Two-unit leaky-wave antenna array structure based on half-mode dielectric ridge parallel-plate waveguide and design method

Abstract

The application discloses a design method of a two-unit leaky-wave antenna array structure based on a half-mode dielectric ridge parallel plate waveguide, and the method comprises the following steps: according to basic mode analysis, a half-mode dielectric ridge parallel plate waveguide is constructed on the basis of a dielectric ridge parallel plate waveguide; based on the transmission characteristics of the half-mode dielectric ridge parallel plate waveguide and the leaky-wave antenna theory, a half-mode dielectric ridge parallel plate waveguide leaky-wave antenna is designed to realize a small-size broadband high-efficiency leaky-wave antenna; based on the half-mode dielectric ridge parallel plate leaky-wave antenna and the array antenna theory, a two-unit half-mode dielectric ridge parallel plate waveguide leaky-wave antenna array structure is designed, and the structure two-port array antenna is fed by a probe in parallel to realize a narrow lobe and a high-gain scanning beam. The application can obtain a narrow beam and a high-gain scanning beam while keeping the advantages of wideband, high efficiency, small size, compact structure, low profile, easy processing and low cost, and further compresses the size of a microwave millimeter wave integrated circuit.

Description

Technical Field

[0001] This invention relates to the field of communication technology, specifically to a two-element leaky wave antenna array structure and design method based on a half-mode dielectric ridge parallel plate waveguide. Background Technology

[0002] With the development of 5G, the Internet of Things (IoT), and the future 6G, communication systems need to support higher data rates and denser spectrum usage. Simultaneously, modern communication equipment demands increasingly more multi-band and multi-functional operation. Therefore, antennas need to maintain good performance over a wider frequency range to adapt to different communication standards and frequency bands, reducing the number and complexity of antennas in devices. Furthermore, to achieve efficient energy utilization and improve overall system performance, efficient antenna designs can provide higher data rates and greater communication capacity, reducing base station and equipment energy consumption, lowering operating costs and energy consumption, and meeting the trend of green communication. More importantly, with the integration of microwave and millimeter-wave circuits and the rapid development of printed circuit board (PCB) technology, smartphones, wearable devices, and IoT devices all require antennas with smaller dimensions without sacrificing performance. Therefore, antenna miniaturization is an inevitable development trend in the integrated application of microwave and millimeter-wave technologies.

[0003] To achieve high radiation efficiency, wide operating bandwidth, and small antenna size, existing frequency-scanning leaky-wave antenna technology commonly employs the following design methods:

[0004] (1) Leaky wave antenna design based on metamaterials. By using metamaterials to control the propagation characteristics of electromagnetic waves, a leaky wave antenna with the desired enhanced radiation performance can be constructed, achieving broadband and high-efficiency characteristics in a small size.

[0005] (2) Design of a dielectric-loaded leaky antenna. By introducing a specific dielectric material into the traditional antenna structure to adjust the ring parameters, the electromagnetic characteristics are changed, thereby achieving bandwidth expansion and efficiency improvement.

[0006] (3) Multi-layer structure design. Multi-layer dielectric substrates are used to increase the effective radiating area to improve radiation efficiency; at the same time, in some antenna designs, the feeding structure can also adopt a multi-layer structure so that energy is coupled to the radiating structure to reduce the antenna size.

[0007] (4) Application of 3D printing and other new manufacturing technologies. By using 3D printing and other new manufacturing technologies to process complex structures, high integration of components can be achieved, further improving design flexibility and antenna performance.

[0008] The classic design methods described above typically combine novel electromagnetic materials and advanced manufacturing technologies, providing a variety of implementation approaches for the development of broadband, high-efficiency frequency-scanning leaky-wave antennas to meet the increasingly stringent and precise requirements of microwave and millimeter-wave systems for antenna design. However, these technologies often require complex structural designs and high processing costs, and have high requirements for processing accuracy, increasing the complexity of antenna design and manufacturing costs. Furthermore, dielectric loading or multilayer structure designs may introduce additional losses, affecting antenna efficiency and significantly increasing the overall thickness of the antenna. Therefore, designing novel antenna structures with high performance such as broadband, high efficiency, and high gain, while simultaneously maintaining the structural characteristics of low profile and small size, as well as the advantages of low cost and easy fabrication, remains one of the hot research directions in the field of frequency-scanning leaky-wave antennas.

