Broadband high-gain microstrip antenna

Abstract

The invention discloses a broadband high-gain microstrip antenna, which is provided with a rectangular radiation patch, a symmetrical grooving parasitic patch, a dielectric substrate, a metal bottom plate and a polytetrafluoroethylene support column, the rectangular radiation patch and the symmetrical grooving parasitic microstrip are attached to the upper layer of the dielectric substrate; a certain distance is formed between the rectangular radiation patch and the slotted parasitic patch and is used for coupling electromagnetic waves; the upper dielectric substrate is provided with two through holes for feeding; the metal bottom plate and the upper-layer substrate are fixed through four polytetrafluoroethylene supporting columns; a space is reserved in the middle to form an air substrate; and an SMA interface is arranged below the floor. According to the microstrip patch antenna, the forms of differential feeding and parasitic patch adding are adopted, the high gain and broadband characteristics of the microstrip patch antenna are achieved, the profile of the antenna is kept within 0.1 lambda, and the unipolar radiation pattern is achieved while high performance is guaranteed. In addition, the antenna is relatively simple in technical structure and convenient for later processing, can be used as an array unit for arraying, and meets the requirements of modern communication.

Description

Technical Field

[0001] The present invention belongs to the technical field of wireless communications, and in particular relates to a high-gain, wide-band microstrip antenna. Background Art

[0002] Microstrip antennas are widely used in 5G communications and satellite navigation due to their low profile and ease of integration. However, traditional designs suffer from inherent drawbacks such as narrow bandwidth (typically <10%), low gain (5-6 dBi), and a large profile (>0.1λ). While recent patented technologies have attempted improvements, significant deficiencies remain. The following comparative analysis of existing patented technologies clarifies the innovative direction and technical challenges of this design.

[0003] Microstrip antennas have been widely used in both military and civilian applications since the 1980s due to their numerous advantages. Microstrip antennas boast bandwidths of approximately 10%, sufficient for most everyday scenarios. However, with the continuous development of mobile communication systems, the balance between bandwidth and gain has become increasingly challenging. Consequently, research on microstrip antennas with wideband and high gain has become a hot topic in recent years. Traditional microstrip antenna designs suffer from inherent drawbacks such as narrow bandwidth, low gain, and a thick profile. To expand the bandwidth of microstrip antenna units, methods such as slotting the radiating patch and adding parasitic structures are commonly employed. Furthermore, patent publication CN112290207A describes a wide-angle scanning antenna unit for communications. This antenna achieves two-dimensional scanning within a ±60° range, but its standing wave ratio (SWR) is less than 2, resulting in a coverage bandwidth of only 27-29 GHz (7.1%). For example, the invention patent described in patent publication number CN119481685A proposes a novel microstrip patch antenna, but its coverage bandwidth is 8.5 GHz-10.5 GHz (22.2%).

[0004] As shown in the examples above, while traditional microstrip patch antennas offer advantages such as simple structure, low profile, and ease of fabrication, their narrow bandwidth is disadvantageous for certain military detection applications. To address these shortcomings, this application proposes a novel microstrip patch antenna that not only exhibits wide bandwidth and high gain, but also possesses a simple structure and ease of fabrication, making it highly practical. Summary of the Invention

[0005] In view of the problems existing in the prior art, the present invention provides a high-gain, wide-bandwidth microstrip patch antenna.

[0006] The present invention is achieved by providing a broadband high-gain microstrip antenna, wherein the broadband high-gain microstrip antenna is provided with a rectangular radiating patch, a symmetrical rectangular slotted parasitic patch, a dielectric substrate, a metal bottom plate, and a polytetrafluoroethylene support column; The rectangular radiation patch and the rectangular parasitic patch are attached to the dielectric substrate and are located on the top layer of the antenna; the dielectric substrate is located in the middle layer of the broadband high-gain microstrip antenna; the metal base plate is located in the lower layer of the dielectric substrate; and the metal base plate and the upper dielectric substrate are connected by four polytetrafluoroethylene support columns of equal height.

