CN206282958U - Radio communication device - Google Patents

Abstract

The utility model provides a kind of radio communication device, it is stacked including metal shell and with the metal shell and the coil antenna on the inside of the radio communication device, the metal shell is provided with perforate, it is characterized in that, the perforate is not connected with the outer of the metal shell, the vortex for supplying to be produced in the metal shell is connected with the width of the perforate on the width by the electric capacity of the perforate, the electric capacity forms resonance circuit, the coil antenna and the metal shell inductive with the stray inductance of the metal shell.

Description

Radio communication device

Technical field

The utility model is related to the radio communication used in radio communication device, more particularly to short-distance wireless communication system Device.

Background technology

Radio frequency identification (RadioFrequencyIdentification：RFID, hereinafter referred to as RFID) technology is a kind of Contactless automatic identification technology, it realizes the automatic identification of article using electromagnetic wave.RFID is used as expense system, Item Management system Uniting, oneself is popularized.In rfid system, the read write line and RFID label tag is set to carry out radio communication in a non contact fashion, at these High-frequency signal is received and dispatched between device.Read write line and RFID label tag include respectively：Wireless IC for processing high-frequency signal (Integrated Circuit：Integrated circuit) chip and the antenna element for sending and receiving high-frequency signal.

If being, for example, using the HF frequency band rfid systems of 13.56MHz frequency bands, antenna to be used as using coil antenna.And And, the coil antenna of read write line side is coupled with the coil antenna of RFID label tag side via induced field.This rfid system Also it is mounted in mobile phone and smart mobile phone etc. in recent years.That is near-field communication (NFC：Near Field Communication) system.

Near-field communication is also called wireless near field communication, is a kind of short-range high frequency wireless communication technology, it is allowed to electronics Contact Point-to-Point Data Transmission exchange data is carried out between equipment.Because near-field communication has natural security, therefore, NFC technique is considered as being had great application prospect in fields such as mobile-phone payments.

In traditional NFC antenna application, NFC antenna radiant body, i.e. flexible PCB are generally arranged on battery top, Simultaneously in order to reduce battery for the negative effect of NFC antenna, it is necessary in flexible PCB and battery middle setting ferrite etc. Magnetic conductor.And, in order to prevent aerial signal from being shielded by metal shell, it is necessary to set opening on metal shell.

As shown in figure 1, coil antenna 2 can produce electromagnetic coupled after being powered with the opening 101 of metal shell 1, therefore in gold Induced and the sense of current (dotted arrow) rightabout (solid arrow) for flowing through coil antenna 2 in the opening 101 for belonging to housing 1 Electric current.The electric current flowed through along the edge of opening 101 is due to edge effect via the edge of slit 102 along metal shell 1 flowing.Therefore, under vertical view state, flowed with coil antenna 2 along the sense of current flowed around metal shell 1 Dynamic sense of current is identical.Therefore, by metal shell 1 magnetic direction for producing and the magnetic direction produced by coil antenna 2 It is identical.The area for being additionally, since metal shell 1 is bigger than coil antenna 2, therefore can utilize the electric current flowed through in metal shell 1 Produce to the magnetic field for extending on a large scale, communication distance expanded.

The content of the invention

Technical problem to be solved in the utility model

However, in said structure, because slit 102 is arranged to be connected with the outward flange of metal shell 1, therefore metal-back The structure of body 1 is more fragile, and deformation is easily produced under external force.

For this problem, it is proposed that a kind of antenna structure.As shown in Fig. 2 offered on metal shell 1 not with the gold Belong to the perforate 103 of the outward flange connection of housing 1.Coil antenna 2 is arranged to be covered under vertical view state the side of the perforate 103 (being downside in figure).Now, the vortex direction (thin arrow) in the sense of current (block arrow) of coil antenna 2 and metal shell 1 As shown in FIG..Specifically, as shown in Fig. 2 due to electromagnetic induction and the effect of edge effect, the shape in metal shell 1 12,13 are vortexed into there are two.The sense of current of vortex 12,13 is as shown in Fig. 2 vortex 12 is for clockwise, vortex 13 is inverse Clockwise, both induced electromotive force opposite polarities.Thus, the part that magnetic field energy is covered from perforate 103 by coil antenna 2 Into, and do not passed by the part that coil antenna 2 is covered from perforate 103, to form loop, so as to carry out signal transmission.