[0009] Existing techniques for improving the bandwidth and efficiency of frequency-scanning leaky wave antennas often require the design of complex feeding or radiating structures based on traditional transmission lines, resulting in high manufacturing costs and demanding high precision, thus increasing the complexity and cost of antenna design. Furthermore, complex structural designs may introduce additional losses, affecting antenna efficiency and significantly increasing the overall antenna size. This invention, however, proposes for the first time a novel half-mode dielectric ridged parallel-plate waveguide (HMDRPW) structure. Its broadband characteristics are superior to traditional single-conductor waveguide structures such as substrate integrated waveguides (SIWs), and its transmission characteristics are similar to those of dielectric ridged parallel-plate waveguides (DRPWs), exhibiting an extremely wide single-mode operating bandwidth, but its size is almost half that of a DRPW. Moreover, a small-sized frequency-scanning leaky wave antenna with broadband and high efficiency can be obtained by etching uniform transverse slots on the upper metal plate of the HMDRPW. Therefore, the designed antenna has a simple structure, low cost, and small size, while also having excellent radiation characteristics, enabling broadband and efficient beam scanning. Summary of the Invention

[0010] Leaky wave antennas based on the above-mentioned existing technologies often have a wide beam. This invention proposes a two-element leaky wave antenna array based on HMDRPW, which can obtain a narrow beam and high-gain scanning beam while maintaining excellent radiation characteristics such as wide bandwidth and high efficiency, volume advantages such as small size, compact structure and low profile, and manufacturing advantages such as easy processing and low cost, thereby further compressing the size of microwave millimeter wave integrated circuits.

[0011] On one hand, the present invention provides a design method for a two-element leaky wave antenna array structure based on a half-mode dielectric ridge parallel plate waveguide, the method comprising,

[0012] S1: Based on the basic mode analysis, a half-mode dielectric ridge parallel plate waveguide is constructed on the basis of the dielectric ridge parallel plate waveguide.

[0013] S2: Based on the transmission characteristics of half-mode dielectric ridge parallel plate waveguide and the theory of leaky wave antenna, a half-mode dielectric ridge parallel plate waveguide leaky wave antenna is designed to realize a small-size broadband high-efficiency leaky wave antenna.

[0014] S3: Based on the theory of half-mode dielectric ridge parallel plate leaky wave antenna and array antenna, a two-element half-mode dielectric ridge parallel plate waveguide leaky wave antenna array structure is designed. The two-port array antenna of the structure is fed by probes in parallel to achieve narrow beam and high gain scanning beam.

[0015] Furthermore, the basic mode of transmission in the dielectric ridge parallel plate waveguide is the quasi-TEM mode, based on the relative permittivity of the dielectric ridge. ε r and its width t d Determine the propagation constant of the fundamental mode of the dielectric ridge parallel plate waveguide. β The specific formula is as follows:

[0016] ;

[0017] ;

[0018] in, k 0 is the propagation constant in a vacuum. β y Let be the transverse propagation constant of the dielectric ridge parallel plate waveguide.

[0019] Furthermore, S1 specifically includes cutting the dielectric ridge parallel plate waveguide in half along the longitudinal central axis of symmetry to obtain a structure with half the transverse dimension of the waveguide, wherein the structure is a half-mode dielectric ridge parallel plate waveguide.

[0020] Furthermore, S2 specifically includes, since the fundamental mode transmitted in the half-mode dielectric ridge parallel plate waveguide is similar to that in the dielectric ridge parallel plate waveguide, an equivalent fast wave mode is obtained by periodically loading and utilizing spatial harmonics, thereby realizing leakage wave radiation;

[0021] Uniform periodic transverse slots are etched on the upper metal plate of the half-mode dielectric ridge parallel plate waveguide to excite the -1st harmonic and achieve leakage wave radiation. m Radiation conditions and beam angle of subspace harmonics θ m Describe it using the following formula:

[0022] ;

[0023] ;

[0024] in λ 0 is the wavelength in a vacuum. p s It is the gap cycle.

