CN115632237A - Efficient IFA antenna system and corresponding electronic equipment - Google Patents

Abstract

The invention discloses a high-efficiency IFA antenna system and corresponding electronic equipment. The antenna system includes a matching network, an IFA antenna, and a switching network. Two transmission lines in the IFA antenna are respectively connected with the matching network and the switch network, double resonance is realized through cooperative work of the matching network and the switch network, and work of transmitting and receiving communication signals of each frequency band of the antenna system is completed. The invention realizes the coverage and switching of each target frequency band by utilizing the cooperative work of the matching network and the switch network, reduces the power loss on the switch of each frequency band on the basis of ensuring the excellent S parameter of the antenna system by changing the distribution connection mode and the inductance value of the series inductor and the branch inductor in the switch network, and obviously improves the radiation efficiency and the system efficiency of the antenna system.

Description

Efficient IFA antenna system and corresponding electronic equipment

Technical Field

The invention relates to a high-efficiency IFA antenna system and electronic equipment comprising the same, belonging to the technical field of wireless communication.

Background

In wireless communication devices, antenna systems are an important component for transmitting and receiving communication signals. An IFA (Inverted-F Antenna) Antenna is an Inverted F-type Antenna, which is obtained by adding a ground path to an Inverted-L monopole Antenna, is a typical built-in Antenna, and is widely used in existing wireless communication devices.

With the trend of increasingly pursuing light weight, thinness and large screen occupation of wireless communication equipment, the space reserved for the antenna system is very limited, and therefore the physical size of the antenna system needs to be further reduced to meet the requirements. Meanwhile, the miniaturized antenna system is required to have multi-band and wide-band operation characteristics. In the prior art, the antenna system miniaturization method generally has technical schemes of material loading, current loading, meander, matching network, coupled feeding, and the like, and the antenna system broadband method generally has technical schemes of widening the antenna width, multi-resonance, multi-mode, matching network, coupled feeding, and the like. On the other hand, the addition of the lumped elements and the switching elements also causes the increase of the loss and the reduction of the efficiency of the antenna system, so how to reduce the loss and improve the efficiency of the antenna system becomes a problem to be solved urgently.

In chinese patent No. CN107394358B, an antenna structure and an electronic device are disclosed. The antenna structure includes: an IFA antenna assembly located adjacent to a first conductive frame section formed by the two break seams on the conductive frame, the feed point and a first ground point of the IFA antenna assembly being electrically connected to the first conductive frame section, respectively; wherein the IFA antenna assembly is relatively close to a first of the two break joints, and the feed point is closer to the first break joint relative to the first ground point; and a second grounding point located on one side of the IFA antenna component far away from the first broken joint, wherein the second grounding point forms a parasitic branch joint towards a second broken joint of the two broken joints so as to be coupled with the first conductive frame section. Through the technical scheme, the full-band coverage of the antenna structure can be realized under the condition that the internal space of the electronic equipment is insufficient.

Disclosure of Invention

The invention provides an IFA antenna system with high efficiency.

Another technical problem to be solved by the present invention is to provide an electronic device including the above-mentioned IFA antenna system.

In order to achieve the purpose, the invention adopts the following technical scheme:

according to a first aspect of the embodiments of the present invention, a high-efficiency IFA antenna system is provided, which includes a matching network, an IFA antenna, and a switch network; the matching network and the switch network work cooperatively to realize double resonance; two transmission lines in the IFA antenna are respectively connected with the matching network and the switch network; the switch network comprises N frequency band branches, and the frequency band branches are connected in parallel, wherein N is a positive integer larger than 1.

