A hybrid coding method of electrically controlled fixed-frequency beamforming scanning leaky-wave antenna

Abstract

The application discloses a kind of electric control fixed frequency beamforming scanning leaky-wave antenna hybrid encoding method, applied to electronic and communication technology field, wherein including: S1, in the case of beamforming scanning, first to determine the relationship and size between beam angle and field intensity along straight path, then according to the secant relationship criterion, the electric field intensity of different positions or angles can be obtained;S2, according to the electric field intensity distribution, the diode encoding state of beam in a certain direction is determined by using hybrid encoding method, so as to design the beamforming scanning beam along the line to meet the requirements of shaping, and the shaping scanning is realized.The present application is the shaping scanning technology proposed for the demand of smooth coverage of electric wave in limited space, can make the radiation field intensity meet the secant square relationship at each position when antenna beam scanning, so as to make the electric field on the horizontal line basically constant.

Description

Technical Field

[0001] This invention relates to the fields of electronics and communication technology, and more specifically to a hybrid coding method for leaky antennas with electronically controlled fixed-frequency beamforming scanning. Background Technology

[0002] Leaky wave antennas (LWAs) have attracted widespread attention over the past few decades due to their high directivity, wide impedance bandwidth, and ease of integration. Typically, the radiation of LWAs is generated by the leakage of traveling waves propagating in a waveguide structure.

[0003] In modern communication and detection systems, such as personal and vehicle communication, evasion systems, and radar tracking systems, antennas with multi-beam or fixed-frequency beam scanning capabilities are more practical, and fixed-frequency beam scanning LWAs have received increasing attention. The implementation methods of fixed-frequency beam scanning LWAs can be divided into two aspects according to their implementation mechanisms. One method involves changing the propagation constant β, which leads to a change in beam elevation angle and thus beam steering. These methods include changing the element phase, waveguide equivalent width, slot period, and element impedance. Secondly, multi-antenna element technology is employed, such as multi-port feeding, multi-layer elements, and beamforming networks. These methods are all based on traditional continuous beam scanning. The most similar implementation to this invention is proposed in X. Li et al., "Leaky-Wave Antenna Array With Bilateral Beamforming Radiation Pattern and Capability of Flexible Beam Switching," in IEEE Transactions on Antennas and Propagation, vol.70, no.2, pp.1535-1540, Feb.2022, doi:10.1109 / TAP.2021.3111157. Bilateral switching beamforming can be achieved through power division and switching between different ports, but the beamforming scanning function is not implemented.

[0004] Compared to CN112751183A, a digitally encoded beam-scanning circularly polarized leaky antenna, the advantages of this invention are: 1) it has a wider beam coverage capability, and 2) it can provide a scanning beam that satisfies the shaping relationship.

[0005] Compared to CN111106451B, a one-dimensional electrically controlled beam scanning circularly polarized antenna and its control method, this invention uses a complementary 1*2 antenna array to enable the antenna to scan with an intensity approximately equal to the square of the cosecant, which is more conducive to stable radio wave coverage and smooth signal reception of objects moving along a one-dimensional straight line.

[0006] Therefore, proposing a hybrid coding method for leaky antennas with electronically controlled fixed-frequency beamforming scanning to solve the difficulties existing in the prior art is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0007] In view of this, the present invention provides a hybrid coding method for leaky wave antennas with electronically controlled fixed-frequency beamforming scanning. The beamforming scanning technology proposed for the requirement of stable radio wave coverage in confined spaces can ensure that the radiation field intensity at each position during antenna beam scanning satisfies the cosecant square relationship, thereby making the electric field on the horizontal line basically constant.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] A hybrid coding method for a leaky antenna with electronically controlled fixed-frequency beamforming scanning includes the following steps:

[0010] S1. In the case of beamforming scanning, the relationship and magnitude between the beam angle and the field strength along the straight path must first be determined, and then the electric field strength at different positions or angles can be obtained according to the cosecant relationship criterion.

[0011] S2. Based on the electric field strength distribution, the diode coding state of the beam in a specific direction is determined by a hybrid coding method, thereby designing a shaped scanning beam that meets the shaping requirements along the line and realizing shaped scanning.

[0012] Optionally, the above method can be used to determine the azimuth angle θ between the antenna and the receiving user based on the height difference H and the horizontal relative position X. n The specific formula is as follows:

[0013]

[0014] Optionally, in the above method, the electric field intensity of each beam in beamforming scanning should conform to or closely approximate an ideal cosecant distribution, and its beam direction θ n and the corresponding electric field strength E n The following formula should be satisfied:

[0015] E j :E0=secθ n :secθ0,(j=1,2,...,n) (2).

