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

Abstract

The invention 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 steps: constructing the half-mode dielectric ridge parallel-plate waveguide on the basis of the dielectric ridge parallel-plate waveguide according to basic mode analysis; based on the transmission characteristics of the half-mode dielectric ridge parallel plate waveguide and the leaky-wave antenna theory, the half-mode dielectric ridge parallel plate waveguide leaky-wave antenna is designed, and a small-size broadband efficient leaky-wave antenna is realized. A two-unit half-mode dielectric ridge parallel plate waveguide leaky-wave antenna array structure is designed based on a half-mode dielectric ridge parallel plate leaky-wave antenna and array antenna theory, a two-port array antenna of the structure is fed in parallel by a probe, and narrow-lobe and high-gain scanning beams are realized. According to the invention, the narrow-beam and high-gain scanning beam can be obtained while the excellent radiation characteristics such as broadband and high efficiency are maintained, the volume advantages such as small size, compact structure and low profile are maintained, the manufacturing advantages such as easy processing and low cost are maintained, and the size of a microwave and millimeter wave integrated circuit is further compressed.

Description

Technical Field

[0001] The present invention relates to the field of communication technology, and in particular to a two-unit leaky wave antenna array structure based on a half-mode dielectric ridge parallel plate waveguide and a design method thereof. Background Art

[0002] With the development of 5G, Internet of Things (IoT) and future 6G, communication systems need to support higher data rates and more intensive spectrum usage. At the same time, modern communication devices have an increasing demand for multi-band and multi-function operations; therefore, antennas need to maintain good performance over a wider frequency range to adapt to different communication standards and frequency bands, and reduce the number and complexity of antennas in the device. Furthermore, in order to achieve efficient energy utilization and thus improve overall system performance, efficient antenna design can provide higher data rates and greater communication capacity, reduce base station and equipment energy consumption, reduce operating costs and energy consumption, and meet 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 to have smaller sizes without sacrificing performance, so antenna miniaturization is also an inevitable development trend for the integrated application of microwave and millimeter waves.

[0003] In order to achieve high radiation efficiency, wide operating frequency band and small antenna size, the existing frequency scanning leaky wave antenna technology has the following commonly used design methods: (1) Design of leaky wave antennas based on metamaterials. Using metamaterials to control the propagation characteristics of electromagnetic waves, leaky wave antennas with enhanced radiation performance can be constructed to achieve broadband and high efficiency in a small size.

[0004] (2) Dielectric-loaded leaky-wave antenna design. By introducing specific dielectric materials into the traditional antenna structure to adjust the ring parameters and change the electromagnetic characteristics, the bandwidth can be expanded and the efficiency can be improved.

[0005] (3) Multi-layer structure design. Multi-layer dielectric plates are used to increase the effective radiation area to improve the radiation efficiency. At the same time, in some antenna designs, the feed structure can also adopt a multi-layer structure to couple the energy into the radiation structure to reduce the size of the antenna.

[0006] (4) Application of 3D printing and other new manufacturing technologies: 3D printing and other new manufacturing technologies can be used to process complex structures, achieve high integration of components, and further improve design flexibility and antenna performance.

[0007] The above classical design methods usually combine new electromagnetic materials and advanced manufacturing technologies, providing a variety of implementation methods for the development of broadband and efficient 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 design and high processing costs, and have high requirements for processing accuracy, which increases the complexity and manufacturing cost of antenna design; and dielectric loading or multi-layer structure design may also introduce additional losses, affecting antenna efficiency and causing the overall thickness of the antenna to increase significantly. Therefore, designing new antenna structures with high performance such as broadband, high efficiency, and high gain, while maintaining the structural characteristics of low profile and small size and the manufacturing advantages of low cost and easy processing, is still one of the hot research directions in the field of frequency scanning leaky wave antennas.