Preferably, the IFA antenna includes a first dielectric substrate 1a, a second dielectric substrate 1b, a third dielectric substrate 1c, a fourth dielectric substrate 1d, a first metal floor 2, a first antenna radiation metal patch 3, a second antenna radiation metal patch 4, a third antenna radiation metal patch 5, a fourth antenna radiation metal patch 6, a first transmission line 7, and a second transmission line 8; the fourth dielectric substrate 1d is vertically connected with the first dielectric substrate 1a, the second dielectric substrate 1b and the third dielectric substrate 1c, a first metal floor 2 covers the lower portion of the fourth dielectric substrate 1d, and a first antenna radiation metal patch 3, a second antenna radiation metal patch 4, a third antenna radiation metal patch 5 and a fourth antenna radiation metal patch 6 respectively cover the outer sides of the first dielectric substrate 1a, the second dielectric substrate 1b and the third dielectric substrate 1 c; one ends of a first transmission line 7 and a second transmission line 8 are respectively connected with the first metal floor 2 and the second antenna radiation metal patch 4, the other end of the first transmission line 7 is connected with the matching network, and the other end of the second transmission line 8 is connected with the switch network.

Preferably, the first metal floor 2 in the IFA antenna is etched on the lower surface of the fourth dielectric substrate 1d by a PCB process, and the first antenna radiating metal patch 3, the second antenna radiating metal patch 4, the third antenna radiating metal patch 5 and the fourth antenna radiating metal patch 6 are etched on the outer surfaces of the first dielectric substrate 1a, the second dielectric substrate 1b and the third dielectric substrate 1c by a PCB process, respectively.

Preferably, the first thickness of the first dielectric substrate 1a, the second dielectric substrate 1b and the third dielectric substrate 1c is 2mm, and the second thickness of the fourth dielectric substrate 1d is 0.8mm; the width of the first metal floor 2 is slightly larger than that of the fourth dielectric substrate 1d.

Wherein preferably the first transmission line 7 and said second antenna radiating metallic patch 4 are both fed by a discrete feed port 9.

Preferably, the switch network comprises N frequency band branches and a first series inductor L0, and the N frequency band branches are respectively formed by connecting a frequency band switch and a branch inductor in series; the branch inductance ends of the N frequency band branches are connected in parallel with each other and then connected with a first series inductance L0, the other end of the first series inductance L0 is connected with a second transmission line 8 in the IFA antenna, and the frequency band switch ends of the N frequency band branches are connected with a ground potential end respectively.

Preferably, the switch network comprises N frequency band branches and N series inductors, wherein each of the N frequency band branches is formed by connecting a frequency band switch and a branch inductor in series; the branch circuit inductance end of the first frequency band branch circuit is connected with a first series inductor L0 and a second series inductor L1, the other end of the first series inductor L0 is connected with a second transmission line 8 in the IFA antenna, N-1 series inductors, which are counted by the second series inductor L1, the third series inductor L2 and the Nth series inductor Ln, are respectively connected between branch circuit inductance ends of the N frequency band branch circuits, and frequency band switch ends of the N frequency band branch circuits are respectively connected with a ground potential end.

Preferably, the series inductance and the branch inductance in the switching network are distributed or lumped inductances, and the frequency band switch is an SP4T or SPST switch.

According to a second aspect of embodiments of the present invention there is provided an electronic device comprising an IFA antenna system of high efficiency as described above.

Compared with the prior art, the IFA antenna system provided by the invention realizes the coverage and switching of each target frequency band by utilizing the cooperative work of the matching network and the switch network, and reduces the power loss on the switch of each frequency band on the basis of ensuring the excellent S parameter of the antenna system by changing the distributed connection mode of the series inductor and the branch inductor in the switch network and the size of the inductance value, so that the radiation efficiency and the system efficiency of the antenna system are obviously improved. Therefore, the invention has the advantages of ingenious and reasonable structural design, lower production cost, smaller chip size, excellent system performance and system efficiency and the like.