[0025] Furthermore, S3 specifically includes: assembling two half-mode dielectric ridge parallel plate waveguide units to obtain a two-unit half-mode dielectric ridge parallel plate waveguide leaky wave array structure; and designing a two-unit half-mode dielectric ridge parallel plate waveguide leaky wave antenna array based on the half-mode dielectric ridge parallel plate waveguide leaky wave antenna and the two-unit half-mode dielectric ridge parallel plate waveguide array.

[0026] On the other hand, the present invention also provides a two-element leaky wave antenna array structure based on a half-mode dielectric ridge parallel plate waveguide, including an upper metal plate, a lower metal plate, a dielectric layer, a probe, a probe through hole, and screw holes.

[0027] Trapezoidal slot array I and trapezoidal slot array II are etched on the upper metal plate, and the trapezoidal slot array I and trapezoidal slot array II are used for energy leakage radiation;

[0028] Long grooves are etched on the upper metal plate and the lower metal plate;

[0029] The array is provided with probes and probe through-holes at both ends, and the probes are used for power feeding and load absorption.

[0030] The screw holes are used to fix the overall structure.

[0031] Furthermore, the trapezoidal slot array I and the trapezoidal slot array II are symmetrically distributed along the long groove, and the slot size and number of slots are the same.

[0032] Furthermore, the long slot does not penetrate the entire upper metal plate or the lower metal plate; the distance between the two waveguide units is measured by the width of the long slot.

[0033] Furthermore, the probe is fed in parallel.

[0034] Furthermore, the upper metal plate and the lower metal plate are brass plates with a thickness of 0.5 mm;

[0035] The dielectric layer is a Rogers RT5880 printed circuit board with a dielectric constant of [missing information]. ε r = 2.2, thickness is 3.175 mm;

[0036] The two-element leaky wave antenna array structure based on a half-mode dielectric ridge parallel plate waveguide is fixed with nylon screws.

[0037] The beneficial effects of this invention are:

[0038] 1. This invention achieves continuous beam scanning, solving the problems of narrow operating bandwidth of traditional leaky antennas, which makes it difficult to meet the needs of multi-band communication, and low radiation efficiency.

[0039] 2. This invention addresses the need for smaller antennas in modern devices, and the leaky wave antenna reduces size while maintaining performance.

[0040] 3. This invention solves the problems of impedance matching difficulties and poor adaptability to complex environments that may exist in traditional leaky antennas through flexible design. It has good impedance matching performance to meet the requirements of broadband and high efficiency, and its design is flexible and can maintain performance in changing environments. Attached Figure Description

[0041] The present invention includes the following figures:

[0042] Figure 1 This invention provides a design flowchart for a two-element leaky wave antenna array structure based on a half-mode dielectric ridge parallel plate waveguide;

[0043] Figure 2 A schematic diagram of the construction process and a three-dimensional structural diagram of a half-mode dielectric ridge parallel plate waveguide;

[0044] Figure 3 Simulation results of two-dimensional electric field distribution in dielectric ridge parallel plate waveguides and half-mode dielectric ridge parallel plate waveguides;

[0045] Figure 4 A schematic diagram of the construction process and a three-dimensional structural diagram of a two-element array of a half-mode dielectric ridge parallel plate waveguide;

[0046] Figure 5 A schematic diagram illustrating the principle of the radiation pattern product theorem for a two-element leaky wave antenna array with a half-mode dielectric ridge parallel plate waveguide.

[0047] Figure 6 Simulation results of two-dimensional electric field distribution of a two-element array of half-mode dielectric ridge parallel plate waveguides;

[0048] Figure 7 A three-dimensional structural diagram of a two-element leaky wave antenna array based on a half-mode dielectric ridge parallel plate waveguide;

[0049] Figure 8 Simulation results of normalized propagation constants for the fundamental modes of two-element arrays of dielectric ridge parallel plate waveguides, half-mode dielectric ridge parallel plate waveguides, and half-mode dielectric ridge parallel plate waveguides;

[0050] Figure 9 S-parameter simulation results of a half-mode dielectric ridge parallel plate waveguide leaky wave antenna;

[0051] Figure 10 Simulation results of normalized radiation pattern for a half-mode dielectric ridge parallel plate waveguide leaky wave antenna;

[0052] Figure 11 S-parameter simulation results of a two-element leaky wave antenna array based on a half-mode dielectric ridge parallel plate waveguide;

[0053] Figure 12 Simulated E-plane radiation patterns of a two-element leaky wave antenna array based on a half-mode dielectric ridge parallel plate waveguide at different frequencies within the operating bandwidth.