However, in the structure, as shown in Fig. 2 vortex 13 is near the vortex direction of coil antenna 2, i.e. inner round portion and line The sense of current for enclosing antenna 2 is opposite and vortex of outer perimeter section is in opposite direction, therefore the vortex of the inner round portion can be to signal Produce weakening effect.

The utility model is completed to solve the above problems, its object is to reduce weakening of the above-mentioned interior coil vortex to signal Effect, further improves antenna performance.

Solve the technical scheme that technical problem is used

Radio communication device of the present utility model includes metal shell and is stacked and is located at the metal shell Coil antenna on the inside of the radio communication device, the metal shell is provided with perforate, it is characterised in that the perforate and institute The outer for stating metal shell does not connect, and is connected with the width of the perforate and existed for the vortex produced in the metal shell By the electric capacity of the perforate on the width, the electric capacity forms resonance electricity with the stray inductance of the metal shell Road, the coil antenna and the metal shell inductive.

Preferably, narrow width part is provided with the perforate, the electric capacity is made up of the parasitic capacitance of the narrow width part.

Preferably, the narrow width part has the shape of bending.

Preferably, the electric capacity is external capacitor, and is arranged at the metal shell inner side, the two poles of the earth difference of the electric capacity It is connected to the both sides of the width of the perforate.

Preferably, the inside of the radio communication device is provided with circuit substrate, and the electric capacity is arranged at the circuit substrate On, the two ends of the electric capacity are connected respectively to the both sides of the width of the perforate by conductor portion.

Preferably, the inside of the radio communication device is provided with gain coil, and the two ends of the gain coil pass through respectively Conductor portion is connected to the both sides of the width of the perforate, and the electric capacity is by between the gain coil and the metal shell Parasitic capacitance and the gain coil itself parasitic capacitance constitute.

Preferably, the inside of the radio communication device is provided with gain metallic plate, and the gain metallic plate is provided with and this The opening of the outward flange connection of gain metallic plate, the gain metallic plate is connected to institute in the both sides of the opening by conductor portion The both sides of the width of perforate are stated, the electric capacity is by the parasitic capacitance structure between the gain coil and the metal shell Into.

Preferably, also including balun circuit, two uneven side terminals of the balun circuit respectively with the electric capacity Two ends electrically connect.

Preferably, two of the balun circuit wherein side ground connection of uneven side terminal.

Preferably, a wherein side of two of the balun circuit uneven side terminals is grounded via filter capacitor.

Preferably, the balun electric capacity includes tuning capacitance.

Preferably, the resonant frequency of the resonance circuit is consistent with the resonant frequency of the coil antenna.

Preferably, the coil antenna is O-shaped, and under vertical view state, the coil antenna only covers the length of the perforate Side on degree direction.

Preferably, the coil antenna is made up of the first coil being electrically connected to each other and the second coil, the first coil The side on the length direction of the perforate is covered, second coil covers the opposite side on the length direction of the perforate.

Preferably, under vertical view state, two sides close to each other of the first coil and second coil are Chong Die.

Preferably, the first coil is connected in series with second coil.

Preferably, the first coil is connected with second coils from parallel connection of coils.

Preferably, the coil antenna is 8-shaped, and the side on the length direction of the perforate is covered under vertical view state And opposite side,

Electric current direction of circling of the coil antenna near the side and the opposite side is opposite.

