CN112072286B

CN112072286B - Wideband PIFA antenna and communication terminal

Info

Publication number: CN112072286B
Application number: CN202010885426.5A
Authority: CN
Inventors: 姚坤
Original assignee: Realme Mobile Telecommunications Shenzhen Co Ltd
Current assignee: Realme Mobile Telecommunications Shenzhen Co Ltd
Priority date: 2020-08-28
Filing date: 2020-08-28
Publication date: 2023-05-05
Anticipated expiration: 2040-08-28
Also published as: CN112072286A

Abstract

The embodiment of the application discloses a broadband PIFA antenna, which comprises: antenna radiator, first feeder and second feeder, wherein: the antenna radiator comprises a first radiation branch, a second radiation branch and a third radiation branch which are respectively used for radiating energy of a first frequency band, a second frequency band and a third frequency band; a coupling gap is formed between the second radiation branch and the third radiation branch and is used for expanding the bandwidth corresponding to the third frequency band; the first feeder connects the first radiation branch with a first feed point; the second feeder is connected with the second radiation branch and the third radiation branch, one end of the second feeder is connected with the feed point, and the other end of the second feeder is connected with the second feed point. The embodiment of the application also provides a communication terminal.

Description

Wideband PIFA antenna and communication terminal

Technical Field

The present application relates to the field of electronic devices, and relates to, but is not limited to, wideband PIFA (Planar Inverted-F antenna) antennas and communication terminals.

Background

With the rapid development of wireless communication technology, the demand for intelligent terminals is increasing. Among them, as a core component for transmitting and receiving signals, an antenna plays an important role, and generally needs to have characteristics of small size, wide coverage frequency band, and the like. In a 5G (5 th generation mobile networks, fifth generation mobile communication technology) mobile terminal, the operating band of the antenna reaches 5GHz (gigahertz). Conventional PIFA antennas suffer from insufficient bandwidth and coverage.

Disclosure of Invention

The embodiment of the application aims at solving the problems of insufficient bandwidth and insufficient coverage of a PIFA antenna in a 5G mobile terminal in the prior art, and provides a broadband PIFA antenna and a communication terminal.

The technical scheme of the embodiment of the application is realized as follows:

in a first aspect, embodiments of the present application provide a wideband PIFA antenna, the PIFA antenna including an antenna radiator, a first feed line, and a second feed line, wherein:

the antenna radiator comprises a first radiation branch, a second radiation branch and a third radiation branch which are respectively used for radiating energy of a first frequency band, a second frequency band and a third frequency band; a coupling gap is formed between the second radiation branch and the third radiation branch and is used for expanding the bandwidth corresponding to the third frequency band;

the first feeder connects the first radiation branch with a first feed point;

the second feeder is connected with the second radiation branch and the third radiation branch, one end of the second feeder is connected with the feed point, and the other end of the second feeder is connected with the second feed point.

In a second aspect, an embodiment of the present application provides a communication terminal, including a housing, a small board, and a PIFA antenna according to an embodiment of the present application, where the PIFA antenna is located in the housing, and the PIFA antenna is fixedly connected to one side of the small board.

The beneficial effects that technical scheme that this application embodiment provided include at least:

the wideband PIFA antenna provided by the embodiment of the application comprises an antenna radiator, a first feeder line and a second feeder line, wherein the coupling gaps are formed in the second radiation branch and the third radiation branch of the antenna radiator, so that current on the antenna radiator can be redistributed, the current length is changed, resonance in the working bandwidth is introduced, and the PIFA antenna is covered in multiple frequencies or wider frequency bands by utilizing smaller sizes. Under the conditions of not using a tuning switch, not increasing the wiring area and not increasing the antenna height, different antenna forms can work simultaneously through wiring optimization, the bandwidth of the PIFA antenna is greatly expanded, and a good communication function is realized.

Drawings

For a clearer description of the technical solutions in the embodiments of the present application, the drawings that are needed in the description of the embodiments will be briefly introduced below, it being obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art, wherein:

fig. 1 is a schematic structural diagram of a wideband PIFA antenna according to an embodiment of the present application;

fig. 2 is a schematic diagram of a part of a structure of a communication terminal according to an embodiment of the present application;

fig. 3 is a schematic diagram of current distribution of a PIFA antenna according to an embodiment of the present application;

fig. 4 is a schematic diagram of current distribution of a PIFA antenna according to an embodiment of the present application;

fig. 5A is a schematic diagram of resonance of a PIFA antenna provided in an embodiment of the present application within an operating bandwidth;

fig. 5B is a schematic diagram of total radiation efficiency of the PIFA antenna provided in the embodiment of the present application within an operating bandwidth;

fig. 6 is a schematic diagram of radiation directions of a PIFA antenna provided in an embodiment of the present application at a resonance position within an operating bandwidth.