[0054] Figure 13 Simulation results of the overall efficiency of a two-element leaky wave antenna array based on a half-mode dielectric ridge parallel plate waveguide.

[0055] Figure 14 A comparison of simulation results of the gain curves of a two-element leaky wave antenna array based on a half-mode dielectric ridge parallel plate waveguide and a half-mode dielectric ridge parallel plate waveguide leaky wave antenna element at different frequencies. Detailed Implementation

[0056] To make the objectives, advantages and features of the present invention more apparent, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0057] The invention will now be described in detail with reference to the accompanying drawings:

[0058] like Figure 1 As shown, this invention discloses a two-element leaky wave antenna array structure based on a half-mode dielectric ridge parallel plate waveguide, including the following design steps:

[0059] S1. Based on the basic mode analysis, a half-mode dielectric ridge parallel plate waveguide is constructed on the basis of the dielectric ridge parallel plate waveguide.

[0060] S2. Based on the transmission characteristics of half-mode dielectric ridge parallel plate waveguide and the theory of leaky wave antenna, a half-mode dielectric ridge parallel plate waveguide leaky wave antenna is designed to realize a small-size broadband high-efficiency leaky wave antenna.

[0061] S3. Based on the theory of half-mode dielectric ridge parallel plate leaky wave antenna and array antenna, a two-element half-mode dielectric ridge parallel plate waveguide leaky wave antenna array structure is designed. The two-port array antenna is fed by probes in parallel to achieve a narrow beam and a high-gain scanning beam.

[0062] The basic mode of DRPW transmission is quasi-TEM mode, based on the relative permittivity of the dielectric spine. ε rand its width t d The propagation constant of the DRPW fundamental mode can be determined. β The specific formula is as follows:

[0063] ;

[0064] ;

[0065] in, k 0 is the propagation constant in a vacuum. β y is the transverse propagation constant of DRPW.

[0066] When the DRPW is halved along its longitudinal central axis of symmetry, as shown... Figure 2 As shown, a novel waveguide structure with half the lateral dimension of the waveguide can be obtained. (Refer to...) Figure 3 The given schematic diagram of the two-dimensional electric field distribution obtained from simulation at 20 GHz for the two waveguides before and after truncation is shown. The basic propagation mode in the region between the upper and lower parallel metal plates of the new waveguide structure is similar to the basic propagation mode in the corresponding half of the waveguide when the DRPW is not truncated, that is, it is approximately a half-mode of the quasi-TEM mode. Therefore, this new waveguide structure is named Half-Mode Dielectric Ridge Parallel Plate Waveguide (HMDRPW). Mode analysis shows that the propagation constant of the HMDRPW operating in the fundamental mode is approximately the same as the propagation constant of the DRPW with the same parameters.

[0067] Based on the simulated electric field distribution diagram, it can be concluded that the electric field is mainly concentrated in the dielectric region; in the transverse direction (i.e., Figure 3 The middle reference coordinate system y In the axial direction, the electric field attenuates from the dielectric region to both sides, and attenuates rapidly outside the waveguide (the part without the upper and lower parallel metal plates). That is, the plane containing the long side of the HMDRPW parallel metal plate flush with the dielectric ridge, i.e., the "cut-off section," can be approximately equivalent to an open circuit, and no serious energy leakage problem occurs at this port. Therefore, even with an open structure instead of a traditional closed waveguide, the vast majority of energy is still confined within the dielectric ridge of the HMDRPW and propagates along it.

[0068] The design method for the half-mode dielectric ridge parallel plate waveguide leaky wave antenna in S2 is as follows:

[0069] First, the theoretical value of the propagation constant of HMDRPW can also be approximately derived by combining equations (1) and (2). Based on the analysis of the propagation constant obtained from the theoretical calculation, it can be concluded that the fundamental mode transmitted in HMDRPW is similar to that in DRPW, which is a slow wave mode confined near the ridge of the medium. Therefore, by periodically loading and utilizing spatial harmonics, an equivalent fast wave mode can be obtained, thereby realizing leakage radiation.

