Terahertz two-dimensional phase control feed source multi-beam antenna system

Abstract

The invention belongs to the field of terahertz communication, and particularly relates to a terahertz two-dimensional phase control feed source multi-beam antenna system. Comprising a terahertz mixer array, a terahertz external extension module, a phased feed source multi-beam antenna and a terahertz local oscillator feed circuit, the terahertz mixer array is arranged below the terahertz external extension module; the phase control feed source multi-beam antenna is arranged above the terahertz external extension module; the terahertz external expansion module is arranged between the terahertz frequency mixing array and the phased feed source multi-beam antenna, integrates a local oscillation power division link and a radio frequency expansion link, and realizes reasonable layout of a two-dimensional phased array. The module integrates two circuits, achieves integration and miniaturization, shares the second non-standard flange, reduces the size, and relieves the problems of wiring and the like. In conclusion, the antenna achieves the two-dimensional wave beam coverage range and the high-gain radiation requirement, and has the advantages of being compact in layout, small in size, easy to integrate and the like. And the communication requirements of the terahertz frequency band in different application scenes can be better met.

Description

Technical Field

[0001] The invention belongs to the field of terahertz communication, and in particular relates to a terahertz two-dimensional phased feed multi-beam antenna system. Background Art

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

[0003] As the front end of the communication system, the antenna is an important carrier for radiating / receiving electromagnetic waves. When designing the antenna, it has a controllable gain characteristic, which can radiate the energy input into the system in a concentrated manner in a fixed direction. Compared with the commonly used wireless communication frequency bands (such as 2.45GHz, 5.8GHz) and other microwave bands (such as X-band, Ku-band, Ka-band), there is an obvious problem in the transmission of terahertz waves, that is, its path loss is quite significant. Moreover, under the condition of the same radiation power, the physical transmission distance of terahertz waves is relatively short. In view of this, in the terahertz frequency band, in order to effectively combat path loss, it is particularly important to use large-diameter antennas to increase radiation gain.

[0004] High-gain antennas include array antennas, reflector antennas, lens antennas and other types. Traditional reflector antennas and lens antennas generally include a single feed antenna and a corresponding reflector or lens. After the feed network is determined, the beam direction of this type of antenna is also determined. In many fields such as medical treatment, communications, and security inspections, antenna beams are often required to achieve coverage within a certain range. However, for traditional single-feed reflector and lens antennas, if beam scanning is to be performed, additional motors need to be installed to achieve mechanical scanning, but the speed and accuracy of mechanical scanning are often limited, and it is difficult to meet some complex requirements in practical applications.

[0005] Phased array antennas are different. By introducing amplitude modulation and phase modulation devices at the front end of the array antenna unit, the beam pointing can be effectively changed by means of amplitude and phase control, thereby achieving fast and large-angle beam range coverage. However, if you want to achieve a higher gain of more than 30dBi or even 35dBi, you will face a thorny problem, that is, the number of array units will increase dramatically, which will inevitably lead to a sharp increase in the number of back-end TR components, and ultimately increase the size of the entire antenna system and the cost. Therefore, when the number of channels is limited, how to simultaneously meet a certain beam coverage range and achieve high-gain radiation requirements is of great practical significance.

[0006] In the terahertz band, due to the limitations of current processing accuracy and high material loss, metal has become a popular material for terahertz band antenna design due to its inherent low loss characteristics. At present, terahertz circuits are more often designed and processed in the form of metal cavities, but doing so often causes the volume of the circuit itself to be much larger than the antenna. Taking into account the difficulties and loss problems in the design and testing of the circuit devices themselves, the current mainstream terahertz phased array antenna system basically still adopts a one-dimensional scanning design. This means that if two-dimensional scanning is to be achieved, additional motors are required to assist in rotation. However, for high-gain antenna systems with operating wavelengths of millimeters or even smaller, this places very high demands on the accuracy and response speed of the motor. At present, it is difficult to find a suitable motor that can fully meet such requirements.

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

[0008] The purpose of the present invention is to provide a terahertz two-dimensional phased feed multi-beam antenna system, which achieves the two-dimensional beam coverage and high-gain radiation requirements under a limited number of channels, and has the advantages of compact layout, small size, and easy integration, etc. It can better meet the communication needs of the terahertz frequency band in different application scenarios.