Detailed Description

For the purposes of making the objects, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is apparent that the described embodiments are some embodiments of the present application, but not all embodiments. The following examples are illustrative of the present application, but are not intended to limit the scope of the present application. All other embodiments, which can be made by one of ordinary skill in the art based on the embodiments herein without making any inventive effort, are intended to be within the scope of the present application.

In the following description, reference is made to "some embodiments" which describe a subset of all possible embodiments, but it is to be understood that "some embodiments" can be the same subset or different subsets of all possible embodiments and can be combined with one another without conflict.

It should be noted that the term "first\second\third" in relation to the embodiments of the present application is merely to distinguish similar objects and does not represent a specific ordering for the objects, it being understood that the "first\second\third" may be interchanged in a specific order or sequence, where allowed, to enable the embodiments of the present application described herein to be practiced in an order other than that illustrated or described herein.

It will be understood that when an element is referred to as being "fixed to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," and the like are used in the examples herein for illustrative purposes only.

It will be understood by those skilled in the art that all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which embodiments of this application belong unless defined otherwise. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

With the rapid development of wireless communication technology, the demand for intelligent terminals is increasing. Among them, as a core component for transmitting and receiving signals, an antenna plays an important role, and generally needs to have characteristics of small size, wide coverage frequency band, and the like.

With the advent of the 5G era, the current 5G smart terminal antenna is basically required to support the 5G communication frequency band (such as Sub6G, i.e. the frequency band below 6G with the operating frequency of 450GHz to 6000 GHz), and in order to adapt to the requirements of overseas operators, the terminal antenna is basically required to cover the N41 frequency band, i.e. the frequency range of 2515 to 2675GHz, the N78 frequency band, i.e. the frequency range of 3300 to 3800GHz and the N79 frequency band, i.e. the frequency range of 4400 to 5000GHz.

In the nonmetal plastic rear shell of the full-screen intelligent terminal, an antenna made of a flexible circuit board (Flexible Printed Circuit, FPC) is mostly used, wherein the PIFA antenna is widely applied to the products because of the advantages of low cost, low profile, wide coverage frequency band and the like. PIFA antennas are known because the entire antenna is shaped like the letter F of the letter F. The basic structure of the antenna is that a plane radiating element is adopted as a radiator, a large ground is adopted as a reflecting surface, and two pins (Pin pins) which are close to each other are arranged on the radiator and are respectively used for grounding and serving as a feed point.

The bandwidth of the PIFA antenna has high requirements on the height of the antenna, the thickness of most ultrathin intelligent antennas at present is much smaller than 10 millimeters (mm), particularly the plastic rear shell is ultrathin, under the condition of considering performance, cost and working bandwidth, the antenna design of the intelligent terminal faces great challenges, and compared with the traditional antenna which does not support the 5G communication frequency band, the antenna of the intelligent terminal is urgently required to expand the working bandwidth.

The embodiment of the present application provides a wideband PIFA antenna, fig. 1 is a schematic structural diagram of the wideband PIFA antenna provided in the embodiment of the present application, as shown in fig. 1, the PIFA antenna 10 includes an antenna radiator 11, a first feeder line 12 and a second feeder line 13, where:

the antenna radiator 11 includes a first radiating branch 111, a second radiating branch 112 and a third radiating branch 113 for radiating energy of a first frequency band, a second frequency band and a third frequency band, respectively.

The antenna radiator 11 has three inherent fundamental resonances, namely a first frequency band, a second frequency band and a third frequency band, wherein the first frequency band, the third frequency band and the second frequency band are in turn high frequency, intermediate frequency and low frequency, respectively, generated by the first radiating branch 111, the second radiating branch 112 and the third radiating branch 113. Wherein the first radiating branch 111 extends from the first feeder line 12, and the second radiating branch 112 and the third radiating branch 113 each extend from the second feeder line 13.

A coupling gap 14 is formed between the second radiating branch 112 and the third radiating branch 113, so as to expand the bandwidth corresponding to the third frequency band.

The coupling slot 14 is obtained by grooving the antenna radiator 11. The coupling slot 14 may redistribute the current on the antenna radiator 11, thereby changing the current length. Therefore, the antenna radiator 11 can realize impedance matching at a higher frequency point, namely a third frequency band, so that a new intermediate frequency resonance is introduced, and the bandwidth of the corresponding frequency point is further expanded. That is, by opening the coupling slot 14, the impedance bandwidth of the PIFA antenna 10 can be further widened on the original basis. The specific frequency value of the intermediate frequency resonance point can be adjusted by adjusting the length, width and position of the coupling slot 14.

