WO2016101136A1

WO2016101136A1 - Multiband dielectric resonance mobile phone terminal antenna

Info

Publication number: WO2016101136A1
Application number: PCT/CN2014/094634
Authority: WO
Inventors: 刘元安; 苏明; 刁一恒; 黎淑兰; 于翠屏; 吴永乐; 王卫民
Original assignee: 北京邮电大学
Priority date: 2014-12-23
Filing date: 2014-12-23
Publication date: 2016-06-30

Abstract

Disclosed is a multiband dielectric resonance mobile phone terminal antenna. The multiband dielectric resonance mobile phone terminal antenna is provided with a high dielectric constant rectangular ceramic dielectric (3) having a groove, a multi-branch monopole (4), a dielectric plate (1), a feeding microstrip line (2), a printing ground (5), and a via hole (6). The antenna structure has the innovations: the high dielectric constant rectangular dielectric is excited by using a multi-branch monopole, the electric field distribution in the dielectric is changed to make the dielectric generate multiple-mode resonance, which allows the terminal antenna to satisfy multimode multiband requirements; in addition, the groove is added to the dielectric of the present invention, the radiation area of the dielectric can be increased while the antenna weight is effectively reduced, and the radiation efficiency of the antenna is improved. The multiband dielectric resonance mobile phone terminal antenna has the characteristics of small size, light weight, simple structure, wide working frequency band, and high radiation efficiency. The present invention has low manufacturing cost, simple structure and is easy to process and integrate, can satisfy 2G, 3G and 4G communication standards at the same time, has good promotion and application prospects.

Description

Multi-band medium resonance mobile phone terminal antenna

Technical field

The invention relates to the technical field of communication antennas, in particular to a multi-band medium resonance mobile phone terminal antenna.

Background technique

With the rapid development of wireless communication technology, communication methods and communication standards are gradually increasing, frequency resources utilization is getting higher and higher, the development of the communication industry can be described as unstoppable, and terminal equipment has become the fastest developing communication product. As the key equipment of the terminal system, the antenna is an indispensable component. In the 4G era, higher standards and requirements are put forward for the terminal antenna. Various wireless communication technologies coexist, and different countries adopt different network standards to determine the mobile communication. The terminal needs to be compatible with different modes, and the mobile terminal will integrate more multimedia communication functions, which requires the multi-band antenna to complete the basic communication task through the cooperative mode. The terminal antenna not only meets the requirements of multi-band, wideband and miniaturization, but also requires higher reliability, high speed and high quality. Therefore, it is a very meaningful research work to design a miniaturized terminal antenna that can support 2G/3G and meet the popular 4G needs.

The main technologies of the traditional terminal antenna include: 1) Inverted F antenna: The structure is simple, and the bandwidth is narrow, which cannot meet the requirements of the current communication broadband multi-band. 2) Planar inverted F antenna (PIFA): It can increase the bandwidth of the antenna, but it can not meet the requirements of multiple communication bands at the same time. The profile is large and the bandwidth is greatly affected by the size of the ground.

In order to meet the requirements of multi-band miniaturization, many improved antennas have been produced on conventional antennas. 1) Single-pole excitation combined with coupling units to generate multiple frequency bands. 2) Using a conventional patch antenna in combination with media loading. Among them, the medium only serves to reduce the size of the antenna, not the main radiating element. Based on the above technologies, the existing antennas are mainly classified into two types of three-dimensional antennas and two-dimensional planar printed antennas, but the three-dimensional antennas have the defects of large size and narrow bandwidth, and it is also difficult to satisfy the antenna shape design, which is flexible and diversified, and is light in size and thin. Requirements. Although the two-dimensional planar printed antenna realizes the thinning and thinning of the volume, there are defects such as complicated structure, insufficient adjustment, and high cost. Therefore, the design is small in size, simple in structure, and low in cost, and can satisfy multi-mode and multi-mode. The mobile phone antenna required for the frequency band is the research direction of the future terminal antenna.

Summary of the invention

In view of this, the object of the present invention is to provide a multi-band dielectric resonant handset antenna that meets the requirements for multi-mode multi-band mobile phone antennas in the future.

