TWI451633B - Antenna - Google Patents

Description

antenna

The present invention relates to antenna technology for communication terminals, and more particularly to an antenna.

The use of multiple antenna systems on a notebook computer requires the installation of multiple antenna units at the same time, but the spatial position at which the antenna units can be mounted is limited, and there must be sufficient spacing between the antenna elements to reduce coupling, so each antenna unit can occupy The space has to shrink. In general, notebook antennas are mounted on the edge of the machine and are elongated. The antenna unit size is usually required to be about a quarter of a wavelength, so that in the 900 MHz GSM band, the antenna unit is about 80 to 90 mm. The antenna unit spacing is greater than one-third of the wavelength, or 110 mm, and it takes about 270 mm to install two antenna elements. Considering that other frequency bands, such as 2.4 GHz WLAN antennas, are required, the notebook computer needs more than 300 mm of side length, which is in contradiction with the trend of miniaturization of notebook computers.

At present, the lumped parameter loading is used to reduce the antenna size, or the antenna size is reduced by folding the dipole, or the antenna size is reduced by slotting and slitting the radiator. However, at least the following problems exist in the prior art:

Capacitance or inductance is used for loading. Although the antenna size can be reduced, the loss of the device at the mobile communication frequency (above 800 MHz) is relatively large, resulting in a lower actual antenna gain. The folded dipole can reduce the antenna size, but in the notebook type. The edge of the computer uses a folded dipole. Because the radiator is close to the metal frame of the notebook computer, the radiation space is very limited, the radiation impedance is very low, the impedance matching is not easy, and the antenna bandwidth is narrow. Although the slotted slit can reduce the antenna size, But on the notebook computer, the antenna needs to be installed on the edge of the screen, and often there is not enough space to slot the slit.

In view of this, the present invention provides an antenna capable of reducing the antenna resonance frequency and reducing the antenna size.

In order to achieve the above object, a technical solution of the present invention is implemented as follows: an antenna including a reference ground, a first radiating branch, and a second radiating branch; The reference ground includes a first grounding point and a second grounding point; the first radiating branch is connected to the reference ground through the first grounding point; and the second radiating branch passes the second ground a grounding point is connected to the reference ground; wherein a gap is formed between the first radiant branch and the second radiant branch, and a distributed capacitance is formed through the slot coupling for coupling a signal; the second radiant branch is used for A connection point of one end of the coupled signal and the RF feed line is a feed point, and the feed point is located between the first ground point and the second ground point.

Preferably, the first radiant branch is a coplanar waveguide coupled radiant branch.

The second radiating branch is a planar inverted-F antenna radiating branch.

The non-ground ends of the first radiant branch and the second radiant branch extend toward the same side or the opposite side.

The RF feed line is any one of a coaxial line, a microstrip line, a strip line, or a waveguide.

The coplanar waveguide coupling radiation branch is a polygonal metal sheet or a three-dimensional structure formed by folding a planar metal sheet.

The planar inverted-F antenna radiating branch is a T-shaped metal piece or a three-dimensional structure formed by folding a planar metal piece.

The reference ground is a planar metal sheet or a three-dimensional structure formed by folding a flat metal sheet.

The antenna provided by the invention has the following advantages: since the co-planar waveguide coupling structure is adopted between the antenna resonance branches, equivalent to the capacitive loading, and the field of the distributed capacitance is mainly concentrated in the air, the lumping is overcome. The power loss caused by the resistance of the device after the parameter capacitor is loaded, thereby reducing the antenna resonance frequency and reducing the antenna size.

The invention adopts the coupling between the antenna radiation branches to form a capacitor, thereby reducing the components and the isolation space, reducing the size of the antenna, and making the antenna more suitable for the size requirements of the portable device.

