JP2014103589A - Composite antenna device and portable terminal electronic apparatus using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composite antenna device compatible with an electromagnetic wave of a plurality of frequency bands neighboring closely to one another while securing an antenna performance corresponding to an NFC, and to provide a portable terminal electronic apparatus using the same.SOLUTION: A composite antenna device 10 includes: a coil conductor 1 connected to a first feeding part 31 through a first matching circuit 12; a conductor layer 2 connected to a second feeding part 32 through a second matching circuit 13; a conductor opening OP connected to a third feeding part 33 through a third matching circuit 14; a first slit part SL1; a second slit part SL2; an auxiliary conductor 11; and an electromagnetic wave shielding body 20.

Description

  The present invention relates to a composite antenna device capable of handling radio waves in a plurality of frequency bands and a portable terminal electronic device using the same.

  NFC (Near Field Communication) is used for payment by electronic money using a non-contact communication function. 2. Description of the Related Art Wireless communication devices typified by mobile phones have become widely used that have functions such as payment of electronic money using NFC. In recent years, multi-functionalization of wireless communication devices has progressed. For example, there is a mobile communication device having a function of searching for a position using a GPS (Global Positioning System) and a function of communicating with another device using a WLAN (Wireless Local Area Network). Such a wireless communication device communicates with a plurality of communication targets using radio waves of a plurality of frequency bands corresponding to the respective functions. Therefore, it is necessary to handle the radio waves of a plurality of frequency bands with a single radio communication device. is there. For example, Patent Document 1 describes a composite antenna in which a far-field communication antenna is arranged at the center of two NFC antenna conductors, reduces interaction with each other, and prevents deterioration of communication characteristics of each antenna. .

JP2011-101293A

  When NFC is used, communication is performed between a wireless communication device and an external device in a non-contact manner. In this case, since it is necessary to read information in a short time without contact, it is preferable that the performance of the antenna used for NFC communication is high. However, multiband antennas that can support multiple frequency bands need to support radio waves in multiple frequency bands, so it is difficult to ensure the required performance in each frequency band, and narrowing the adjacent area by reducing the mounting area However, the mutual coupling between the antenna elements becomes large, and there is a problem that good characteristics of each antenna cannot be obtained.

  The present invention has been made in view of the above, and has a composite antenna device that can handle radio waves in a plurality of frequency bands that are narrowly adjacent while securing the performance of an antenna that supports NFC, and a mobile phone using the same. An object is to provide a terminal electronic device.

  The present invention relates to an antenna substrate, a loop-shaped or spiral coil conductor having a coil opening at a winding center formed on one surface of the antenna substrate, and a conductor layer formed on the other surface of the antenna substrate. The conductor layer has a conductor opening, a first slit connected to the conductor opening, and a second slit connected to the outer edge of the conductor layer. In the composite antenna device, the coil conductor has a first feeding part, the conductor layer has a second feeding part, a third feeding part, and an auxiliary conductor connected to the ground, and the third feeding part And the auxiliary conductor are arranged with the second slit portion interposed therebetween, and the coil conductor is a region other than the first slit portion and the second slit portion in the conductor layer, and in the coil opening portion of the coil conductor and the conductor layer. Opposite the conductor opening through the antenna substrate It is disposed a composite antenna device according to the first aspect.

  The composite antenna device having the above characteristics can handle radio waves in a plurality of frequency bands. In the coil conductor antenna, when a current flows through the coil conductor formed on one surface of the antenna substrate, a current flows around the conductor opening of the conductor layer formed on the other surface of the antenna substrate. Passes around the periphery of the first slit portion and the second slit portion, and further circulates around the outer edge portion of the conductor layer. As a result, a magnetic field is generated from the conductor layer, and the magnetic flux is circulated greatly, so that the maximum communicable distance between the composite antenna device and the external communication device is increased, and the performance of the coil conductor antenna can be ensured.