[0008] Existing technologies for improving the bandwidth and efficiency of frequency scanning leaky wave antennas often require the design of complex feeding structures or radiation structures based on traditional transmission lines, which have high processing costs and high requirements for processing accuracy, increasing the complexity and manufacturing cost of antenna design; and complex structural design may also introduce additional losses, affecting antenna efficiency and causing the overall size of the antenna to increase significantly. The present invention proposes for the first time a new type of half-mode dielectric ridged parallel-plate waveguide (HMDRPW) structure, which has broadband characteristics superior to traditional single-conductor waveguide structures such as substrate integrated waveguides (SIW), and the transmission characteristics of the waveguide are similar to those of dielectric ridged parallel-plate waveguides (DRPW), that is, it has an extremely wide single-mode working bandwidth, but its size is almost half of that of DRPW; and a small-sized frequency scanning leaky wave antenna with broadband and high efficiency characteristics can be obtained by etching uniform transverse gaps on the upper metal plate of the HMDRPW. Therefore, the designed antenna has a simple structure, low cost, and small size, and at the same time has excellent radiation characteristics and can achieve broadband and efficient beam scanning. Summary of the invention

[0009] Based on the above-mentioned prior art leaky wave antennas often have a wider beam. The present invention proposes a two-unit leaky wave antenna array based on HMDRPW, which can obtain a narrow beam, high-gain scanning beam while maintaining excellent radiation characteristics such as broadband 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.

[0010] On the one hand, the present invention provides a design method for a two-unit leaky wave antenna array structure based on a half-mode dielectric ridge parallel plate waveguide, the method comprising: S1: According to the fundamental 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 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-sized broadband and 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-unit half-mode dielectric ridge parallel plate waveguide leaky wave antenna array structure is designed. The two-port array antenna of the structure is fed in parallel by probes to achieve narrow lobe and high gain scanning beam.

[0011] Furthermore, the basic mode of the dielectric ridge parallel plate waveguide transmission is the quasi-TEM mode. ε r and its width t d Determining the propagation constant of the fundamental mode of a dielectric ridge parallel plate waveguide β , the specific formula is as follows: ; ; in, k 0 is the propagation constant in vacuum, β y is the lateral propagation constant of the dielectric ridge parallel plate waveguide.

[0012] Furthermore, the S1 specifically includes cutting the dielectric ridge parallel plate waveguide in half along the longitudinal central symmetry axis to obtain a structure in which the lateral dimension of the waveguide is halved, and the structure is a half-mode dielectric ridge parallel plate waveguide.

[0013] Furthermore, the S2 specifically includes that, since the fundamental mode transmitted in the half-mode dielectric ridge parallel plate waveguide is similar to that of the dielectric ridge parallel plate waveguide, an equivalent fast wave mode is obtained by periodic loading and utilizing spatial harmonics, thereby realizing leaky wave radiation; Uniform periodic transverse gaps are etched on the upper metal plate of the half-mode dielectric ridge parallel plate waveguide to excite the -1 harmonic and realize leaky wave radiation; m Radiation conditions and beam angles of subspatial harmonics θ m Described by the following formula: ; ; in λ 0 is the wavelength in vacuum, p sis the gap period.

[0014] Furthermore, the S3 specifically includes: arraying 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; 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.

[0015] On the other hand, the present invention also provides a two-unit leaky wave antenna array structure based on a half-mode dielectric ridge parallel plate waveguide, comprising an upper metal plate, a lower metal plate, a dielectric layer, a probe, a probe through hole, and a screw hole; 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; Long grooves are etched on the upper metal plate and the lower metal plate; The probes and the probe through holes are arranged at both ends of the array, and the probes are used for power feeding and load absorption; The screw holes are used to fix the overall structure.

[0016] Furthermore, the trapezoidal slot array I and the trapezoidal slot array II are symmetrically distributed along the long slot, and have the same slot size and slot number.

[0017] Furthermore, the long groove does not penetrate the entire upper metal plate and the lower metal plate; the distance between two waveguide units is measured by the width of the long groove.

[0018] Furthermore, the probes are fed in parallel.

[0019] Furthermore, 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 ε r = 2.2, thickness is 3.175 mm; The two-unit leaky wave antenna array structure based on the half-mode dielectric ridge parallel plate waveguide is fixed with nylon screws.