[0007] The symmetrical rectangular slotted parasitic patch cuts out two rectangles, and there is a certain distance between the two symmetrical patches for coupling linearly polarized electromagnetic waves. The slotted parasitic patch refers to a coupled parasitic structure formed by cutting out a rectangular area; There is a gap between the rectangular radiation patch and the slotted parasitic patch for coupling linearly polarized electromagnetic waves; Two holes are opened on the dielectric substrate at two symmetrical positions along the center for power feeding; The metal base plate is located at the bottom of the entire antenna and is installed with a radio frequency connector.

[0008] Furthermore, the broadband high-gain microstrip antenna is characterized in that the rectangular radiating microstrip is the radiating unit of the antenna and is fed by a coaxial probe; the length and width of the rectangular radiating microstrip are 0.4λ and 0.067λ respectively.

[0009] Furthermore, the slotted parasitic patch is a parasitic unit of the antenna. By cutting out a rectangular patch with a length and width of 0.26λ and 0.38λ along the central axis, a rectangular patch with a length and width of 0.19λ and 0.13λ and a rectangular patch with a length and width of 0.067λ and 0.076λ respectively can be controlled to adjust the resonant characteristics of the antenna.

[0010] Furthermore, there is a slot with a width of 0.03λ between the symmetrical slotted parasitic patches to couple linearly polarized electromagnetic waves, and the slot spacing is adjusted to adjust the impedance matching of the antenna.

[0011] Furthermore, there are gaps of 0.037λ and 0.012λ between the symmetrical slotted parasitic patch and the main radiation patch for coupling linearly polarized electromagnetic waves, and the gap spacing is adjusted to adjust the resonance point of the antenna.

[0012] Furthermore, the dielectric substrate is located in the middle layer of the antenna, the thickness of the dielectric substrate is 0.017λ, and the length and width are both 0.83λ. Two through holes are opened at corresponding positions of the dielectric substrate for feeding.

[0013] Furthermore, four polytetrafluoroethylene support columns with a height of 0.067λ are provided between the upper substrate and the floor to enhance the stability of the antenna structure. An air substrate is added to the antenna structure to reduce the cost of antenna production. Furthermore, the RF connector is placed on the lower side of the metal base plate, the coaxial probe of the RF connector passes through the dielectric substrate and is welded to the radiating microstrip patch, and the outer skin of the RF connector is connected to the metal base plate.

[0014] In summary, the beneficial effects of the present invention are: Symmetrically slotted parasitic patches and multi-slot coupling: 0.19λ×0.13λ and 0.067λ×0.076λ regions are cut out of a 0.26λ×0.38λ rectangular patch. Combined with 0.037λ / 0.012λ slots between the rectangular radiating patch and the parasitic patch, multi-level slot coupling excites multi-point resonance, merging the resonant points within the 3.56-6.54 GHz frequency band. This achieves an impedance bandwidth of 59.6% (S11 <-10 dB), breaking through the narrowband limitation of traditional microstrip antennas.

[0015] Differential feeding and air substrate structure: Two coaxial probes with a phase difference of 180° are used for feeding, and impedance matching is optimized through symmetrical excitation. Four 0.067λ polytetrafluoroethylene support columns are combined to introduce an air substrate to reduce the Q value. While expanding the bandwidth, the peak gain is increased to 9.6dB and cross-polarization is significantly suppressed.

[0016] Compact and highly stable design: The lightweight combination of a dielectric substrate and copper foil patch, coupled with a polytetrafluoroethylene support column fixing structure, reduces the antenna's overall dimensions to 0.83λ × 0.83λ × 0.083λ. It maintains a stable unidirectional radiation pattern within the 3.6-6.4GHz frequency band, meeting the requirements of modern communication systems for highly integrated antennas. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the structure of a broadband, high-gain microstrip antenna provided by an embodiment of the present invention (with a dielectric substrate in perspective).

[0018] Figure 2 4 is a top view of a broadband high-gain microstrip antenna provided by an embodiment of the present invention.