Based on the above object, the present invention provides a multi-band dielectric resonant mobile phone terminal antenna, which is provided with a high dielectric constant ceramic medium with a groove, a multi-branch monopole excited by a ceramic medium, and a 50-ohm feed. Microstrip lines, dielectric plates, vias connecting monopoles and microstrip lines, and printed ground. The antenna has the characteristics of small size, light weight, simple structure, frequency bandwidth and easy processing and integration. Therefore, the invention has low manufacturing cost, simple structure and wide frequency band of operation, and has good application prospects.

The medium of the antenna has a groove, and the slot has little effect on the performance of the antenna, and can still meet the design requirements. The purpose of the slot is to effectively reduce the weight of the antenna. At the same time, it is also possible to increase the radiation area of the medium and improve the radiation efficiency of the antenna.

The dielectric of the antenna requires a high dielectric constant (greater than 10). Since the selection of the dielectric constant of the dielectric affects the size of the antenna, the dielectric constant of 38 is selected in the embodiment of the present invention to better reduce the antenna. size of.

The reference ground of the antenna is printed on the front side of the dielectric board, and the feed microstrip line is printed on the reverse side of the dielectric board.

The rectangular dielectric having a dielectric constant of 38 is located on the front side of the dielectric plate, placed at a corner of the dielectric plate outside the reference ground, and the multi-branched monopole is printed on the bottom surface of the ceramic medium.

The multi-branch monopole of the antenna acts as an excitation unit to radiate energy through the medium, and is equivalent to changing the boundary condition of the medium and the distribution characteristics of the electric field and the magnetic field in the medium, and the required size can be obtained by adjusting the size of the monopole. The frequency band excites the ceramic medium to produce multiple modes, resulting in multiple bands.

The microstrip line is a conversion unit of the antenna printed on the reverse side of the dielectric board, the beginning of the feeding microstrip line is connected to the radio antenna interface reverse level male head (SMA), and the tail end is connected to the multi-branch monopole through the via hole. child.

The via hole is a connection unit of the antenna, and connects the microstrip line at the bottom end of the dielectric board and the multi-branched monopole at the bottom end of the medium.

The dielectric plate is made of an insulating material suitable for the radio frequency microwave band and having a corresponding dielectric constant.

As can be seen from the above, the multi-band medium resonance mobile phone terminal antenna provided by the present invention. Its The acquisition of multiple frequency bands mainly relies on multi-branch monopole feeding under the medium, and the rectangular dielectric with high dielectric constant is excited to generate high-order modes. At the same time, a groove is added to the rectangular dielectric to effectively reduce the size and weight of the antenna. The antenna can cover Global System for Mobile Communications (GSM)/Decentralized Control System (DCS)/Personal Communication Service (PCS)/Universal Mobile Telecommunications System (UMTS)/Long Term Evolution Project 2300 (LTE2300)/Long Term Evolution Project 2500 (LTE2500), etc. The frequency band can meet the requirements of various frequency bands of mobile phone terminals today, and has high radiation efficiency and stable gain, and has a larger bandwidth than a terminal antenna that resonates with other media. Its main structure is characterized by small size, light weight, flexible design, simple feeding system and frequency bandwidth. Therefore, compared with other dipole antennas, the invention has low manufacturing cost, simple feeding, and wide frequency band of operation, and has good application prospects.

DRAWINGS

1 is a schematic diagram of a three-dimensional structure of a multi-band dielectric resonant mobile phone terminal antenna according to an embodiment of the present invention;

2 is a front elevational view of a multi-band dielectric resonant mobile phone terminal antenna according to an embodiment of the present invention;

3 is a schematic rear view of a multi-band dielectric resonant mobile phone terminal antenna according to an embodiment of the present invention;

4 is a measured view of frequency characteristics of a multi-band dielectric resonant mobile phone terminal antenna according to an embodiment of the present invention.

detailed description

The present invention will be further described in detail below with reference to the specific embodiments of the invention.

Referring to Fig. 1, Fig. 2 and Fig. 3, the structural composition of an embodiment of the multiband medium resonance mobile phone terminal antenna of the present invention will be mainly described.

