CN101286592A - Broadband Circular Polarization Wide Beam Multimode Satellite Navigation Terminal Antenna - Google Patents

Abstract

The invention discloses a wide-band circular polarization wide-beam multi-mode satellite navigation terminal antenna used in occasions requiring high broadband characteristics and circular polarization characteristics, which is composed of two parts: an antenna body and a feed network. The antenna body includes a radome (1), a dielectric support, a metal radiation patch (2), four L-shaped metal feed probes (3) and a metal reflector (4); the feed network includes a microstrip divided into four Power-dividing phase-shifting network (5) and metal shielding box; four L-shaped metal feeding probes (3) of the antenna body and the microstrip power-dividing phase-shifting network (5) of the antenna feeding network are electrically connected together through metal . The antenna of the invention can make the relative bandwidth of the microstrip antenna reach more than 40%. At the same time, due to the use of the medium-embedded microstrip antenna to realize the technology, the low elevation gain of the microstrip antenna is greatly improved. The 5° elevation gain of the antenna of the present invention is greater than -5dBi, and has good mechanical characteristics and temperature characteristics.

Description

Broadband Circular Polarization Wide Beam Multimode Satellite Navigation Terminal Antenna

technical field

The invention relates to antenna technology in the field of wireless communication, in particular to occasions such as multi-mode satellite navigation terminals and the like that have high requirements on broadband characteristics and circular polarization characteristics.

Background technique

Usually satellite navigation antenna terminal (user) antennas are single-frequency, dual-frequency or triple-frequency, and they are all aimed at a single satellite navigation system, such as foreign GPS, GLONASS, GALILEO and my country's Beidou-1 and Beidou-2. The disadvantage of this type of antenna is that it cannot receive all navigation signals at the same time, and cannot meet the needs of multi-mode navigation reception. However, in practical applications, users need to select one or more navigation signals of the above-mentioned different satellite navigation systems according to actual needs, and need a broadband multi-mode navigation terminal antenna capable of receiving multiple modes of navigation signals at the same time.

The United States GPS has 24 satellites for global users, while my country's Beidou system and GPS satellite orbits are different, and the number is small, which requires the terminal antenna to have better low elevation gain.

After retrieval, the details closely related to the content of the patent of the present invention are as follows: Patent No.: ZL200520079254.3 "Dual Bandwidth Wide Beam Circular Polarization Antenna with Good Low Elevation Angle Performance", the disclosed antenna structure is a deformation of a monopole antenna , by increasing the parasitic part to improve the low elevation gain, but the antenna has a narrow frequency band and can only be used for dual-band work. Patent application number: 200620078410.9 "Three-band wide-beam circularly polarized antenna". Its composition structure is a three-layer structure. The topmost layer is a dipole antenna, and the bottom two layers are microstrip antennas. It is realized by the combination of these three antennas. Tri-band work, but this antenna does not mention low elevation characteristics. Patent No.: ZL 200520079197.9 "A dual-band wide-beam circularly polarized antenna with improved low-elevation angle performance". Low elevation gain. Patent No.: "Broadband Microstrip Antenna" of ZL 200420081255.7, which uses an inclined L-shaped probe to widen the bandwidth, and the relative bandwidth can reach 37%. The antenna is linearly polarized. Due to different application occasions, low elevation gain is not mentioned.

In addition, the general microstrip antenna is made by printing process, that is, the corrosion printing operation is performed on both sides of the double-sided copper-clad microwave dielectric board, and the useless copper foil is removed, and the useful part is retained. Because the copper foil is very thin (generally 17 microns or 35 microns), the copper foil is easy to peel off under the conditions of rapid temperature fusion and a wide range of changes, resulting in damage to the antenna. Moreover, the microstrip antenna realized by the printing process is generally very thin, and it is difficult to achieve good low elevation gain.

To sum up, there are no relevant literature reports on broadband multi-mode navigation terminal antennas that can simultaneously receive multiple modes of navigation signals.

Contents of the invention

The technical solution problem of the present invention is: provide a kind of relative bandwidth greater than 40%, can cover all satellite navigation signals, circular polarization axis ratio is less than 1.5dB in the broadband range, improve the low elevation angle gain of antenna, can receive all navigation signals Broadband circular polarization wide beam multi-mode satellite navigation terminal antenna.

The technical solution of the present invention is: a broadband circularly polarized wide beam multi-mode satellite navigation terminal antenna, which consists of two parts: a feeding network and an antenna body, and the antenna body includes a radome, a dielectric support, a metal radiation patch, four L Type metal feeding probe and metal reflector; L-shaped metal feeding probe is embedded in the dielectric support, and the metal radiation patch is embedded in the groove above the dielectric support; the dielectric support and the external radome are connected as a whole; the feed network Including microstrip power division phase-shifting network and metal shielding box, the microstrip power division phase-shifting network adopts a microstrip power division phase-shifting network divided into four, and the four feeding points have a phase difference of 90°; the metal shielding box is located on the antenna body Under the metal reflector, the microstrip power division phase-shifting network is installed in the metal shielding box, and the SMA connector is installed at the network output port; the four L-shaped metal feed probes of the antenna body and the microstrip power division of the antenna feed network The phase-shifting network is electrically connected together through metal.

