in the transmission structure is a low-loss transmission line obtained by simulating with electromagnetic simulation software. At the same time, different transmission structures need to be designed according to the input requirements of different radiation structure antennas.

[0014] Furthermore, the acquisition structure is a gap electrode on a photoconductive substrate, with a signal acquisition outlet on one side and a signal input port on the other side.

[0015] Furthermore, the signal at the signal input port is obtained after the spatial electromagnetic wave is collected by the radiation structure antenna and converted into an electrical signal. When there is an electrical signal at the signal input port, after the laser irradiates the photoconductive substrate between the gaps, the signal is transmitted to the signal acquisition outlet to complete the signal acquisition.

[0016] Furthermore, the radiation structure is composed of multiple passive antennas, and the number can be adjusted according to application requirements, and the number is designed to be not less than one.

[0017] The method for the radar array device based on on-chip antenna-pulse source integration includes the following steps: Apply a DC bias to the lower port of the excitation structure to pre-bias the photoconductive switch of the excitation structure; Use femtosecond laser to excite the photoconductive substrate in the gap of the excitation structure to generate high-frequency pulses; The high-frequency pulses are transmitted to the radiation structure through the transmission structure to radiate electromagnetic waves outward; When the external electromagnetic wave is transmitted to the radiation structure, the spatial electromagnetic wave is converted into an on-chip current; When the current is transmitted downward through the transmission structure, apply a voltage bias to the right port of the acquisition structure; Use femtosecond laser to excite the photoconductive switch in the gap of the acquisition structure to conduct the current and complete the signal acquisition.

[0018] Compared with the prior art, the present invention provides a radar array device and method based on on-chip antenna-pulse source integration, having the following beneficial effects: The radar array device and method based on on-chip antenna-pulse source integration have the following advantages: high integration: integrating the excitation, transmission, acquisition, and radiation structures into one, reducing the complexity of the antenna system; low loss: reducing the transmission loss through an optimized coplanar waveguide transmission structure; efficient acquisition: achieving efficient signal acquisition by utilizing the fast response characteristics of photoconductive switches; reciprocity: the reciprocity of the antenna enables the same structure to be used for the transmission and reception of electromagnetic waves. This application can effectively excite and acquire electromagnetic waves, and the bandwidth can be extended to millimeter waves or even higher frequency bands, having higher signal-to-noise ratio, lower power consumption, and smaller size compared with the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0020] Figure 1 It is a schematic diagram of a radiation structure of the present invention; Figure 2 It is a schematic diagram of two radiation structures of the present invention; In the figure: 1, radiation structure; 2, acquisition structure; 3, transmission structure; 4, excitation structure. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] In order to make the above objects, features, and advantages of the present invention more obvious and understandable, the following will describe the specific embodiments of the present invention in detail with reference to the drawings of the specification.

[0022] In the following description, many specific details are set forth to fully understand the present invention. However, the present invention can also be implemented in other ways different from those described herein. Those skilled in the art can make similar generalizations without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0023] Secondly, the so-called "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that can be included in at least one implementation manner of the present invention. The "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor is it an independent or selectively exclusive embodiment with other embodiments.

[0024] Please refer to Figure 1-2 , the present invention discloses a radar array device based on on-chip antenna-pulse source integration, including a radiation structure 1, an acquisition structure 2, a transmission structure 3, and an excitation structure 4; The radiation structure 1, composed of an array of passive antennas, is used for the mutual conversion of electromagnetic waves and current.

[0025] The acquisition structure 2, composed of photoconductive switches, receives electromagnetic signals from the array antenna and converts them into current signals for signal acquisition and transmission.

[0026] The transmission structure 3 uses a low-loss GSG coplanar waveguide to transmit high-frequency current to the array antenna for low-loss transmission.

[0027] The excitation structure 4, composed of photoconductive switches, generates high-frequency pulsed current through laser excitation for exciting the array antenna.

[0028] The objective of this application is to construct an ultrafast integrated antenna array of photoconductive materials with high efficiency, low loss, and high integration, to achieve a series of potential application scenarios, such as high-frequency millimeter-wave communication, high-precision radar detection, and ultra-high-speed photodetection.

[0029] The integration scheme of the array antenna and the array photoconductive device in this application enables excitation and sampling to be completed on the same chip through the cooperation of the array antenna and the array photoconductive device.

[0030] This application achieves the objective through the following methods: 1) Based on the characteristics of photoconductive materials, an efficient excitation structure 4, transmission structure 3, and acquisition structure 2 are designed, implemented using gap electrode photoconductive switches and GSG coplanar waveguides respectively, and the structural parameters are optimized through electromagnetic simulation software to reduce transmission loss.

[0031] 2) Using the array of passive antennas, the conversion between the electrical pulses generated by the photoconductive material and external electromagnetic waves is realized: effectively exciting spatial electromagnetic waves and achieving the acquisition of external spatial electromagnetic waves.