Drawings

Fig. 1 is a block diagram of a high efficiency IFA antenna system according to the present invention;

fig. 2 is a schematic structural diagram of an IFA antenna according to a first embodiment of the present invention;

fig. 3 is a schematic diagram of a dielectric structure of an IFA antenna according to a first embodiment of the present invention;

fig. 4 is a schematic diagram of a metal structure of an IFA antenna according to a first embodiment of the present invention;

fig. 5 is a structural dimension diagram of an IFA antenna according to the first embodiment of the present invention;

fig. 6 is a diagram illustrating the feeding port and the structural dimensions of the IFA antenna in the first embodiment of the present invention;

FIG. 7 is a schematic circuit diagram of a switching network according to a first embodiment of the present invention;

FIG. 8 is a circuit schematic of a switching network in a second embodiment of the present invention;

fig. 9 shows the test result of S11 parameters of the antenna system in the B28 band according to the first embodiment of the present invention;

fig. 10 shows the radiation efficiency and system efficiency test results of the antenna system in the B28 band according to the first embodiment of the present invention;

fig. 11 shows the result of S11 parameter test of the antenna system in B28 band according to the second embodiment of the present invention;

fig. 12 shows the radiation efficiency and system efficiency test results of the antenna system in the B28 band according to the second embodiment of the present invention;

fig. 13 is an exemplary diagram of an electronic device employing an IFA antenna system provided by the present invention.

Detailed Description

The technical solution of the present invention is further described in detail with reference to the accompanying drawings and specific embodiments.

As shown in fig. 1, the present invention provides a high efficiency IFA antenna system, which at least includes a matching network, an IFA antenna and a switch network. Two transmission lines in the IFA antenna are respectively connected with the matching network and the switch network, double resonance is realized through cooperative work of the matching network and the switch network, and work of transmitting and receiving communication signals of each frequency band of the antenna system is completed.

The matching network is composed of conventional adjustable LC elements, and is used for adjusting the impedance matching of the antenna system and realizing matching resonance together with the switching network.

In the first embodiment of the present invention, taking a mobile phone antenna in a wireless communication device as an example, as shown in fig. 2, an IFA antenna is composed of a first dielectric substrate 1a, a second dielectric substrate 1b, a third dielectric substrate 1c, a fourth dielectric substrate 1d, a first metal floor 2, a first antenna radiating metal patch 3, a second antenna radiating metal patch 4, a third antenna radiating metal patch 5, a fourth antenna radiating metal patch 6, a first transmission line 7, and a second transmission line 8. The fourth dielectric substrate 1d is vertically connected to the first dielectric substrate 1a, the second dielectric substrate 1b and the third dielectric substrate 1c, the first metal floor 2 covers the lower portion of the fourth dielectric substrate 1d, and the first antenna radiation metal patch 3, the second antenna radiation metal patch 4, the third antenna radiation metal patch 5 and the fourth antenna radiation metal patch 6 cover the outer sides of the first dielectric substrate 1a, the second dielectric substrate 1b and the third dielectric substrate 1c respectively. One end of a first transmission line 7 and one end of a second transmission line 8 are respectively connected with the first metal floor 2 and the second antenna radiation metal patch 4, the other end of the first transmission line 7 is connected with a matching network, and the other end of the second transmission line 8 is connected with a switch network.

The first metal floor 2 is etched on the lower surface of the fourth dielectric substrate 1d through a PCB process, and the first antenna radiation metal patch 3, the second antenna radiation metal patch 4, the third antenna radiation metal patch 5 and the fourth antenna radiation metal patch 6 are etched on the outer surfaces of the first dielectric substrate 1a, the second dielectric substrate 1b and the third dielectric substrate 1c through the PCB process respectively.

As shown in FIG. 3, the first dielectric substrate 1a, the second dielectric substrate 1b, the third dielectric substrate 1c, and the fourth dielectric substrate 1d are made of FR-4 flame-retardant material. In one embodiment of the invention, the dielectric constant is preferably 4.3. The first thickness of the first dielectric substrate 1a, the second dielectric substrate 1b, and the third dielectric substrate 1c is 2mm, and the second thickness of the fourth dielectric substrate 1d is 0.8mm.

