Low-profile dual-frequency dual-mode patch antenna unit and beam scanning array

Abstract

The invention discloses a low-profile dual-frequency dual-mode patch antenna unit and a beam scanning array. The low-profile dual-frequency dual-mode patch antenna unit comprises a metal patch, a dielectric substrate and a floor, the rectangular radiation patch is respectively provided with rectangular gaps at the left upper part, the right upper part and the right lower part, an L-shaped branch is added at the left lower part, an arrow branch is added at the right lower part, and the floor is tightly attached to the dielectric substrate; the patch antennas are used as units to be arranged into a 4 * 4 antenna array, the array is a single beam at 1.6 GHz, the scanning angle is + / -36 degrees, and the gain can reach 9.4 dBi, and the array is a double beam at 2.5 GHz, the scanning angle is-55 degrees to-25 degrees, the scanning angle is 25 degrees to 55 degrees, and the gain can reach 15.06 dBi. According to the invention, a potential antenna solution can be provided for unmanned aerial vehicle communication, a single-beam mode can guarantee a basic communication link, and a dual-beam mode can support multi-target relay.

Description

Technical Field

[0001] The present invention relates to antennas, in particular to a low-profile dual-frequency dual-mode patch antenna unit and a beam scanning array. Background Art

[0002] For UAV communications in complex electromagnetic environments, the antenna's multi-band service compatibility and the beam's rapid pointing capability have become important evaluation indicators for measuring the performance of UAV communication systems.

[0003] Existing antenna designs face significant challenges: Traditional single-band antennas, due to their limited frequency coverage, struggle to meet the demands of multi-band services; dual-band designs often sacrifice beam steering freedom and may not meet the complex and ever-changing demands of practical applications. While low-profile planar array antennas offer advantages such as lightweight and low cost, their single-band, single-beam mode still presents inherent drawbacks in complex scenarios. Dynamic switching between single-band antennas requires frequent parameter reconfiguration, increasing system latency. Traditional dual-band solutions, however, increase their profile height due to their stacked structure, which conflicts with the lightweight requirements of UAV platforms. Summary of the Invention

[0004] The purpose of the present invention is to provide a low-profile dual-frequency dual-mode patch antenna unit and beam scanning array, establish a scalable beam scanning architecture, and provide a solution for the development of planar beam scanning array antennas. The single-beam mode can guarantee the basic communication link, while the dual-beam mode can support multi-target relay, which is suitable for communication of unmanned aerial vehicles in complex electromagnetic environments.

[0005] The technical solution for achieving the purpose of the present invention is:

[0006] A low-profile dual-band, dual-mode patch antenna unit includes a metal patch, a dielectric substrate, and a floor. The metal patch uses a rectangular patch as a radiator, with a first rectangular slot, a second rectangular slot, and a third rectangular slot added to the upper left, upper right, and lower right, respectively. An L-shaped branch is added to the lower left, and an arrow-shaped branch is added to the lower right. The floor is tightly attached to the dielectric substrate.

[0007] Furthermore, the upper dielectric substrate and the lower floor panel are both square.

[0008] Furthermore, the dielectric substrate has a side length of 80 mm and a thickness of 3 mm.

[0009] Furthermore, the rectangular patch has a length a=60 mm and a width b=54 mm.

[0010] Furthermore, the length of the first rectangular gap is L1 = 19.5 mm, the width is g1 = 5 mm, and the distance from the left edge of the patch is m1 = 2 mm. The length of the second rectangular gap is L2 = 11 mm, the width is g2 = 4.5 mm, and the distance from the right edge of the patch is m2 = 17.4 mm. The length of the third rectangular gap is L3 = 7 mm, the width is g3 = 5 mm, and the distance from the right edge of the patch is m3 = 8 mm.

[0011] Furthermore, the horizontal length of the L-shaped branch is d=26.7 mm, the left edge thereof is aligned with the left edge of the rectangular patch, and the distance between the horizontal side thereof and the lower edge of the rectangular patch is c=0.5 mm.

[0012] A low-profile dual-frequency dual-mode beam scanning array includes 4×4 low-profile dual-frequency dual-mode patch antenna units and a coaxial probe feed. The radiation patch of each array unit has the same size and is arranged in an array with a suitable unit distance.