It should be noted that the use of the coupling gap 14 between the second radiating branch 112 and the third radiating branch 113 in the embodiment of the present application to expand the bandwidth of the third frequency band, i.e. the intermediate frequency band, is only a preferred embodiment, and in other possible embodiments, the coupling gap may also be used to expand the bandwidth of other frequency bands. The present invention is not particularly limited, and may be determined according to actual conditions.

The first feed line 12 connects the first radiating branch 111 with a first feed point 15; the second feeder line 13 connects the second radiating branch 112 and the third radiating branch 113, and one end of the second feeder line 13 is connected to the feeding point 16, and the other end of the second feeder line 13 is connected to the second feeding point 17.

The first feeder 12 and the second feeder 13 may be microstrip lines connecting the feed source and the radiating element, but are not limited to microstrip lines, and may be connection lines with pins, etc. as signal transmission. After entering the feeding point 16, for example, energy in the corresponding frequency band is radiated via the three branches of the antenna radiator 11 through the first feeder line 12 and the second feeder line 13, respectively.

The first feeder 12 and the second feeder 13 may take the form of coaxial wires or any other suitable form during implementation. The arrangement of the first feeder line 12 and the second feeder line 13 is not limited herein, and may be determined according to practical situations.

In some possible embodiments, the first radiating branch 111 also acts as a parasitic element for generating resonance operating in the first frequency band range.

When the antenna radiator 11 radiates electromagnetic waves, the electromagnetic waves can be coupled to the first radiating branch 111, so that the first radiating branch 111 can generate higher-frequency resonance, that is, a new high-frequency resonance point is introduced, and impedance matching can be realized at the higher-frequency point. Wherein the frequency of the high-frequency resonance point is higher than the frequency of the medium-frequency resonance point. That is, by providing the first radiating branch as a parasitic element, the impedance bandwidth of the PIFA antenna 10 is further widened on an as-is basis. Due to the coupling slot 14 and the parasitic element, the antenna radiator 11 can achieve multi-frequency or wider-band coverage with a smaller size.

In some possible embodiments, by properly processing the slot position and the slot position on the trace of the PIFA antenna 10, the current generated when the antenna radiator 11 receives the electromagnetic wave signal forms a loop current path through the coupling slot 14, that is, a loop current distribution is generated between the second radiating branch 112 and the third radiating branch 113, and an additional loop current mode is added, so that resonance is generated, and the antenna bandwidth is expanded.

In some possible embodiments, the coupling slot 14 is sized according to the frequency size of the third frequency band. That is, the circulation distribution formed by the slots and the grooves in the embodiment of the application is not unique, and can be adjusted accordingly according to the actual antenna frequency band requirement.

In some possible embodiments, the third radiating branch 113 comprises a first radiating arm of adjustable length and a second radiating arm connected to the first radiating arm.

In some possible embodiments, the length of the coupling slot 14 is adjusted by adjusting the length of the first radiating arm.

In some possible embodiments, the PIFA antenna 10 operates in a New Radio (NR) 5G band, where the first band is an N79 band (frequency range 4600GHz to 5000 GHz), the second band is an N1 band (frequency range 1920GHz to 2170 GHz), and the third band is an N78 band (frequency range 3300GHz to 3800 GHz).

In some possible embodiments, the second radiating branch 112 and the third radiating branch 113 are each L-shaped traces, and an end of the second radiating branch 112 near the second feeder 13 is narrower than the trace of the end of the second radiating branch 112.

Here, the end position of the second radiating branch 112 is at the top end of the bracket (not shown in fig. 1) of the PIFA antenna 10, and a wider trace patch is advantageous for antenna radiation; the second radiating branch 112 is implemented by a narrower trace near the feeder line portion, so that on one hand, the narrower antenna trace can reduce coupling with the wide trace portion at the same end, such as the third radiating branch, and reduce negative influence on antenna radiation, and on the other hand, the narrow trace has stronger sensitivity, and further reduces the occupied volume of the antenna.

In some possible embodiments, the routing design of the PIFA antenna 10 is implemented by a flexible FPC. That is, the PIFA antenna 10 is a miniaturized FPC antenna, and the wiring design of the antenna is realized by attaching an FPC to the inside of the plastic rear housing.