1 is a schematic structural view of a first embodiment of the present invention. As shown in FIG. 1, a coplanar waveguide coupled dual-frequency antenna is coupled with a ground plane 1, a coplanar waveguide, a radiating branch 2, and a planar inverted-F antenna (PIFA, Planar Inverted F Antenna). ) radiant branches 3 constitute. Wherein, the reference ground 1 is a plane metal of a narrow strip structure; the coplanar waveguide coupling radiant branch 2 is a strip-shaped narrow strip of metal strip, one end is parallel to the reference ground 1, and the other end is connected to the reference ground 1 as a ground point A; PIFA Radiation Branch 3 is T The metal piece is connected to the reference ground 1 as the grounding point B, one branch end is the feeding point C, and the other branch is the radiating branch and the end is suspended. The coplanar waveguide coupled radiation branch 2 and the PIFA radiation branch 3 have no direct electrical connection, but are fed by the slot 4 coupling to form a distributed capacitance.

The coplanar waveguide coupling structure 5 is formed by coplanar coupling of the folded portion of the coplanar waveguide coupling radiation branch 2 and the non-radiative end of the PIFA radiation branch 3, and the coplanar waveguide coupling structure 5 is connected to the reference ground 1 through a coaxial line, and the feeding point C Connect the inner conductor of the coaxial line, and connect the connection point D of the ground 1 to the outer conductor of the coaxial line. This structure is equivalent to the loading of the capacitor and can reduce the resonance frequency of the antenna. The coplanar waveguide couples the radiating branch 2 in the low frequency band (GSM 960 MHz) to resonate the PIFA radiating branch 3 in the high frequency band (DCS/PCS 1800 MHz). The entire antenna has a narrow strip structure. FIG. 2 is an effect diagram of the first embodiment. The antenna can be attached to the edge of the notebook computer case or the liquid crystal screen 6 and has a nearly omnidirectional pattern and gain.

3 is a schematic view showing a second embodiment of the present invention, in which the radiant end of the PIFA radiant branch 3 is changed to be coplanar with the coplanar waveguide coupling radiant branch 2 co-planar waveguide waveguide radiant branch 2, PIFA radiant branch 3 and coplanar waveguide The coupled radiant branches 2 are three-dimensional structures in which the planar metal sheets are folded. Thus, the length of the slit 4 is increased, so that the resonance frequency is lowered to suit different needs. Fig. 4 is an effect diagram of the embodiment. As can be seen from Fig. 4, the outer dimensions of the antenna are different as compared with the first embodiment, and the demand can be more satisfactorily satisfied.

Figure 5 is a schematic view of a third embodiment of the present invention, in which the radiating end of the coplanar waveguide coupled radiating branch 2 and the radiating end of the PIFA radiating branch 3 are extended toward the side of the PIFA radiating branch 3, which also increases the length of the slit 4, in addition The reference ground 1 can be designed as a three-dimensional structure in which flat metal sheets are folded to suit different space requirements.

6 is a schematic view of a fourth embodiment of the present invention, in which the radiating end of the coplanar waveguide coupling radiation branch 2 faces the radiating end of the PIFA radiation branch 3, that is, extends to the opposite side, further reducing the size of the antenna, and the gap 4 at this time The length is increased, and the resonance frequency can be increased by adjusting the width of the slit 4 to satisfy the demand. The RF feed line connecting the connection point C of the feed point C and the reference ground 1 may also be a microstrip line, a strip line or a waveguide or the like.

The return loss value measured from the feed point C by simulation test is shown in Fig. 7. At frequencies around 980 MHz and 1780 Mhz, the return loss values are only -10 dB and -20 dB, respectively, and this is GSM. The frequency band and the DCS/PCS band indicate that the performance of the present invention satisfies the requirements.

The simulation test also detected the antenna gain. The so-called antenna gain is the ratio of the power density of the signal generated by the actual antenna to the ideal radiating element at the same point in space under the condition of equal input power. The antenna gain quantitatively describes the degree to which an antenna concentrates the input power. Fig. 8 is a view showing the establishment of a coordinate system of the radiation direction of the antenna in the simulation experiment. According to the coordinate system in Fig. 8, Fig. 9 is a three-dimensional view of the antenna gain in the GSM band. The antenna has a nearly omnidirectional pattern and gain. The radiation pattern coordinate system is shown in Figure 8. The dipole axis is in the Y direction, the reference ground and the earth are in the center of the coordinate system, and the antenna unit is on the left side of the coordinate system. The average gain is about 0 dBi.