  In addition, the antenna using the conductor layer is connected to the second power feeding unit and operates at a frequency higher than the use frequency of the coil conductor antenna. Furthermore, the antenna formed of the conductor opening, and the first slit portion and the second slit portion is connected to the third power feeding portion and operates at a frequency higher than the operating frequency of the antenna using the conductor layer. To do. The antenna of the coil conductor, the antenna using the conductor layer, the conductor opening, and the antenna constituted by the first slit portion and the second slit portion are arranged on the same antenna substrate. As a result, the area of the composite antenna device can be reduced.

  Further, in the composite antenna device according to the present invention, the first feeding unit is arranged in a region including a location where the impedance of the resonance frequency of the antenna having the third feeding unit is minimized, and the second feeding unit is A composite antenna device having a second feature is that the antenna having the third power feeding portion is disposed apart from a region including a portion where the impedance of the resonance frequency of the antenna is minimized.

  According to the composite antenna device having the above characteristics, the first feeding unit and the second feeding unit are arranged on the basis of the location where the impedance of the resonance frequency of the antenna having the third feeding unit is minimized. The current flowing through the antenna formed by the conductor opening and the first slit portion and the second slit portion can be controlled to ensure the performance of the antenna. In this case, the region in which the antenna performance can be ensured in this way is referred to as “a region including a portion where the impedance of the resonance frequency is minimized”. In addition, the area | region which ensures antenna performance is an area | region which can maintain 50% or more of the radiation efficiency of the frequency band of the area | region W, and the antenna outside a band, as shown to FIG.

  The composite antenna device according to claim 1, wherein the composite antenna device according to the present invention is characterized in that the slit length of the first slit portion is longer than the slit length of the second slit portion. is there.

  According to the composite antenna device having the above characteristics, it is easy to match the impedance matching of the antenna formed by the conductor opening and the first slit portion and the second slit portion, and the radiation efficiency of the antenna is increased. Performance can be ensured.

  Furthermore, in the composite antenna device according to the present invention, the conductor layer is connected to the auxiliary conductor having a capacitive component between the conductor layer and the ground with the antenna substrate interposed therebetween, and the capacitive element is connected to the third feeding portion. 4 is a composite antenna device characterized by being connected.

  According to the composite antenna device having the above characteristics, the conductor layer is connected to the auxiliary conductor having a capacitive component between the conductor layer and the ground with the antenna substrate interposed therebetween, and the capacitive element is connected to the third feeding portion. As a result, the current of the antenna using the conductor layer is less likely to flow to the ground, and the radiation efficiency of the antenna is increased, so that the performance degradation of the antenna using the conductor layer can be suppressed. In addition, since the capacitive element matches the impedance matching of the antenna formed by the conductor opening, and the first slit portion and the second slit portion, and the radiation efficiency of the antenna is increased, the conductor opening and the first The performance of the antenna composed of the slit portion and the second slit portion can be ensured.

  Furthermore, the composite antenna device according to the present invention is a composite antenna device having a fifth characteristic that an electromagnetic wave shielding body is provided in a region other than the first slit portion and the second slit portion in the conductor layer.

  According to the composite antenna device having the above characteristics, while suppressing the performance of the antenna of the coil conductor, it is possible to suppress the performance degradation of the antenna configured by the conductor opening and the first slit portion and the second slit portion. Can do.

  Furthermore, a portable terminal electronic device according to the present invention is characterized in that any one of the composite antenna devices described above is provided in a housing.

  According to the portable terminal electronic device having the above characteristics, it is possible to provide a multiband portable terminal electronic device associated with a plurality of frequency bands while supporting NFC.

  The present invention has been made in view of the above, and provides a composite antenna device and a portable terminal electronic device that can cope with radio waves in a plurality of narrowly adjacent frequency bands while ensuring the performance of an antenna corresponding to NFC. Can be provided.