[0016] Optionally, when the electric field radiation pattern satisfies the cosecant distribution, the antenna gain G satisfies the cosecant square distribution, which can be expressed by the following equation (3) or equation (4):

[0017] G j :G0=sec 2 θ n :sec2 θ0,(j=1,2,...,n) (3)

[0018] G j =G0+20log 10 (secθ n / secθ0) (dB) (4).

[0019] The above method, optionally, includes the following hybrid encoding method in S2:

[0020] S21 determines the maximum scanning angle θ of the antenna array based on its radiation characteristics. max And at the maximum angle θ max The maximum radiated electric field value E at that location θ_max Based on the maximum radiated electric field value and the cosecant relationship, the ideal distribution of the electric field along the line is determined;

[0021] S22 determines the angular resolution of the shaping scan; based on the angular resolution and the maximum scanning angle θ max This allows us to determine the number of beams j being scanned, the pointing angle of each beam, and the ideal electric field strength at the maximum angle corresponding to each beam.

[0022] S23 encodes different states accordingly. By adjusting the diode encoding, each diode encoding state that meets the beamforming scanning conditions is designed to obtain a beamforming scanning beam that meets the beamforming requirements along the line, thus realizing beamforming scanning.

[0023] Optionally, in the above method, if the radiation intensity of a single row of slots satisfies the cosecant relationship during the encoding process, only one row of slots is used; otherwise, the other row of slots should also participate in radiation partially or completely so that the total field strength satisfies the cosecant relationship.

[0024] Optionally, the above-described method includes an electrically controlled substrate integrated waveguide leaky antenna array with shaped scanning capability, comprising a bias circuit layer, a top dielectric substrate, a top metal layer, two rows of C-shaped slots etched on the top metal layer, an intermediate metal layer, two rectangular slots etched on the intermediate metal layer for energy coupling, a bottom dielectric substrate, two substrate integrated waveguides, a microstrip to substrate integrated waveguide transition section, a coaxial signal connector one, a microstrip line, a coaxial signal connector two, a 1-to-2 power divider, a bottom metal layer, and holes for fixing the overall structure.

[0025] Optionally, in the above method, coaxial signal connector 1, coaxial signal connector 2, microstrip line and adapter structure are disposed on both ends of the bottom dielectric substrate, DC bias circuit is disposed above the top dielectric substrate to control the on / off state of the slots, and slot array is loaded on the radiation port surface of the substrate integrated waveguide and the slot state is controlled by diodes for each beam of fixed frequency shaping scanning.

[0026] As can be seen from the above technical solution, compared with the prior art, the present invention discloses a hybrid coding method for leaky antennas with electronically controlled fixed-frequency beamforming scanning, which has the following beneficial effects:

[0027] (1) By using diode loading, the gap state can be made more flexible and controllable, and a wider angular space beam coverage (from -51° to 51°) can be achieved. The corresponding beam can be switched arbitrarily within ±50 degrees according to the user's location. The angular resolution is higher (about 10°), and the beam can be continuously scanned from the back space to the front space and cover the normal phase region.

[0028] (2) A novel antenna with cosecant square beam scanning capability is proposed. This antenna features high gain at low elevation angles and low scanning gain at high elevation angles, enabling the target to receive almost the same signal level when moving along a restricted straight path. Furthermore, during the scanning process, most of the antenna's radiated power will always be concentrated on the moving target, which is of great significance for improving mobile communication quality and energy efficiency. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0030] Figure 1 A flowchart of an electrically controlled fixed-frequency beamforming scanning leaky antenna and a hybrid coding method provided by the present invention;

[0031] Figure 2 The diagrams show different scanning antennas, including 2a, a conventional beam scanning antenna, and 2b, a working diagram of the leaky wave antenna of the present invention with electronically controlled fixed-frequency beamforming scanning.