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

[0010] 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; the terahertz mixer array is arranged below the terahertz extension module; the phased-feed multi-beam antenna is arranged above the terahertz extension module;

[0011] The terahertz mixer array is composed of n waveguide terahertz mixers, each waveguide terahertz mixer is provided with n first non-standard flanges and n radio frequency connectors, the first non-standard flange is provided with a local oscillator port and a radio frequency port, and 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 division 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 division 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 the radio frequency port on the corresponding first non-standard flange via the local oscillator port and the radio frequency port on the second non-standard flange;

[0013] The phased-feed multi-beam antenna includes a silicon product horn antenna array and a generalized Luneburg lens antenna; the silicon product horn antenna array is arranged in the terahertz extension module and is connected to the terahertz extension module by a heterogeneous bonding method; the silicon product horn antenna array is composed of n silicon product horn antennas, each of which is connected to a second non-standard flange and connected to the radio frequency port of the second non-standard flange, that is, connected to the radio frequency extension link through the radio frequency port; the generalized Luneburg lens antenna is placed above the silicon product horn antenna array;

[0014] The terahertz local oscillator feeding circuit is used to provide local oscillator signals for n local oscillator power division links.

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

[0016] Furthermore, the silicon-on-silicon horn antenna is a horn-shaped antenna formed by stacking multiple layers of silicon-on-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 connected to form an outer spherical cavity, and the inner sphere is placed in the outer spherical cavity.

[0018] Furthermore, a plurality of air holes with different radii are provided on the outer upper hemisphere and the outer lower hemisphere of the generalized Luneburg lens antenna, so that different equivalent relative dielectric constants are achieved by using the same material.

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

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

[0021] The standard gain antenna is used to receive the energy emitted by the terahertz two-dimensional phased feed multi-beam antenna, send the received energy to the terahertz power meter for display, and adjust the amplitude and phase of the intermediate frequency link according to the display result until the value displayed on the terahertz power meter is the maximum. It is determined that the normal gain of the phased feed multi-beam antenna is the maximum value at this time, and the current amplitude and phase state of the intermediate frequency link is determined as equal phase and equal amplitude feeding indicators as reference data, which are sent to the control circuit as the basis for regulating the amplitude and phase calibration of each intermediate frequency link, thereby realizing the calibration of the amplitude and phase of the intermediate frequency link.

[0022] Furthermore, n≥4.

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

[0024] 1. The present invention integrates the power division link of the local oscillator and the radio frequency extension link in the terahertz extension module, so that the same device can be arranged with two circuits, realizing the integration and miniaturization of the device circuit; the port of each radio frequency extension link and each branch port of the local oscillator power division link share a second non-standard flange, reducing the number of flanges in the structure, effectively reducing the volume occupancy, and also alleviating the subsequent wiring, connection and testing problems.

[0025] 2. The present invention arranges the terahertz extension module between the terahertz mixing array and the phased feed multi-beam antenna, and cooperates with the local oscillator power division link and the radio frequency extension link integrated in the terahertz extension module to achieve an overall reasonable layout of the two-dimensional phased array, a smaller device size, and the integration and miniaturization of the terahertz antenna system.

[0026] 3. The present invention realizes the function of fully automatic phase rapid calibration by setting a phase calibration module, reduces the phase drift caused by environmental factors such as late temperature drift, and thus avoids the situation of repeated manual phase adjustment, which is beneficial to system testing and application. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

[0029] Figure 3 This is a schematic diagram of the structure of a terahertz silicon speaker array according to an embodiment;

[0030] Figure 4 This is a schematic diagram of the structure of the terahertz mixer extension module after connecting the silicon product speaker in the embodiment;

[0031] Figure 5 Schematic diagram of the structure of a terahertz generalized Luneburg lens antenna in an embodiment;

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

[0033] Figure 7 A mixer array diagram of a terahertz antenna system of an embodiment;

[0034] Figure 8 It is a schematic diagram of the connection between the intermediate frequency module and the mixer array of the terahertz antenna system of the embodiment;

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

[0036] Fig.10 It is an overall exploded diagram of the terahertz two-dimensional phased feed multi-beam antenna system of the present invention;

[0037] Reference numerals:

[0038] 1. RF extension link, 2. THz extension module, 3. Power divider, 4. First non-standard flange, 5. RF port of second non-standard flange, 6. RF port of first non-standard flange, 7. Local oscillator port of first non-standard flange, 8. Local oscillator power division 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. THz mixer array, 18. THz receiving antenna, 19. THz two-dimensional phased feed multi-beam antenna array, 20. FPGA control board, 21. Generalized Bo lens bracket, 22. Intermediate frequency bent waveguide cavity, 23 Local oscillator feeding circuit. DETAILED DESCRIPTION

[0039] The technical solution of the present invention is described in detail below in conjunction with the accompanying drawings and embodiments.

[0040] The present embodiment provides a terahertz two-dimensional phased-feed multi-beam antenna system, comprising 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 arranged below the terahertz extension module 2, and the phased-feed multi-beam antenna is arranged above the terahertz mixer array 17.