[0070] Secondly, uniform periodic transverse slits are etched on the upper metal plate of HMDRPW to excite the -1st harmonic to achieve leakage radiation. m Radiation conditions and beam angle of subspace harmonics θ m This can be described using the following formula:

[0071] ;

[0072] ;

[0073] in λ 0 is the wavelength in a vacuum. p s It is the gap cycle.

[0074] The design method for the two-element array of the half-mode dielectric ridge parallel plate waveguide leaky wave antenna in S3 is as follows:

[0075] First, a two-element half-mode dielectric ridge parallel plate waveguide array structure is constructed based on HMDRPW, and an appropriate waveguide element spacing is selected. This waveguide array transitions from DRPW to a two-element HMDRPW array without requiring the design of an additional power divider.

[0076] By assembling two HMDRPW units, the novel waveguide array structure proposed in this invention is obtained, such as... Figure 4 As shown, structurally, this two-unit waveguide array approximates a DRPW with a perfectly symmetrical long slot running longitudinally through the center of the upper and lower metal plates. The two waveguide units share the upper and lower parallel metal plates and a dielectric rod structure. The dielectric rod includes the dielectric ridge structure of the two HMDRPW units and the dielectric portion connecting them, located in the middle of the parallel metal plates with the long slot. The portions of the dielectric rod on both sides, positioned between the parallel metal plates of the two waveguide units, are perfectly symmetrical, serving as the dielectric ridges of the two HMDRPW units, confining and guiding electromagnetic waves. The middle portion of the dielectric rod is not covered by any metal plates, serving as the connecting portion between the two dielectric ridges and also connecting the two waveguide units. This allows the dielectric layer of the array to be considered as a whole, facilitating PCB fabrication. The long slot on the upper and lower parallel metal plates does not extend longitudinally through the entire metal plate, thus retaining transition sections from the DRPW to the two HMDRPW units at both ends of the waveguide array. The transmission characteristics of this HMDRPW array differ from those of the DRPW. Due to the presence of the long slot, the two waveguide units of this array transmit half-modes of the quasi-TEM mode.

[0077] The spacing between two waveguide units can be determined by the width of the long slot. g Measurement. When gWhen the waveguide array is too small, the open-circuit effect provided by the long slot is very weak, and the waveguide array is approximately equivalent to a DRPW structure, thus changing the transmission characteristics of the waveguide; when g When the impedance is too large, the waveguide array structure becomes too large, which may distort the radiation pattern when designing the leaky antenna array later, and also makes impedance matching more difficult. Therefore, it is necessary to choose a suitable impedance. g This allows the two elements in the designed waveguide array to operate independently while maintaining a compact array structure. It is worth noting that the coupling between HMDRPW elements affects the propagation constant of the waveguide array, but the fundamental mode remains a slow-wave mode.

[0078] Secondly, a two-element half-mode dielectric ridge parallel plate waveguide leaky wave antenna array is designed based on HMDRPW LWA and a two-element half-mode dielectric ridge parallel plate waveguide array. Figure 5 This is a schematic diagram of the pattern product theorem. According to the pattern product theorem, the required radiation intensity of the two HMDRPW LWA elements should be consistent to ensure that the radiation pattern of the final leaky antenna array is not distorted. Therefore, according to the required radiation intensity, a slot array with consistent size and period is etched along the longitudinal center symmetry on the upper metal plate of the two HMDRPW elements.

[0079] This two-element leaky wave antenna array is fed by probes connected in parallel, with the probes positioned at the DRPW structure of the array. This allows the energy fed into the DRPW through the probes to be transferred to the HMDRPW array and evenly distributed to the two waveguide elements on either side for transmission. Loads are placed symmetrically at the array's ends to absorb any remaining energy transmitted to the ends. The slot elements in the slot array are designed in a trapezoidal shape to increase the radiation capability of the slot array while avoiding excessive resonance from a single slot. Therefore, a leaky wave antenna array with narrow beamwidth and high gain can be obtained based on the broadband and efficient HMDRPW LWA element, while maintaining a small array size, compact structure, and simple design.