[0032] Figure 3 This is a schematic diagram of the multi-beam relationship principle of the leaky antenna with electronically controlled fixed-frequency beamforming scanning according to the present invention;

[0033] Figure 4 This is a three-dimensional structural schematic diagram of the leaky wave antenna with electronically controlled fixed-frequency beamforming scanning according to the present invention;

[0034] Among them, 1-bias circuit layer, 2-top dielectric substrate, 3-top metal layer, 4-C-type slot, 5-middle metal layer, 6-rectangular slot, 7-bottom dielectric substrate, 8-two substrate integrated waveguides, 9-microstrip to substrate integrated waveguide transition part, 10-coaxial signal connector one, 11-microstrip line, 12-coaxial signal connector two, 13-one-to-two power divider, 14-bottom metal layer, 15-hole position;

[0035] Figure 5 This is a flowchart illustrating the implementation of the hybrid coding scheme used in the beamforming scanning process of the leaky antenna of the electronically controlled fixed-frequency beamforming scanning invention.

[0036] Figure 6 The radiation electric field patterns of the leaky wave antenna with electronically controlled fixed-frequency beamforming scanning according to the present invention under different scanning states are shown.

[0037] Figure 7 This is a physical image of the leaky wave antenna with electronically controlled fixed-frequency beamforming scanning according to the present invention;

[0038] Figure 8 This is a schematic diagram of the system for determining the specific radiation state based on different positions when the leaky wave antenna of the present invention, which is an electronically controlled fixed-frequency beamforming scanning device, is working. Detailed Implementation

[0039] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] Reference Figure 1 As shown, this invention discloses a hybrid coding method for leaky antennas with electronically controlled fixed-frequency beamforming scanning, comprising the following steps:

[0041] S1. In the case of beamforming scanning, the relationship and magnitude between the beam angle and the field strength along the straight path must first be determined. Then, the electric field strength at different positions or angles can be obtained according to the cosecant relationship criterion.

[0042] S2. Based on the field strength distribution, the diode coding state of the beam in a specific direction is determined by a hybrid coding method, thereby designing a shaped scanning beam that meets the shaping requirements along the line and realizing shaped scanning.

[0043] Furthermore, the azimuth angle θ between the antenna and the receiving user is determined based on the height difference H between them and the horizontal relative position X. n The specific formula is as follows:

[0044]

[0045] Furthermore, in beamforming scanning technology, the electric field intensity of each beam should conform to or closely approximate an ideal cosecant distribution, and its beam direction θ n and the corresponding electric field strength E n The following formula should be satisfied:

[0046] E j :E0=secθ n :secθ0,(j=1,2,...,n) (2).

[0047] Furthermore, when the electric field radiation pattern satisfies the cosecant distribution, the antenna gain G satisfies the cosecant square distribution, which can be expressed by the following equation (3) or equation (4):

[0048] G j :G0=sec 2 θ n :sec 2 θ0,(j=1,2,...,n) (3)

[0049] G j =G0+20log 10 (secθ n / secθ0)(dB) (4).

[0050] Furthermore, the hybrid encoding method in S2 is as follows:

[0051] First, determine the maximum scanning angle θ of the antenna array based on its radiation characteristics. max And at the maximum angle θ max The maximum radiated electric field value E at that location θ_max Based on the maximum radiated electric field value and the cosecant relationship, the ideal distribution of the electric field along the line is determined;

[0052] Secondly, determine the angular resolution of the shaping scan; based on the angular resolution and the maximum scanning angle θ max The number of scanning beams j can be determined, and the pointing angle of each beam angle and the ideal electric field intensity corresponding to the maximum angle of each beam can be determined.

[0053] Then, different states are encoded accordingly. By precisely adjusting the diode encoding, each diode encoding state that meets the beamforming scanning conditions is designed, thereby designing a beamforming scanning beam that meets the beamforming requirements along the line and realizing beamforming scanning.

[0054] Furthermore, during the encoding process, if the radiation intensity of a single row of slots is sufficient to satisfy the cosecant relationship, then only one row of slots is used; otherwise, the other row of slots should also participate in the radiation partially or completely so that the total field strength satisfies the cosecant relationship.

[0055] Furthermore, the electrically controlled substrate integrated waveguide leaky antenna array with shape-forming scanning capability includes a bias circuit layer 1, a top dielectric substrate 2, a top metal layer 3, two rows of C-shaped slots 4 etched on the top metal layer 3, an intermediate metal layer 5, two rectangular slots 6 etched on the intermediate metal layer 5 for energy coupling, a bottom dielectric substrate 7, two substrate integrated waveguides 8, a microstrip to substrate integrated waveguide transition section 9, a coaxial signal connector 10, a microstrip line 11, a coaxial signal connector 2 12, a 1-to-2 power divider 13, a bottom metal layer 14, and holes 15 for fixing the overall structure.