As shown in fig. 4, in one embodiment of the present invention, the thickness of the first antenna radiating metal patch 3, the second antenna radiating metal patch 4, the third antenna radiating metal patch 5, and the fourth antenna radiating metal patch 6 is 0.02mm. The width of the first metal floor 2 is slightly larger than that of the fourth dielectric substrate 1d.

As shown in fig. 5, in one embodiment of the present invention, the first antenna radiating metal patch 3 and the fourth antenna radiating metal patch 6 have a length of 142mm and a height of 7mm, and the total length of the second antenna radiating metal patch 4 and the third antenna radiating metal patch 5 is 84mm.

As shown in fig. 6, in one embodiment of the present invention, the first transmission line 7 and the second transmission line 8 are spaced apart by a predetermined distance, the first transmission line 7 is spaced apart from the short point by 15mm, the second transmission line 8 is spaced apart from the open point by 8mm, and the total length of the antenna is 58.5mm. The first transmission line 7 and the second antenna radiation metal patch 4 are both fed by a feed port 9, and the feed port 9 is fed in a discrete port mode.

In the high-efficiency IFA antenna system provided by the invention, the switch network is formed by connecting the switch branches of each target frequency band in parallel. In the first embodiment of the present invention, the B28, B20, B5, and B8 frequency bands are taken as examples for analysis.

As shown in fig. 7, the switch network is composed of a B28 frequency band branch, a B20 frequency band branch, a B5 frequency band branch, a B8 frequency band branch, and a first series inductor L0. One end of the B28 frequency band branch, one end of the B20 frequency band branch, one end of the B5 frequency band branch, and one end of the B8 frequency band branch are connected in parallel and then connected to one end of the first series inductor L0, and the other end of the first series inductor L0 is connected to the second transmission line 8 in the IFA antenna. Each frequency band branch is formed by connecting a frequency band switch and a branch inductor in series, specifically, the B28 frequency band branch is formed by connecting a first frequency band switch K28 and a first branch inductor L28 in series, the other end of the first branch inductor L28 is connected with a first series inductor L0, and the other end of the first frequency band switch K28 is connected with a ground potential end. The B20 frequency band branch circuit is formed by connecting a second frequency band switch K20 and a second branch circuit inductor L20 in series, the other end of the second branch circuit inductor L20 is connected with the first series inductor L0, and the other end of the second frequency band switch K20 is connected with a ground potential end. The B5 frequency band branch circuit is formed by connecting a third frequency band switch K5 and a third branch circuit inductor L5 in series, the other end of the third branch circuit inductor L5 is connected with the first series inductor L0, and the other end of the third frequency band switch K5 is connected with a ground potential end. The B8 frequency band branch circuit is formed by connecting a fourth frequency band switch K8 and a fourth branch inductor L8 in series, the other end of the fourth branch inductor L8 is connected with the first series inductor L0, and the other end of the fourth frequency band switch K8 is connected with the ground potential end.

The series inductance and the branch inductance may be distributed or lumped inductance, and other types of inductance. The band switch may be an SP4T or SPST switch, among other forms of switches.

The operation principle of the high efficiency IFA antenna system according to the present invention will be described in detail with reference to fig. 7.

The IFA antenna system provided by the embodiment of the invention realizes double resonance by utilizing a reconfigurable technology through the cooperative work of the matching network and the switch network, and realizes the coverage of the whole target frequency band through the switching of the frequency band switch. In view of the problems of increased loss and reduced efficiency of the antenna system caused by the lumped elements and the switching elements, as shown in fig. 7, the present invention adopts a technical scheme of reducing the branch inductance in series between branches of each frequency band in the switching network and increasing the series inductance between the switching network and the IFA antenna.

When each frequency band branch is conducted, the frequency band switch can be equivalent to a small resistor; when each frequency band branch is disconnected, the frequency band switch can be equivalent to the parallel connection of a large resistor Roff and a capacitor Coff. Therefore, in the state where the band branch is disconnected, the load voltage V2 on the band switch is calculated as follows:

wherein V1 is a loading voltage on the frequency band branch, i.e. a voltage at a node a in fig. 7; v2 is the load voltage on the band switch, i.e. the voltage at node B in fig. 7; roff is the equivalent resistance of the frequency band switch in the off state; coff is equivalent capacitance of the frequency band switch in an off state; l is a branch inductor connected in series on the frequency band branch.