It is a perspective view of the compound antenna device concerning an embodiment. It is a top view of the composite antenna apparatus of FIG. It is a schematic diagram which shows the cross-section of the composite antenna apparatus of FIG. FIG. 2 is an exploded perspective view of the composite antenna device of FIG. 1. It is a top view which shows the compound antenna apparatus and external communication apparatus which concern on this embodiment. FIG. 5B is a plan view of the composite antenna device and the external communication device of FIG. 5A when the first slit portion and the second slit portion are not present in the composite antenna device. It is A-A 'sectional drawing which shows the magnetic field coupling state of the composite antenna apparatus of FIG. 5A, and an external communication apparatus. FIG. 5B is a B-B ′ sectional view showing a magnetic field coupling state between the composite antenna device of FIG. 5B and the external communication device. FIG. 7A is a distribution diagram of an antenna current density vector when the first feeding unit is arranged in a region including a portion where the impedance of the antenna having the third feeding unit is minimized. FIG. 7B is a distribution diagram of the current density vector of the antenna when the first feeding unit is arranged apart from the region including the portion where the impedance of the antenna having the third feeding unit is minimized. FIG. 7C is a diagram illustrating a radiation characteristic of the antenna having the third power feeding unit due to a difference in arrangement of the first power feeding unit. FIG. 8A is a distribution diagram of the antenna current density vector when the second feeding unit is arranged away from a region including a portion where the impedance of the antenna having the third feeding unit is minimized. FIG. 8B is a distribution diagram of the current density vector of the antenna when the second feeding unit is arranged in a region including a portion where the impedance of the antenna having the third feeding unit is minimized. FIG. 8C is a diagram illustrating a radiation characteristic of the antenna having the third power feeding unit due to a difference in arrangement of the second power feeding unit. It is a top view which shows the dimension and shape of the composite antenna apparatus with which it used for evaluation. It is a figure which shows the transmission loss of the antenna of a coil conductor. It is a figure which shows the electrical property of the antenna using a conductor layer. It is a figure which shows the electrical property of the antenna comprised by the conductor opening part and the 1st slit part and the 2nd slit part.

  Preferred embodiments for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited by the contents described in the following embodiments. The constituent elements described below include those that can be easily assumed by those skilled in the art, those that are substantially the same, and those that are equivalent. Furthermore, the constituent elements described below can be appropriately combined. In addition, various omissions, substitutions, or changes of components can be made without departing from the scope of the present invention.

  A composite antenna device 10 according to an embodiment of the present invention will be described with reference to FIGS. 1, 2, 3, and 4. FIG. 1 is a perspective view of the composite antenna device 10 according to the present embodiment, and FIG. 2 is a plan view of the composite antenna device 10. Further, FIG. 3 is a cross-sectional view taken along the line A-A ′ of FIG. 2. FIG. 4 is an exploded perspective view of the composite antenna device 10. The composite antenna device 10 is mounted on a wireless communication device such as a mobile phone and has a function of receiving or transmitting radio waves in a plurality of frequency bands, and is referred to as a multiband antenna as an example. The application target of the composite antenna device 10 may be any wireless communication device having a plurality of wireless communication functions, and is not limited to a mobile phone.

  As shown in FIG. 1, the composite antenna device 10 according to the present embodiment includes a coil conductor 1, a first feeding unit 31, a conductor layer 2, and a second matching circuit via a first matching circuit 12. 13 through the second power feeding section 32, the conductor opening OP, the first slit section SL1 and the second slit section SL2, the ground (not shown) through the auxiliary conductor 11, and the third The third power supply unit 33 is connected via the matching circuit 14. The electromagnetic wave shielding sheet 20 is disposed at a position where the first slit portion SL1 and the second slit portion SL2 do not overlap.

  As shown in FIG. 2, the composite antenna device 10 according to the present embodiment includes a first feeder line 21 </ b> A on terminal electrodes 34 </ b> A and 34 </ b> Ba for the antenna of the coil conductor 1 (not shown) disposed on the circuit board 30. , 21B are connected, and the second feeder 22 is connected to the terminal electrode 35 for the antenna using the conductor layer 2, and the conductor opening OP and the first slit portion SL1 and the second slit portion SL2 A third feed line 23 is connected to the terminal electrode 36A for the configured antenna. Further, the first power supply unit 31 is connected to the terminal electrode 34A and the terminal electrode 34Bb, and the first matching circuit capacitor 12Ca is connected to the terminal electrode 34A and the terminal electrode 34Ba in parallel to each other. In the circuit capacitor 12Cb, a terminal electrode 34Ba and a terminal electrode 34Bb are connected in series. Further, in the third matching circuit capacitor 14C, the terminal electrode 36A and the terminal electrode 36B are connected in series.

