CN102163767B - A Coplanar Integrated GPS/ITS Antenna - Google Patents

Abstract

The invention provides a coplanar integrated GPS/ITS antenna, which is oriented to the application of the Global Positioning System (GPS) and the Intelligent Transportation System (ITS), and meets the requirements of simple manufacturing process, low cost and low profile of the terminal antenna. The antenna is confined within a spatial volume of 55 x 55 x 3 mm ³ , ideal for placement on top of traffic equipment. The coplanar integrated GPS/ITS multifunctional antenna can not only generate a right-handed circularly polarized signal that satisfies the GPS L2 frequency band (1.227GHz), but also provide a vertically polarized omnidirectional pattern covering the 5.8GHz frequency band of the ITS service. In the implementation, only ordinary printed circuit double-layer boards are used, the manufacturing process is simple, the cost is low, and all the structures of the antenna are coplanar, which is very suitable for placement on the top of the transportation equipment.

Description

A Coplanar Integrated GPS/ITS Antenna

technical field

The invention belongs to the technical field of terminal antennas of wireless communication technology, in particular to a coplanar integrated GPS/ITS antenna.

Background technique

With the rapid development of wireless communication technology, various communication services in modern life have become interrelated and complementary. In order to improve the effective utilization of space resources of the terminal antenna, the user terminal needs to integrate multiple services on the same antenna. Since different communication services have different requirements on pattern and polarization, traditional single-port multi-frequency antennas cannot meet the requirements of multi-functional antennas. A typical example is the vehicle-mounted multifunction antenna, which produces both a circularly polarized pattern corresponding to a satellite positioning system and a vertically polarized omnidirectional pattern corresponding to a land mobile communication service. This is because many land mobile communications services require the Global Positioning System (GPS) to know where the vehicle is.

The Intelligent Transportation System (ITS) collects vehicle information on the expressway to implement traffic command and control, so as to reduce congestion time, reduce traffic accidents, facilitate travel and protect the environment. The development potential of intelligent transportation system is huge, and it will lead the reform of my country's traffic management system and model. It is an inevitable choice for my country's traffic management to become informatized, intelligent, efficient and socialized. At present, China and the United States have allocated the 5.8GHz frequency band to the short-range communication service (DSRCS) of ITS. In the UK, the unlicensed 5.470-5.725GHz frequency band of global wireless access technology (WiMAX) is also considered as a possible candidate frequency band for ITS. According to the standards of the Institute of Electrical and Electronics Engineers (IEEE), ITS services must be timed by the Global Positioning System (GPS), thus obtaining synchronized clocks. Therefore, the automotive electronics market has an urgent demand for the research and development of GSP/ITS multifunctional antennas with simple and compact structure and low cost.

GPS Global Positioning System is the second generation of satellite navigation system in the United States, which is widely used in consumer electronics products, such as mobile phones and personal data assistant (PDA) devices. Car GSP navigation system has developed rapidly in recent years and has become a standard equipment in the automotive market. The most important receiving part in the GSP user terminal is the GPS antenna, and its performance will directly determine the transceiver performance of the GPS terminal. Traditional GPS antennas often adopt a four-walled helical structure, with four helical metal arms extending out as antennas. The four-wall helical antenna is bulky and has a high profile, which is not suitable for use in vehicle antennas, nor is it conducive to integration with ITS antennas. Therefore, a technical problem that urgently needs to be solved by those skilled in the art is how to innovatively propose a new GPS/ITS multifunctional antenna to meet the requirements of vehicle-mounted ITS services.

Contents of the invention

The technical problem to be solved by the present invention is to provide a coplanar integrated GPS/ITS antenna, which is oriented to the application of Global Positioning System (GPS) and Intelligent Transportation System (ITS) at the same time, and meets the requirements of simple manufacturing process, low cost and low profile of the terminal antenna. requirements.

In order to solve the above problems, the present invention discloses a coplanar integrated GPS/ITS antenna, including a square microwave dielectric substrate (1), a square ring patch (2), a square patch (3), a floor (4), micro With feed (5), short-circuit through hole (6), center feed probe (7), GPS signal feed port (8) and ITS signal feed port (9), the circular microwave dielectric substrate ( 1) It is made of polytetrafluoroethylene material, the dielectric constant is 2.65, the loss tangent angle is 0.002, the thickness is 3mm, the size is 100mm×100mm, and the thickness of both sides of the substrate is 0.07mm;

The terminal of the microstrip feeder (5) is short-circuit connected to the floor (4) through the short-circuit through hole (6).