[0080] Figure 6 Simulation results of the electric field distribution of the designed two-unit HMDRPW array structure at 20 GHz (top view) are presented. It can be concluded that after energy is fed from one end of the waveguide array, there is a transition from DRPW to the HMDRPW array. Furthermore, due to the presence of long slots on the upper and lower parallel metal plates, the mode propagating in the HMDRPW array is a half-mode of the quasi-TEM mode, rather than a higher-order mode of the DRPW. And, from... Figure 6 It can be further seen that after the energy enters the waveguide array, it is divided into two parts, which are respectively bound in the dielectric ridges of the two waveguide units and transmitted along the ridges.

[0081] like Figure 7As shown, the HMDRPW LWA two-unit array consists of an upper metal plate 1, a trapezoidal slot array I2 etched on the upper metal plate 1, a trapezoidal slot array II3 for energy leakage radiation, long grooves 4 etched on the upper metal plate 1 and the lower metal plate 6, a dielectric layer 5, a lower metal plate 6, probes 7 at both ends of the array for power feeding and load absorption, probe through holes 8, screw holes 9 for fixing the overall structure, and some other structures.

[0082] The upper metal plate 1 and the lower metal plate 6 (serving as a grounding plane) form a shared parallel metal plate for the two units. The rectangular slot arrays I2 and II3 etched on the upper metal plate 1 are both uniform trapezoidal arrays, and the two sets of slot arrays have the same period. Furthermore, the trapezoidal slot arrays I2 and II3 are longitudinally symmetrically distributed about the HMDRPW LWA array, and their parameters are completely identical (including slot size and number of slots). The dielectric layer 5 consists of the dielectric ridges of the two units and the dielectric portion connecting them, forming two independent energy propagation paths.

[0083] A brass plate, 0.5 mm thick, is used in the design of the upper metal plate 1 and the lower metal plate 6. A Rogers RT5880 printed circuit board is used in the design of the dielectric layer 5, with a dielectric constant of... ε r = 2.2, thickness is 3.175 mm; the three-layer structure is fixed with nylon screws.

[0084] For example Figure 7 The working principle of the two-element leaky wave antenna array shown is described in detail below:

[0085] One end of the antenna array is fed by a probe. The energy is first fed into the DRPW and propagates along the medium, confined within the medium region. It is then divided into two equal parts by the HMDRPW array and propagates along the medium ridges of the two HMDRPW elements on both sides. Simultaneously, leakage radiation is generated outward through two sets of trapezoidal slot arrays. The coupling between the two leaky antenna elements affects their transmission characteristics, but they still operate in slow wave mode and have the same propagation constant. Both sets of slots operate in the frequency band described by equation (3), where only the -1st harmonic satisfies the outward radiation condition. Since the two sets of slot arrays have the same slot period, according to equation (4), the two leaky antenna elements have the same beam pointing angle. According to the pattern product theorem, this leaky antenna array can obtain a narrower scanning beam than the LWA element, and correspondingly, it also has a higher antenna gain.

[0086] Figure 8Simulation results of the normalized propagation constants of the fundamental modes of DRPW, HMDRPW, and HMDRPW two-element arrays are presented. In the HMDRPW, both the metal plate width and the dielectric ridge width are half that of the DRPW, and the relative permittivity of the dielectric ridges is completely consistent with the thickness. The HMDRPW two-element array is constructed by... Figure 4 The array configuration shown is used for construction. From... Figure 8 It can be seen that, under the above parameter conditions, the propagation constant of HMDRPW is very close to that of DRPW, proving that HMDRPW obtained by symmetrically cutting DRPW retains the original electromagnetic properties while reducing the size of the transmission structure to half of its original size. Furthermore, due to the inter-element coupling, the propagation constant of the two-element HMDRPW array is slightly larger than that of HMDRPW, but its transmission characteristics can still be analyzed using the theories of HMDRPW or DRPW.