[0019] Figure 3 It is a side view of a broadband high-gain microstrip antenna provided by an embodiment of the present invention.

[0020] Figure 4 This is a reflection coefficient curve diagram of a broadband high-gain microstrip antenna port provided by an embodiment of the present invention.

[0021] Figure 5 This is a graph showing gain variation within a bandwidth range of a wide-band, high-gain microstrip antenna provided by an embodiment of the present invention.

[0022] Figure 6The broadband high-gain microstrip antenna provided by the embodiment of the present invention has a Phi=0° (H) plane radiation pattern and a Phi=90° (E) plane radiation pattern at a low frequency of 3.6 GHz.

[0023] Figure 7 The broadband high-gain microstrip antenna provided by the embodiment of the present invention has a Phi=0° (H) plane radiation pattern and a Phi=90° (E) plane radiation pattern at a frequency center of 5 GHz.

[0024] Figure 8 The low-profile dual-bandwidth beam microstrip antenna provided by an embodiment of the present invention has a Phi=0° (H) plane radiation pattern and a Phi=90° (E) plane radiation pattern at a high frequency of 6.4 GHz. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0026] To address the problems of small operating bandwidth and low gain in existing microstrip antenna units in mobile communications, the present invention adds a coupled parasitic structure to the microstrip patch and adopts differential feeding to achieve both wide bandwidth and high gain characteristics of the antenna, thus solving the problems of small bandwidth and low gain of traditional microstrip antennas.

[0027] The application principle of the present invention is described in detail below with reference to the accompanying drawings.

[0028] like Figure 1 、 Figure 2 and Figure 3 As shown, the broadband high-gain microstrip antenna provided by the embodiment of the present invention includes: (1) Rectangular radiating patch 1, which is located at the top layer of the antenna. Rectangular radiating patch 1 is manufactured using a printed circuit process and printed on dielectric substrate 2. Two through holes are drilled in longitudinally symmetrical positions on rectangular radiating patch 1 to pass through a coaxial probe 5 and feed power to rectangular radiating patch 1 through the coaxial probe 5. (2) Slotted parasitic patch 3, which is located at the top layer of the antenna. Slotted parasitic patch 3 is manufactured using a printed circuit process and printed on dielectric substrate 2. Two rectangular slots are cut on slotted parasitic patch 3, and the size of the slots is adjusted to control the resonant frequency and impedance matching of the antenna. The two slotted parasitic patches are placed symmetrically, with a certain distance between them to control the coupling of linearly polarized electromagnetic waves and improve the antenna radiation performance. (3) Dielectric substrate 2, which is located in the middle layer of the entire antenna. Two through holes are drilled on the dielectric substrate 2 along the central axis of the rectangular radiation patch 1 for passing the coaxial probe 5; (4) Support column 4, the polytetrafluoroethylene support column 4 is fixed between the metal base plate 6 and the dielectric substrate 2 using bolts, and the introduction of the air substrate reduces the Q value and improves the stability of the antenna structure; (5) Metal base plate 6, which is located at the bottom of the antenna; the coaxial probe 5 of the RF connector passes through the metal base plate 6 and the dielectric substrate 2, and is welded to the rectangular radiating microstrip 1 through a through hole in the dielectric substrate 2, and the outer skin of the coaxial probe 5 of the RF connector is connected to the metal base plate 6.

[0029] The present invention achieves broadband characteristics by the following principles: A polytetrafluoroethylene support column 4 is added between the antenna substrate 2 and the metal base plate 6 to introduce an air substrate, thereby reducing the antenna's Q factor and increasing its bandwidth. Simultaneously, a symmetrical slotted parasitic patch 3 is added. The slotting operation creates multiple gaps. At high frequencies, these gaps in the parasitic patch excite higher-order modes through coupling, merging multiple resonant points and ultimately expanding the antenna bandwidth. Furthermore, a differential feeding mode is employed, using two coaxial probes 5 with a 180° phase difference for feeding. This symmetrical excitation improves the antenna's impedance matching. The present invention achieves high gain characteristics by the following principles: The addition of the symmetrical slotted parasitic patch 3 increases the antenna's radiation aperture and enhances its gain. The multi-stage gaps created by the slotting generate equivalent magnetic flux element radiation, concentrating the energy in the main radiation direction and increasing the antenna's peak gain. The differential feeding mode, with the two coaxial probes 5 feeding at a 180° phase difference, reduces the antenna's cross-polarization and enhances its main polarization gain.