The same dielectric material is used for the radome and the dielectric support, and the range of relative permittivity ε _r of the dielectric material is 1<ε _r <20.

The radome and the dielectric support are designed as a whole.

The metal radiation patch is circular, and its radius $r=\frac{8.794}{f\sqrt{{\mathrm{\&epsiv;}}_r}},$ Where f is the operating frequency of the antenna in GHz, ε _r is the relative permittivity of the dielectric support, and the unit of r is cm.

The metal radiation patch is a square with a side length of $a=\frac{c}{2f\sqrt{{\mathrm{\&epsiv;}}_r}},$ c is the speed of light in free space, f is the operating frequency of the antenna in GHz, ε _r is the relative permittivity of the dielectric support, and the unit of side length a is cm.

The metal shielding box and the antenna metal reflection plate are designed as a whole, and the upper wall of the metal shielding box serves as the antenna metal reflection plate, which reduces the volume of the antenna.

Compared with the prior art, the present invention has the following advantages:

1. Due to the adoption of the new L-shaped probe feeding technology, the antenna of the present invention can greatly widen the bandwidth of the microstrip antenna, so that the relative bandwidth can reach more than 40%. The inherent disadvantage of the microstrip antenna is a narrow frequency band, generally less than 5% of the relative bandwidth. In order to widen the bandwidth of the microstrip antenna, this antenna adopts the L-shaped probe feeding technology, because the common feeding probe behaves as a capacitor, and the inductance of the feeding probe can be increased by L-shaped loading, so by optimizing the L-shaped probe The size of the antenna makes the relative bandwidth of the antenna wider.

2. Since the present invention adopts the microstrip antenna technology embedded in the medium, the low elevation gain of the microstrip antenna is greatly improved, and the 5° elevation gain of the antenna is greater than -5dBi. At the same time, it has good mechanical properties and temperature characteristics. The microstrip antenna pattern itself has the characteristics of hemispherical and wide beam. The antenna of the present invention nests the metal radiation patch in the supporting medium. By optimizing the size of the metal patch and the medium, the beam of the microstrip antenna can be made wider. This results in good low elevation gain.

3. The present invention adopts the four-point feed technology to reasonably control the amplitude and phase imbalance of the four feed points of the feed network, so that the antenna has good circular polarization characteristics, and the main working angle of the antenna in the frequency band is circular pole Shaft ratio AR<3dB. The four L-shaped feeding probes are symmetrically distributed, which ensures the omnidirectionality of the antenna azimuth pattern and has a small out-of-roundness.

4. The broadband characteristics of the antenna of the present invention can be obtained after the antenna is assembled, the structure is simple, no debugging is required, and it has good consistency.

Description of drawings

Fig. 1 is a structural representation of the present invention;

Fig. 2 is a side view of the present invention;

Fig. 3 is a feed network structural diagram of the present invention;

Fig. 4 is standing wave ratio (VSWR) bandwidth test figure of the present invention;

Fig. 5 is the direction diagram and gain design diagram of the present invention.

Detailed ways

The present invention will be further described below in conjunction with accompanying drawing.

As shown in Figures 1, 2 and 3, the wide-band circularly polarized wide-beam multi-mode satellite navigation terminal antenna of the present invention includes two parts: the envelope antenna body and the feed network.

The antenna body includes a radome and a dielectric support 1 , a metal radiation patch 2 , an L-shaped metal feeding probe 3 and a metal reflector 4 . In this embodiment, the radome and the dielectric support 1 are designed in an integrated manner, and both are made of the same dielectric material. The dielectric material is mainly concerned with the environmental requirements of its work, such as ambient temperature, vibration requirements, etc. The most important thing is its electrical parameter relative permittivity ε _r , the selection range is 1<ε _r <20, 1 is the theoretical minimum value of free space , if the relative permittivity is greater than 20, the loss increases, resulting in a decrease in the antenna radiation efficiency, which in turn reduces the antenna gain. The relative permittivity ε _r of the material selected in this embodiment is 3.15.

By drilling a hole inside the medium support 1, the vertical part of the L-shaped metal probe 3 is embedded therein, and then a groove is made on the medium support 1, and the horizontal part of the L-shaped metal probe 3 is embedded, and the vertical part and the horizontal part are welded and connected .

A circular groove is opened on the dielectric support 1, and the metal radiation patch 2 is embedded. The specific process is: set the 5° elevation gain as the optimization target, first keep the size of the metal patch unchanged, change the thickness and side length of the medium respectively, observe the change of gain, and take the thickness and side length corresponding to the maximum gain as the design result. The 5° elevation gain of this antenna is greater than -5dBi.

Finally, the radome and the dielectric support 1 are connected as a whole, and the installation of the antenna body is completed.

The main parameter of the L-shaped metal probe 3 is the position of its feed point. In this embodiment, the feed point is located at a position with an impedance of 50 ohms. The specific size selection and optimization of the height of the vertical part and the height of the horizontal part of the L-shaped metal probe 3 can be determined according to the designed frequency and the selected material test.