  As shown in FIG. 3, the composite antenna device 10 according to the present embodiment is disposed inside a housing 100 of a mobile phone. The material of the housing 100 is, for example, PC (Poly Carbonate) / ABS (Acrylonitrile Butadiene Styrene) resin. The coil conductor 1 is provided on one surface of the antenna substrate 10FB, the conductor layer 2, the conductor opening OP (not shown), the first slit portion SL1 (not shown), and the second surface on the other surface of the antenna substrate 10FB. Slit portion SL2 (not shown) is formed. These are formed, for example, by bonding a predetermined conductor pattern (a metal foil such as copper or aluminum) to the surface of the antenna substrate 10FB with an adhesive. In this embodiment, the antenna substrate 10FB is FPC (Flexible Print Circuits), but the antenna substrate 10FB is not limited to this, and may be a dielectric or magnetic ceramic. An effective relative permittivity or relative permeability is appropriately set according to desired characteristics. Members having different material characteristics may be combined.

  As shown in FIG. 4, the composite antenna device 10 according to the present embodiment is configured by the above-described elements, and the antenna of the coil conductor 1 (not shown) having the first power feeding unit is the backbone of the present application. As an antenna that can handle radio waves in a plurality of frequency bands in which an NFC antenna and two or more antennas are narrowly adjacent to each other, for example, a FM feeder having a second power feeding unit using a conductor layer 2 (not shown) A WLAN antenna (2400-2484 MHz) having a corresponding antenna, a conductor opening OP, and a third feeding portion (not shown) constituted by the first slit portion SL1 and the second slit portion SL2. The antenna structure corresponding to is shown.

  At this time, the antenna of the coil conductor 1 transmits and receives radio waves with a wavelength of λ1 at the resonance frequency f1, and the antenna using the conductor layer 2 transmits and receives radio waves with a wavelength of λ2 at the resonance frequency f2, and the conductor opening OP, And the antenna comprised by 1st slit part SL1 and 2nd slit part SL2 transmits / receives the electromagnetic wave whose wavelength in the resonant frequency f3 is (lambda) 3.

  When the coil conductor 1 functions as an NFC antenna, the first resonance frequency f1 is controlled by the first matching circuit 12. The first matching circuit 12 is provided in order to obtain a good reflection loss characteristic in NFC which is a predetermined band of the coil conductor 1. Specifically, the first matching circuit 12 includes a parallel first matching circuit capacitor 12Ca (220 pF) and a series first matching circuit capacitor 12Cb (75 pF).

  When the conductor layer 2 functions as an FM band antenna, the length of the conductor layer 2 and the second matching circuit 13 control the second resonance frequency f2. Since the auxiliary conductor 11 is provided between the conductor layer 2 and the ground with the FPC antenna substrate 10FB having a small thickness interposed therebetween, high impedance is obtained at a frequency equal to or lower than the frequency (108 MHz) of the FM band that is a predetermined band of the antenna. It has the capacitive component of a low-frequency cut capacitive element. Further, the third matching circuit capacitor 14C also has a capacitor value (1.8 pF) that becomes high impedance (960 Ω) at a frequency equal to or higher than the frequency (76 MHz) of the FM band, which is a predetermined band of the antenna using the conductor layer 2. doing.

  When the conductor opening OP and the first slit portion SL1 and the second slit portion SL2 function as a WLAN band antenna, the conductor opening OP, the first slit portion SL1, and the second slit are provided. The length of the portion SL2 and the third matching circuit 14 control the third resonance frequency f3. The capacitor 14C for the third matching circuit has a frequency equal to or higher than the resonance frequency (2400 MHz) of the WLAN band, which is a predetermined band of the antenna formed by the conductor opening OP and the first slit portion SL1 and the second slit portion SL2. The capacitor value (1.8 pF) is low and low impedance (28Ω).