[0087] Figure 9 The S-parameter simulation results of the HMDRPW LWA are presented. The designed HMDRPW LWA operates in the 14 GHz to 26 GHz frequency band. Within this single-beam operating bandwidth, |S 11 | Below -10 dB, with good impedance matching performance. Figure 10 The normalized polar coordinate radiation pattern of the E-plane of the leaky antenna is presented. It can be seen that the designed leaky antenna achieves back-to-forward beam scanning (total scanning angle of 78°) within an extremely wide single-beam operating bandwidth (relative bandwidth of 60%). Therefore, the HMDRPW LWA maintains the broadband and efficient radiation characteristics of the DRPW LWA, while its size is only half that of the DRPW LWA, further compressing the size of microwave and millimeter-wave integrated circuits. The two-element leaky antenna array proposed in this invention is based on this leaky antenna element. The final optimization results, some comparative results, and analyses of this invention will be presented below.

[0088] Figure 11 The figure shows the |S| of the proposed two-element leaky antenna array. 11 |and|S 21 The simulation results. From Figure 9 Simulation results show that the proposed leaky antenna array |S 11 The impedance matching characteristics are good, with a range of | < -10 dB from 13.2 GHz to 31.7 GHz, and within this frequency range, |S 11 |and|S 21 The values ​​are all below -10 dB, proving that the gaps in the leaky antenna array can leak most of the energy into space to achieve leaky radiation. Figure 12The simulated E-plane polar coordinate normalized radiation pattern of the leaky wave antenna array of the present invention in the -1 harmonic operating range is given. It can be seen that the array antenna can achieve a single beam scanning angle from -75° to 8° in the range of 13.5 GHz to 26 GHz, with a single beam operating relative bandwidth of 63.3% and a total scanning angle of 83° from front to back, achieving an extremely wide operating bandwidth and strong beam scanning capability. Figure 13 The simulation results show the overall efficiency of the proposed array antenna in the range of 13.6 GHz to 26 GHz. The simulation results show that the overall efficiency of the present invention is higher than 93% in the single-beam operating frequency band. Figure 14 Simulation results of the proposed two-element leaky antenna array's gain in the range of 13.6 GHz to 26 GHz are presented, along with a gain comparison with that of a single leaky antenna element. The proposed leaky antenna array can achieve a gain of 10 dBi to 17.6 dBi within the single-beam operating frequency band, and the comparison with the gain curves of a single element shows that the two-element array significantly improves the antenna gain.

[0089] In summary, this invention proposes a two-element leaky wave antenna array based on a half-mode dielectric ridge parallel plate waveguide. By symmetrically trimming the DRPW (Dielectric Ridge Parallel Plate Waveguide), an HMDRPW (High-Medium Dielectric Ripple Waveguide) is obtained. The two HMDRPW elements are then arrayed to design a two-element HMDRPW array. Furthermore, based on leaky wave theory and array theory, the two-element HMDRPW leaky wave antenna array is designed. This array maintains the broadband characteristics of the DRPW, achieving ultra-wideband and efficient single-beam scanning. More importantly, due to the half-mode characteristics and arraying, the invented leaky wave antenna array is small in size, compact and simple in structure, and possesses excellent radiation characteristics of narrow beam and high gain.

[0090] The above embodiments have provided a detailed description of the technical solution of the present invention. Obviously, the present invention is not limited to the described embodiments. Based on the embodiments of the present invention, those skilled in the art can make various modifications, but any modifications that are equivalent to or similar to the present invention fall within the scope of protection of the present invention.

[0091] The contents not described in detail in this specification are existing technologies known to those skilled in the art.

Claims

1. A two-element leaky wave antenna array structure based on a half-mode dielectric ridge parallel plate waveguide, characterized in that, Includes an upper metal plate, a lower metal plate, a dielectric layer, a probe, probe through holes, and screw holes; the upper and lower metal plates together form two units sharing a common upper and lower parallel metal plate. Trapezoidal slot array I and trapezoidal slot array II are etched on the upper metal plate, and the trapezoidal slot array I and trapezoidal slot array II are used for energy leakage radiation; The upper metal plate and the lower metal plate are etched with longitudinal grooves; the longitudinal grooves do not penetrate the entire upper metal plate and the lower metal plate. The dielectric layer consists of two dielectric ridges and a dielectric portion connecting them; The array is provided with probes and probe through-holes at both ends, and the probes are used for power feeding and load absorption. The screw holes are used to fix the overall structure.