The size of the metal radiation patch 2 is mainly determined by the working frequency and the dielectric constant of the antenna. In this embodiment, the metal radiation patch 2 is circular, and its radius is:

$\mathrm{<span\; class="notranslate">\; r</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 8.794</span>}}{\mathrm{<span\; class="notranslate">\; f</span>}\sqrt{{\mathrm{<span\; class="notranslate">\; \&epsiv;</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}}}$

Wherein, the working center frequency of the antenna is f=1.5GHz, and r=3.3cm.

The feeding network of the present invention includes a microstrip power-dividing phase-shifting network 5 and a metal shielding box 4. The microstrip power-dividing phase-shifting network 5 adopts a microstrip power-dividing phase-shifting network divided into four, and the phases of the four feeding points are different in turn. 90°, that is, the relative phases of the four feeding points are 0°, 90°, 180°, and 270° respectively. In this embodiment, the metal shielding box and the antenna metal reflector 4 are integrated, and the upper wall of the metal shielding box serves as the antenna reflector, thereby reducing the volume of the antenna. Install the microstrip power-dividing phase-shifting network 5 in the metal shielding box, and install the SMA connector at the total output port of the network, and then the installation of the antenna feeding network is completed.

The function of the metal reflector is to suppress the radiation of the antenna rear lobe and increase the forward gain. In theory, the larger the size of the metal reflector, the better, but in practice, its size is generally determined according to practical constraints (such as installation size restrictions).

The four L-shaped metal feeding probes 3 of the antenna body and the microstrip power division phase-shifting network 5 of the antenna feeding network are electrically connected together through metal. The structural parts of the two are connected as a whole by screws, and the whole antenna is installed to form a wide-band, circularly polarized, wide-beam multi-mode satellite navigation terminal antenna.

Fig. 4 is the VSWR bandwidth test chart of the present embodiment, the bandwidth of its VSWR<2) is 1.02GHz～1.7GHz, and the relative bandwidth is greater than 50%, which can satisfy the application of all current and future satellite navigation systems need.

FIG. 5 is the main plane pattern of this embodiment, which describes the relationship between the gain and the angle. It can be seen that the gain of the antenna at a 5° elevation angle is greater than -5dBi.

Claims (7)

1. The broadband circularly polarized wide-beam multi-mode satellite navigation terminal antenna is characterized in that it consists of two parts: a feed network and an antenna body, and the antenna body includes a radome, a dielectric support (1), and a metal radiation patch (2) , four L-shaped metal feed probes (3) and metal reflectors (4); the four L-shaped metal feed probes (3) are sequentially embedded in the dielectric support (1) with a difference of 90°, and the metal radiation patch ( 2) Embedded in the slot in the upper middle of the dielectric support (1); the feed network includes a microstrip power-splitting phase-shifting network (5) and a metal shielding box, and the microstrip power-splitting phase-shifting network (5) adopts a microstrip divided into four Power-dividing phase-shifting network, the phase difference of the four feeding points is 90°; the metal shielding box is located under the metal reflector (4) of the antenna body, and the microstrip power-dividing phase-shifting network (5) is installed in the metal shielding box. SMA connectors are installed at the total output port of the network; four L-shaped metal feed probes (3) of the antenna body and the microstrip power-dividing phase-shifting network (5) are electrically connected together through metal. 2, according to the broadband circular polarization wide-beam multimode satellite navigation terminal antenna of claim 1, it is characterized in that: described radome and dielectric support (1) adopt identical dielectric material, the relative permittivity ε _r of dielectric material The selection range is 1< _εr <20. 3. The broadband circularly polarized wide-beam multi-mode satellite navigation terminal antenna according to claim 1 or 2, characterized in that: the radome and the dielectric support (1) are designed as a whole. 4. The broadband circularly polarized wide-beam multi-mode satellite navigation terminal antenna according to claim 1 or 2, characterized in that: the metal radiation patch (2) is circular, and its radius $r=\frac{8.794}{f\sqrt{{\mathrm{\&epsiv;}}_r}},$ Where f is the operating frequency of the antenna in GHz, and _εr is the relative permittivity of the dielectric support (1). 5. The broadband circularly polarized wide-beam multi-mode satellite navigation terminal antenna according to claim 1, characterized in that: the metal radiation patch (2) is a square with a side length of $a=\frac{c}{2f\sqrt{{\mathrm{\&epsiv;}}_r}},$ where c is the speed of light in free space, f is the operating frequency of the antenna in GHz, and _εr is the relative permittivity of the dielectric support (1). 6. The broadband circularly polarized wide-beam multi-mode satellite navigation terminal antenna according to claim 1, characterized in that: the feeding point of the L-shaped metal probe (3) is located at a position with an impedance of 50 ohms. 7. The broadband circularly polarized wide-beam multi-mode satellite navigation terminal antenna according to claim 1, characterized in that: the metal shielding box and the metal reflector (4) are designed as a whole, and the upper wall of the metal shielding box serves as the antenna metal The reflector reduces the size of the antenna.

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