Figure 10, Figure 11, and Figure 12 show the X-Y, X-Z, and Y-Z plane views of the GSM band antenna gain, respectively, at a frequency of 980 MHz. Figure 13 is a three-dimensional view of the antenna gain in the DCS/PCS band with an average gain of approximately 0 dBi. Figure 14, Figure 15, and Figure 16 show the X-Y, X-Z, and Y-Z plane views of the GSM band antenna gain, respectively, at a frequency of 1780 MHz. Simulation experiments show that the antenna gain is above 0 dBi and has good practicability.

The foregoing is a description of the preferred embodiments of the present invention, and the present invention may be modified and modified without departing from the spirit and scope of the invention. Changes and modifications are to be covered in the scope defined by the scope of the patent application below.

1‧‧‧ reference ground

2‧‧‧coplanar waveguide coupled radiation branch

3‧‧‧PLFA radiation branch

4‧‧‧ gap

5‧‧‧Coplanar waveguide coupling structure

6‧‧‧ LCD screen

A‧‧‧ Grounding point

B‧‧‧ Grounding point

C‧‧‧Feeding point

D‧‧‧ connection point

1 is a schematic structural view of a first embodiment of the present invention; FIG. 2 is a schematic view of a first embodiment of the present invention; FIG. 3 is a schematic structural view of a second embodiment of the present invention; Figure 5 is a schematic structural view of a third embodiment of the present invention; Figure 6 is a schematic structural view of a fourth embodiment of the present invention; Figure 7 is a schematic diagram of simulation parameters of an embodiment of the present invention; Figure 9 is a three-dimensional view of the gain of the GSM band antenna according to an embodiment of the present invention; Figure 10 is an XY plane projection view of the GSM band antenna gain according to an embodiment of the present invention; Figure 11 is an XZ plane of the GSM band antenna gain according to an embodiment of the present invention. Projection view 12 is a JPEG plane antenna gain YZ plane projection view according to an embodiment of the present invention; FIG. 13 is a three-dimensional view of a DCS/PCS band antenna gain according to an embodiment of the present invention; FIG. 14 is a DCS/PCS band antenna gain XY plane according to an embodiment of the present invention; FIG. 15 is a view showing a DCS/PCS band antenna gain XZ plane projection view according to an embodiment of the present invention; FIG. 16 is a DCS/PCS band antenna gain YZ plane projection view according to an embodiment of the present invention.

1‧‧‧ reference ground

2‧‧‧coplanar waveguide coupled radiation branch

3‧‧‧PIFA radiation branch

4‧‧‧ gap

5‧‧‧Coplanar waveguide coupling structure

A‧‧‧ Grounding point

B‧‧‧ Grounding point

C‧‧‧Feeding point

D‧‧‧ connection point

Claims (6)

An antenna comprising: a reference ground, a first radiating branch and a second radiating branch; the reference ground comprising a first grounding point and a second grounding point; the first radiating branch passing the first a grounding point is connected to the reference ground; the second radiating branch is connected to the reference ground through the second grounding point, and the second radiating branch is separately formed as a planar inverted F-type antenna radiating branch; a gap is formed between the first radiant branch and the second radiant branch, and a distributed capacitance is formed through the slot coupling for coupling a signal; the second radiant branch is used for feeding a connection point of the coupled signal with the RF feed line. And an electrical point, the feeding point is located between the first grounding point and the second grounding point; and the non-grounding ends of the first radiating branch and the second radiating branch are opposite to each other and extend toward each other. The antenna of claim 1, wherein the first radiant branch is a coplanar waveguide coupled radiant branch. The antenna according to claim 1, wherein the RF feed line is any one of a coaxial line, a microstrip line, a strip line or a waveguide. The antenna according to claim 2, wherein the coplanar waveguide coupling radiation branch is a polygonal metal sheet or a three-dimensional structure formed by folding a planar metal sheet. The antenna according to claim 1, wherein the planar inverted-F antenna radiating branch is a T-shaped metal piece or a three-dimensional structure formed by folding a planar metal piece. The antenna according to claim 1, wherein the reference ground is a planar metal sheet or a three-dimensional structure formed by folding a flat metal sheet.