[0020] Beneficial effects of the present invention: 1. The present invention realizes continuous beam scanning, solving the problem that the traditional leaky wave antenna has a narrow working frequency band and is difficult to meet the needs of multi-band communication, as well as low radiation efficiency.

[0021] 2. The present invention solves the demand of modern devices for smaller antennas. The leaky wave antenna is compacted in size while maintaining performance.

[0022] 3. The present invention solves the problems of impedance matching difficulties and poor adaptability to complex environments that may exist in traditional leaky wave antennas through flexible design. It has good impedance matching performance to meet the requirements of broadband and high-efficiency performance, and is flexible in design and can maintain performance in a changing environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention has the following accompanying drawings: Figure 1 A design flow chart of a two-unit leaky wave antenna array structure based on a half-mode dielectric ridge parallel plate waveguide provided by the present invention; Figure 2 Schematic diagram of the construction process and three-dimensional structure of the half-mode dielectric ridge parallel plate waveguide; Figure 3 Simulation results of two-dimensional electric field distribution of dielectric ridge parallel plate waveguide and half-mode dielectric ridge parallel plate waveguide; Figure 4 Schematic diagram of the construction process and three-dimensional structure of a two-unit array of half-mode dielectric ridge parallel plate waveguides; Figure 5 Schematic diagram of the directional pattern product theorem for the radiating elements in a two-element leaky wave antenna array designed with a half-mode dielectric ridge parallel plate waveguide; Figure 6 Simulation results of the two-dimensional electric field distribution of a two-unit array of half-mode dielectric ridge parallel plate waveguides; Figure 7 Schematic diagram of the three-dimensional structure of a two-unit leaky wave antenna array based on a half-mode dielectric ridge parallel plate waveguide; Figure 8 Simulation results of normalized propagation constants of the fundamental mode of dielectric ridge parallel plate waveguide, half-mode dielectric ridge parallel plate waveguide and half-mode dielectric ridge parallel plate waveguide two-unit array; Fig. 9 S-parameter simulation results of half-mode dielectric ridge parallel plate waveguide leaky wave antenna; Fig.10 Simulation results of normalized radiation pattern of half-mode dielectric ridge parallel plate waveguide leaky wave antenna; Fig.11 S-parameter simulation results of a two-element leaky-wave antenna array based on a half-mode dielectric ridge parallel plate waveguide; Fig.12 The E-plane simulated radiation pattern of the two-unit leaky wave antenna array based on the half-mode dielectric ridge parallel plate waveguide at different frequencies within the working bandwidth; Fig.13 The total efficiency simulation results of a two-element leaky wave antenna array based on a half-mode dielectric ridge parallel plate waveguide; Fig.14Comparison of simulation results of gain curves of two-unit leaky wave antenna array based on half-mode dielectric ridge parallel plate waveguide and leaky wave antenna unit based on half-mode dielectric ridge parallel plate waveguide at different frequencies. DETAILED DESCRIPTION

[0024] In order to make the objects, advantages and features of the present invention more obvious, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] In conjunction with the accompanying drawings, the present invention is described in detail: like Figure 1 As shown, the present invention discloses a two-unit leaky wave antenna array structure based on a half-mode dielectric ridge parallel plate waveguide, comprising the following design steps: S1. According to 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 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-sized broadband and 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-unit half-mode dielectric ridge parallel plate waveguide leaky wave antenna array structure is designed. The two-port array antenna is fed in parallel by probes to achieve a narrow lobe and high-gain scanning beam.

[0026] The basic transmission mode of DRPW is the quasi-TEM mode. ε r and its width t d The propagation constant of the fundamental mode of DRPW can be determined β , the specific formula is as follows: ; ; in, k 0 is the propagation constant in vacuum, β y is the lateral propagation constant of DRPW.