Utility model effect

According to radio communication device of the present utility model, including metal shell and it is stacked simultaneously with the metal shell Coil antenna on the inside of the radio communication device, the outward flange that the metal shell is provided with not with the metal shell connects Logical perforate, is connected with for the vortex that produces in the metal shell on the width on the width of the perforate By the electric capacity of the perforate, the electric capacity forms resonance circuit, the coil antenna with the stray inductance of the metal shell With the metal shell inductive, accordingly, it is capable to eliminate interior coil vortex (reversely vortex) on metal shell to aerial signal Declining profit effect, and the signal intensity in coil antenna can be strengthened using resonance circuit and inductive, improve the property of antenna Energy.

Further, since narrow width part has the shape of bending, therefore can further improve the parasitic capacitance and parasitism of narrow width part Inductance, so as to advantageously reduce resonant frequency, reaches design requirement.

Additionally, in the case of using external capacitor, can easily control capacitance size so as to control resonant frequency.

Additionally, in the case where electric capacity is formed using gain line circle, can easily by change gain antenna 4 shape, Size etc. adjusts resonant frequency.And in the case where electric capacity is formed using gain metallic plate, because metallic plate is easy to process, because This can reduces cost.

Additionally, by setting balun circuit, metal shell 1 can be directly used as a part for antenna, therefore can be further Enhancing signal intensity.

Additionally, by further setting tuning capacitance in balun circuit, can easily be adjusted by adjusting tuning capacitance Whole resonant frequency.

Additionally, when coil antenna is figure-eight coil, and cover another on the length direction of the perforate under vertical view state Side, when electric current direction of circling of the coil antenna near the side and the opposite side is opposite, coil antenna around The opposite two parts of line direction produce rightabout magnetic field respectively.Compared with above-mentioned O-shaped coil, due to opposite side be formed with around The opposite coil of line direction, therefore magnetic field formation loop is more beneficial for, can further improve the signal intensity of antenna.

Additionally, in the case where first coil and twin coil as the second coil is set, first coil and the second coil Connected in series or in parallel, under vertical view state, two sides close to each other of the first coil and second coil are Chong Die, Thus, the area of perforate can be maximally utilised, so that more magnetic fields pass through, it is strong so as to further improve aerial signal Degree.

Brief description of the drawings

Fig. 1 is the schematic diagram of sense of current when representing that opening 102 connects with the outward flange of metal shell 1.

Fig. 2 is the schematic diagram of sense of current when representing that opening 102 does not connect with the outward flange of metal shell 1.

Fig. 3 is the schematic diagram of the antenna structure of the radio communication device for representing implementation method 1.

Fig. 4 is the equivalent circuit diagram of the antenna structure of the radio communication device for representing implementation method 1.

Fig. 5 (A)~Fig. 5 (D) is the schematic diagram of other examples for representing narrow width part.

Fig. 6 is the schematic diagram of the variation for representing electric capacity C0.

Fig. 7 is the schematic diagram of another variation for representing electric capacity C0.

Fig. 8 is the schematic diagram of another variation for representing electric capacity C0.

Fig. 9 (A) and Fig. 9 (B) are the schematic diagrames of another variation for representing electric capacity C0.

Figure 10 (A)~Figure 10 (C) is the schematic diagram of another variation for representing electric capacity C0.

Figure 11 is the circuit diagram of the radio communication device of implementation method 2.

Figure 12 is the circuit diagram of the variation of the radio communication device of implementation method 2.

Figure 13 is the circuit diagram of another variation of the radio communication device of implementation method 2.

Figure 14 is the top view of the variation for showing coil antenna 2.

Figure 15 is the stereogram of another variation for showing coil antenna 2.

Figure 16 is the stereogram of another variation for showing coil antenna 2.

Figure 17 is the stereogram of another variation for showing coil antenna 2.

Specific embodiment

Below, each implementation method and its variation of radio communication device of the present utility model are said based on accompanying drawing It is bright, in the various figures same or equivalent part, position are marked identical label to illustrate.Additionally, in following explanation, will be wireless The back side of communicator, i.e. housing (or metal shell) side is set to top.