As shown in FIG. 1 , the antenna includes: as shown in FIG. 1 , the antenna includes: a dielectric plate 1 , a feeding microstrip line 2 on the reverse side of the dielectric plate 1 , and a high dielectric located at a corner of the front surface of the dielectric plate a constant rectangular dielectric 3, a multi-branched monopole 4 on the bottom surface of the rectangular ceramic dielectric, a printed reference ground 5 under the rectangular ceramic dielectric, and a via 6 connecting the monopole and the feeding microstrip line; Wherein, the multi-branch monopole and the feeding microstrip line are connected through a via; the starting end of the feeding microstrip line 2 is soldered with a reverse-level male head (SMA), and then the external signal source is connected, and the tail end passes through the via hole. 6 Connect the multi-branch monopole 4.

Among them, the dielectric plate 1 is made of an insulating material suitable for the radio frequency microwave band and having a corresponding dielectric constant. In the present embodiment, a medium having a flame resistant material grade of FR4 is selected, and the dielectric constant is 4.4. In the embodiment, the dielectric plate 1 has a rectangular shape with a length of 100 mm, a width of 60 mm, and a thickness of 1mm.

The reference ground 5 of the antenna is printed on the front side of the dielectric plate 1, which is 70 mm*60 mm in this embodiment; the feed microstrip line 2 is printed on the reverse side of the dielectric plate 1, and the impedance value is 50 in this embodiment. ohm.

As shown in FIG. 2, a rectangular dielectric 3 having a high dielectric constant is located on the front side of the dielectric plate 1. It can be placed at a corner of the dielectric plate 1 outside the reference ground 5.

In the present embodiment, ceramic is selected as the material of the rectangular dielectric 3, and the dielectric constant is not less than 10, and may be 38 as a preferred embodiment. It is verified by simulation that in order to ensure that the antenna covers the 1.7G-2.7G frequency range at high frequencies, when the thickness of the dielectric is reduced to 3mm, the frequency increases due to the decrease of the dielectric size, and the frequency rises to 1.74G. Therefore, in order to ensure effective frequency coverage, the rectangular dielectric 3 in the present embodiment has a thickness of not less than 3 mm, and preferably has a length of 25 mm, a width of 15 mm, and a thickness of 4 mm.

In order to further reduce the weight of the rectangular dielectric 3, at least one groove is formed on the front surface of the rectangular dielectric. In the present embodiment, three horizontally parallel grooves are added to the rectangular dielectric 3. The rectangular groove has a depth of 1 mm and a width of 2 mm, and the spacing between the grooves is 8 mm.

In addition, as another embodiment, only a groove having a width of 6 mm can be added to the rectangular dielectric 3, and the same technical effect can be achieved, that is, the antenna can cover 1.7G-2.7G at a high frequency.

In this embodiment, it is verified by simulation experiments that in order to ensure an effective coverage of the antenna at a high frequency, if a groove having a depth of 1 mm is opened, the width of the groove should be no more than 12 mm.

The multi-branch monopole 4 of the antenna acts as an excitation unit for exciting the rectangular dielectric 3 to generate multiple modes, thereby generating multiple frequency bands. The multi-branched monopole 4 can be printed on the bottom surface of the rectangular dielectric 3 in contact with the dielectric plate 1, and is an anti-S-shaped metal copper foil in the embodiment. Among them, the bottom horizontal branch (the section connected to the via) has a great influence on the performance of the antenna. In order to ensure the performance of the antenna, in the preferred embodiment of the present invention, the lengths of the branches of the multi-branch monopole 4 from top to bottom (from one end away from the via 6 to the end connected to the via) are: 8.5 mm, 13 mm. , 12mm, 11mm, 10mm, thickness is about 1mm.

As shown in FIG. 3, the feed microstrip line 2 is an antenna conversion unit that transmits energy input from the SMA port to the antenna. It is printed on the reverse side of the dielectric board 1, the beginning is connected to the radio antenna interface SMA, and the tail end is connected to the multi-branch monopole 4 through the via 6. Because the impedance of the feed microstrip line needs to match the characteristic impedance of the SMA, and the industry standard value of the latter is 50 ohms, therefore, the feed The impedance of the microstrip line is also set to 50 ohms. Its width is 1.9mm.