  The electromagnetic wave shielding sheet 20 is a sheet of a material such as a metal or a magnetic material. The electromagnetic wave shielding sheet 20 is provided on the surface of the coil conductor 1 in order to suppress the influence of electromagnetic waves radiated or reflected from the circuit board 30 of the wireless communication device such as a mobile phone. Improved performance.

  Furthermore, the material loss of the magnetic material used in the electromagnetic wave shielding sheet 20 is larger in the WLAN band than in the NFC band. When the electromagnetic wave shielding sheet 20 is affixed to the conductor opening OP, the conductor opening OP and the first slit portion SL1 and the second slit portion SL2 are configured as compared to the case where the electromagnetic wave shielding sheet 20 is not affixed. The magnetic field radiated from the formed antenna passes through the electromagnetic wave shielding sheet 20 widely. And due to the material loss used for the electromagnetic wave shielding sheet 20, the radiation magnetic field from the antenna constituted by the conductor opening OP and the first slit portion SL1 and the second slit portion SL2 is weakened, and the radiation characteristics are to degrade. That is, by narrowing the region where the radiated magnetic field does not pass through the electromagnetic wave shielding sheet 20, the radiation characteristics of the antenna constituted by the conductor opening OP and the first slit portion SL1 and the second slit portion SL2 are improved. Meanwhile, the radiation characteristics of the antenna of the coil conductor 1 can be improved.

  Furthermore, the composite antenna device 10 according to the present embodiment includes the coil conductor 1 on one surface of the antenna substrate 10FB, the conductor layer 2, the conductor opening OP, the first slit portion SL1, and the second surface on the other surface. By providing the slit portion SL2 and providing the first matching circuit 12, the second matching circuit 13, and the third matching circuit 14 on the circuit board 30, the dead space between the composite antenna device 10 and the circuit board 30 is utilized. Thus, the radiation characteristics of each antenna of the composite antenna device 10 can be improved.

  As described above, in the embodiment of the present invention, an antenna including the coil conductor 1 antenna, the antenna using the conductor layer 2, the conductor opening OP, and the first slit portion SL1 and the second slit portion SL2 is provided. By arranging them integrally, it is possible to ensure the performance of the antenna of the coil conductor 1 corresponding to NFC by effectively utilizing the limited space of the base. As a result, the composite antenna device 10 of the present embodiment is suitable for a device that supports radio waves in a plurality of frequency bands and has a limited space inside the housing, for example, a portable wireless communication device.

  Next, FIG. 5A is a plan view showing a magnetic field coupling state between the composite antenna device 10 and the external communication device 40 according to the present embodiment. FIG. 6A is a cross-sectional view taken along the line A-A ′ showing a magnetic field coupling state between the composite antenna device 10 of FIG. 5A and the external communication device 40. 5B is a plan view showing a state in which the first slit portion SL1 and the second slit portion SL2 of the conductor layer 2 do not exist for the composite antenna device 10 according to this embodiment. FIG. 6B is a B-B ′ sectional view showing a state where the first slit portion SL <b> 1 and the second slit portion SL <b> 2 of the conductor layer 2 do not exist.

  5A and 5B indicate eddy currents flowing through the conductor layer 2. As indicated by the wavy lines, eddy currents I <b> 1, I <b> 2, and I <b> 3 flow through the conductor layer 2 when approaching the external communication device 40. The eddy current I1 is a current that flows along the edge of the conductor layer 2, and the eddy current I2 is a current that flows around the conductor opening OP and the first slit portion SL1 and the second slit portion SL2. The current I3 is a current that flows only around the conductor opening OP.

  Comparing FIG. 5A and FIG. 5B, the eddy current I2 in FIG. 5A has the first slit portion SL1 and the second slit portion SL2, and therefore the eddy current I1 goes around the edge of the conductor layer 2. It is not possible to bypass the first slit portion SL1 and the second slit portion SL2. Since the conductor opening OP is provided at the detour destination (the inner ends of the first slit portion SL1 and the second slit portion SL2), an eddy current I2 that is reverse to the eddy current I1 is generated. The eddy current I3 in FIG. 5B flows in the same direction as the eddy current I1 only around the conductor opening OP because the first slit portion SL1 and the second slit portion SL2 do not exist.

