Microstrip ultra-wideband antenna

Abstract

A microstrip ultra-wideband antenna is provided, including: an upper dielectric substrate, a radiation patch, an open-circuit line, a short-circuit line, a ground plane, a lower dielectric substrate, a vertical dielectric substrate, isolation walls, a hyperbolic microstrip balun feeder and an ideal wave port. The radiation patch is attached to a lower surface of the upper dielectric substrate; the ground plane is attached to an upper surface of the lower dielectric substrate; the short-circuit line and the open-circuit line are attached to a rear surface and a front surface of the vertical dielectric substrate respectively; the hyperbolic microstrip balun feeder is attached to the front and rear surface of the vertical dielectric substrate; the isolation walls are located between the upper dielectric substrate and the lower dielectric substrate perpendicularly to an end of the radiation patch; and the ideal wave port is provided below the hyperbolic microstrip balun feeder.

Claims

1. A microstrip ultra-wideband antenna, comprising: an upper dielectric substrate, a radiation patch, an open-circuit line, a short-circuit line, a ground plane, a lower dielectric substrate, a vertical dielectric substrate, isolation walls, a hyperbolic microstrip balun feeder and an ideal wave port, wherein, the radiation patch is attached to a lower surface of the upper dielectric substrate; the ground plane is attached to an upper surface of the lower dielectric substrate; the short-circuit line is attached to a rear surface of the vertical dielectric substrate; the open-circuit line is attached to a front surface of the vertical dielectric substrate; the hyperbolic microstrip balun feeder is attached to the front surface and the rear surface of the vertical dielectric substrate; the isolation walls are located between the upper dielectric substrate and the lower dielectric substrate perpendicularly to an end of the radiation patch; and the ideal wave port is provided below the hyperbolic microstrip balun feeder; and the radiation patches are provided in pairs, and are thin sheets of metal material, and two outer ends of a pair of radiation patches are connected to upper ends of the isolation walls.

2. The microstrip ultra-wideband antenna according to claim 1, wherein the isolation walls are thin sheets of metal material.

3. The microstrip ultra-wideband antenna according to claim 1, wherein the ground plane is a thin sheet of metal material, and the isolation walls are connected to an upper surface of the ground plane, and then connected to the radiation patches to form a loop structure.

4. The microstrip ultra-wideband antenna according to claim 1, wherein the short-circuit line is a thin sheet of metal material, an upper end of the short-circuit line is connected to the radiation patch, and a lower end of the short-circuit line is connected to the ground plane.

5. The microstrip ultra-wideband antenna according to claim 1, wherein the open-circuit line is a thin sheet of metal material, and is connected to an upper end of a balanced end of the hyperbolic microstrip balun feeder.

6. The microstrip ultra-wideband antenna according to claim 1, wherein the hyperbolic microstrip balun feeder is a thin sheet of metal material, and an upper part of an unbalanced end of the hyperbolic microstrip balun feeder is connected to the radiation patch.

7. The microstrip ultra-wideband antenna according to claim 1, wherein the open-circuit line is attached to the front surface of the vertical dielectric substrate, and the short-circuit line serves as a radiation ground of the open-circuit line.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic structural diagram of a microstrip ultra-wideband antenna according to an embodiment of the present disclosure.

(2) FIG. 2 is a schematic structural diagram of a hyperbolic microstrip balun feeder of a microstrip ultra-wideband antenna according to an embodiment of the present disclosure.

(3) FIG. 3 is a schematic diagram of a shape of radiation patches of a microstrip ultra-wideband antenna according to an embodiment of the present disclosure.

(4) FIG. 4a and FIG. 4b are simulation result diagrams when an antenna of a microstrip ultra-wideband antenna is connected in parallel to a short-circuit line according to an embodiment of the present disclosure.

(5) FIG. 5a and FIG. 5b are simulation result diagrams when an antenna of a microstrip ultra-wideband antenna is connected in parallel to a short-circuit line and then connected in series to an open-circuit line according to an embodiment of the present disclosure.

(6) FIG. 6a and FIG. 6b are simulation result diagrams when an antenna of a microstrip ultra-wideband antenna is connected in parallel to a short-circuit line and then in series to an open-circuit line, and then a hyperbolic microstrip balun is applied according to an embodiment of the present disclosure.