[0027] When DRPW is cut in half along the longitudinal central symmetry axis, Figure 2 As shown, a new waveguide structure with half the lateral dimension of the waveguide can be obtained. Figure 3The schematic diagram of the two-dimensional electric field distribution of the two waveguides before and after truncation at 20 GHz shows that the basic mode transmitted in the region between the upper and lower parallel metal plates of the new waveguide structure is similar to the basic mode transmitted in the corresponding half waveguide when the DRPW is not truncated, that is, it is close to the half mode of the quasi-TEM mode. Therefore, this new waveguide structure is named half-mode dielectric ridge parallel plate waveguide (HMDRPW). From the mode analysis, it can be obtained that the propagation constant of the HMDRPW working in the fundamental mode is similar to the propagation constant of the DRPW with the same parameters.

[0028] According to the simulated electric field distribution diagram, it can be concluded that the electric field is mainly concentrated in the dielectric region; in the lateral direction (i.e. Figure 3 Reference coordinate system y axial direction), the electric field decays from the dielectric area to both sides, and decays rapidly outside the waveguide (the part without the upper and lower parallel metal plates). In other words, the plane where the long side of the parallel metal plate of HMDRPW is flush with the dielectric ridge, that is, the "truncation surface", can be approximately equivalent to an open end, and there will be no serious energy leakage problem at this port. Therefore, even if there is an open structure instead of a traditional closed waveguide, most of the energy is still confined in the dielectric ridge of HMDRPW and transmitted along the dielectric ridge.

[0029] The design method of the half-mode dielectric ridge parallel plate waveguide leaky wave antenna in S2 is as follows: First, the theoretical value of the propagation constant of HMDRPW can also be approximately derived by combining equations (1) and (2). According to the analysis of the propagation constant obtained by theoretical calculation, it can be concluded that the fundamental mode transmitted in HMDRPW is similar to DRPW, which is a slow wave mode bounded near the dielectric ridge. Therefore, the equivalent fast wave mode can be obtained by periodic loading and using spatial harmonics to achieve leaky wave radiation.

[0030] Secondly, uniform periodic transverse gaps are etched on the upper metal plate of HMDRPW to excite the -1st harmonic to achieve leaky wave radiation. m Radiation conditions and beam angles of subspatial harmonics θ m It can be described by the following formula: ; ; in λ 0 is the wavelength in vacuum, p s is the gap period.

[0031] The design method of the two-element array of half-mode dielectric ridge parallel plate waveguide leaky wave antenna in S3 is as follows: Firstly, a two-unit half-mode dielectric ridge parallel plate waveguide array structure is constructed based on HMDRPW, and a suitable waveguide unit spacing is selected. The waveguide array transitions from DRPW to a two-unit HMDRPW array without the need to design an additional power divider.

[0032] The novel waveguide array structure proposed in the present invention is obtained by arranging two HMDRPW units, such as Figure 4 As shown, from a structural point of view, the two-unit waveguide array is similar to a DRPW with a completely symmetrical long groove in the center of the upper and lower metal plates along the longitudinal direction. The two waveguide units share the upper and lower parallel metal plates and a dielectric rod structure, wherein the dielectric rod includes the dielectric ridge structure of the two HMDRPW units and the dielectric part that connects them, and is located in the middle of the parallel metal plates with long grooves. The parts of the dielectric rod placed between the parallel metal plates of the two waveguide units on both sides are completely symmetrical, and serve as the dielectric ridges of the two HMDRPW units to bind and guide electromagnetic waves; the middle part of the dielectric rod is not covered by metal plates above and below, and serves as the connecting part of the two dielectric ridges, and also connects the two waveguide units, so that the dielectric layer of the array can be used as a whole, which is convenient for PCB processing; the long grooves on the upper and lower parallel metal plates do not run through the entire metal plate in the longitudinal direction, so the transition section from DRPW to the two HMDRPW units is retained at both ends of the waveguide array. The transmission characteristics of the HMDRPW array are different from those of the DRPW. Due to the presence of the long grooves, the two waveguide units of the array transmit the half-mode of the quasi-TEM mode respectively.