In the off state of the frequency band switch, the power loss P of the equivalent resistor Roff is calculated as follows:

according to the formula (1) and the formula (2), when the branch inductance L in the frequency band branch is reduced, the load voltage V2 on the frequency band switch is reduced, the power loss P on the equivalent resistance Roff of the frequency band switch is reduced, and the efficiency of the antenna system is improved.

In the first embodiment of the present invention, taking the B28 frequency band branch as an example, the inductance L0 is added between the IFA antenna and the switch network, so as to reduce the inductance value of the branch inductance L28 connected in series on the B28 frequency band branch, and accordingly reduce the load voltage V2 on the frequency band switch K28, and reduce the power loss caused by the frequency band switch, thereby effectively improving the efficiency of the antenna system, and the working principles of the other frequency band branches are the same and are not described again.

In a second embodiment of the present invention, as shown in fig. 8, a high efficiency IFA antenna system provided by the present invention includes at least a matching network, an IFA antenna, and a switch network. The matching network and the IFA antenna are the same as those in the first embodiment, and the switching network further increases the series inductance between the branches of each frequency band on the basis of the first embodiment, and reduces the inductance value of the branch in series of the branches of each frequency band to the maximum extent, so as to further reduce the power loss caused by the switching of the frequency band, thereby improving the efficiency of the antenna system to the maximum extent.

As shown in fig. 8, the second series inductor L1 is connected in series between the B28 frequency band branch and the B20 frequency band branch, the third series inductor L2 is connected in series between the B20 frequency band branch and the B5 frequency band branch, and the fourth series inductor L3 is connected in series between the B5 frequency band branch and the B8 frequency band branch.

Other aspects of the second embodiment of the present invention, such as the matching network, the IFA antenna, the working principle, and the system performance, are the same as or similar to those of the first embodiment, and therefore, are not repeated herein.

In order to verify the excellent performance of the technical solutions of the IFA antenna system provided by the embodiment of the present invention, the inventor first performs two-term (antenna reflection coefficient S11, radiation efficiency, and system efficiency) comparative simulation tests on the B28 frequency band with respect to the technical solution provided by the first embodiment shown in fig. 7 and the technical solution provided by the second embodiment shown in fig. 8, where compared with the two technical solutions, the prior art solution is a system solution when the series inductance L0 is not added in the IFA antenna system shown in fig. 7.

Fig. 9 is a result of S11 parameter testing of an antenna system in a B28 frequency band according to a first embodiment of the present invention; fig. 10 is a test result of the radiation efficiency and the system efficiency of the antenna system in the B28 frequency band in the technical solution provided by the first embodiment of the present invention.

Fig. 11 is a result of S11 parameter testing of an antenna system in a B28 frequency band according to a second embodiment of the present invention; fig. 12 is a test result of the radiation efficiency and the system efficiency of the antenna system in the B28 frequency band in the second embodiment of the present invention.

As can be seen in fig. 9 and 11, the prior art solution antenna system resonates at f1 and f2 in the 700MHz to 780MHz bandwidth. In the technical solutions provided by the first and second embodiments of the present invention, the series inductance and branch inductance in the matching network and the switching network are adjusted respectively, so that the antenna system resonates at f1 and f2, and then the comparative test of the radiation efficiency and the system efficiency is performed.

As can be seen from FIG. 10 and FIG. 12, in the bandwidth of 700MHz to 780MHz, the radiation efficiency of the prior art reaches-5.83 dB, and the system efficiency reaches-6.36 dB; the radiation efficiency of the technical scheme provided by the first embodiment of the invention reaches-5.36 dB, and the system efficiency reaches-5.91 dB; the radiation efficiency of the technical scheme provided by the second embodiment of the invention reaches-5.13 dB, and the system efficiency reaches-5.73 dB. Compared with the prior art, the radiation efficiency of the technical scheme provided by the first embodiment of the invention is improved by 0.47dB, and the system efficiency is improved by 0.45dB; the radiation efficiency of the technical scheme provided by the second embodiment of the invention is improved by 0.7dB, and the system efficiency is improved by 0.63dB.