  Therefore, since the eddy current flowing in the conductor layer 2 is generated by the magnetic field generated from the external communication device 40, the eddy currents I1 and I3 flow in the direction of generating a magnetic field that weakens this magnetic field. On the other hand, since the eddy current I2 flows in a direction opposite to the eddy current I1, the eddy current I2 is a current that generates a magnetic field in a direction that strengthens the magnetic field generated from the external communication device 40. Accordingly, the magnetic field is rather strengthened by the flow of the eddy current I2, and the case where the first slit portion SL1 and the second slit portion SL2 are not provided in the conductor layer 2 is of course compared to the case without the conductor layer 2. Ring characteristics will be improved.

  Next, FIG. 6A and FIG. 6B show the comparison results obtained by simulating magnetic field radiation intensity from the conductor opening OP toward the external communication device 40. As demonstrated from both figures, a strong magnetic field is generated by providing the first slit portion SL1 and the second slit portion SL2. This is caused by the eddy current I2 described above. The use of the conductor layer 2 provided with the first slit portion SL1 and the second slit portion SL2 improves the coupling characteristics because this magnetic field is generated. is there.

  As described above, by providing the conductor layer 2 with the first slit portion SL1 and the second slit portion SL2, the coupling characteristics between the composite antenna device 10 and the external communication device 40 are improved. This is because this magnetic field is generated.

  Next, FIG. 7A is a distribution diagram of the antenna current density vector when the first feeding unit 31 is arranged in a region including a portion where the impedance of the resonance frequency of the antenna having the third feeding unit 33 is minimized. It is. FIG. 7B is a distribution diagram of the current density vector of the antenna when the antenna having the third power feeding portion 33 is arranged away from the region including the portion where the impedance of the resonance frequency is minimum. FIG. 7C is a diagram illustrating the radiation characteristics of the antenna having the third power feeding unit 33 depending on the arrangement of the first power feeding unit 31. The area W in the figure is an index indicating the frequency band of the WLAN band. N in the figure is the radiation efficiency of the antenna when the first power feeding unit 31 is disposed in a region including a portion where the impedance of the antenna having the third power feeding unit 33 is minimized. F in the figure is the radiation efficiency of the antenna when the first power supply unit 31 is arranged away from the region including the portion where the impedance of the antenna having the third power supply unit 33 is minimized.

  In addition, the 1st electric power feeding part 31 (2nd electric power feeding part 32) is arrange | positioned on the basis of the location where the impedance of the resonant frequency of the antenna which has the 3rd electric power feeding part 33 becomes the minimum. This reference location is a location where the resonance frequency of the antenna is a quarter wavelength apart without inserting the first slit portion SL1 and the second slit portion SL2.

  In view of the above, the line with an arrow shown in FIGS. 7A and 7B indicates the current of the antenna having the third feeding portion 33 flowing in the conductor layer 2. As indicated by this line, when the first feeding unit 31 is arranged in a region including a portion where the impedance of the resonance frequency of the antenna having the third feeding unit 33 is minimized, the current of the antenna is Currents flowing in opposite directions are flowing. On the other hand, when the first feeding unit 31 is arranged away from the region including the portion where the impedance of the resonance frequency of the antenna having the third feeding unit 33 is minimized, the direction in which the current flows through the antenna is changed. Since they are messy and cancel each other, the radiation magnetic field of the antenna becomes weak, and the radiation characteristics of the antenna deteriorate as shown by F in FIG. 7C.