(7) FIG. 7 is a radiation pattern of a microstrip ultra-wideband antenna at a frequency of 5 GHz according to an embodiment of the present disclosure.

(8) FIG. 8 is a radiation pattern of a microstrip ultra-wideband antenna at a frequency of 7 GHz according to an embodiment of the present disclosure.

(9) FIG. 9 is a schematic diagram of a voltage standing wave ratio (VSWR) of a microstrip ultra-wideband antenna according to an embodiment of the present disclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(10) To make the intentions, technical solutions, and advantages of the present disclosure clearer, the following further describes the present disclosure in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely intended to illustrate the present disclosure and are not intended to limit the present disclosure.

(11) Instead, the present disclosure covers any substitutions, modifications, equivalent methods and solutions defined by the claims in the spirit and scope of the present disclosure. Further, for better understanding of the present disclosure, some specific details are described in detail in the following detailed description of the present disclosure. Those skilled in the art can fully understand the present disclosure without the description of these details.

(12) FIG. 1 is a schematic structural diagram of a microstrip ultra-wideband antenna according to an embodiment of the present disclosure. FIG. 2 is a schematic structural diagram of a hyperbolic microstrip balun feeder. A microstrip ultra-wideband antenna includes an upper dielectric substrate 1, a radiation patch 2, an open-circuit line 7, a short-circuit line 6, a ground plane 4, a lower dielectric substrate 3, a vertical dielectric substrate 5, isolation walls 9, a hyperbolic microstrip balun feeder 8, and an ideal wave port 10.

(13) The radiation patch 2 is attached to a lower surface of the upper dielectric substrate 1; the ground plane 4 is attached to an upper surface of the lower dielectric substrate 3; the short-circuit line 6 is attached to a rear surface of the vertical dielectric substrate 5; the open-circuit line 7 is attached to a front surface of the vertical dielectric substrate 5; the hyperbolic microstrip balun feeder 8 is attached to the front surface and the rear surface of the vertical dielectric substrate 5; the isolation walls 9 are located between the upper dielectric substrate 1 and the lower dielectric substrate 3 perpendicularly to an end of the radiation patch 2; and the ideal wave port 10 is provided below the hyperbolic microstrip balun feeder 8.

(14) FIG. 3 is a schematic diagram of a shape of the radiation patches 2. The radiation patches 2 are provided in pairs, and are thin sheets of metal material, and two outer ends of a pair of radiation patches 2 are connected to upper ends of the isolation walls 9. Specifically, a=7 mm, b=3.4 mm, c=0.05 mm, and d=12.5 mm.

(15) The isolation walls 9 are a thin sheet of metal material; the ground plane 4 is a thin sheet of metal material, and the isolation walls 9 are connected to the upper surface of the ground plane 4, and then connected to the radiation patches 2 to form a loop structure; the short-circuit line 6 is a thin sheet of metal material, an upper end of the short-circuit line 6 is connected to the radiation patch 2, and a lower end of the short-circuit line 6 is connected to the ground plane 4; the open-circuit line 7 is a thin sheet of metal material, and is connected to an upper end of a balanced end 81 of the hyperbolic microstrip balun feeder 8; the hyperbolic microstrip balun feeder 8 is a thin metal material, and an upper part of an unbalanced end 82 of the hyperbolic microstrip balun feeder 8 is connected to the radiation patch 2; and the open-circuit line 7 is attached to the front surface of the vertical dielectric substrate 5, and the short-circuit line 6 serves as a radiation ground for the open-circuit line 7.

(16) The entire impedance matching process intends to reduce a reactance value, thereby radiating more energy, and finally match a resistance value. The impedance matching of a microstrip ultra-wideband antenna includes four steps:

(17) step 1: performing impedance simulation after the isolation walls 9 are placed between the radiation patches 2 and the ground plane 4;

(18) step 2: further optimizing an impedance of the antenna considering that an impedance characteristic of the short-circuit line 6 between both ends of a center frequency is exactly opposite to that between both ends of a resonance frequency of the antenna;

(19) step 3: further optimizing a reactance of the antenna considering that an impedance characteristic of the open-circuit line 7 between both ends of the center frequency is exactly opposite to that between both ends of the resonance frequency of the antenna; and

(20) step 4: continuously adjusting parameters of the hyperbolic microstrip balun based on a combination of an impedance characteristic of the balance-nonbalance hyperbolic microstrip balun with that of the antenna, to achieve an ideal antenna impedance finally.