By adopting the simulation test method, the inventor respectively carries out two-term (antenna reflection coefficient S11, radiation efficiency and system efficiency) comparison simulation test on the technical scheme of the IFA antenna system provided by the invention aiming at B20, B5 and B8 frequency bands, and the comparison with the data of the prior art shows that the radiation efficiency of the technical scheme provided by the first embodiment of the invention can be improved by 0.47dB to 0.79dB on average, and the system efficiency can be improved by 0.45dB to 0.68dB on average; according to the technical scheme provided by the second embodiment of the invention, the radiation efficiency can be improved by 0.7 dB-0.76 dB on average, and the system efficiency can be improved by 0.63 dB-0.68 dB on average.

It should be noted that the application range of the high-efficiency IFA antenna system provided by the present invention is not limited to the B28, B20, B5, and B8 frequency bands proposed in the embodiments, nor to the structural dimensions given in the embodiments, and is not limited to the structural forms and parameters of the matching network and the switching network.

The high efficiency IFA antenna system provided by the invention can be used in electronic equipment as an important component of a communication component. The electronic device mentioned herein is a computer device that can be used in a mobile environment and supports multiple communication systems such as GSM, EDGE, TD _ SCDMA, TDD _ LTE, FDD _ LTE, and the like, and includes a mobile phone, a notebook computer, a tablet computer, a vehicle-mounted computer, and the like. In addition, the technical scheme provided by the invention is also suitable for other radio frequency integrated circuit application occasions, such as a communication base station, an intelligent networking automobile and the like.

As shown in fig. 13, the electronic device at least includes a processor and a memory, and may further include a communication component, a sensor component, a power component, a multimedia component, and an input/output interface according to actual needs. The memory, the communication component, the sensor component, the power supply component, the multimedia component and the input/output interface are all connected with the processor. The memory may be a Static Random Access Memory (SRAM), an Electrically Erasable Programmable Read Only Memory (EEPROM), an Erasable Programmable Read Only Memory (EPROM), a Programmable Read Only Memory (PROM), a Read Only Memory (ROM), a magnetic memory, a flash memory, etc., and the processor may be a Central Processing Unit (CPU), a Graphics Processing Unit (GPU), a Field Programmable Gate Array (FPGA), an Application Specific Integrated Circuit (ASIC), a Digital Signal Processing (DSP) chip, etc. Other communication components, sensor components, power components, multimedia components, etc. may be implemented using common components and are not specifically described herein.

It can be seen from the detailed description of the technical solutions of the embodiments that, in the IFA antenna system provided by the present invention, the matching network and the switching network cooperate to implement the coverage and switching of each target frequency band, and the power loss on the switches of each frequency band is reduced by changing the distribution connection manner and the inductance value of the series inductor and the branch inductor in the switching network on the basis of ensuring the excellent S parameter of the antenna system, so that the radiation efficiency and the system efficiency of the antenna system are both significantly improved. Therefore, the high-efficiency IFA antenna system provided by the invention has the beneficial effects of ingenious and reasonable structural design, lower production cost, smaller chip size, excellent system performance and system efficiency and the like.

The above details the high efficiency IFA antenna system and the corresponding electronic device provided by the present invention. It will be apparent to those skilled in the art that various modifications can be made without departing from the spirit of the invention.

Claims (9)

1. A high-efficiency IFA antenna system comprises a matching network, and is characterized by also comprising an IFA antenna and a switch network; wherein the content of the first and second substances,

the matching network and the switch network work cooperatively to realize double resonance;

two transmission lines in the IFA antenna are respectively connected with the matching network and the switch network;

the switch network comprises N frequency band branches, the frequency band branches are connected in parallel, and N is a positive integer larger than 1.