Preferably, the square patch (3) is located at the center of the upper surface of the microwave dielectric substrate (1), and is evenly surrounded by the square ring patch (2), the square patch (3) and the square ring patch (2) There are gaps etched between them.

Preferably, the terminal of the microstrip feeder (5) is short-circuit connected to the floor (4) through a short-circuit through hole (6).

Preferably, one end of the ITS signal feeding port (9) is connected to the square patch (2) on the upper surface through the central feeding probe (7), and the other end is connected to the floor (4).

Preferably, the integration of the GPS antenna and the ITS antenna is realized by using a common printed circuit double-layer board, and all structures of the antenna are coplanar.

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

The invention provides a coplanar integrated GPS/ITS antenna, which is oriented to the application of the Global Positioning System (GPS) and the Intelligent Transportation System (ITS), and meets the requirements of simple manufacturing process, low cost and low profile of the terminal antenna. The antenna is confined within a spatial volume of 55 x 55 x 3 mm ³ , ideal for placement on top of traffic equipment. The coplanar integrated GPS/ITS multifunctional antenna can not only generate a right-hand circularly polarized signal that meets the GPS L2 frequency band (1.227GHz), but also provide a vertically polarized omnidirectional pattern covering the ITS service 5.8GHz frequency band. In the implementation, only ordinary printed circuit double-layer boards are used, the manufacturing process is simple, the cost is low, and all the structures of the antenna are coplanar, which is very suitable for placement on the top of the transportation equipment.

Simultaneously, the design method of the coplanar integrated GPS/ITS multifunctional antenna provided by the present invention can not only be used in GPS/ITS services, but also can be applied to the design of other multifunctional antennas for mobile communications, and the correspondingly adjust the The size of the antenna.

In addition, the invention provides good support for the promotion and industrialization of ITS services, promotes the development of ITS antenna technology, and realizes the miniaturized, coplanar and easy-to-install multifunctional vehicle antenna.

Description of drawings

Fig. 1 is the three-dimensional diagram schematic diagram of the GPS/ITS antenna of coplanar integration provided by the present invention;

Fig. 2 is the A-direction view of Fig. 1, that is, the top view;

Fig. 3 is the B direction view of Fig. 1, that is, the central sectional view;

Fig. 4 is a dimensional drawing of an implementation example of the A and B direction view structure in Fig. 1, and the units are millimeters (mm);

Fig. 5 is a measurement diagram of the reflection coefficient (S11) and axial ratio coefficient of the GPS feed port of the coplanar integrated GPS/ITS multifunctional antenna of the implementation example in Fig. 4;

Fig. 6 is a measurement diagram of the reflection coefficient (S22) of the ITS feed port of the coplanar integrated GPS/ITS multifunctional antenna of the implementation example of Fig. 4;

Figure 7 is a measurement diagram of the port isolation of the coplanar integrated GPS/ITS multifunctional antenna of the implementation example of Figure 4: (a) the port isolation of the GPS L2 frequency band; (b) the port isolation of the ITS frequency band;

Fig. 8 is the power gain pattern when the GPS feeding port of the coplanar integrated GPS/ITS multifunctional antenna of the implementation example of Fig. 4 works at 1227MHz: (--: the power gain pattern of the right-handed circular polarization component; ...: Power gain pattern of left-handed circular polarization component): (a): X-Z plane power gain pattern; (b): Y-Z plane power gain pattern;

Fig. 9 is the power gain pattern when the ITS feeding port of the coplanar integrated GPS/ITS multifunctional antenna of the implementation example of Fig. 4 works at 5800MHz: ( : θ component power gain pattern; : Component power gain pattern): (a): XZ plane power gain pattern; (b): YZ plane power gain pattern.

