A terahertz two-dimensional phased-feed multi-beam antenna system

Abstract

This invention belongs to the field of terahertz communication, specifically a two-dimensional phased-array multi-beam antenna system. It includes a terahertz mixer array, a terahertz extension module, a phased-array multi-beam antenna, and a terahertz local oscillator (LO) feeding circuit. The terahertz mixer array is located below the terahertz extension module; the phased-array multi-beam antenna is located above the terahertz extension module. The terahertz extension module is positioned between the terahertz mixer array and the phased-array multi-beam antenna, integrating a LO power divider link and a radio frequency extension link to achieve a reasonable layout of the two-dimensional phased array. This module integrates two types of circuits, achieving integration and miniaturization, and shares a second non-standard flange, reducing volume and alleviating wiring difficulties. In summary, this invention achieves the requirements for two-dimensional beam coverage and high-gain radiation, while also possessing advantages such as compact layout, small size, and easy integration. It can better meet the communication needs of the terahertz band in different application scenarios.

Description

Technical Field

[0001] This invention belongs to the field of terahertz communication, specifically relating to a terahertz two-dimensional phased feed multi-beam antenna system. Background Technology

[0002] Terahertz waves are electromagnetic waves with frequencies ranging from 100 GHz to 10 THz, with wavelengths between infrared and millimeter waves. Terahertz waves possess technical characteristics such as strong penetration, high safety, good directionality, and high bandwidth. They are widely used in fields such as biomedicine, non-destructive testing, space physics, and military communications.

[0003] As the front end of a communication system, the antenna is a crucial carrier for radiating and receiving electromagnetic waves. Antenna design incorporates controllable gain characteristics, concentrating the energy input to the system towards a fixed direction. Compared to commonly used wireless communication frequency bands (such as 2.45 GHz and 5.8 GHz) and other microwave bands (such as X-band, Ku-band, and Ka-band), terahertz waves present a significant challenge during transmission: substantial path loss. Furthermore, under the same radiated power conditions, the physical transmission distance of terahertz waves is relatively short. Therefore, in the terahertz band, employing large-aperture antennas to enhance radiation gain is particularly important to effectively combat path loss.

[0004] High-gain antennas encompass various types, including array antennas, reflector antennas, and lens antennas. Traditional reflector and lens antennas typically consist of a single feed antenna and a corresponding reflector or lens. Once the feed network is determined, the beam pointing of this type of antenna is also determined. In many fields such as medical, communications, and security inspection, it is often required that the antenna beam can achieve coverage over a certain range. However, for traditional single-feed reflector and lens antennas, beam scanning requires the addition of a motor to achieve mechanical scanning. The speed and accuracy of mechanical scanning are often limited, making it difficult to meet some complex requirements in practical applications.

[0005] Phased array antennas differ from traditional ones. By introducing amplitude and phase modulation devices at the front end of the array antenna elements, they can effectively change the beam direction through amplitude and phase control, thereby achieving rapid, wide-angle beam coverage. However, achieving higher gains than 30dBi or even 35dBi presents a significant challenge: the number of array elements increases dramatically, inevitably leading to a surge in the number of back-end TR components, ultimately increasing the overall size and cost of the antenna system. Therefore, given a limited number of channels, simultaneously meeting the requirements for a certain beam coverage range and achieving high-gain radiation is of paramount practical importance.

[0006] In the terahertz band, due to limitations in current manufacturing precision and high material loss, metals, with their inherent low-loss characteristics, have become a popular material for terahertz antenna design. Currently, terahertz circuits are mostly designed and fabricated using metal cavities, but this often results in the circuit itself being much larger than the antenna. Considering the design and testing difficulties and loss issues inherent in the circuit components, most mainstream terahertz phased array antenna systems still employ a one-dimensional scanning design. This means that to achieve two-dimensional scanning, an additional motor is needed to assist in rotation. However, for high-gain antenna systems operating at wavelengths in the millimeter range or even smaller, this places extremely high demands on the motor's precision and response speed, and currently, it is difficult to find a suitable motor that can fully meet these requirements.