  Next, FIG. 8A is a distribution diagram of the current density vector of the antenna when the second feeding unit 32 is arranged away from the region including the portion where the impedance of the antenna having the third feeding unit 33 is minimized. It is. FIG. 8B is a distribution diagram of the current density vector of the antenna when the second power feeding unit 32 is arranged in a region including a portion where the impedance of the antenna having the third power feeding unit 33 is minimized. FIG. 8C is a diagram illustrating the radiation characteristics of the antenna having the third power feeding unit 33 due to the difference in the arrangement of the second power feeding unit 32. The area W in the figure is an index indicating the frequency band of the WLAN band. N in the figure is the radiation efficiency of the antenna when the second feeding unit 32 is arranged away from the region including the portion where the impedance of the antenna having the third feeding unit 33 is minimized. F in the figure is the radiation efficiency of the antenna when the second power feeding unit 32 is arranged in a region including a portion where the impedance of the antenna having the third power feeding unit 33 is minimized.

  In view of the above, the line with an arrow shown in FIGS. 8A and 8B indicates the current of the antenna having the third feeding portion 33 flowing through the conductor layer 2. As shown by this line, when the second power feeding unit 32 is arranged away from the region including the portion where the impedance of the resonance frequency of the antenna having the third power feeding unit 33 is minimized, the antenna Currents in opposite directions flow through each other. On the other hand, when the second power feeding unit 32 is arranged in a region including a portion where the impedance of the resonance frequency of the antenna having the third power feeding unit 33 is minimized, the direction of current flow of the antenna becomes messy. Since they cancel each other, the radiated magnetic field of the antenna becomes weak, and the radiation characteristics of the antenna deteriorate as shown by N in FIG. 8C.

  As described above, the first power supply unit 31 and the second power supply unit 32 are arranged with reference to the location where the impedance of the resonance frequency of the antenna having the third power supply unit 33 is minimized. The current flowing through the antenna can be controlled to ensure the performance of the antenna.

  Further, in the antenna using the conductor layer 2, the auxiliary conductor 11 having a capacitive component between the conductor layer 2 and the ground and the third matching circuit capacitor 14C have high impedance at the resonance frequency f2, The current flowing through the antenna is less likely to flow to the ground, and the performance degradation of the antenna can be suppressed.

  The contents of the present invention will be described more specifically with reference to examples. However, the technical scope of the present invention is not limited to the following examples.

(Example)
FIG. 9 is a plan view showing the dimensions and shape of a composite antenna device used for the evaluation of the composite antenna device 10A according to this example. For example, the composite antenna device 10 (see FIGS. 1 and 2) according to the embodiment was evaluated by computer simulation. The software used for the simulation is HFSS from ANSYS. The dimensions of the composite antenna device 10A used for the evaluation are L = 56 mm, W = 19 mm, S1 = 9 mm, S2 = 15 mm, OP1 = 7.3 mm, OP2 = 11.6 mm, N1A = N1B = 7.5 mm, N2A = N2B = 6.5 mm, N3 = 22.5 mm, N4 = 28.5 mm, and N5 = 7.5 mm. The width of the coil conductor 1 was 0.2 mm, the thickness was 0.033 mm, and the material was copper. The widths of the first slit portion SL1 and the second slit portion SL2 are 1 mm. The specifications of the first matching circuit 12, the second matching circuit 13, and the third matching circuit 14 shown in FIG. 1 are as described in the above embodiment.

  FIG. 10 is a diagram illustrating the transmission loss of the NFC antenna of the coil conductor 1 of the composite antenna device 10A according to the present embodiment. A straight line N in the figure is an index indicating the frequency band of the NFC band. T in the figure is a transmission loss. The transmission loss is the ratio of signal passing between the composite antenna device 10 and the external communication device 40. The larger the transmission loss value, the longer the communication distance between the NFC antenna and the external communication device 40. The resonance frequency of NFC is 13.56 MHz. The value of transmission loss between the NFC antenna and the external communication device 40 is −20.4 dB. The value of this transmission loss does not affect the antenna characteristics of other wireless communication devices, and further, the communication distance necessary for the non-contact communication function can be secured, so that the characteristics of the NFC antenna are good characteristics.