Fig. 2 is a schematic diagram of a portion of a structure of a communication terminal provided in an embodiment of the present application, which may be any network terminal including a PIFA antenna, such as a wireless router, a portable wireless fidelity (Wireless Fidelity, wi-Fi) hotspot transmitter, etc., as shown in fig. 2, the communication terminal 20 includes a housing 21, a small board 22, and a PIFA antenna 10.

The PIFA antenna 10 is a wideband antenna in the above embodiment, and is located in the housing 21, and the PIFA antenna 10 is fixedly connected to one side of the small plate 22. The signal receiving and transmitting function between the communication terminal and the outside is realized.

The housing 21 is typically made of a nonmetallic material such as ABS (Acrylonitrile Butadiene Styrene ) or PC (polycarbonate).

The tablet 22 serves as a charging interface and is typically connected to a USB module, a headset module, in the communication terminal 20.

The resonance principle of the PIFA antenna provided in the embodiments of the present application is analyzed as follows. The formation of the loop current can be observed by the current distribution over the antenna.

Fig. 3 is a schematic diagram of current distribution of a PIFA antenna according to an embodiment of the present application, and the directions and distribution densities of arrows in fig. 3 respectively represent the direction and intensity of the current on the antenna surface, where the black arrows indicate the portions, and indicate that the current distribution density is larger.

As shown in part a of fig. 3, which shows the current distribution on the antenna radiator corresponding to a frequency of 2.0GHz, it can be seen that the current on the path of the second radiating branch 112 is stronger when the frequency is within the N1 frequency band.

As shown in parts B and C of fig. 3, which respectively represent the current distribution on the antenna radiator corresponding to the frequencies 3.3GHz and 3.67GHz, it can be seen that when the frequency is within the N78 band, there is a strong annular current distribution between the second radiating branch 112 and the third radiating branch 113 in addition to a strong current distribution on the third radiating branch 113, as shown by the black arrow part of fig. 3. That is, in addition to the third radiating branch radiating energy in the N78 band, another resonance operating in the N78 band is now generated in the gap region between the second radiating branch 112 and the third radiating branch 113.

As shown in part D of fig. 3, which shows the current distribution on the corresponding antenna radiator at a frequency of 4.76GHz, it can be seen that when the frequency is within the N79 frequency band, the current mainly flows through the path of the first radiating branch 111. Thus, an N79 resonance is generated by the first radiating branch 111.

Meanwhile, the electric field distribution condition of the surface of the PIFA antenna can be observed, and the working principle of the PIFA antenna can be further observed.

Fig. 4 is a schematic diagram of current distribution of a PIFA antenna according to an embodiment of the present application, and as shown in fig. 4, A, B, C, D is an electric field distribution diagram at frequencies of 2GHz, 3.3GHz, 3.67GHz and 4.76GHz, respectively. The darker the color of the shaded portion in fig. 4 represents the more intense the radiation there. As part a in fig. 4 shows that the radiation on the second radiation branch 112 is stronger; parts B and C show that the radiation is stronger in the area annularly distributed between the second radiating branch 112 and the third radiating branch 113, i.e. by adding the coupling slit 14 to create an extra loop current pattern, the bandwidth of N78 is extended; part D shows the first radiating branch 111 as a parasitic element, the radiation on this path being stronger, indicating that resonance is generated operating in the N79 frequency band.

Fig. 5A is a schematic diagram of resonance of a PIFA antenna provided in an embodiment of the present application in an operating bandwidth, where, as shown in fig. 5, a horizontal axis represents frequency, a vertical axis represents radiation energy, and a trough appears in each frequency range at intervals in fig. 5, which indicates that a resonance is generated in a corresponding frequency range. It can be seen that there is only one resonance between frequency point 51 and frequency point 52 (frequency range 1.92GHz to 2.17GHz, corresponding to the N1 frequency band) and between frequency point 55 and frequency point 56 (frequency range 4.6GHz to 5GHz, corresponding to the N79 frequency band), while there is two resonances between frequency point 53 and frequency point 54 (frequency range 3.3GHz to 3.8GHz, corresponding to the N78 frequency band). That is, the PIFA antenna generates two resonances within the N78 bandwidth, effectively expanding the bandwidth of the PIFA antenna.

Fig. 5B is a schematic diagram of total radiation efficiency of the PIFA antenna provided in the embodiment of the present application within an operating bandwidth. As shown in fig. 5B, the overall radiation efficiency of the PIFA antenna 10 in the N1 band, the N78 band, and the N79 band is-3.5 dB, -3.2dB, and-4.3 dB, respectively.