[0007] In summary, there is an urgent need for an antenna system capable of achieving high-gain two-dimensional beam coverage to better meet the communication needs of the terahertz band in different application scenarios. Summary of the Invention

[0008] The purpose of this invention is to provide a terahertz two-dimensional phased-feed multi-beam antenna system that achieves two-dimensional beam coverage and high-gain radiation requirements with a limited number of channels, while also possessing advantages such as compact layout, small size, and easy integration. It can better meet the communication needs of the terahertz band in different application scenarios.

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] A terahertz two-dimensional phased-feed multi-beam antenna system includes a terahertz mixer array, a terahertz extension module, a phased-feed multi-beam antenna, and a terahertz local oscillator feeding circuit; the terahertz mixer array is located below the terahertz extension module; the phased-feed multi-beam antenna is located above the terahertz extension module.

[0011] The terahertz mixer array consists of n waveguide terahertz mixers. Each waveguide terahertz mixer is equipped with n first non-standard flanges and n radio frequency connectors. The first non-standard flanges are equipped with local oscillator ports and radio frequency ports. The n radio frequency connectors are connected to the intermediate frequency module.

[0012] The terahertz extension module includes n second non-standard flanges, n local oscillator power divider links, and n radio frequency extension links; each second non-standard flange is also provided with a local oscillator port and a radio frequency port; the output port of each local oscillator power divider link and the output port of each radio frequency extension link share a second non-standard flange, and the two are respectively connected to the local oscillator port and radio frequency port on the corresponding first non-standard flange through the local oscillator port and radio frequency port on the second non-standard flange;

[0013] The phased-array feed multi-beam antenna includes a silicon horn antenna array and a generalized Luneburg lens antenna. The silicon horn antenna array is located on the terahertz extension module and is connected to the terahertz extension module via a heterogeneous connection. The silicon horn antenna array consists of n silicon horn antennas, each of which is connected to a second non-standard flange and to the RF port of the second non-standard flange, i.e., connected to the RF extension link through the RF port. The generalized Luneburg lens antenna is placed above the silicon horn antenna array.

[0014] The terahertz local oscillator feed circuit is used to provide local oscillator signals for the n-channel local oscillator power divider links.

[0015] Furthermore, the terahertz local oscillator feed circuit consists of an X-band frequency source, an 8-fold frequency multiplier, a filter, and a terahertz adjustable power amplifier connected in sequence.

[0016] Furthermore, the silicon stacked horn antenna is a horn-shaped antenna formed by stacking multiple silicon substrates.

[0017] Furthermore, the generalized Luneburg lens antenna includes an outer upper hemisphere, an outer lower hemisphere, and an inner sphere. The outer upper hemisphere and the outer lower hemisphere are joined together to form an outer spherical cavity, and the inner sphere is placed inside the outer spherical cavity.

[0018] Furthermore, the outer upper and lower hemispheres of the generalized Luneburg lens antenna are provided with several air holes of different radii, using the same material to achieve different equivalent relative permittivity.

[0019] Furthermore, the intermediate frequency module is located at the bottom of the terahertz mixer array and includes n intermediate frequency links and control circuits connected to them; each of the n intermediate frequency links is connected to n radio frequency connectors one by one through a coaxial connector; the control circuit is used to adjust the phase and amplitude of the intermediate frequency links.

[0020] Furthermore, the aforementioned terahertz two-dimensional phased feed multi-beam antenna system also includes a phase calibration module, which consists of a standard gain antenna placed in the antenna normal direction and a terahertz power meter.