The via 6 is a connection unit of the antenna, and is connected to the feeding microstrip line 2 at the bottom end of the dielectric board 1 and the multi-branched monopole 4 at the bottom end of the rectangular ceramic dielectric 3.

A rectangular ceramic dielectric 3 having a high dielectric constant with a groove is selected as the main radiating element of the antenna. Compared with the conventional metal patch antenna, the dielectric resonant antenna has low frequency loss and high efficiency. For the required frequency band and fixed dielectric constant, the rectangular medium has greater design flexibility, and can reduce the size of the antenna and reduce the antenna by notching the surface of the medium without affecting the radiation performance of the antenna. the weight of.

In this embodiment, the field distribution of the rectangular dielectric resonator involved can be analyzed by an ideal rectangular dielectric waveguide model, as shown in FIG. The resonant frequency of a rectangular dielectric resonator can be obtained by solving a rectangular waveguide model:

Where m and n are positive integers, k ₀ is the propagation constant of free space, and k _x , k _y , and k _z are propagation constants in the x, y, and z directions, respectively. The size of the high dielectric constant rectangular ceramic dielectric with a groove in this embodiment is 25×15×4 mm ³ , and the resonant frequency formula of the dielectric resonant antenna can be obtained by the formula (1)(2)(3)(4):

Where F is the calculation factor and c is the speed of light, the basic mode of the medium with a size of 25×15×4 mm ³ can be obtained as 6.17 GHz, which cannot meet the frequency band required by the mobile phone antenna. Since the metal on the surface of the medium can change the distribution of the electric field in the medium, the radiation characteristics of the medium can be changed by changing the feeding method.

The excitation method used in the embodiment of the present invention is a multi-branch monopole 4 printed on the bottom surface of the medium, because the electric field and magnetic field distribution of the rectangular dielectric resonator are determined by the boundary conditions thereof, so that the loading is performed at the bottom end of the medium. Branching monopole 4 is equivalent to the introduction of an ideal electrical conductor. Change the distribution characteristics of the electromagnetic field in the medium. The resonant frequency of the dielectric resonant antenna can be varied by adjusting the length of the multi-branch monopole to obtain the desired bandwidth.

The rectangular dielectric selected for the examples of the present invention is a dielectric having a high dielectric constant, generally requiring a dielectric constant greater than 10, and more preferably, the dielectric used in the examples of the present invention is a ceramic dielectric having a dielectric constant of 38. The quality factor Q of the medium is in accordance with the dielectric constant of the medium as follows:

The relationship between the impedance bandwidth (BW) of the dielectric resonant antenna and the quality factor is:

Where S is the acceptable maximum standing wave ratio. It can be concluded from equations (5) and (6) that the bandwidth of the dielectric resonant antenna is inversely proportional to the quality factor. The larger the dielectric constant of the medium, the narrower the bandwidth of the medium, but the medium with high dielectric constant is beneficial to reduce the antenna. size.

The feeding mode of the dielectric resonator has a great influence on its resonant frequency and quality factor. Common feeding methods include coupled feed, coaxial feed and microstrip feed. In various embodiments of the invention, we choose a form of multi-branch monopole (4) feed similar to microstrip line feed. On the one hand, the main branch of the multi-branch monopole can be regarded as a monopole with a wavelength of λ/4, which can meet the requirements of the low-band GSM900 of the mobile terminal antenna; on the other hand, the short-branch can be combined to change the quality of the dielectric resonator. The factor and the electric field and magnetic field distribution of the dielectric resonator can produce multi-frequency resonance, which mainly satisfies the dielectric resonant antenna in the high frequency band and obtains a wider bandwidth.

In various examples of the present invention, the reference ground (6) is selected to be coplanar with the multi-branch monopole (4), and the size of the reference ground has a great influence on the low frequency of the antenna, and the size of the reference ground is 70×60 mm. ² , located below the dielectric resonator, can improve the bandwidth requirements of low frequency resonance.