[0013] Furthermore, the four units in the y-axis direction are used as sub-arrays with the same amplitude and phase. The sub-arrays are used as element factors. The beam scanning is achieved by changing the phase between the array factors in the x-axis direction; and better sidelobe suppression is achieved by adjusting the amplitude.

[0014] Furthermore, the low profile dual frequency dual mode beam scanning array is 10 mode is single beam, in TM 11 Dual beam mode.

[0015] Compared with the prior art, the present invention has the following remarkable effects:

[0016] (1) The present invention realizes dual-frequency and dual-mode collaborative operation while maintaining a low profile and low cost. In single-beam mode, it can achieve high-precision directional communication. Compared with existing single-frequency antennas, it has stronger anti-interference ability in complex environments and more stable signal transmission. In dual-beam mode, it can communicate with multiple targets at the same time, greatly improving communication efficiency and data transmission volume, and solving the problem of sacrificing beam control freedom in traditional dual-frequency designs.

[0017] (2) The present invention has a scanning angle of ±36° at 1.6 GHz and a gain of up to 9.4 dBi. At 2.5 GHz, it has dual beams with scanning angles of -55° to -25° and 25° to 55°, and a gain of up to 15.06 dBi.

[0018] (3) The present invention has a simple structure and is easy to process, and has potential application value and application potential in UAV communications in complex electromagnetic environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1A top view of the low-profile dual-band dual-mode patch antenna unit structure.

[0020] Figure 2 Axonometric view of the low-profile dual-band, dual-mode patch antenna unit structure.

[0021] Figure 3 is the simulated reflection coefficient of the low-profile dual-band dual-mode patch antenna unit.

[0022] Figure 4 This is the input impedance curve of the low-profile dual-band dual-mode patch antenna unit.

[0023] Figure 5 The simulated radiation characteristics of the low-profile dual-band dual-mode patch antenna unit at low frequency.

[0024] Figure 6 The simulated radiation characteristics of the low-profile dual-band dual-mode patch antenna unit at high frequencies.

[0025] Figure 7 A top view of the low-profile dual-frequency dual-mode beam scanning array structure.

[0026] Figure 8 A side view of the low-profile dual-frequency, dual-mode beam scanning array structure.

[0027] Figure 9 The radiation pattern of the low-profile dual-frequency dual-mode beam scanning array with a phase difference of 0° at 1.6 GHz.

[0028] Figure 10 The radiation pattern of a low-profile dual-frequency dual-mode beam scanning array with a phase difference of 120° at 1.6GHz.

[0029] Figure 11 The radiation pattern of a low-profile dual-frequency dual-mode beam scanning array with a phase difference of 180° at 2.5GHz.

[0030] Figure 12 A comparison of the radiation characteristics of the low-profile dual-frequency dual-mode beam scanning array at different phases at 1.6 GHz.

[0031] Figure 13 A comparison of the radiation characteristics of the low-profile dual-frequency dual-mode beam scanning array at different phases at 2.5GHz. DETAILED DESCRIPTION

[0032] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0033] Example 1

[0034] This embodiment is a low-profile dual-frequency dual-mode patch antenna unit structure, combined with Figure 1 and Figure 2 , the unit structure consists of a patch antenna, a square dielectric substrate and a floor. The radiation patch is fixed on the dielectric substrate, the side length of the dielectric substrate is 80mm and the thickness is 3mm. The radiation patch is composed of a rectangular patch by adding gaps and branches. The center of the rectangular patch and the center of the dielectric plate are both located on the z-axis. The length of the rectangular patch is a = 60mm and the width is b = 54mm. The first rectangular gap 1, the second rectangular gap 2 and the third rectangular gap 3 of different sizes are added to the upper left, upper right and lower right positions of the rectangular patch respectively. The length and width of the rectangular gap are L respectively. n and g n , the distance from the nearest edge of the rectangular patch is m n The length of the first rectangular slit 1 is L1 = 19.5 mm, the width is g1 = 5 mm, and the distance from the left edge of the patch is m1 = 2 mm. The length of the second rectangular slit 2 is L2 = 11 mm, the width is g2 = 4.5 mm, and the distance from the right edge of the patch is m2 = 17.4 mm. The length of the third rectangular slit 3 is L3 = 7 mm, the width is g3 = 5 mm, and the distance from the right edge of the patch is m3 = 8 mm. An L-shaped branch is added at the lower left of the rectangular patch, and the branch length is d = 26.7 mm, its left edge is aligned with the left edge of the rectangular patch, and the distance from the bottom edge of the rectangular patch is c = 0.5mm; an arrow-shaped branch is added to the lower right corner of the rectangular patch. The arrow-shaped branch includes a middle straight edge and two side edges on both sides. The starting point of the middle straight edge is the lower right vertex of the rectangular patch. The angle between the two side edges is 90 degrees, and they are parallel to the two adjacent sides of the rectangular patch respectively. The length of the two sides of the arrow is s1 = 17mm, and the distance from the nearest edge of the rectangular patch is f = 9mm. By changing the parameters to adjust the impedance matching, the -10dB impedance bandwidth is as large as possible. Figure 3 To simulate the reflection coefficient at different frequencies, the metal floor is placed close to the underlying dielectric substrate.