(21) As shown in FIG. 4a and FIG. 4b, for the reactance of the antenna, there is only one resonant frequency at high frequencies when the isolation walls 9 are applied, but this resonant frequency does not fluctuate much. Therefore, the resonant frequency is set as a resonant frequency of the short-circuit line 6, and ¼ wavelength of the short-circuit line 6 can be calculated. Through continuous simulation, it is found that an actual resonant frequency of the short-circuit line 6 is higher than an assumed resonant frequency of the short-circuit line 6. After the isolation walls 9 and the actually used short-circuit line 6 are applied to the antenna, the resonant frequency moves to a low frequency.

(22) As shown in FIG. 5a and FIG. 5b, two resonant frequencies appear in the simulation result after the antenna is connected in parallel to the short-circuit line 6. When the frequency of the antenna is below the first resonant frequency, the antenna is inductive (with a value close to 200). When the frequency of the antenna is between the first resonant frequency and the second resonant frequency, the antenna is capacitive (with a value close to 20). In this case, the antenna is connected in series to the open-circuit line 7, so that the antenna shows a balance of inductance and capacitance around the first resonant frequency. First, it is assumed that the first resonant frequency is a resonant frequency of the open-circuit line 7, and then ¼ wavelength of the open-circuit line 7 can be calculated. Through continuous simulations, an actual length of the open-circuit line 7 used by the antenna is different from a theoretical value, and the inductance and capacitance of the antenna shown near the first resonant frequency are more balanced, which is conducive to the next impedance matching.

(23) FIG. 6a and FIG. 6b show simulation results after the antenna is connected in parallel to the short-circuit line 6 and in series to the open-circuit line 7, and the hyperbolic microstrip balun is applied. FIG. 6 is also a schematic diagram of the impedance of the microstrip ultra-wideband antenna according to the present disclosure. The structure, size, and broadband range of the ultra-wideband antenna have been determined in this case. As shown in FIG. 6, after the hyperbolic microstrip balun is applied, the reactance value is matched to around 0, and the resistance value is matched to around 50 ohms, achieving an ideal situation within the entire bandwidth.

(24) FIG. 7 and FIG. 8 are radiation patterns of the antenna at frequencies of 5 GHz and 7 GHz. The radiation pattern of the antenna is an important diagram used to measure performance of the antenna, and some parameters of the antenna can be observed from the radiation pattern. As shown in FIG. 7 and FIG. 8, there is no large distortion in the far field, indicating that the performance of the antenna is still good and a matching circuit has implemented a balance-nonbalance conversion.

(25) FIG. 9 shows a VSWR of the antenna. The VSWR is also an important parameter to measure the performance of the antenna. The closer the value of the VSWR to 1, the more desirable. Herein, the VSWR is an important indicator to measure the quality of impedance matching. As shown in FIG. 9, the VSWR is less than 2.1, and the VSWR is greater than 2 and less than 2.1 only in a band of 7.3 GHz to 8.1 GHz. Most ideally, the VSWR of the antenna is less than 2. Therefore, the antenna according to the present disclosure can basically meet the antenna requirements.

(26) Table 1 shows the comparison of scanning blind spots of the antenna with and without the isolation walls 9. According to Table 1, after the isolation walls 9 are applied, all scanning blind spots are removed out of the band, achieving a wider scanning angle in the band and a better performance.

(27) TABLE-US-00001 TABLE 1 Scanning blind spots at different angles on plane E Blind spot (with Blind spot (without Scanning angle metal walls) Grating lobe metal walls)  0° none none none  15° none 10.0 GHz  none −15° none 10.0 GHz  none  30° none 8.6 GHz 4.2 GHz −30° none 8.6 GHz none  45° none 7.7 GHz 4.9 GHz −45° none 7.7 GHz 4.9 GHz  60° none 7.0 GHz 6.0 GHz −60° none 7.0 GHz 5.9 GHz

(28) The above descriptions are merely preferred embodiments of the present disclosure, and are not intended to limit the present disclosure. Any modification, equivalent substitution and improvement without departing from the spirit and principle of the present disclosure shall be included within the scope of the present disclosure.