《Implementation method 1》

Fig. 3 is the schematic diagram of the antenna structure of the radio communication device for representing implementation method 1.Fig. 4 is to represent implementation method 1 Radio communication device antenna structure equivalent circuit diagram.Fig. 5 (A)~Fig. 5 (D) is that other examples for representing narrow width part are shown It is intended to.Fig. 6 is the schematic diagram of the variation for representing electric capacity C0.Fig. 7 is the schematic diagram of another variation for representing electric capacity C0.Fig. 8 It is the schematic diagram of another variation for representing electric capacity C0.Fig. 9 (A) and Fig. 9 (B) are the signals of another variation for representing electric capacity C0 Figure.Figure 10 (A)~Figure 10 (C) is the schematic diagram of another variation for representing electric capacity C0.

As shown in figure 3, antenna communication device includes metal shell 1, coil antenna 2 and is arranged on metal shell 1 Perforate 103.Perforate 103 is not connected with the outward flange of metal shell 1.ANT1, ANT2 are the current feed terminal of coil antenna 2, with nothing Line IC etc. is connected.Coil antenna 2 is stacked with metal shell 1, and positioned at radio communication device inner side, and the coil day Line 2 is electrically insulated with metal shell 1.

In present embodiment, narrow width part is provided with perforate 103.Due to the presence of narrow width part, near the narrow width part Parasitic capacitance, i.e. electric capacity C0 are formd, electric capacity C0 enables the inner round portion of the vortex 12,13 of the explanation of reference picture 2 along institute The width for stating perforate 103 passes through, therefore can eliminate weakening effect of the vortex inner round portion to aerial signal.

If as shown in figure 3, the inductance of the closed circuit of the top half of metal shell 1 is set into L1, by the latter half The inductance of closed circuit is set to L2, and the inductance of coil antenna 2 is set into LANT, then equivalent circuit is as shown in figure 4, electric capacity C0 and electricity Sense L1, L2 form resonance circuit.Also, coil antenna 2 be arranged on the lower section of metal shell 1 and with the inductive of metal shell 1.

In present embodiment, inductance L1, L2 shape of electric capacity C0, electric capacity C0 and metal shell is formed by setting narrow width part Into resonance circuit, and coil antenna 2 and the inductive of metal shell 1, therefore the interior coil vortex on metal shell 1 can be eliminated (reversely vortex) can strengthen coil antenna 2 to the declining profit effect of aerial signal using resonance circuit and inductive Signal intensity, improves the performance of antenna.

Narrow width part is not limited to shown in Fig. 3, can be as shown in Fig. 5 (A)~Fig. 5 (D), the shape with bending.Many institutes It is known, the resonant frequency f=1/ (2 π √ LC) of series resonant circuit.If desired resonance is reduced by increasing capacitance frequently Rate, in addition to the length of increase narrow width part is to increase parasitic capacitance when using the narrow width part shown in Fig. 3, it is also possible that by making Narrow width part can increase parasitic capacitance and the parasitism electricity of narrow width part with the bending shape as shown in such as Fig. 5 (A)~Fig. 5 (D) Sense, so as to reduce resonant frequency, is so conducive to circuit parameter design.Certainly, as long as parasitic capacitance can be produced, technology people Member can as needed, the size of for example required parasitic capacitance carried out come the shape to narrow width part it is arbitrarily devised.

It should be noted that narrow width part is not necessarily, it is also possible to form electric capacity otherwise.Fig. 6 is to represent electricity The figure of the variation of appearance.As shown in fig. 6, foring two tie points P1, P2 on metal shell 1, and perforate 103 is located at respectively Width both sides.As a mode for forming electric capacity, for example, can be directly connected to electric capacity between tie point P1, P2 C0.In the case where external capacitor, i.e. electric capacity C0 is directly connected to, can be humorous to adjust conveniently by the capacity of adjustment external capacitor Vibration frequency.Or, it is also possible to as shown in fig. 7, on the circuit substrate 3 that electric capacity C0 is arranged on inside radio communication device, and make Tie point P1, P2 are connected to the two ends of electric capacity C0 by conductor portion 14,15.Conductor portion 14,15 can be shell fragment, thimble, spiral shell The conductive parts such as nail.Furthermore, can be with as shown in figure 8, tie point P1, P2 be connected by conductor portion 14,15 While being connected to electric capacity C0 two ends, one end is connected to ground terminal GND.By being connected to ground terminal GND, filtering can be produced Effect.Moreover it is possible to electric capacity is separately set between GND as needed to strengthen filter effect.