[0035] In the design of dual-band antenna, when the main radiator adopts a square structure, according to the antenna mode theory, the fundamental mode of the patch antenna is TM 10 mode, there are also other resonant modes, Figure 4The input impedance curve clearly reveals the mode response at different frequency points. In order to ensure the symmetry of the radiation pattern, the feeding point position is limited. At this time, the matching effect of the two resonant modes is poor, and the operating frequency deviates from the target frequency. It is necessary to load gaps and branches to achieve target frequency resonance and better impedance matching. In order to improve its radiation characteristics, a fusion analysis strategy of multi-mode theory and loading technology is introduced. Through fine control and optimized design, not only the side-radiation mode at low frequency is achieved, but also the conical beam is achieved at high frequency. Figure 5 and Figure 6 These are the simulated radiation characteristics at low and high frequencies respectively.

[0036] A low-profile dual-frequency dual-mode beam scanning array includes 4×4 low-profile dual-frequency dual-mode patch antenna units and a probe feed. The radiation patch of each array unit has the same size and is arranged in an array with a suitable unit distance.

[0037] Example 2

[0038] This embodiment provides a low-profile dual-frequency dual-mode beam scanning array structure, such as Figure 7 and Figure 8 As shown in the figure, the array antenna structure consists of a dielectric substrate, a metal floor, and 4×4 unit radiation patches of the same size. The dielectric substrate has a side length of 420mm and a thickness of 3mm. The four units in the y-axis direction are used as subarrays with the same amplitude and phase. The subarrays are used as element factors. By changing the phase between the array factors in the x-axis direction, beam scanning is achieved; by adjusting the amplitude, better sidelobe suppression is achieved. To reduce the grating lobes of the antenna beam, the configuration of the antenna array must satisfy the equation Taking into account the patch coupling effect, the patch spacing in the design is fine-tuned to achieve greater mainlobe gain and minimize sidelobe effects. Based on the above formula and taking into account the different wavelengths corresponding to different frequencies, the optimized distance between antennas is 100mm.

[0039] At low frequencies, the antenna operates in TM 10 The beam of the array antenna can be steered in the desired direction by applying the required phase gradient excitation to each element. The phase gradient is obtained by considering the element position, the beam steering angle (θ) and the equation , E total (θ,φ)=E element The calculation is based on the inter-element row spacing in (θ, φ) × AF(θ, φ). When the phase difference between adjacent array factors is 0°, the antenna beam points to 0°, the cross-polarization level is lower than -18dB, and the radiation pattern is as follows: Figure 9As the phase difference between the array factors gradually increases, the main beam of the antenna gradually deflects and the sidelobe suppression gradually deteriorates. When the phase difference between the array factors reaches 120°, the sidelobe suppression of the antenna is close to -10dB. At this time, the beam pointing of the antenna is 36°, the cross-polarization level is lower than -36dB, and the radiation pattern is as shown in the figure. Figure 10 shown.

[0040] At high frequencies, the antenna operates in TM 11 Mode. Among them TM 11 The inherent radiation characteristics of the mode make the patch unit present a radiation pattern similar to that of a dipole. By applying a fixed 180° phase difference to the sub-array, the array forms two symmetrical beams in space with a cross-polarization level lower than -38dB. Figure 11 As shown in Figure 1. When a fixed 180° phase difference is applied between adjacent subarrays, a periodic phase gradient is introduced into the array. This gradient causes constructive interference in symmetric directions (such as the ±θ directions) when electromagnetic waves propagate in space, while phase cancellation in other directions suppresses sidelobes.