[0041] like Figure 7 As shown, the terahertz mixer array is composed of 16 waveguide terahertz mixers arranged in a 4×4 array. Each waveguide terahertz mixer is provided with 16 first non-standard flanges 4 and 16 RF connectors. The first non-standard flange 4 is provided with a local oscillator port and a RF port, the local oscillator port on the first non-standard flange is a local oscillator input port 6, and the RF port on the first non-standard flange is a RF output port 7. The 16 RF connectors are connected to the intermediate frequency module 14 as the intermediate frequency input port 16, and receive the intermediate frequency signal provided by the intermediate frequency module. Energy is input from the intermediate frequency input port 16 and the local oscillator input port 6, and after internal circuit mixing, the 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, including n intermediate frequency links and a control system; each of the 16 intermediate frequency links is connected to 16 RF connectors one by one through a coaxial line; the control circuit is used to adjust the phase and amplitude of the intermediate frequency link.

[0043] like Figure 1-Figure 2 As shown, the terahertz extension module 2 includes 16 second non-standard flanges, a power divider 3 and 16 RF extension links 1. Each second non-standard flange is also provided with a local oscillator port and a RF port. The input end of the power divider 3 is connected to the local oscillator feeding circuit 23, which is used to divide the energy provided by the terahertz local oscillator feeding circuit 23 into 16 equal parts to form a local oscillator power division link 8. The output of each local oscillator power division link and the output of each RF extension link share a second non-standard flange. When the power divider 3 receives the external input energy, it is divided into 16 parts, and the 16 local oscillator power division links are transmitted one by one to the local oscillator ports of the 16 second non-standard flanges, and then transmitted to the subsequent docking terahertz mixer through the local oscillator port of the first non-standard flange 4. After each RF port receives the external input energy, it will be guided to the RF port of the second non-standard flange through an RF extension link, and then output by the RF port of the corresponding first non-standard flange 4. This embodiment realizes the tightening from sparse layout to compact feeding. In this embodiment, the radio frequency extension link is a bent radio frequency extension link, and the tightening from sparse layout to compact feeding is achieved by adopting a bent radio frequency extension link.

[0044] In addition, during implementation, since both the second non-standard flange and the first non-standard flange integrate the RF port and the local oscillator port, there is no need to use two flanges, thereby achieving a reduction in volume.

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

[0046] The silicon product horn antenna array is arranged on the terahertz extension module and is connected to the terahertz extension module by a heterogeneous bonding method. In order to improve the mechanical stability and connection strength, the silicon product horn antenna array of this embodiment is also provided with through holes 9 around it. The through holes 9 are used to place bolts, and the silicon product horn antenna array and the terahertz extension module 2 can be more closely combined together through bolts. The silicon product horn antenna array is composed of 16 air-filled silicon product horn antennas 10 arranged in 4×4. Each silicon product horn antenna 10 is stacked by multiple layers of silicon product silicon substrates with a layer height of 50um. A metal coating is formed inside the silicon product horn antenna through micro-processing. Each silicon product horn antenna is connected to a second non-standard flange, and is connected to the RF port of the second non-standard flange, that is, it is connected to the RF expansion link through the RF port of the second non-standard flange. As Figure 4As shown, after the terahertz energy is input into the RF ports of the 16 second non-standard flanges in the terahertz extension module 2, the RF ports are fed to the 16 silicon horn antennas 10 through the RF extension link 1 in the terahertz extension module 2, and the silicon horn antennas 10 act as feed sources for radiation.

[0047] like Figure 5 As shown, the generalized Luneburg lens of this embodiment is made by high-precision 3D printing. Among them, 11 and 13 are outer spheres, and 12 is an inner sphere. After 11 and 13 wrap 12, they are positioned and fixed through the positioning holes and through holes on the disk. 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 the outer lower hemisphere 13 are connected to form an outer spherical cavity, and the connection point is fixed by a circular ring fixing plate, and the inner sphere 12 is placed in the outer spherical cavity.

[0048] In practical applications, in addition to the differences between each terahertz mixer due to manufacturing tolerance, 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 above-mentioned terahertz two-dimensional phased feed multi-beam antenna system.

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

[0050] The standard gain antenna is used to receive the energy emitted by the terahertz two-dimensional phased feed multi-beam antenna, send the received energy to the terahertz power meter for display, and adjust the amplitude and phase of the intermediate frequency link according to the display result until the value displayed on the terahertz power meter is the maximum. It is determined that the normal gain of the phased feed multi-beam antenna is the maximum at this time, and the current amplitude and phase state of the intermediate frequency link is determined as the equal phase and equal amplitude feeding index as reference data, which is sent to the control circuit as the basis for adjusting the amplitude and phase calibration of each intermediate frequency link, thereby realizing the calibration of the amplitude and phase of the intermediate frequency link. .