Also a gain antenna 4 can be set up between metal shell 1 and coil antenna 2 as shown in Fig. 9 (A), Fig. 9 (B), should The two ends of gain antenna 4 are connected to tie point P1, P2.Now, parasitic capacitance is produced between gain antenna 4 and metal shell 1 C01, gain antenna 4 itself has parasitic capacitance C02 and stray inductance.The electric capacity C0 of the variation by parasitic capacitance C01 and Parasitic capacitance C02 is constituted.Due to being provided with gain antenna 4, therefore can easily by changing shape, the size of gain antenna 4 Etc. adjusting resonant frequency, and because gain antenna 4 itself has stray inductance, therefore it is more beneficial for reducing resonant frequency.

In addition it is also possible to as shown in Figure 10 (A)~Figure 10 (C), an increasing be set up between metal shell 1 and coil antenna 2 Beneficial metallic plate 5, the gain metallic plate 5 is connected with tie point P1, P2.Gain metallic plate 5 is provided with opening 501 and slit 502, with Make the vortex direction in gain metallic plate 5 consistent with the sense of current in coil antenna 2.Gain metallic plate 5 and tie point P1, P2 Connecting portion be located at the both sides of slit 502.As shown in Figure 10 (C), in the variation, electric capacity C0 is gain metallic plate 5 and metal Parasitic capacitance between housing 1.Compared with using the situation of gain antenna 4, gain metallic plate 5 is easy to process, can reduces cost.

Furthermore it is preferred that make the resonant frequency of the resonance circuit formed by inductance L1, L2 of electric capacity C0 and metal shell 1 with The resonant frequency of itself of coil antenna 2 is consistent, so as to further promotion signal intensity.

《Implementation method 2》

The radio communication device to implementation method 2 is illustrated below.

Figure 11 is the circuit diagram of the radio communication device of implementation method 2.Figure 12 is the radio communication device of implementation method 2 The circuit diagram of variation.Figure 13 is the circuit diagram of another variation of the radio communication device of implementation method 2.

As shown in figure 11, the radio communication device of present embodiment is compared with implementation method 1, on the basis of implementation method 1 On, balun circuit 6 is further set up between tie point P1, P2.Two of balun circuit 6 uneven side terminals respectively be connected Point P1, P2 are connected, and balance side terminal Tx1, Tx2 are for example connected to wireless IC 7.

In implementation method 1, resonance circuit is formed come inductance L1, the L2 with metal shell 1 itself by setting electric capacity C0. In other words, the metal shell 1 of implementation method 1 plays a role as the coil of resonance circuit.And in present embodiment 2, by gold Tie point P1, the P2 for belonging to housing 1 are connected to wireless IC 7 by balun circuit 6, thus metal shell 1 is directly as antenna performance Effect, can further enhance signal intensity.

Figure 12 shows the variation of the radio communication device of present embodiment.In the variation, two of balun circuit 6 are not The wherein side ground connection of balance side terminal (being P2 in figure).By ground connection, filter effect can be further produced.Moreover it is possible to Electric capacity is separately set between GND as needed to strengthen filter effect.

Figure 13 shows another variation of the radio communication device of present embodiment.In the variation, inside balun circuit 6 It is additionally arranged tuning capacitance C1.By setting tuning capacitance C1, resonant frequency easily can be adjusted by adjusting tuning capacitance C1. In this variation, tuning capacitance C1 is arranged on the earth terminal of the uneven side of balun circuit 6, but the utility model is not limited to This, it is also possible to it is arranged near other terminals of balun circuit 6, for example, balances side terminal, the ungrounded end of uneven side terminal Deng.