[0021] A standard gain antenna is used to receive energy emitted by a terahertz two-dimensional phased-feed multi-beam antenna. The received energy is sent to a terahertz power meter for display. Based on the display result, the amplitude and phase of the intermediate frequency (IF) link are adjusted until the value displayed on the terahertz power meter is at its maximum. At this point, the normal gain of the phased-feed multi-beam antenna is determined to be at its maximum value. The current amplitude and phase state of the IF link is determined as an equal-phase, equal-amplitude feeding index as reference data and sent to the control circuit as the basis for regulating the amplitude and phase calibration of each IF link, thereby achieving the calibration of the IF link amplitude and phase.

[0022] Furthermore, n≥4.

[0023] By adopting the above technical solution, the present invention has the following advantages:

[0024] 1. This invention integrates the local oscillator power divider link and the radio frequency extension link into the terahertz extension module, enabling the same device to be used for two types of circuits, thus achieving integration and miniaturization of the device circuit. Each port of the radio frequency extension link shares a second non-standard flange with each sub-port of the local oscillator power divider link, reducing the number of flanges in the structure, effectively reducing the volume occupation, and also alleviating the difficulties of subsequent wiring, connection and testing.

[0025] 2. This invention places the terahertz extension module between the terahertz mixer array and the phased feed multi-beam antenna. Combined with the local oscillator power divider link and RF extension link integrated in the terahertz extension module, it achieves a reasonable overall layout of the two-dimensional phased array, resulting in smaller device size and realizing the integration and miniaturization of the terahertz antenna system.

[0026] 3. By setting up a phase calibration module, this invention realizes the function of fully automatic rapid phase calibration, which reduces phase drift caused by environmental factors such as temperature drift in the later stage, thereby avoiding the need for repeated manual phase adjustment, which is beneficial to system testing and application. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the terahertz extension module structure in an embodiment.

[0028] Figure 2 This is a bottom view of the terahertz extension module in the embodiment;

[0029] Figure 3 This is a schematic diagram of a terahertz silicon horn array structure as an example.

[0030] Figure 4 This is a schematic diagram of the structure of the terahertz mixer external module connected to the silicon horn in an embodiment.

[0031] Figure 5 This is a schematic diagram of the terahertz generalized Luneburg lens antenna structure in the embodiment;

[0032] Figure 6 This is a schematic diagram of the mid-frequency module structure in the terahertz antenna system of the embodiment;

[0033] Figure 7 The mixer array diagram of the terahertz antenna system is shown in the embodiment.

[0034] Figure 8 This is a schematic diagram showing the interface between the mid-frequency module and the mixer array in the terahertz antenna system of this embodiment.

[0035] Figure 9 This is a schematic diagram of the phase calibration module structure in the embodiment;

[0036] Figure 10 This is an exploded view of the terahertz two-dimensional phased feed multi-beam antenna system of the present invention.

[0037] Figure label:

[0038] 1. RF extension link, 2. Terahertz extension module, 3. Power divider, 4. First non-standard flange, 5. RF port of the second non-standard flange, 6. RF port of the first non-standard flange, 7. Local oscillator port of the first non-standard flange, 8. Local oscillator power divider link, 9. Through hole, 10. Horn antenna, 11. Outer upper hemisphere, 12. Inner sphere, 13. Outer lower hemisphere, 14. Intermediate frequency module, 15. Support cavity, 16. Intermediate frequency input port, 17. Terahertz mixer array, 18. Terahertz receiving antenna, 19. Terahertz two-dimensional phased feed multi-beam antenna array, 20. FPGA control board, 21. Generalized Burr lens bracket, 22. Intermediate frequency bent waveguide cavity, 23. Local oscillator feed circuit. Detailed Implementation

[0039] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0040] This embodiment provides a terahertz two-dimensional phased-feed multi-beam antenna system, including a terahertz mixer array 17, an intermediate frequency module 14, a terahertz extension module 2, a phased-feed multi-beam antenna, and a terahertz local oscillator feeding circuit. The terahertz mixer array 17 is located below the terahertz extension module 2, and the phased-feed multi-beam antenna is located above the terahertz mixer array 17.