Detailed ways

In order to make the above objects, features and advantages of the present invention more comprehensible, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

Referring to Fig. 1, Fig. 2 and Fig. 3, a kind of coplanar integrated GPS/ITS antenna of the present invention is shown, and described antenna specifically comprises:

Square microwave dielectric substrate 1, square ring patch 2, square patch 3, floor 4, microstrip feed 5, short-circuit via 6, center feed probe 7, GPS signal feed port 8, and ITS signal feed port 9;

The square microwave dielectric substrate 1 includes two layers of the upper surface and the lower surface; the square ring patch 2, the square patch 3, and the microstrip feed 5 are processed on the upper surface of the microwave dielectric substrate 1 by etching; the microwave dielectric substrate 1 The lower surface is all metal, namely the floor 4;

The terminal of the microstrip feeder 5 is short-circuited to the floor 4 through the short-circuit through hole 6;

One end of the GPS signal feed port 8 is connected to the microstrip feeder 5, and the other end is connected to the floor 4;

One end of the ITS signal feed port 9 is connected to the square patch 2 on the upper surface through the central feed probe 7, and the other end is connected to the floor 4;

The realization idea of the technical solution of the present invention: to realize the GPS/ITS multifunctional antenna, it is necessary to obtain the right-handed circular polarization pattern covering the GPS frequency band and the vertical polarization omnidirectional pattern covering the ITS frequency band. The design method of the novel coplanar capacitive coupling single-port excitation of the present invention realizes circular polarization, and the traveling wave mode of the square ring patch 2 is excited by the microstrip feeder 5 coupling feeding mode of the terminal short circuit, thereby obtaining the GPS right For circularly polarized signals, its working mode is approximately considered as a directional coupler. In order to obtain a vertically polarized omnidirectional pattern covering the ITS frequency band, the square patch 3 is excited through the central feeding probe 7 to make it work in the TM02 mode. The TM02 mode is the radial line mode of the patch antenna, and the pattern is similar to that of a monopole, which is the required vertically polarized omnidirectional pattern. However, the TM02 mode is a high-order mode with high Q value and narrow impedance bandwidth, which cannot fully cover the ITS frequency band. In order to widen the bandwidth of the ITS antenna, the square ring patch 2 is looped on the square patch 3 . The square patch 3 is coupled with the square ring patch 2 through the slot, so that the square ring patch 2 also works in the TM02 mode, thereby obtaining double resonance in the ITS frequency band, thereby enhancing the bandwidth of the ITS antenna.

The structure is specified as follows:

To realize the GPS right-handed circularly polarized antenna, first design the size of the square ring patch 2 according to the GPS L2 frequency band (1.227GHz). The average circumference of the square ring patch 2 is approximately equal to the equivalent working wavelength of a GPS L2 frequency band ; Secondly, realize the impedance matching of the GPS feeding port 8 by adjusting the width of the microstrip feeder 5 and the distance from the square ring patch; finally adjust the axial ratio coefficient of its pattern by adjusting the length of the microstrip feeder 5;

To realize the ITS vertically polarized omnidirectional antenna, firstly, the size of the square ring patch 3 is designed according to the ITS frequency band (5.8GHz); secondly, the central feeding probe 7 is used to excite it at the center of the square patch, and by changing The diameter of the central feed probe 7 realizes the impedance matching of the ITS feed port 9; then, adjust the size of the gap between the square patch 3 and the square ring patch to change their coupling strength to achieve double resonance in the ITS frequency band, Thereby widening the bandwidth of the ITS frequency band.

Microwave dielectric substrate 1 is made of low-cost polytetrafluoroethylene material, with a dielectric constant of 2.65, a loss tangent angle of 0.002, a thickness of 3mm, and a size of 100mm×100mm; both the GPS feed port and the ITS feed port use SMA heads. The characteristic impedance is 50Ω; the dimensions of other parts are shown in Figure 4, and the units are millimeters (mm).

The test results of the reflection coefficient (S11) and axial ratio coefficient of the GPS feed port of the coplanar integrated GPS/ITS multifunctional antenna of the implementation example shown in Figure 4 are shown in Figure 5. The echo of the GPS antenna The bandwidth of loss S11<-10dB is 1210-1238MHz (29MHz), the axial ratio bandwidth is 9MHz, and the center frequency is 1227MHz, which can cover the GPS L2 frequency band (1.227GHz).

The test results of the reflection coefficient (S22) of the ITS feed port of the coplanar integrated GPS/ITS multifunctional antenna made in the dimensions shown in Figure 4 are shown in Figure 6, and the return loss of the ITS antenna S11<- The 10dB bandwidth is 5550-6570MHz (1020MHz, 17.5%).

The test result of the port isolation of the coplanar integrated GPS/ITS multifunctional antenna of the implementation example in Fig. 4 is shown in Fig. 7, in the GPS working frequency band and the ITS working frequency band, the GPS feed port 8 and the ITS feed port 9 The isolation is higher than 20dB.