Additionally, in present embodiment, electric capacity C0 can be formed using the any-mode illustrated in above-mentioned implementation method 1. Can also select to set or be not provided with ground terminal GND as needed.Also, in the case where tuning capacitance C1 is provided with, can Removed with by electric capacity C0.

《Other variations》

In implementation method 1 and 2, to coil antenna 2 for O-shaped situation is illustrated, but coil of the present utility model Antenna 2 is not limited to this.

Figure 14 is the top view of the variation for showing coil antenna 2.

As shown in figure 14, coil antenna 2 can by be covered each by under vertical view state on the length direction of perforate 103 two The coil antenna 2A and coil antenna 2B of side are constituted.And the direction of circling of coil antenna 2A and coil antenna 2B can it is opposite or Person is identical.F1, F2 are current feed terminal.When coil antenna 2A is opposite with the direction of circling of coil antenna 2B, both connect for series connection Connect, conversely, when coil antenna 2A is identical with the direction of circling of coil antenna 2B, both are to be connected in parallel.It is either in parallel to connect Connect or be connected in series, compared with prior art, the intensity of aerial signal can be improved.In the case where being connected in series, coil Therefore electric current direction of circling in antenna 2A, 2B conversely, being more beneficial for magnetic field and forming loop.

Figure 15 is the stereogram of another variation for showing coil antenna 2.

As shown in figure 15, hithermost each other two of coil antenna 2A and coil antenna 2B while, i.e. while a1, a2 in vertical view Overlapped under state.Now, the area of perforate 103 can be maximally utilised, so that more magnetic fields pass through, so as to further Improve antenna signal strength.

Figure 16 and Figure 17 are the stereograms of another variation for showing coil antenna 2.

As shown in figure 16, coil antenna 2 is wound into the both sides in 8-shaped, and the length direction of covering perforate 103 simultaneously. The sense of current of coil antenna 2 is as shown in the figure.Due to being wound into 8-shaped, therefore the electric current of the latter half flows along clockwise direction Dynamic, the electric current of top half flows in the counterclockwise direction.Therefore, two-part coil antenna 2 is produced in the opposite direction respectively up and down Magnetic field so that magnetic field can enter from side and pass from opposite side, so as to form loop, to carry out signal transmission.Phase Than in the situation of O shape coils, figure-eight coil is with the side on the length direction of opposite sense of current covering perforate 103 and separately Side, therefore the magnetic field intensity of the opposite side is further improved, so as to improve the performance of the entirety of coil antenna 2.Certainly, Figure-eight coil is not limited to the situation shown in Fig. 8.As long as the electric current direction of circling phase in the coil antenna 2 of upper and lower both sides can be made It is anti-, for example can also be coil antenna 2 as shown in figure 17.

In the variation shown in above-mentioned Figure 14~Figure 17, what electric capacity C0 can be disclosed using above-mentioned implementation method 1~2 appoints A kind of mode is anticipated to be formed.

Preferred embodiment of the present utility model described in detail above and its variation.It should be appreciated that this practicality is new Type can use various implementation methods and deformation in the case where its broad spirit and scope is not departed from.The ordinary skill of this area Personnel just can make many modifications and variations without creative work according to design of the present utility model.Therefore, all this areas Technical staff on the basis of existing technology can by logical analysis, reasoning, or a limited experiment according to design of the present utility model With the technical scheme for obtaining, should all belong in the protection domain determined by claims of the present utility model.