[0032] Specifically, the structure of the excitation structure 4 is a gap electrode on the photoconductive substrate. By providing a DC bias from the lower end, when the photoconductive substrate material between the electrode gaps is irradiated by laser, picosecond electrical pulses are excited upward to feed the array antenna. The output power of the excitation structure 4 is increased by increasing the number of excitation structures 4 ( Figure 1 only 1 integrated excitation structure 4 is shown in Figure 2 only 2 integrated excitation structures 4 are shown in ), and a matching transmission structure 3 needs to be designed for the coupling structure of multiple excitation structures 4 for transmission.

[0033] Specifically, the transmission structure 3 is optimized by electromagnetic simulation to match the transmission of electromagnetic waves with different frequencies and powers. The low-loss GSG coplanar waveguide adopted by the transmission structure 3 is a low-loss transmission line obtained through simulation by electromagnetic simulation software. At the same time, different transmission structures 3 need to be designed according to the input requirements of different radiation structures 1 of the radiating antennas.

[0034] Specifically, the acquisition structure 2 is a gap electrode on a photoconductive substrate. The left side is the signal acquisition outlet, and the right side is the signal input port. The signal at the signal input port is obtained after the radiating structure 1 antenna collects the spatial electromagnetic wave and converts it into an electrical signal. When there is an electrical signal at the signal input port, after the laser irradiates the photoconductive substrate between the gaps, the signal is transmitted to the signal acquisition outlet to complete the signal acquisition.

[0035] Specifically, the radiating structure 1 is composed of multiple passive antennas, and the quantity can be adjusted according to application requirements, and the quantity design is not less than one.

[0036] Specifically, the laser input of the excitation structure 4 and the acquisition structure 2 can be free-space light and can be replaced by the input of an on-chip fabricated silicon optical waveguide.

[0037] Specifically, the optical acquisition module of the acquisition structure 2 can be replaced by a pure electrical acquisition scheme of a radio frequency circuit.

[0038] Specifically, for the low-frequency band, the coplanar waveguide of the transmission structure 3 can be replaced by a microstrip line.

[0039] In use: The femtosecond laser is vertically irradiated on the gap of the photoconductive switch excitation structure 4 to excite the photoconductive material to generate a high-frequency pulsed current; through a well-designed transmission structure 3, the high-frequency current is transmitted to the array antenna; the array antenna converts the high-frequency current into spatial electromagnetic waves and radiates them outward; when external electromagnetic waves or signals of a specific frequency irradiate the array antenna, according to the reciprocity characteristic of the antenna principle, the electromagnetic waves are converted into an on-chip current, which flows through the transmission structure 3 and reaches the acquisition structure 2; when the voltage bias received by the acquisition structure 2 reaches a certain threshold, the laser irradiates the gap of the acquisition structure 2 to turn on the photoconductive switch and collect and transmit the received current.

[0040] The method of the radar array device based on on-chip antenna-pulse source integration is specifically an electromagnetic wave excitation and acquisition method, including the following steps: Apply a DC bias to the lower port of the excitation structure 4 to pre-bias the photoconductive switch of the excitation structure 4; Use a femtosecond laser to excite the photoconductive substrate in the gap of the excitation structure 4 to generate high-frequency pulses; The high-frequency pulses are transmitted to the radiating structure 1 through the transmission structure 3 to radiate electromagnetic waves outward; When external electromagnetic waves are transmitted to the radiation structure 1, the spatial electromagnetic waves are converted into on-chip current; When the current passes through the transmission structure 3 and reaches the right port of the acquisition structure 2, it provides a voltage bias for the photoconductive switch of the acquisition structure 2; The photoconductive switch in the gap of the acquisition structure 2 is excited by femtosecond laser to conduct the current and complete signal acquisition.

[0041] A method for a radar array device based on on-chip antenna-pulse source integration includes the following steps: Apply a DC bias to the lower port of the excitation structure 4 to pre-bias the photoconductive switch of the excitation structure 4; The photoconductive substrate in the gap of the excitation structure 4 is excited by femtosecond laser to generate high-frequency pulses; The high-frequency pulses are transmitted to the radiation structure 1 through the transmission structure 3 to radiate electromagnetic waves outward; When external electromagnetic waves are transmitted to the radiation structure 1, the spatial electromagnetic waves are converted into on-chip current; When the current passes through the transmission structure 3 and transmits downward, a voltage bias is applied to the right port of the acquisition structure 2; The photoconductive switch in the gap of the acquisition structure 2 is excited by femtosecond laser to conduct the current and complete signal acquisition.

[0042] The technical solution of this patent application mainly adopts the following design ideas: Adopt a feedback structure: By applying a DC bias voltage and a laser signal, control the conductivity of the photoconductive material, so as to achieve efficient signal transmission and reception.

[0043] Exquisite transmission design: Through a carefully designed coplanar waveguide circuit, reduce the loss during transmission and ensure efficient signal transmission.

[0044] Optimized acquisition structure: By designing a specific photoconductive switch structure, it can not only quickly acquire feedback signals, but also effectively reduce noise interference.

[0045] The radiation structure 1 - an array passive antenna for transmitting and receiving electromagnetic waves.

[0046] The transmission structure 3 - a coplanar waveguide for transmitting electrical signals.

[0047] The acquisition structure 2 - a photoconductive switch for acquiring feedback signals.