[0030] The following is a detailed description of the application effect of the present invention in combination with simulation. All dimensional parameters in the present invention are normalized based on the wavelength λ (λ≈60mm) of the center frequency 5GHz. 1. Simulation content Please refer to Figures 4 to 8 The port reflection coefficient, gain and antenna pattern of the antenna in the above embodiment were simulated using simulation software.

[0031] 2. Simulation results Figure 4 This curve shows the port reflection coefficient versus operating frequency, obtained from simulation of the antenna in the example. As can be seen, the port exhibits excellent broadband characteristics. The frequency band where the port reflection coefficient is below -10dB is 3.56GHz-6.54GHz (59.6%), effectively achieving the antenna's broadband characteristics and meeting the bandwidth requirements of mobile communications.

[0032] Figure 5 1 is a gain diagram of the antenna simulation in the embodiment within the bandwidth range.

[0033] Figure 6These are the Phi=0° plane radiation pattern and the Phi=90° plane radiation pattern obtained by simulating the antenna of the embodiment at 3.6 GHz.

[0034] Figure 7 These are the Phi=0° plane radiation pattern and the Phi=90° plane radiation pattern obtained by simulating the antenna of the embodiment at 5 GHz.

[0035] Figure 8 These are the Phi=0° plane radiation pattern and the Phi=90° plane radiation pattern obtained by simulating the antenna of the embodiment at 6.4 GHz.

[0036] from Figure 6 、 7 ,8 It can be seen that the radiation pattern performance is good within the working frequency band and can well meet the engineering needs.

[0037] The rectangular radiation patch in the present invention is the radiation unit of the antenna, which is fed by a coaxial probe. The length and width of the rectangular patch are 0.4λ and 0.067λ respectively. The slotted parasitic patch is the parasitic unit of the antenna. A rectangular patch with a length and width of 0.19λ and 0.13λ and a rectangular patch with a length and width of 0.067λ and 0.076λ are cut along the central axis from a rectangular patch with a length and width of 0.26λ and 0.38λ. The resonant characteristics of the antenna can be adjusted by cutting out the size of the rectangle. There is a gap with a width of 0.03λ between the symmetrical slotted parasitic patches to couple linearly polarized electromagnetic waves. The gap spacing is adjusted to adjust the impedance matching of the antenna. There are gaps of 0.037λ and 0.012λ between the symmetrical slotted parasitic patch and the main radiation patch to couple linearly polarized electromagnetic waves. The gap spacing is adjusted to adjust the resonance point of the antenna and increase the radiation bandwidth of the antenna. The dielectric substrate is located in the middle layer of the antenna. It has a thickness of 0.017λ and a length and width of 0.83λ. Two through-holes are provided in corresponding locations on the dielectric substrate for power feed. Four 0.067λ-high polytetrafluoroethylene support columns are placed between the upper substrate and the floor to enhance the stability of the antenna structure. Incorporating an air substrate into the antenna structure reduces manufacturing costs, achieving the antenna's wideband and high gain characteristics.