[0041] like Figure 7 As shown, the terahertz mixer array consists of 16 waveguide terahertz mixers arranged in a 4×4 configuration. Each waveguide terahertz mixer has 16 first non-standard flanges 4 and 16 RF connectors. The first non-standard flange 4 has a local oscillator port and an RF port. The local oscillator port on the first non-standard flange is the local oscillator input port 6, and the RF port on the first non-standard flange is the RF output port 7. The 16 RF connectors serve as intermediate frequency (IF) input ports 16, connecting to the intermediate frequency (IF) module 14 to receive the IF signal provided by the IF module. Energy is input from the IF input port 16 and the local oscillator input port 6, and after mixing by the internal circuitry, a terahertz RF signal is output from the RF output port 7.

[0042] like Figure 6 and Figure 8As shown, the intermediate frequency module 14 is located at the bottom of the terahertz mixer array and includes n intermediate frequency links and a control system; each of the 16 intermediate frequency links is connected to one of the 16 radio frequency connectors via a coaxial cable; the control circuit is used to adjust the phase and amplitude of the intermediate frequency links.

[0043] like Figures 1-2 As shown, the terahertz expansion module 2 includes 16 second non-standard flanges, a power divider 3, and 16 RF extension links 1. Each second non-standard flange also has a local oscillator port and an RF port. The input of the power divider 3 is connected to the local oscillator feed circuit 23, which is used to divide the energy provided by the terahertz local oscillator feed circuit 23 into 16 equal parts to form local oscillator power divider links 8. The output of each local oscillator power divider link and the output of each RF extension link share a second non-standard flange. When the power divider 3 receives externally input energy, it divides it into 16 equal parts, which are then transmitted one-to-one to the local oscillator ports of the 16 second non-standard flanges by the 16 local oscillator power divider links, and then transmitted to the subsequently connected terahertz mixer via the local oscillator port of the first non-standard flange 4. After each RF port receives externally input energy, it is guided to the RF port of the second non-standard flange through an RF extension link, and then output by the corresponding RF port of the first non-standard flange 4. This embodiment achieves a tightening from sparse layout to compact power supply. In this embodiment, the RF extension link is a bent RF extension link. By adopting a bent RF extension link, the sparse layout is reduced to a compact power supply.

[0044] Furthermore, during implementation, since both the second non-standard flange and the first non-standard flange integrate RF ports and local oscillator ports, there is no need to use two flanges, thus achieving a reduction in size.

[0045] like Figure 3 As shown, the phased-feed multi-beam antenna includes: a silicon horn antenna array and a generalized Luneburg lens antenna 21 disposed above the silicon horn antenna array.

[0046] The silicon-based horn antenna array is mounted on the terahertz extension module and connected to it via a heterogeneous bonding method. To improve mechanical stability and connection strength, the silicon-based horn antenna array in this embodiment is also provided with through holes 9 around its perimeter for placing bolts, allowing the silicon-based horn antenna array and the terahertz extension module 2 to be more tightly bonded together. The silicon-based horn antenna array consists of 16 air-filled silicon-based horn antennas 10 arranged in a 4×4 pattern. Each silicon-based horn antenna 10 is constructed from multiple layers of 50µm high silicon-based substrates stacked together. A metal coating is formed inside the silicon-based horn antenna using microprocessors. Each silicon-based horn antenna is connected to a second non-standard flange and to the RF port of the second non-standard flange, i.e., connected to the RF extension link through the RF port of the second non-standard flange. Figure 4As shown, the RF ports of the 16 second non-standard flanges in the terahertz extension module 2, after receiving terahertz energy, are fed to the 16 silicon horn antennas 10 through the RF extension link 1 in the terahertz extension module 2. The silicon horn antennas 10 radiate as feed sources.