[0033] The distance between two waveguide units can be determined by the width of the long slot. g Measure. When g When the opening effect provided by the long slot is too small, the waveguide array is approximately equivalent to a DRPW structure, and the transmission characteristics of the waveguide change accordingly. g If it is too large, the size of the waveguide array structure will increase, the radiation pattern may be distorted when designing the leaky wave antenna array, and impedance matching will be difficult. Therefore, it is necessary to select a suitable g This allows the two units in the designed waveguide array to work independently while maintaining a compact array structure. It is worth noting that the coupling between the HMDRPW units will affect the propagation constant of the waveguide array, but the fundamental mode is still a slow-wave mode.

[0034] Secondly, a two-unit half-mode dielectric ridge parallel plate waveguide leaky wave antenna array is designed based on HMDRPW LWA and a two-unit half-mode dielectric ridge parallel plate waveguide array. Figure 5This is the principle diagram of the pattern product theorem. According to the pattern product theorem, the radiation intensity required by the two HMDRPW LWA units should be consistent to ensure that the radiation pattern of the final leakage antenna array is not distorted. Therefore, according to the required radiation intensity, a slot array with consistent size and period and symmetrical distribution along the longitudinal center is etched on the upper metal plate of the two HMDRPW units.

[0035] The two-unit leaky wave antenna array is fed in parallel by probes, and the probes are placed at the DRPW structure of the array, so that the energy fed into the DRPW by the probes can be transferred to the HMDRPW array through the DRPW and evenly divided into two waveguide units on both sides for transmission; and loads are set symmetrically at the end of the array to absorb the remaining energy transmitted to the end. The slot units in the slot array are designed to be trapezoidal, which increases the radiation capacity of the slot array while avoiding excessive resonance effects of a single slot. Therefore, a leaky wave antenna array with narrow beam and high gain can be obtained on the basis of the HMDRPW LWA unit with broadband and high efficiency characteristics, while the array size is small, the structure is compact, and the design is simple.

[0036] Figure 6 The simulation results of the electric field distribution diagram of the designed two-unit HMDRPW array structure at 20 GHz are given. It can be concluded that after the energy is fed into one end of the waveguide array, there is a transition from DRPW to HMDRPW array transmission, and due to the existence of the long grooves on the upper and lower parallel metal plates, the mode transmitted in the HMDRPW array is the half mode of the quasi-TEM mode, rather than the higher-order mode of DRPW. And, from Figure 6 It can be further seen that after the energy enters the waveguide array, it is equally divided into two parts, which are respectively confined in the dielectric ridges of the two waveguide units and transmitted along the ridges.

[0037] like Figure 7 As 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 feeding and load absorption, probe through holes 8, screw holes 9 for fixing the overall structure, and some other structures.

[0038] The upper metal plate 1 and the lower metal plate 6 (as the ground plane) form the upper and lower parallel metal plates shared by the two units, and the rectangular slot arrays I2 and II3 etched on the upper metal plate 1 are both uniform trapezoidal arrays, and the periods of the two slot arrays are the same; and the trapezoidal slot arrays I2 and II3 are symmetrically distributed with respect to the HMDRPW LWA array in the longitudinal direction, and the parameters are exactly the same (including the slot size and the number of slots). The dielectric layer 5 is composed of the dielectric ridges of the two units and the dielectric parts connecting them, forming two independent energy propagation paths.

[0039] The brass plate is used for the design of the upper metal plate 1 and the lower metal plate 6, and its thickness is 0.5 mm; the Rogers RT5880 printed circuit board is used for the design of the dielectric layer 5, and its dielectric constant is ε r = 2.2, thickness is 3.175 mm; the three-layer structure is fixed with nylon screws.

[0040] For example Figure 7 The working principle of the two-element leaky wave antenna array shown is described in detail as follows: One end of the antenna array is fed by a probe. The energy is first fed into the DRPW and transmitted along the medium, and is confined in the medium area. It is then divided into two equal parts by the HMDRPW array and transmitted along the medium ridges in the two HMDRPW units on both sides, while leaking radiation is generated outward through two sets of trapezoidal slot arrays. The coupling between the two leaky wave antenna units will affect their transmission characteristics, but they still work in the slow wave mode and have the same propagation constant. Both sets of slots work in the frequency band described by equation (3) where only the -1 harmonic meets the outward radiation condition, and since the two sets of slot arrays have the same slot period, according to equation (4), the two leaky wave antenna units have the same beam pointing angle. According to the pattern product theorem, the leaky wave antenna array can obtain a narrower scanning beam than the LWA unit, and accordingly, it also has a higher antenna gain.