[0041] Figure 12 and Figure 13 The following figure compares the radiation characteristics of the array antenna at different frequencies. The results show that at low frequencies, when the phase difference between adjacent array elements is 0°, the antenna's beam pointing is 0°. As the phase difference between the array elements increases, the antenna's main beam gradually deflects and its sidelobe suppression deteriorates. When the phase difference between the array elements reaches 120°, the antenna's sidelobe suppression approaches -10dB, and the antenna's beam pointing is 36°. At high frequencies, by applying a fixed 180° phase difference to the subarrays, the array forms two symmetrical beams in space. As the phase difference gradually changes, the antenna can achieve precise dual-beam scanning within the ranges of -55° to -25° and 25° to 55°, respectively. When the phase difference between the array elements is 100°, the beam pointing is -25° and 55°, respectively; when the phase difference between the array elements is 260°, the beam pointing is -55° and 25°, respectively.

[0042] The array antenna exhibits single-beam radiation at low frequencies and dual-beam radiation at high frequencies. This design innovatively combines dual-frequency characteristics with beamforming capabilities, making it suitable for UAV communications in complex electromagnetic environments. Single-beam mode ensures basic communication links, while dual-beam mode supports multi-target relay.

[0043] In summary, the present invention is a low-profile dual-frequency dual-mode beam scanning array structure that exhibits different radiation characteristics at different frequencies, and has advantages such as easy manufacturing and low profile. It has potential application value in UAV communications in complex electromagnetic environments.

[0044] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A low-profile dual-band dual-mode patch antenna unit, comprising an upper metal patch, a dielectric substrate, and a lower floor, characterized in that: The upper left, upper right and lower right of the metal patch are respectively provided with a first rectangular gap, a second rectangular gap and a third rectangular gap. An L-shaped branch is added to the lower left of the metal patch and an arrow branch is added to the lower right.

2. The low-profile dual-band dual-mode patch antenna unit according to claim 2, characterized in that: The dielectric substrate and the lower floor are both square, and the metal patch is a rectangular patch.

3. The low-profile dual-band dual-mode patch antenna unit according to claim 2, characterized in that: The dielectric substrate has a side length of 80 mm and a thickness of 3 mm.

4. The low-profile dual-band dual-mode patch antenna unit according to claim 2, characterized in that: The rectangular patch has a length a=60 mm and a width b=54 mm.

5. The low-profile dual-band dual-mode patch antenna unit according to claim 4, characterized in that: The length of the first rectangular gap is L1 = 19.5 mm, the width is g1 = 5 mm, and the distance from the left edge of the patch is m1 = 2 mm. The length of the second rectangular gap is L2 = 11 mm, the width is g2 = 4.5 mm, and the distance from the right edge of the patch is m2 = 17.4 mm. The length of the third rectangular gap is L3 = 7 mm, the width is g3 = 5 mm, and the distance from the right edge of the patch is m3 = 8 mm.

6. The low-profile dual-band dual-mode patch antenna unit according to claim 4, characterized in that: The horizontal length of the L-shaped branch is d=26.7 mm, the left edge thereof is aligned with the left edge of the rectangular patch, and the distance between the horizontal side thereof and the lower edge of the rectangular patch is c=0.5 mm.

7. The low-profile dual-band dual-mode patch antenna unit according to claim 4, characterized in that: The included angle between the two sides of the arrow branch is 90 degrees, which are parallel to the two adjacent sides of the rectangular patch respectively. The length of the two sides of the arrow is 17 mm, and the distance from the edge of the rectangular patch is 9 mm.

8. A low-profile dual-frequency dual-mode beam scanning array, characterized in that: The invention comprises a plurality of dual-frequency dual-mode patch antenna units and coaxial probe feed sources as described in any one of claims 1 to 7.

9. The low-profile dual-frequency dual-mode beam scanning array according to claim 8, characterized in that: The dual-frequency dual-mode patch antenna has 16 units, distributed in 4 rows and 4 columns. The 4 units in the y-axis direction are used as subarrays, and the subarrays are used as element factors. Beam scanning is achieved by changing the phase between the array factors in the x-axis direction; sidelobe suppression is achieved by adjusting the amplitude.

10. The low-profile dual-frequency dual-mode beam scanning array according to claim 9, characterized in that: In TM 10 mode is single beam, in TM 11 Dual beam mode.

Images