[0047] like Figure 5 As shown, the generalized Luneburg lens in this embodiment is manufactured using high-precision 3D printing. 11 and 13 are the outer spheres, and 12 is the inner sphere. After 11 and 13 enclose 12, they are positioned and fixed using positioning holes and through holes on the disc. The generalized Luneburg lens antenna includes an outer upper hemisphere 11, an outer lower hemisphere 13, and an inner sphere 12. The outer upper hemisphere 11 and outer lower hemisphere 13 are joined to form an outer spherical cavity, and their joint is fixed by a circular fixing plate. The inner sphere 12 is placed inside the outer spherical cavity.

[0048] In practical applications, in addition to the differences between each terahertz mixer due to manufacturing tolerances, there are also phase differences caused by factors such as ambient temperature and humidity. To overcome this problem, this embodiment adds a phase calibration module to the aforementioned terahertz two-dimensional phased-array feed multi-beam antenna system.

[0049] like Figure 9 As shown, the phase calibration module consists of a standard gain antenna placed in the antenna normal direction and a terahertz power meter;

[0050] A standard gain antenna is used to receive energy emitted by a terahertz two-dimensional phased-feed multi-beam antenna. The received energy is transmitted to a terahertz power meter for display. Based on the display result, the amplitude and phase of the intermediate frequency (IF) link are adjusted until the value displayed on the terahertz power meter reaches its maximum. At this point, the normal gain of the phased-feed multi-beam antenna is considered to be at its maximum. The current amplitude and phase state of the IF link is then determined as an equal-phase, equal-amplitude feeding index as reference data and sent to the control circuit as the basis for adjusting the amplitude and phase calibration of each IF link, thereby achieving the calibration of the IF link amplitude and phase.

[0051] The principle by which this embodiment achieves phase adjustment is as follows:

[0052] According to the antenna aperture field theory, the antenna efficiency is highest, i.e., the normal direction gain is maximum, only when the amplitude and phase of the aperture electric field are consistent. Taking the two-dimensional phased-feed multi-beam antenna system of this embodiment as the transmitter, a terahertz receiving horn antenna, used as a standard gain antenna, is placed in the normal direction. This horn antenna is externally connected to a terahertz power meter, which converts the received power into a digital signal for display. When the value displayed on the terahertz power meter is maximum, it is determined that the normal gain of the two-dimensional phased-feed multi-beam antenna system is at its maximum. Subsequently, the amplitude and phase of each intermediate frequency link are quickly adjusted using the control circuit, and the equivalent signal of the received power is recorded. The maximum received energy is found through a search algorithm, and the amplitude and phase distribution corresponding to the maximum received energy is found. According to the theory, this amplitude and phase distribution is identified as the feeding state with consistent amplitude and phase at the front end of the transmitter. Phase calibration is quickly performed based on this as a reference. Subsequent phase control is further adjusted based on this reference, which greatly reduces the phase drift caused by environmental factors such as temperature drift, thus reducing the need for repeated manual phase adjustments.

[0053] With the addition of the phase calibration module, the workflow of this embodiment is as follows:

[0054] After the 16 intermediate frequency (IF) links achieve amplitude and phase calibration, they output 16 phase-modulated and amplitude-modulated IF signals. The local oscillator (LO) link inputs the LO signal, which, after passing through a 1-to-16 power divider in the terahertz extension module, outputs 16 equal-power LO signals. These 16 LO signals, along with the 16 modulated IF signals, are input to a 16-terahertz mixer array. After harmonic mixing, they output 16 radio frequency (RF) signals. These 16 RF signals are also fed into the RF bending circuit in the terahertz extension module, powering 16 silicon-embedded loudspeakers. Once excited, the loudspeakers act as primary feed sources to illuminate a generalized Luneburg lens, ultimately achieving a two-dimensional terahertz spatial beam coverage effect.

[0055] It is understood that the present invention has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the invention. Furthermore, under the teachings of the present invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of the present invention.