Label declaration

1 metal shell

101 openings

102 slits

103 perforates

2nd, 2A, 2B coil antenna

3 circuit substrates

4 gain antennas

5 gain metallic plates

501 openings

502 slits

12nd, 13 vortex

P1, P2 tie point

14th, 15 conductor portion

C0 electric capacity

C01, C02 parasitic capacitance

ANT1, ANT2 current feed terminal

F1, F2 current feed terminal

L1, L2 inductance

Claims (18)

1. a kind of radio communication device, including metal shell and it is stacked with the metal shell and positioned at the channel radio Coil antenna on the inside of T unit, the metal shell is provided with perforate, it is characterised in that

The perforate is not connected with the outer of the metal shell,

It is connected with the width of the perforate and is passed through on the width for the vortex produced in the metal shell The electric capacity of the perforate,

The electric capacity forms resonance circuit with the stray inductance of the metal shell,

The coil antenna and the metal shell inductive.

2. radio communication device as claimed in claim 1, it is characterised in that

Narrow width part is provided with the perforate,

The electric capacity is made up of the parasitic capacitance of the narrow width part.

3. radio communication device as claimed in claim 2, it is characterised in that

The narrow width part has the shape of bending.

4. radio communication device as claimed in claim 1, it is characterised in that

The electric capacity is external capacitor, and is arranged at the metal shell inner side,

The two poles of the earth of the electric capacity are connected respectively to the both sides of the width of the perforate.

5. radio communication device as claimed in claim 1, it is characterised in that

The inside of the radio communication device is provided with circuit substrate, and the electric capacity is arranged on the circuit substrate,

The two ends of the electric capacity are connected respectively to the both sides of the width of the perforate by conductor portion.

6. radio communication device as claimed in claim 1, it is characterised in that

The inside of the radio communication device is provided with gain coil, and the two ends of the gain coil are connected to by conductor portion respectively The both sides of the width of the perforate,

The electric capacity is by the parasitic capacitance between the gain coil and the metal shell and the gain coil itself Parasitic capacitance is constituted.

7. radio communication device as claimed in claim 1, it is characterised in that

The inside of the radio communication device is provided with gain metallic plate, and the gain metallic plate is provided with and the gain metallic plate The opening of outward flange connection,

The gain metallic plate is connected to the both sides of the width of the perforate in the both sides of the opening by conductor portion,

The electric capacity is made up of the parasitic capacitance between the gain coil and the metal shell.

8. radio communication device as claimed in claim 1, it is characterised in that

Also include balun circuit, the two ends of two of the balun circuit uneven side terminals respectively with the electric capacity electrically connect.

9. radio communication device as claimed in claim 8, it is characterised in that

The wherein side ground connection of the uneven side terminal of two of the balun circuit.

10. radio communication device as claimed in claim 8, it is characterised in that

A wherein side of the uneven side terminal of two of the balun circuit is grounded via filter capacitor.

11. radio communication devices as claimed in claim 8, it is characterised in that

The balun electric capacity includes tuning capacitance.

12. radio communication devices as claimed in claim 1, it is characterised in that

The resonant frequency of the resonance circuit is consistent with the resonant frequency of the coil antenna.

13. radio communication device as described in any one of claim 1 to 12, it is characterised in that

The coil antenna for O-shaped,

Under vertical view state, the coil antenna only covers the side on the length direction of the perforate.

14. radio communication device as described in any one of claim 1 to 12, it is characterised in that

The coil antenna is made up of the first coil being electrically connected to each other and the second coil,

The first coil covers the side on the length direction of the perforate, and second coil covers the length of the perforate Opposite side on direction.

15. radio communication devices as claimed in claim 14, it is characterised in that

Under vertical view state, two sides close to each other of the first coil and second coil are Chong Die.

16. radio communication devices as claimed in claim 14, it is characterised in that

The first coil is connected in series with second coil.

17. radio communication devices as claimed in claim 14, it is characterised in that

The first coil is connected with second coils from parallel connection of coils.

18. radio communication device as described in any one of claim 1 to 12, it is characterised in that

The coil antenna is 8-shaped, and the side on the length direction of the perforate and opposite side are covered under vertical view state,

Electric current direction of circling of the coil antenna near the side and the opposite side is opposite.