[0051] The principle of phase adjustment in this embodiment is as follows:

[0052] According to the antenna aperture field theory, it can be known that only when the aperture electric field amplitude and phase are consistent, the antenna efficiency is the highest, that is, the gain in the normal direction is the largest. The two-dimensional phased feed multi-beam antenna system of this embodiment is used as the transmitter, and a terahertz receiving horn antenna used as a standard gain antenna is placed in the normal direction. The horn antenna is externally connected to a terahertz power meter, and the power meter converts the received power into a digital signal for display. When the value displayed on the terahertz power meter is the largest, it is determined that the normal gain of the two-dimensional phased feed multi-beam antenna system is the maximum value at this time, and then the control circuit is used to quickly adjust the amplitude and phase of each intermediate frequency link, and the equivalent signal of the received power is recorded. The maximum energy receiving energy is found by searching the algorithm, and the amplitude and phase distribution corresponding to the maximum receiving energy are found. According to the theory, the amplitude phase distribution is identified as the feeding state of the front end of the transmitter with consistent amplitude and phase, and phase calibration is quickly performed based on this, and the subsequent phase control is additionally adjusted on this basis, which greatly reduces the phase drift caused by environmental factors such as temperature drift in the later stage, thereby causing the process of manually adjusting the phase repeatedly.

[0053] After the phase calibration module is added in this embodiment, the working process is as follows:

[0054] After the 16-channel intermediate frequency link has achieved amplitude and phase calibration, the intermediate frequency link outputs 16 phase-modulated intermediate frequency signals, and the local oscillator link inputs the local oscillator signal, which is output as 16 equal-power local oscillator signals through the local oscillator 1-to-16 power divider in the terahertz extension module. The 16 local oscillator signals and the 16 regulated intermediate frequency signals are input into the 16-channel terahertz mixer array, and after harmonic mixing, 16 RF signals are output. The 16 RF signals are also input into the RF bending circuit in the terahertz extension module to feed 16 silicon-integrated speakers. After being excited, the speakers serve as primary feed sources to illuminate the generalized Luneburg lens, ultimately achieving a two-dimensional terahertz spatial beam coverage effect.

[0055] It is to be understood that the present invention is described by some embodiments, and it is known to those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the scope of protection 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 arranged below the terahertz extension module; the phased-feed multi-beam antenna is arranged above the terahertz extension module; The terahertz mixer array is composed of n waveguide terahertz mixers, each waveguide terahertz mixer is provided with n first non-standard flanges and n radio frequency connectors, the first non-standard flange is provided with a local oscillator port and a radio frequency port, and 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 division 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 division 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 the radio frequency port on the corresponding first non-standard flange via the local oscillator port and the radio frequency port on the second non-standard flange; The phased-feed multi-beam antenna includes a silicon product horn antenna array and a generalized Luneburg lens antenna; the silicon product horn antenna array is arranged in the terahertz extension module and is connected to the terahertz extension module by a heterogeneous bonding method; the silicon product horn antenna array is composed of n silicon product horn antennas, each of which is connected to a second non-standard flange and connected to the radio frequency port of the second non-standard flange, that is, connected to the radio frequency extension link through the radio frequency port; the generalized Luneburg lens antenna is placed above the silicon product horn antenna array; The terahertz local oscillator feeding circuit is used to provide local oscillator signals for n local oscillator power division links.

2. A terahertz two-dimensional phased feed multi-beam antenna system according to claim 1, characterized in that: The terahertz local oscillator feeding circuit is composed of an X-band frequency source, an 8-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-on-silicon horn antenna is a horn-shaped antenna formed by stacking multiple layers of silicon-on-silicon substrates.

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

5. A terahertz two-dimensional phased feed multi-beam antenna system according to claim 4, characterized in that: A plurality of air holes with different radii are arranged on the outer upper hemisphere and the outer lower hemisphere of the generalized Luneburg lens antenna.

6. The 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 a control circuit connected thereto. 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 link.

7. A terahertz two-dimensional phased feed multi-beam antenna system according to any one of claims 1 to 6, characterized in that: The above-mentioned terahertz two-dimensional phased feed multi-beam antenna system also includes a phase calibration module, which is composed of a standard gain antenna placed in the normal direction of the antenna and a terahertz power meter; The standard gain antenna is used to receive the energy emitted by the terahertz two-dimensional phased feed multi-beam antenna, send the received energy to the terahertz power meter for display, and adjust the amplitude and phase of the intermediate frequency link according to the display result until the value displayed on the terahertz power meter is the maximum. It is determined that the normal gain of the phased feed multi-beam antenna is the maximum value at this time, and the current amplitude and phase state of the intermediate frequency link is determined as equal phase and equal amplitude feeding indicators as reference data, which are sent to the control circuit as the basis for regulating the amplitude and phase calibration of each intermediate frequency link, thereby realizing the calibration of the amplitude and phase of the intermediate frequency link.

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