  FIG. 11 is a diagram illustrating electrical characteristics of the FM band antenna using the conductor layer 2 of the composite antenna device 10A according to the present embodiment. The area F in the figure is an index indicating the frequency band of the FM band. Ga in the figure is a gain. The gain indicates the power radiated from the antenna in dB, and the larger the value of dB, the stronger the power radiated from the antenna. As for the frequency band of the FM band, the bandwidth from 76 MHz to 108 MHz is 32 MHz. The maximum value of the gain of the FM band antenna is −29.7 dB, and when the low noise amplifier (LNA) is connected, the maximum value of the gain of the FM band antenna is about −19 dB. Since the total length (56 mm) of the FM band antenna is shorter than a quarter wavelength (694 mm to 987 mm) of the frequency band of the FM band, the maximum value of the gain of the FM band antenna is low. Since the gain characteristic for receiving is sufficient, the radiation characteristic of the FM band antenna is a good characteristic.

  FIG. 12 is a diagram illustrating the electrical characteristics of the WLAN band antenna configured by the conductor opening OP of the composite antenna device 10A according to the present embodiment and the first slit portion SL1 and the second slit portion SL2. The area W in the figure is an index indicating the frequency band of the WLAN band. In the figure, R is the reflection loss, and E is the radiation efficiency. The minimum value of the reflection characteristic of the WLAN band antenna is −13.3 dB, the maximum value of the radiation efficiency is 62.6%, and the bandwidth of the radiation efficiency when the radiation efficiency is 50% is 244.1 MHz. Since the reflection loss value of the WLAN band antenna is -10 dB or less, the maximum value of the radiation efficiency is 50% or more and the bandwidth is more than that, both the reflection characteristic and the radiation characteristic of the WLAN band antenna are good characteristics. .

DESCRIPTION OF SYMBOLS 1 ... Coil conductor 2 ... Conductor layer 10, 10A ... Composite antenna apparatus 10FB ... Antenna board 11 ... Auxiliary conductor 12 ... 1st matching circuit 12Ca, 12Cb ... 1st matching circuit capacitor 13 ... 2nd matching circuit 14 ... 1st 3 matching circuit 14C ... third matching circuit capacitor 20 ... electromagnetic wave shielding sheet 21A, 21B ... first feeding line 22 ... second feeding line 23 ... third feeding line 30 ... circuit board 31 ... first feeding Portion 32 ... Second feeding portion 33 ... Third feeding portion 34A, 34Ba, 34Bb, 35, 36A, 36B Terminal electrode 40 ... External communication device 100 ... Case CP ... Coil opening OP ... Conductor opening SL1 ... No. 1 slit part SL2 ... 2nd slit part

Claims (6)

  An antenna substrate, a looped or spiral coil conductor having a coil opening at a winding center formed on one surface of the antenna substrate, and a conductor layer formed on the other surface of the antenna substrate The conductor layer includes a conductor opening, a first slit connected to the conductor opening, and a second slit connected to the outer edge of the conductor layer. The coil conductor has a first feeding part, the conductor layer has a second feeding part, a third feeding part, and an auxiliary conductor connected to the ground, The third power feeding portion and the auxiliary conductor are arranged with the second slit portion interposed therebetween, and the coil conductor is a region other than the first slit portion and the second slit portion in the conductor layer, and The coil opening of the coil conductor and the Said conductor openings in the body layer, a composite antenna apparatus characterized by being arranged to face each other through the antenna substrate.   The first power feeding unit is disposed in a region including a portion where the impedance of the resonance frequency of the antenna having the third power feeding unit is minimized, and the second power feeding unit includes the third power feeding unit. 2. The composite antenna device according to claim 1, wherein the composite antenna device is disposed apart from a region including a portion where the impedance of the resonance frequency of the antenna is minimized.   The composite antenna device according to claim 1, wherein a slit length of the first slit portion is longer than a slit length of the second slit portion.   The conductor layer is connected to the auxiliary conductor having a capacitive component between the conductor layer and the ground with the antenna substrate interposed therebetween, and a capacitive element is connected to a third feeding portion. Item 4. The composite antenna device according to Item 1.   The composite antenna device according to claim 1, further comprising an electromagnetic wave shielding body in a region other than the first slit portion and the second slit portion in the conductor layer.   A portable terminal electronic device comprising the composite antenna device according to claim 1 in a housing.