[0041] Figure 8 The simulation results of the normalized propagation constants of the fundamental mode of DRPW, HMDRPW and HMDRPW two-unit array are given. The metal plate width and dielectric ridge width of HMDRPW are half of those of DRPW, and the relative dielectric constant and thickness of the dielectric ridges of the two are exactly the same. The HMDRPW two-unit array is the HMDRPW according to Figure 4 The array is constructed as shown. Figure 8It can be seen that under the above parameter conditions, the propagation constant of HMDRPW is very close to that of DRPW, which proves that the HMDRPW obtained by symmetric tailoring of DRPW retains the original electromagnetic properties and can reduce the size of the transmission structure to half of the original. Furthermore, due to the coupling between units, the propagation constant of the HMDRPW two-unit array is slightly larger than that of HMDRPW, but its transmission characteristics can still be analyzed using the theory of HMDRPW or DRPW.

[0042] Fig. 9 The S parameter simulation results of HMDRPW LWA are given. The designed HMDRPW LWA operates in the frequency band from 14 GHz to 26 GHz. Within this single beam operating bandwidth, |S 11 | Below -10 dB, with good impedance matching performance. Fig.10 The polar coordinate normalized radiation pattern of the leaky wave antenna on the E plane is given. It can be seen that the designed leaky wave antenna realizes beam scanning from backward to forward (total scanning angle is 78°) within an extremely wide single-beam working bandwidth (relative bandwidth is 60%). It can be obtained that the HMDRPW LWA can maintain the excellent radiation characteristics of DRPW LWA with broadband and high efficiency, while its size is only half of that of DRPW LWA, which can further compress the size of microwave millimeter wave integrated circuits. The two-unit leaky wave antenna array proposed in the present invention is studied on the basis of this leaky wave antenna unit. The final optimization results of the present invention and some comparative results and analysis are given below.

[0043] Fig.11 The figure shows the |S of the proposed two-element leaky-wave antenna array. 11 | and |S 21 |The simulation results. Fig. 9 It can be seen from the simulation results that the proposed leaky wave antenna array |S 11 | < -10 dB in the range of 13.2 GHz to 31.7 GHz, the impedance matching characteristics are good, and in this frequency range, |S 11 | and |S 21 | are all lower than -10 dB, proving that the gaps in the leaky-wave antenna array can leak most of the energy into space to achieve leaky-wave radiation. Fig.12 The E-plane polar coordinate normalized radiation pattern of the leaky wave antenna array of the present invention simulated in the -1 harmonic working 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, the relative bandwidth of the single-beam operation is 63.3%, and the total scanning angle is 83° from forward to backward, achieving an extremely wide working bandwidth and having a strong beam scanning capability. Fig.13The total efficiency of the proposed array antenna in the range of 13.6 GHz to 26 GHz obtained by simulation is given. From the simulation results, it can be obtained that the total efficiency of the present invention is higher than 93% in the single-beam operating frequency band. Fig.14 The gain simulation results of the invented two-element leaky wave antenna array in the range of 13.6 GHz to 26 GHz and the gain comparison with the leaky wave antenna unit are given. The proposed leaky wave antenna array can achieve a gain of 10 dBi to 17.6 dBi in the single-beam operating frequency band, and from the comparison with the gain curve of the unit, it can be seen that the two-element array has a significant effect on improving the antenna gain.

[0044] In summary, the present invention proposes a two-unit leaky wave antenna array based on a half-mode dielectric ridge parallel plate waveguide. HMDRPW is obtained by symmetric tailoring of DRPW. A two-unit HMDRPW array can be designed by arranging two units of HMDRPW, and then a two-unit HMDRPW leaky wave antenna array is designed based on leaky wave theory and array theory. The array can maintain the broadband characteristics of DRPW and realize ultra-wideband and efficient single beam scanning; more importantly, due to the half-mode characteristics and array formation, the invented leaky wave antenna array is small in size, compact and simple in structure, and has excellent radiation characteristics of narrow beam and high gain.