2. The two-element leaky wave antenna array structure based on a half-mode dielectric ridge parallel plate waveguide as described in claim 1, characterized in that, The trapezoidal slot array I and the trapezoidal slot array II are symmetrically distributed along the long groove, and the slot size and number of slots are the same.

3. The two-element leaky wave antenna array structure based on a half-mode dielectric ridge parallel plate waveguide as described in claim 2, characterized in that, The spacing between two waveguide units is measured by the width of the long slot.

4. The two-element leaky wave antenna array structure based on a half-mode dielectric ridge parallel plate waveguide as described in claim 3, characterized in that, The probe is fed in parallel.

5. The two-element leaky wave antenna array structure based on a half-mode dielectric ridge parallel plate waveguide as described in claim 4, characterized in that, The upper metal plate and the lower metal plate are brass plates with a thickness of 0.5 mm; The dielectric layer is a Rogers RT5880 printed circuit board with a dielectric constant of [missing information]. ε r = 2.2, thickness is 3.175 mm; The two-element leaky wave antenna array structure based on a half-mode dielectric ridge parallel plate waveguide is fixed with nylon screws.

6. A design method for a two-element leaky wave antenna array structure based on a half-mode dielectric ridge parallel plate waveguide as described in claim 1, characterized in that, The method includes, S1: Based on the basic mode analysis, a half-mode dielectric ridge parallel plate waveguide is constructed on the basis of the dielectric ridge parallel plate waveguide. S2: Based on the transmission characteristics of half-mode dielectric ridge parallel plate waveguide and the theory of leaky wave antenna, a half-mode dielectric ridge parallel plate waveguide leaky wave antenna is designed to realize a small-size broadband high-efficiency leaky wave antenna. S3: Based on the theory of half-mode dielectric ridge parallel plate leaky wave antenna and array antenna, a two-element half-mode dielectric ridge parallel plate waveguide leaky wave antenna array structure is designed. The two-port array antenna of the structure is fed by probes in parallel to achieve narrow beam and high gain scanning beam.

7. The design method for a two-element leaky wave antenna array structure based on a half-mode dielectric ridge parallel plate waveguide as described in claim 6, characterized in that, The basic mode of transmission in the dielectric ridge parallel plate waveguide is the quasi-TEM mode, based on the relative permittivity of the dielectric ridge. ε r and its width t d Determine the propagation constant of the fundamental mode of the dielectric ridge parallel plate waveguide. β The specific formula is as follows: ; ; in, k 0 is the propagation constant in a vacuum. β y Let be the transverse propagation constant of the dielectric ridge parallel plate waveguide.

8. The design method of a two-element leaky wave antenna array structure based on a half-mode dielectric ridge parallel plate waveguide as described in claim 7, characterized in that, S1 specifically includes cutting the dielectric ridge parallel plate waveguide in half along the longitudinal central axis of symmetry to obtain a structure with half the transverse dimension of the waveguide, wherein the structure is a half-mode dielectric ridge parallel plate waveguide.

9. The design method of a two-element leaky wave antenna array structure based on a half-mode dielectric ridge parallel plate waveguide as described in claim 8, characterized in that, S2 specifically includes, Since the fundamental mode transmitted in the half-mode dielectric ridge parallel plate waveguide is similar to that in the dielectric ridge parallel plate waveguide, the equivalent fast wave mode can be obtained by periodic loading and using spatial harmonics, thereby realizing leakage radiation. Uniform periodic transverse slots are etched on the upper metal plate of the half-mode dielectric ridge parallel plate waveguide to excite the -1st harmonic and achieve leakage wave radiation. m Radiation conditions and beam angle of subspace harmonics θ m Describe it using the following formula: ; ; in λ 0 is the wavelength in a vacuum. p s It is the gap cycle.

10. The design method of a two-element leaky wave antenna array structure based on a half-mode dielectric ridge parallel plate waveguide as described in claim 9, characterized in that, S3 specifically includes: assembling two half-mode dielectric ridge parallel plate waveguide units to obtain a two-unit half-mode dielectric ridge parallel plate waveguide leaky wave array structure; and designing a two-unit half-mode dielectric ridge parallel plate waveguide leaky wave antenna array based on the half-mode dielectric ridge parallel plate waveguide leaky wave antenna and the two-unit half-mode dielectric ridge parallel plate waveguide array.

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