Fig. 6 is a schematic diagram of a radiation direction of a resonance position of a PIFA antenna provided in an embodiment of the present application in an operating bandwidth, and as shown in fig. 6, a radiation direction characteristic of the PIFA antenna 10 is good in a two-dimensional direction of a horizontal plane θ=90°. At four frequency points of 2GHz, 3.3GHz, 3.67GHz and 4.76GHz, the corresponding gains are 5.4dBi, 6.4dBi, 3.53dBi and 5.91dBi respectively.

By observing the patterns at resonance in the three operating bandwidths N1, N78, N79, the antenna maintains good radiation directivity characteristics in the operating bandwidths. That is, the PIFA antenna 10 completely covers the N1, N78, N79 frequency bands of 5G, has good radiation characteristics at the operating frequency of each communication system, basically maintains omni-directionality, and completely meets the requirement of omnidirectional radiation of the antenna.

According to the wideband PIFA antenna provided by the embodiment of the application, the coupling gap is designed in the antenna radiator, the current distribution in the antenna radiator is changed, the resonance in the working bandwidth is introduced by adding an extra circulation mode, and the coverage of the PIFA antenna in multiple frequencies or wider frequency bands is realized by utilizing a smaller size. Under the conditions of not using a tuning switch, not increasing the wiring area and not increasing the height of the PIFA antenna, different PIFA antenna forms can work simultaneously through wiring optimization, the bandwidth of the PIFA antenna is greatly expanded, and good communication functions are realized.

It should be appreciated that reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present application. Thus, the appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. It should be understood that, in various embodiments of the present application, the sequence numbers of the foregoing processes do not mean the order of execution, and the order of execution of the processes should be determined by the functions and internal logic thereof, and should not constitute any limitation on the implementation process of the embodiments of the present application. The foregoing embodiment numbers of the present application are merely for describing, and do not represent advantages or disadvantages of the embodiments.

It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

In the several embodiments provided in this application, it should be understood that the disclosed apparatus and method may be implemented in other ways. The above described device embodiments are only illustrative, e.g. the division of the units is only one logical function division, and there may be other divisions in practice, such as: multiple units or components may be combined or may be integrated into another system, or some features may be omitted, or not performed. In addition, the various components shown or discussed may be coupled or directly coupled or communicatively coupled to each other via some interface, whether indirectly coupled or communicatively coupled to devices or units, whether electrically, mechanically, or otherwise.

The units described above as separate components may or may not be physically separate, and components shown as units may or may not be physical units; can be located in one place or distributed to a plurality of network units; some or all of the units may be selected according to actual needs to achieve the purposes of the embodiments of the present application.

In addition, each functional unit in each embodiment of the present application may be integrated in one processing unit, or each unit may be separately used as one unit, or two or more units may be integrated in one unit; the integrated units may be implemented in hardware or in hardware plus software functional units.

The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The foregoing is merely an embodiment of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think about changes or substitutions within the technical scope of the present application, and the changes and substitutions are intended to be covered in the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A wideband PIFA antenna, comprising an antenna radiator, a first feed line, and a second feed line, wherein:

the first feeder connects the first radiation branch with a first feed point;

the second feeder line is connected with the second radiation branch and the third radiation branch, one end of the second feeder line is connected with a feed point, and the other end of the second feeder line is connected with a second feed point;

the size of the coupling gap is determined according to the frequency of the third frequency band.

2. The PIFA antenna of claim 1, wherein the first radiating branch further acts as a parasitic element for producing resonance operating in the first frequency band range.

3. The PIFA antenna of claim 1, wherein the antenna radiator, upon receiving an electromagnetic wave signal, generates a current that forms a loop current path through the coupling slot.

4. The PIFA antenna of claim 1, wherein the third radiating branch includes a first radiating arm of adjustable length and a second radiating arm connected to the first radiating arm.

5. The PIFA antenna of claim 4, wherein the length of the coupling slot is adjusted by adjusting the length of the first radiating arm.

6. The PIFA antenna of any one of claims 1-5, wherein the first frequency band is an N79 frequency band, the second frequency band is an N1 frequency band, and the third frequency band is an N78 frequency band.

7. The PIFA antenna of claim 1, wherein the second radiating branch and the third radiating branch are each L-shaped traces, and an end of the second radiating branch proximate the second feed line is narrower than the traces at the end of the second radiating branch.

8. The PIFA antenna of claim 1, wherein the trace design of the PIFA antenna is implemented by a flexible circuit board, FPC.

9. A communication terminal comprising a housing, a small board and a PIFA antenna according to any one of claims 1 to 8, wherein the PIFA antenna is located in the housing and is fixedly connected to one side of the small board.