[0056] Furthermore, coaxial signal connector 10, coaxial signal connector 2 12, microstrip line 11 and adapter structure 9 are disposed on both ends of the bottom dielectric substrate 7, and DC bias circuit 1 is disposed above the top dielectric substrate 2 to control the on / off state of the slots. The slot array 4 is loaded on the radiation port surface of the substrate integrated waveguide and the slot state is controlled by diodes for each beam of fixed frequency shaping scanning.

[0057] Reference Figure 2 As shown, the difference lies in the fact that the gain of a traditional beam scanning antenna will decrease when scanning to a large angle (low elevation angle), while the shaped scanning of this invention can generate a basically constant electric field along the receiving line, which is of great significance for efficient communication.

[0058] Reference Figure 3 The diagram shown is a schematic diagram of the multi-beam relationship principle of the leaky wave antenna of the present invention, which is an electronically controlled fixed-frequency beamforming scanning antenna.

[0059] Reference Figure 4As shown, this invention discloses an electrically controlled substrate integrated waveguide leaky antenna array with shaped scanning capability, comprising a bias circuit layer 1, a top dielectric substrate 2, a top metal layer 3, two rows of C-shaped slots 4 etched on the top metal layer 3, an intermediate metal layer 5, two rectangular slots 6 etched on the intermediate metal layer 5 for energy coupling, a bottom dielectric substrate 7, two substrate integrated waveguides 8, a microstrip to substrate integrated waveguide transition section 9, a coaxial signal connector 10, a microstrip line 11, a coaxial signal connector 2 12, a 1-to-2 power divider 13, a bottom metal layer 14, and holes 15 for fixing the overall structure. The coaxial signal connector 10, coaxial signal connector 2 12, microstrip line 11, and transition structure 9 are disposed at both ends of the bottom dielectric substrate 7. The DC bias circuit 1 is disposed above the top dielectric substrate 2 to control the on / off state of the slots. The slot array 4 is loaded onto the radiating surface of the substrate integrated waveguide and the slot state is controlled by diodes for each beam of fixed-frequency shaped scanning.

[0060] Specifically, this invention obtains planar leaky wave antennas with different pointing angles and gains by loading diodes and DC bias control circuits onto the radiating surface of a 1*2 substrate integrated waveguide slot array. These antennas are highly flexible and controllable in terms of gain and beam pointing, making them suitable for short-range communication, confined space, and other scenarios.

[0061] Reference Figure 5 As shown, firstly, the maximum scanning angle θ of the antenna array is determined based on the radiation characteristics of the antenna array. max And at the maximum angle θ max The maximum radiated electric field value E at that location θ_max Based on the maximum radiated electric field value and the cosecant relationship, the ideal distribution of the electric field along the line can be determined. Secondly, the resolution of the shaping scan is determined. This is based on the angular resolution and the maximum scanning angle θ. max The number of scanning beams, j, can be determined, as can the pointing angle of each beam and the ideal electric field strength corresponding to the maximum angle of each beam. Then, different states are encoded accordingly. During this process, if the radiation intensity of a single row of slots is sufficient to satisfy the cosecant relationship, only one row of slots is needed. Otherwise, the other row of slots should also partially or completely participate in radiation to ensure the total field strength satisfies the cosecant relationship. Finally, by precisely adjusting the diode encoding, each diode encoding state that satisfies the beamforming scanning conditions can be designed, thereby designing a shaped scanning beam that meets the shaping requirements along the line, achieving shaped scanning.

[0062] Specifically, condition 1 is "Can a single row of slot coding generate the electric field strength required for shaping at the corresponding angle?", and condition 2 is "When two rows of slots work with the same coding, does the maximum electric field value generated at the corresponding angle exceed the electric field strength required for shaping?".

[0063] Reference Figure 6 As shown, by using the proposed hybrid coding method to modulate the two rows of slot arrays, the antenna can finally generate 11 different beam states, and the radiation fields at different angles approximately satisfy the cosecant relationship distribution.

[0064] Specifically, the encoded state and radiation gain for each angle in each state are shown in Table 1 below:

[0065] Table 1

[0066]

[0067] Reference Figure 7 The image shown is a physical diagram of the leaky wave antenna with electronically controlled fixed-frequency beamforming scanning according to the present invention.