Claims

1. A terahertz two-dimensional phased-feed multi-beam antenna system, comprising a terahertz mixer array, a terahertz extension module, a phased-feed multi-beam antenna, and a terahertz local oscillator feeding circuit, characterized in that: The terahertz mixer array is located below the terahertz extension module; the phased-array feed multi-beam antenna is located above the terahertz extension module. The terahertz mixer array consists of n waveguide terahertz mixers. Each waveguide terahertz mixer is equipped with n first non-standard flanges and n radio frequency connectors. The first non-standard flanges are equipped with local oscillator ports and radio frequency ports. The n radio frequency connectors are connected to the intermediate frequency module. The terahertz extension module includes n second non-standard flanges, n local oscillator power divider links, and n radio frequency extension links; each second non-standard flange is provided with a local oscillator port and a radio frequency port; the output port of each local oscillator power divider link and the output port of each radio frequency extension link share a second non-standard flange, and the two are respectively connected to the local oscillator port and radio frequency port on the corresponding first non-standard flange through the local oscillator port and radio frequency port on the second non-standard flange; The phased-array feed multi-beam antenna includes a silicon horn antenna array and a generalized Luneburg lens antenna. The silicon horn antenna array is located on the terahertz extension module and is connected to the terahertz extension module via a heterogeneous connection. The silicon horn antenna array consists of n silicon horn antennas, each of which is connected to a second non-standard flange and to the RF port of the second non-standard flange, and is connected to the RF extension link through the RF port of the second non-standard flange. The generalized Luneburg lens antenna is placed above the silicon horn antenna array. The terahertz local oscillator feed circuit is used to provide local oscillator signals for the n-channel local oscillator power divider links.

2. The terahertz two-dimensional phased-feed multi-beam antenna system according to claim 1, characterized in that: The terahertz local oscillator feed circuit consists of an X-band frequency source, an 8-fold frequency multiplier, a filter, and a terahertz adjustable power amplifier connected in sequence.

3. The terahertz two-dimensional phased-feed multi-beam antenna system according to claim 1, characterized in that: The silicon stacked horn antenna is a horn-shaped antenna formed by stacking multiple silicon substrates.

4. A terahertz two-dimensional phased-feed multi-beam antenna system according to claim 1, characterized in that: The generalized Luneburg lens antenna includes an outer upper hemisphere, an outer lower hemisphere, and an inner sphere. The outer upper hemisphere and the outer lower hemisphere are joined together to form an outer spherical cavity, and the inner sphere is placed inside the outer spherical cavity.

5. A terahertz two-dimensional phased-feed multi-beam antenna system according to claim 4, characterized in that: The generalized Luneburg lens antenna has several air holes of different radii on its outer upper and lower hemispheres.

6. A terahertz two-dimensional phased-feed multi-beam antenna system according to claim 1, characterized in that: The intermediate frequency module is located at the bottom of the terahertz mixer array and includes n intermediate frequency links and control circuits connected to them. Each of the n intermediate frequency links is connected to n radio frequency connectors through a coaxial connector. The control circuit is used to adjust the phase and amplitude of the intermediate frequency links.

7. A terahertz two-dimensional phased-feed multi-beam antenna system according to claim 6, characterized in that: The aforementioned terahertz two-dimensional phased feed multi-beam antenna system also includes a phase calibration module, which consists of a standard gain antenna placed in the antenna normal direction and a terahertz power meter. A standard gain antenna is used to receive energy emitted by a terahertz two-dimensional phased-feed multi-beam antenna. The received energy is sent to a terahertz power meter for display. Based on the display result, the amplitude and phase of the intermediate frequency (IF) link are adjusted until the value displayed on the terahertz power meter is at its maximum. At this point, the normal gain of the phased-feed multi-beam antenna is considered to be at its maximum value. The current amplitude and phase state of the IF link is determined as an equal-phase, equal-amplitude feeding index as reference data and sent to the control circuit as the basis for regulating the amplitude and phase calibration of each IF link, thereby achieving the calibration of the IF link amplitude and phase.

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