[0038] The broadband, high-gain microstrip antenna of the present invention utilizes differential feeding and radiates linearly polarized electromagnetic waves. The antenna has overall dimensions of 0.83λ x 0.83λ and a thickness of 0.083λ. This antenna has an impedance bandwidth of 3.56GHz to 6.54GHz, achieving a relative bandwidth of 59.6%. Within this frequency band, the antenna achieves a peak gain of 9.6dB, achieving high gain characteristics. The present invention achieves broadband characteristics by adding polytetrafluoroethylene support columns between the antenna substrate and the metal base plate, introducing an air substrate, thereby reducing the antenna's Q factor and increasing the antenna's bandwidth. Furthermore, a symmetrical slotted parasitic patch is added. The slotting operation creates multiple slots. At high frequencies, the slots in the parasitic patch excite higher-order modes through coupling, causing multiple resonant points to merge, ultimately achieving bandwidth expansion. Furthermore, a differential feeding mode is employed, utilizing two coaxial probes with a 180° phase difference for feeding. Symmetrical excitation improves impedance matching within the antenna's frequency band. The high gain characteristic achieved by this invention is achieved by adding symmetrically slotted parasitic patches to increase the antenna's radiation aperture and enhance antenna gain. The multi-stage gaps created by the slots generate equivalent magnetic flux element radiation, concentrating energy in the primary radiation direction and increasing the antenna's peak gain. A differential feed mode is employed, with the two coaxial probes feeding the antenna 180° out of phase, to reduce cross-polarization and enhance the primary polarization gain.

[0039] In summary, the present invention utilizes a microstrip patch with slotted parasitic patches and differential feeding, achieving both broadband and high-gain antenna characteristics, addressing the narrow bandwidth and low gain issues of conventional microstrip patch antennas. While maintaining high antenna performance, the present invention also features a monopolar radiation pattern. Furthermore, the antenna's technical structure is relatively simple, facilitating subsequent processing. It can also be used as an array unit to meet the demands of modern communications.

[0040] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A broadband high-gain microstrip antenna, characterized in that: include: A dielectric substrate (2), wherein two through holes are symmetrically opened along the center of the dielectric substrate (2); A rectangular radiation patch (1) is attached to the upper surface of the dielectric substrate (2); A symmetrical slotted parasitic patch (3) is attached to the upper surface of the dielectric substrate (2), and is composed of two symmetrical rectangular patches, with a rectangular area cut out along the central axis, wherein the rectangular radiation patch (1) is surrounded by the symmetrical slotted parasitic patch (3); A metal base plate (6) is located below the dielectric substrate (2) and is connected to the dielectric substrate (2) via four polytetrafluoroethylene support columns (4) with a height of 0.067λ by bolts, with an air base plate formed between the polytetrafluoroethylene support columns (4); A radio frequency connector is installed on the lower side of the metal base plate (6), wherein the coaxial probe (5) passes through the through hole of the dielectric substrate (2) and is welded to the rectangular radiation patch (1), and the outer skin of the radio frequency connector is connected to the metal base plate (6); Gaps with widths of 0.037λ and 0.012λ are provided between the rectangular radiation patch (1) and the slotted parasitic patch (3); and a gap with a width of 0.03λ is provided between the symmetrical slotted parasitic patches (3).

2. The broadband high-gain microstrip antenna according to claim 1, wherein: The length and width of each rectangular patch of the symmetrical slotted parasitic patch (3) are 0.26λ and 0.38λ respectively.

3. The broadband high-gain microstrip antenna according to claim 1, wherein: The length and width of the rectangular area cut out along the central axis of the symmetrical slotted parasitic patch (3) are 0.19λ×0.13λ and 0.067λ×0.076λ respectively.

4. The broadband high-gain microstrip antenna according to claim 1, wherein: The rectangular area cut out of the symmetrical slotted parasitic patch (3) has an adjustable size and is used to control the resonant frequency and impedance matching of the antenna.

5. The broadband high-gain microstrip antenna according to claim 1, wherein: The coaxial probes (5) of the radio frequency connector are two differential feeding probes with a phase difference of 180°.

6. The broadband high-gain microstrip antenna according to claim 1, characterized in that: The thickness of the air substrate is defined by the height of the polytetrafluoroethylene support column (4).

7. The broadband high-gain microstrip antenna according to claim 1, wherein: The dielectric substrate (2) has a thickness of 0.017λ, and a length and width of 0.83λ.

8. The broadband high-gain microstrip antenna according to claim 1, wherein: The length and width of the rectangular radiation patch (1) are 0.4λ and 0.067λ respectively.

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