[0068] Reference Figure 8 As shown, in practical use, this antenna can be placed at the top of a one-dimensional confined space. The coaxial signal connector 10 feeds in the corresponding radio frequency signal to enable its normal operation, while the coaxial signal connector 12 connects to an absorption load to absorb the remaining electromagnetic waves and reduce reflection. The receiving user is on a horizontal plane, and the angle between the receiving antenna and the leaky wave antenna of this invention can be determined by the height difference and horizontal distance between them. Then, a hybrid coding method is used to generate the corresponding beam to achieve shaped scanning.

[0069] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0070] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A hybrid coding method for electrically controlled fixed-beam shaped beam scanning leaky-wave antennas, characterized by, It comprises the following steps: S1, in the case of beamforming scanning, first determine the relationship and size between beam angle and field strength along the straight path, and then get the electric field intensity at different positions or angles according to the cotangent relationship criterion; S2, according to the electric field intensity distribution, the method of mixed coding is used to determine the diode coding state of the beam in a certain direction, so as to design the beamforming scanning beam along the line to meet the requirements of beamforming, and realize beamforming scanning; The mixed coding method in S2 is as follows: S21 determining the maximum scanning angle θ of the antenna array according to the radiation characteristics of the antenna array max and the maximum radiation electric field value E max at the maximum angle θ θ_max , according to the maximum radiation electric field value and the cotangent relationship, determining the ideal distribution of the electric field along the line S22 determining the angular resolution of the shaped scan; determining the number of beams j of the scan, determining the pointing angle of each beam angle and determining the ideal electric field strength of each beam corresponding to the maximum angle θ max i.e. determining the number of beams j of the scan, determining the pointing angle of each beam angle and determining the ideal electric field strength of each beam corresponding to the maximum angle θ S23, corresponding coding is carried out for different states, and each diode coding state that meets the beamforming scanning condition is designed by adjusting the diode coding, so as to get the beamforming scanning beam along the line to meet the requirements of beamforming, and realize beamforming scanning; In the coding process, if the radiation intensity of the single row of slots meets the cotangent relationship, only one row of slots is used; Otherwise, another row of slots should also participate in radiation partially or completely, so that the total field intensity meets the cotangent relationship.

2. The hybrid coding method of the electrically controlled fixed frequency beamforming scanning leaky-wave antenna according to claim 1, wherein According to the difference in height between the antenna and the receiving user H and the relative horizontal position X determine the direction angle between them θ n The specific formula is as follows: (1)。 3. The hybrid coding method of the electrically controlled fixed frequency beamforming scanning leaky-wave antenna according to claim 1, wherein The electric field intensity of each beam in the beamforming scanning should conform to or be close to the ideal cotangent distribution, and the beam direction θ n and the corresponding electric field intensity E n The following formula should be satisfied: (2)。 4. The hybrid coding method of the electrically controlled fixed frequency beamforming scanning leaky-wave antenna according to claim 1, wherein When the electric field radiation pattern satisfies the cotangent distribution, the antenna gain G satisfies the cotangent square distribution, and can be represented by the following equation (3) or equation (4): (3) (dB) (4).

5. The hybrid encoding method of electrically controlled fixed-beamwidth beamforming scanned leaky-wave antenna according to claim 1, wherein, The electrically controlled substrate integrated waveguide leaky-wave antenna array with beamforming scanning capability comprises a bias circuit layer (1), a top layer dielectric substrate (2), a top layer metal layer (3), two rows of C-shaped slots (4) engraved on the top layer metal layer (3), a middle metal layer (5), two rectangular slots (6) engraved on the middle metal layer (5) for energy coupling, a bottom layer dielectric substrate (7), two substrate integrated waveguides (8), a microstrip to substrate integrated waveguide adapter (9), a coaxial signal connector one (10), a microstrip line (11), a coaxial signal connector two (12), a one-to-two power divider (13), a bottom layer metal layer (14), and hole positions (15) for fixing the overall structure.

6. The hybrid coding method of the electrically controlled fixed frequency beamforming scanning leaky-wave antenna according to claim 5, wherein The coaxial signal connector one (10), the coaxial signal connector two (12), the microstrip line (11), and the microstrip to substrate integrated waveguide adapter (9) are arranged on both ends of the bottom layer dielectric substrate (7), the bias circuit layer (1) is arranged above the top layer dielectric substrate (2) for controlling the on-off state of the slots, the C-shaped slots (4) are loaded on the radiation port surface of the substrate integrated waveguide and are used to control the state of the slots for fixed frequency beamforming scanning.

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