[0048] The excitation structure 4 - a photoconductive switch for generating high-frequency pulses.

[0049] This application realizes a significant improvement in transmission efficiency through the feedback structure design, while maintaining the low energy consumption and miniaturization of the device; How to achieve: Optimize the transmission structure through a finely designed electromagnetic simulation software to reduce losses; optimize the acquisition structure through feedback design to improve the reliability of signals.

[0050] Implementation description: This technical solution integrates a photoconductive switch, a transmission structure, an acquisition structure, and a radiation structure to achieve efficient and low-loss electromagnetic wave acquisition and emission, and is easily integrated into a system-on-chip due to its compact structure.

[0051] In summary, for the radar array device and method based on on-chip antenna-pulse source integration, the radar array device and method based on on-chip antenna-pulse source integration have high integration: integrating the excitation, transmission, acquisition, and radiation structures into one, reducing the complexity of the antenna system; low loss: reducing transmission loss through the optimized coplanar waveguide transmission structure 3; efficient acquisition: achieving efficient signal acquisition using the fast response characteristics of the photoconductive switch; reciprocity: the reciprocity of the antenna enables the same structure to be used for the transmission and reception of electromagnetic waves. This application can effectively excite and acquire electromagnetic waves, and the bandwidth can be extended to millimeter waves and even higher frequency bands, with characteristics of higher signal-to-noise ratio, lower power consumption, and smaller size compared with the prior art.

[0052] It should be understood that each part of the present invention can be implemented by hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, any one or a combination of the following technologies well known in the art can be used: discrete logic circuits with logic gate circuits for implementing logical functions on data signals, application-specific integrated circuits with appropriate combinational logic gate circuits, programmable gate arrays (PGAs), field programmable gate arrays (FPGAs), etc.

[0053] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A radar array device based on the integration of an on-chip antenna and a pulse source, characterized in that: It includes a radiation structure, a collection structure, a transmission structure and an excitation structure; The radiation structure, composed of an array of passive antennas, is used for the mutual conversion of electromagnetic waves and currents; The collection structure, composed of photoconductive switches, receives electromagnetic signals from the array antenna and converts them into current signals for signal collection and transmission; The transmission structure uses a low-loss GSG coplanar waveguide to transmit high-frequency current to the array antenna for low-loss transmission; The excitation structure, composed of photoconductive switches, generates high-frequency pulsed current through laser excitation for exciting the array antenna.

2. The radar array device based on the integration of an on-chip antenna and a pulse source according to claim 1, wherein: The excitation structure is a gap electrode on a photoconductive substrate. By providing a DC bias from the lower end, when the photoconductive substrate material between the electrode gaps is irradiated by a laser, picosecond electrical pulses are excited upward to feed the array antenna.

3. The radar array device based on the integration of on-chip antenna and pulse source according to claim 2, characterized in that: The excitation structure increases the output power by increasing the number of excitation structures. The coupling structure of multiple excitation structures requires a designed matching transmission structure for transmission.

4. The radar array device based on the integration of on-chip antenna and pulse source according to claim 1, characterized in that: The transmission structure is optimized by electromagnetic simulation to match the transmission of electromagnetic waves with different frequencies and powers.

5. The radar array device based on the integration of on-chip antenna and pulse source according to claim 4, characterized in that: The low-loss GSG coplanar waveguide used in the transmission structure is a low-loss transmission line obtained by simulation with electromagnetic simulation software. At the same time, different transmission structures need to be designed according to the input requirements of the radiation antennas of different radiation structures.

6. The radar array device based on the integration of on-chip antenna and pulse source according to claim 1, characterized in that: The collection structure is a gap electrode on a photoconductive substrate, with a signal collection outlet on one side and a signal input port on the other side.

7. The radar array device based on the integration of on-chip antenna and pulse source according to claim 6, characterized in that: The signal at the signal input port is obtained after the spatial electromagnetic wave is converted into an electrical signal by the radiation structure antenna. When there is an electrical signal at the signal input port, after the laser irradiates the photoconductive substrate between the gaps, the signal is transmitted to the signal collection outlet to complete signal collection.

8. A radar array device based on the integration of an on-chip antenna and a pulse source according to claim 1, characterized in that: The radiation structure is composed of multiple passive antennas, and the number can be adjusted according to application requirements, and the number design is not less than one.

9. A method for a radar array device based on the integration of an on-chip antenna and a pulse source according to any one of claims 1-8, characterized in that: It includes the following steps: Apply a DC bias to the lower port of the excitation structure to pre-bias the photoconductive switch of the excitation structure; Use femtosecond laser to excite the photoconductive substrate in the gap of the excitation structure to generate high-frequency pulses; The high-frequency pulses are transmitted to the radiation structure through the transmission structure to radiate electromagnetic waves outward; When the external electromagnetic wave is transmitted to the radiation structure, the spatial electromagnetic wave is converted into an on-chip current; When the current is transmitted downward through the transmission structure, apply a voltage bias to the right port of the collection structure; Use femtosecond laser to excite the photoconductive switch in the gap of the collection structure to conduct the current and complete signal collection.

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