[0045] The above embodiments describe the technical solutions of the present invention in detail. Obviously, the present invention is not limited to the described embodiments. Based on the embodiments of the present invention, people familiar with the technical field can also make various changes accordingly, but any changes that are equivalent or similar to the present invention belong to the scope of protection of the present invention.

[0046] The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in this field.

Claims

1. A design method for a two-unit leaky wave antenna array structure based on a half-mode dielectric ridge parallel plate waveguide, characterized in that: The method comprises, S1: According to the fundamental 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 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-sized broadband and 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-unit half-mode dielectric ridge parallel plate waveguide leaky wave antenna array structure is designed. The two-port array antenna of the structure is fed in parallel by probes to achieve narrow lobe and high gain scanning beam.

2. A design method for a two-unit leaky wave antenna array structure based on a half-mode dielectric ridge parallel plate waveguide as claimed in claim 1, characterized in that: The basic mode of the dielectric ridge parallel plate waveguide transmission is the quasi-TEM mode. and its width Determining the propagation constant of the fundamental mode of a dielectric ridge parallel plate waveguide , the specific formula is as follows: ； ； in, is the propagation constant in vacuum, is the lateral propagation constant of the dielectric ridge parallel plate waveguide.

3. A design method for a two-unit leaky wave antenna array structure based on a half-mode dielectric ridge parallel plate waveguide as claimed in claim 2, characterized in that: Said S1 specifically includes cutting the dielectric ridge parallel plate waveguide in half along the longitudinal central symmetry axis to obtain a structure with half the lateral dimension of the waveguide, and said structure is a half-mode dielectric ridge parallel plate waveguide.

4. A design method for a two-unit leaky wave antenna array structure based on a half-mode dielectric ridge parallel plate waveguide as claimed in claim 3, characterized in that: The 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 is obtained by periodic loading and utilizing spatial harmonics, thereby realizing leaky wave radiation; Uniform periodic transverse gaps are etched on the upper metal plate of the half-mode dielectric ridge parallel plate waveguide to excite the -1 harmonic and realize leaky wave radiation; m Radiation conditions and beam angles of subspatial harmonics θ m Described by the following formula: ； ； in λ 0 is the wavelength in vacuum, p s is the gap period.

5. A design method for a two-unit leaky wave antenna array structure based on a half-mode dielectric ridge parallel plate waveguide as claimed in claim 4, characterized in that: The S3 specifically includes: arranging 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; 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.

6. A two-unit leaky wave antenna array structure based on a half-mode dielectric ridge parallel plate waveguide, characterized in that: Including upper metal plate, lower metal plate, dielectric layer, probe, probe through hole, screw hole; 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; Long grooves are etched on the upper metal plate and the lower metal plate; The probes and the probe through holes are arranged at both ends of the array, and the probes are used for power feeding and load absorption; The screw holes are used to fix the overall structure.

7. A two-unit leaky wave antenna array structure based on a half-mode dielectric ridge parallel plate waveguide as claimed in claim 6, characterized in that: The trapezoidal slot array I and the trapezoidal slot array II are symmetrically distributed along the long slot, and have the same slot size and slot number.

8. A two-unit leaky wave antenna array structure based on a half-mode dielectric ridge parallel plate waveguide as claimed in claim 7, characterized in that: The long groove does not penetrate the entire upper metal plate and the lower metal plate; the distance between two waveguide units is measured by the width of the long groove.

9. A two-unit leaky wave antenna array structure based on a half-mode dielectric ridge parallel plate waveguide as claimed in claim 8, characterized in that: The probes are fed in parallel.

10. A two-unit leaky wave antenna array structure based on a half-mode dielectric ridge parallel plate waveguide as claimed in claim 9, 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 ε r = 2.2, thickness is 3.175 mm; The two-unit leaky wave antenna array structure based on the half-mode dielectric ridge parallel plate waveguide is fixed with nylon screws.

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