The present invention has been carried out a number of tests, and the simulation implementation test is described as follows:

At the beginning of the 50 ohm feeder microstrip line (2) of the antenna, the SMA connector is used for welding, and then the external signal source is applied. The additional excitation signal is transmitted through the 50 ohm feeder microstrip line (1) and the via (6). Branch monopole (4). The ceramic medium (3) having a high dielectric constant is excited by the multi-branched monopole (4), and the energy of the electromagnetic wave is radiated by the ceramic medium to complete the function of wireless communication.

Referring to FIG. 4, the frequency characteristics of the embodiment of the present invention, that is, the experimental results of the return loss parameter are introduced. The abscissa in the figure is the frequency component in GHz; the ordinate is the amplitude component in dB. A multi-frequency dielectric resonant terminal antenna according to an embodiment of the present invention can cover a frequency band of 880 MHz-960 MHz and 1.70 G-2.70 G, and the return loss parameter is less than -6 dB in the operating frequency band. Therefore, the test of this embodiment was successful and achieved the object of the invention.

It should be understood by those skilled in the art that the above description is only the embodiment of the present invention, and is not intended to limit the present invention, and any modifications, equivalents, and improvements made within the spirit and principles of the present invention. And the like should be included in the scope of protection of the present invention.

Claims

A multi-band dielectric resonant mobile phone terminal antenna, comprising: a dielectric plate (1), a feeding microstrip line (2) on a reverse side of the dielectric plate (1), and a high angle at a front corner of the dielectric plate a dielectric constant rectangular dielectric (3), a multi-branched monopole (4) on the bottom surface of the rectangular ceramic dielectric, a printed reference ground (5) under the rectangular ceramic dielectric, and a multi-branched monopole connected ( 4) a via (6) with the feeding microstrip line (2);

Wherein, the multi-branch monopole and the feeding microstrip line are connected through a via; the starting end of the feeding microstrip line (2) is soldered with a reverse-stage male SMA, and then the external signal source is externally connected, and the tail end passes through the via hole. (6) Connect the multi-branch monopole (4).
The multi-band medium resonance mobile phone terminal antenna according to claim 1, wherein the rectangular dielectric (3) has a dielectric constant of not less than 10; and/or the rectangular dielectric (3) has a thickness At 3mm.
The multi-band medium resonance mobile phone terminal antenna according to claim 2, wherein the rectangular dielectric (3) has a dielectric constant of 38; and/or the rectangular dielectric (3) has a length of 25 mm and a width of 15 mm. The thickness is 4mm.
The multi-band medium resonance mobile phone terminal antenna according to claim 1, characterized in that the rectangular dielectric (3) has at least one groove on the front side.
The multi-band medium resonance mobile phone terminal antenna according to claim 4, wherein the rectangular dielectric (3) has three horizontally parallel rectangular grooves on the front side, and the rectangular groove has a depth of 1 mm and a width of 2 mm. The spacing between them is 8mm;

or

The rectangular dielectric (3) has a rectangular groove on the front surface thereof, and the groove has a depth of 1 mm and a width of 12 mm.
The multi-band medium resonance mobile phone terminal antenna according to claim 1, characterized in that the multi-branch monopole (4) of the antenna is printed in an inverse S shape on the bottom surface of the ceramic medium (3).
The multi-band medium resonance mobile phone terminal antenna according to claim 6, wherein the length of the branch of the multi-branch monopole from the end of the via hole (6) to the end of the segment connected to the via hole (6) is in turn It is: 8.5mm, 13mm, 12mm, 11mm, 10mm, and the thickness is about 1mm.
The multi-band medium resonance mobile phone terminal antenna according to claim 1, wherein a reference ground (5) of the antenna is printed on a front surface of the dielectric plate (1), and has a length of 70 mm. The width is 60mm and the thickness is 1mm.
The multi-band medium resonance mobile phone terminal antenna according to claim 1, characterized in that the feeding microstrip line (2) is printed on the reverse side of the dielectric plate (1) and has an impedance value of 50 ohms.
The multi-band medium resonance mobile phone terminal antenna according to claim 1, wherein the dielectric plate (1) is made of a flame resistant material grade FR4 medium having a dielectric constant of 4.4, a thickness of 1 mm, a length of 100 mm, and a width. It is 60mm.