2. The IFA antenna system of claim 1, wherein:

the IFA antenna comprises a first dielectric substrate (1 a), a second dielectric substrate (1 b), a third dielectric substrate (1 c), a fourth dielectric substrate (1 d), a first metal floor (2), a first antenna radiation metal patch (3), a second antenna radiation metal patch (4), a third antenna radiation metal patch (5), a fourth antenna radiation metal patch (6), a first transmission line (7) and a second transmission line (8); the fourth dielectric substrate (1 d) is vertically connected with the first dielectric substrate (1 a), the second dielectric substrate (1 b) and the third dielectric substrate (1 c), a first metal floor (2) covers the lower portion of the fourth dielectric substrate (1 d), and the first antenna radiation metal patch (3), the second antenna radiation metal patch (4), the third antenna radiation metal patch (5) and the fourth antenna radiation metal patch (6) respectively cover the outer sides of the first dielectric substrate (1 a), the second dielectric substrate (1 b) and the third dielectric substrate (1 c); one ends of a first transmission line (7) and a second transmission line (8) are respectively connected with the first metal floor (2) and the second antenna radiation metal patch (4), the other end of the first transmission line (7) is connected with the matching network, and the other end of the second transmission line (8) is connected with the switch network.

3. The IFA antenna system of claim 2, wherein:

the first metal floor (2) is etched on the lower surface of the fourth dielectric substrate (1 d) through a PCB process, and the first antenna radiation metal patch (3), the second antenna radiation metal patch (4), the third antenna radiation metal patch (5) and the fourth antenna radiation metal patch (6) are etched on the outer surfaces of the first dielectric substrate (1 a), the second dielectric substrate (1 b) and the third dielectric substrate (1 c) through the PCB process respectively.

4. The IFA antenna system of claim 2, wherein:

the first dielectric substrate (1 a), the second dielectric substrate (1 b) and the third dielectric substrate (1 c) are of a first thickness, and the fourth dielectric substrate (1 d) is of a second thickness; the width of the first metal floor (2) is slightly larger than that of the fourth medium substrate (1 d).

5. The IFA antenna system of claim 1 or 2, wherein:

the first transmission line (7) and the second transmission line (8) are spaced apart by a predetermined distance; the first transmission line (7) and the second antenna radiation metal patch (4) are both fed by a discrete feeding port (9).

6. The IFA antenna system of claim 1, wherein:

the switch network comprises N frequency band branches and a first series inductor (L0), wherein the N frequency band branches are respectively formed by connecting a frequency band switch and a branch inductor in series; the frequency band antenna comprises N frequency band branch circuits, wherein the branch circuit inductance ends of the N frequency band branch circuits are connected with a first series inductor (L0) in parallel, the other ends of the first series inductors (L0) are connected with a second transmission line (8) in the IFA antenna, and the frequency band switch ends of the N frequency band branch circuits are connected with a ground potential end respectively.

7. The IFA antenna system of claim 1, wherein:

the switch network comprises N frequency band branches and N series inductors, wherein the N frequency band branches are respectively formed by connecting a frequency band switch and a branch inductor in series; wherein, the branch road inductance end and the first series inductance (L0) and the second series inductance (L1) of first frequency channel branch road are connected, the other end of first series inductance (L0) with second transmission line (8) in the IFA antenna are connected, second series inductance (L1), third series inductance (L2) and the N series inductance (Ln) total N-1 series inductance divide equally to be connected respectively between the branch road inductance end of frequency channel branch road, N the frequency channel switch end of frequency channel branch road is connected with the earth potential end respectively.

8. The IFA antenna system of claim 6 or 7, wherein:

the series inductance and the branch inductance in the switch network adopt distributed or lumped inductance, and the frequency band switch adopts SP4T or SPST switch.

9. An electronic device comprising an IFA antenna system as claimed in any one of claims 1 to 8.

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