The power gain pattern when the GPS feeding port of the coplanar integrated GPS/ITS multifunctional antenna of the implementation example made with the dimensions shown in FIG. 4 works at 1227MHz is shown in FIG. 8 . In the X-Z plane and Y-Z plane, the main radiation direction of the GPS antenna points to the top, and the cross-polarization is better than 20dB within the 3dB beam bandwidth, and it has good right-handed circular polarization characteristics. In the range of GPS L2 frequency band (1.227GHz), the antenna gain is 5.4dBi.

The power gain pattern of the coplanar integrated GPS/ITS multifunctional antenna of the implementation example in FIG. 4 when the ITS feed port works at 5800 MHz is shown in FIG. 9 . It can be seen that the ITS antenna is the radiation zero point in the top direction, the main lobe direction is 40°, has a good vertical polarization omnidirectional pattern, and the cross polarization is better than 20dB within the 3dB beam bandwidth. In the ITS frequency range, the antenna gain is 5.3-6.0dBi.

It can be seen that the GPS/ITS multifunctional antenna integrated with coplanar antennas has good impedance matching, that is, it can generate a right-handed circularly polarized signal that meets the GPS L2 frequency band (1.227GHz), and can also provide coverage for ITS services in the 5.8GHz frequency band The vertical polarization is omnidirectional; at the same time, the antenna only uses an ordinary printed circuit double-layer board, the manufacturing process is simple, the cost is low, and all the structures of the antenna are coplanar, which is very suitable for placement on the top of the traffic equipment. The invention provides good support for the promotion and industrialization of the ITS service, promotes the development of the ITS antenna technology, and realizes the miniaturized, coplanar and easy-to-install multifunctional vehicle-mounted antenna.

The design method of the coplanar integrated GPS/ITS multifunctional antenna provided by the present invention can not only be used in GPS/ITS services, but also can be applied to the design of other multifunctional antennas for mobile communications, and the antenna can be adjusted accordingly according to the service operating frequency. size. The invention has simple manufacturing process and low cost, realizes the coplanar integration of the GPS antenna and the ITS antenna, meets the structural requirements of low profile, coplanar and easy installation, has good antenna stability, and has high practical value.

Above, a kind of coplanar integrated GPS/ITS antenna provided by the present invention has been introduced in detail. In this paper, specific examples are used to illustrate the principle and implementation of the present invention. The description of the above embodiments is only used to help understand the present invention. The method of the invention and its core idea; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation and scope of application. In summary, the content of this specification should not be understood To limit the present invention.

Claims (1)

1. A coplanar integrated GPS/ITS antenna, comprising a square microwave dielectric substrate (1), a square ring patch (2), a square patch (3), a floor (4), a microstrip feed (5), The short-circuit through hole (6), the central feeding probe (7), the GPS signal feeding port (8) and the ITS signal feeding port (9), are characterized in that: The square patch (3) is located at the center of the upper surface of the microwave dielectric substrate (1), and is evenly surrounded by the square ring patch (2). There are gaps in the erosion; The square microwave dielectric substrate (1) is made of polytetrafluoroethylene material, the dielectric constant is 2.65, the loss tangent angle is 0.002, the thickness is 3mm, the size is 100mm×100mm, and the thickness of both sides of the substrate is 0.07mm. ; The size of the square ring patch (2) is 55mm * 55mm, the size of the square patch (3) is 34mm * 34mm, the square ring patch (2) and the square patch (3) The gap is 1 mm, the length of the microstrip feed (5) is 63 mm, and the width is 3 mm, the gap between the microstrip feed (5) and the square patch (3) is 1.1 mm, and the center feed The diameter of electric probe (7) is 1.3mm; The terminal of the microstrip feeder (5) is short-circuited with the floor (4) through a short-circuit through hole (6); One end of the GPS signal feed port (8) is connected to the microstrip feeder (5) on the upper surface, and the other end is connected to the floor (4); One end of the ITS signal feeding port (9) is connected to the square patch (2) on the upper surface through the central feeding probe (7), and the other end is connected to the floor (4); Both the GPS signal feed port (8) and the ITS signal feed port (9) use SMA heads with a characteristic impedance of 50Ω; The integration of the GPS antenna and the ITS antenna is realized by using a common printed circuit double-layer board, and the square ring patch (2), the square patch (3) and the microstrip feed (5) are coplanar.