TWI692907B - Antenna module - Google Patents

Abstract

An antenna module includes an antenna unit and a floating member. The antenna unit includes a feed-in end. The floating member is disposed above the antenna unit and separated from the antenna unit. The floating member covers the feed-in end of the antenna unit and is coupled to the antenna unit.

Description

Antenna module

The present disclosure relates to an antenna module, and particularly to an antenna module with low electromagnetic wave energy specific absorption rate (SAR).

Currently, smartphones or tablets are widely used. However, since such electronic devices are quite close to the human body during use, when transmitting data, electromagnetic waves are easily absorbed by the human body and affect the user's health. Internationally, the Specific Absorption Rate (SAR) of electromagnetic wave energy is used to represent the power absorbed by the organism (including the human body) per unit kilogram per unit time when the electronic device is used, in w/kg, the lower the SAR value , Representing less electromagnetic waves absorbed.

The Federal Communications Commission (FCC) and the Conformite Europende (CE) regulations of the EU countries strictly require SAR values. One way for the industry to avoid the effects of electromagnetic waves on the human body is to use a sensor pad circuit to detect whether the human body is close to the antenna. If so, the communication device will reduce the power output of the RF amplifier to reduce the SAR value. However, in practical applications, the power output of the RF amplifier needs to be reduced by more than 7 decibel milliwatts (dBm) to be in the GSM1900 band, WCDMA band II band, WCDMA band IV band, LTE band II band, LTE bandIV band Regulations with a value of 1.6. This design will slow down the transmission of data, which is a difficult issue for antenna design.

The present disclosure provides an antenna module that has a low electromagnetic wave energy specific absorption rate.

An antenna module of the present disclosure includes an antenna unit and a floating element. The antenna unit includes a feed-in end. The floating element is arranged above the antenna unit and is separated from the antenna unit by a distance, the floating element shields the feeding end of the antenna unit, and the antenna unit is coupled to the floating element.

Based on the above, the antenna module of the present disclosure disposes the floating element above the antenna unit and is separated from the antenna unit by a distance, the floating element shields the feeding end of the antenna unit and is coupled to the antenna unit. When the resonance frequency mode is excited by the antenna unit, the energy at the feeding end is coupled to the floating element. The floating element can at least act as a reflector to reduce the SAR value. It can avoid the human body approaching the antenna unit. Electromagnetic waves are absorbed by the human body while maintaining a good transmission rate.

In order to make the above-mentioned features and advantages of the disclosure more comprehensible, the embodiments are specifically described below and described in detail in conjunction with the accompanying drawings.

FIG. 1A is a schematic diagram of an antenna unit and a floating element of an antenna module according to an embodiment of the present disclosure. FIG. 1B is a schematic side view of the antenna module of FIG. 1A disposed on the back cover. Please refer to FIGS. 1A and 1B. The antenna module 5 of this embodiment includes an antenna unit 10 and a floating element 100. In this embodiment, the monopole antenna (Monopole Antenna) is used as an example of the antenna unit 10, but the type of the antenna unit 10 is not limited thereto. In other embodiments, the antenna unit includes at least a monopole antenna, a dipole antenna, a planar inverted-F antenna, a loop antenna, a coupled antenna, or a slot antenna. That is, the antenna unit may be one of the above-mentioned antennas or a combination of the above-mentioned antennas.

In this embodiment, the antenna unit 10 includes a ground plane element 12, a first radiator 16 disposed above the ground plane element 12, and a signal feed line 14. The first radiator 16 has a feeding end 15 and an open end 18 relative to the feeding end 15. The signal feed line 14 is connected to the feed end 15 of the first radiator 16 to lead the signal.

In this embodiment, the floating element 100 is disposed above the antenna unit 10 and is separated from the antenna unit 10 by a distance D1, as shown in FIG. 1B. In this embodiment, the floating element 100 and the antenna unit 10 are arranged in parallel, for example, but the positional relationship between the floating element 100 and the antenna unit 10 is not limited to this. In addition, in this embodiment, the floating element 100 is attached to the inner bottom surface 21 of a back cover 2 of an electronic device (not shown), for example. The distance D1 between the floating element 100 and the feeding end 15 of the antenna unit 10 is, for example, 5 mm to 10 mm, but the distance D1 is not limited thereto.

It is worth mentioning that any type of antenna unit will have different impedance distribution at different locations. For example, in this embodiment, the impedance distribution of the antenna unit 10 is from 50 ohms at the feed end 15 to 377 ohms at the open end 18. Since the impedance of the feeding terminal 15 is the smallest and the current intensity is the largest, the magnetic field strength and the SAR value of the feeding terminal 15 are also the largest. Conversely, the impedance value of the open end 18 of the first radiator 16 is the largest, where the current intensity is the smallest, and the magnetic field intensity and the SAR value are the smallest.

Since the SAR value of the feeding end 15 is the largest, in this embodiment, the floating element 100 will shield the feeding end 15 of the antenna unit 10 to reduce the SAR value of the antenna unit 10. The floating element 100 shielding the feeding end 15 represents that when the floating element 100 projects the plane where the antenna unit 10 is located, the feeding end 15 will be located within the projection range.

In this embodiment, when the antenna unit 10 excites the resonance frequency mode, the energy of the feeding end 15 of the antenna unit 10 will be coupled to the floating element 100, and the floating element 100 may at least serve as a reflector to reduce the back cover. The effect of the SAR value near the inner bottom surface 2 of 2 can prevent the electromagnetic waves generated by the antenna unit 10 from being absorbed by the human body when the human body approaches the back cover 2 (for example, a user places an electronic device such as a tablet computer on the thigh).

In addition, in this embodiment, the floating element 100 is U-shaped. The floating element 100 includes a first section 110 and a second section 120 in parallel and a third section 130 connecting the first section 110 and the second section 120. In this embodiment, the first section 110 shields the feeding end 15 of the antenna unit 10. When the floating element 100 has a U-shaped structure, when the energy of the feeding end 15 is coupled to the floating element 100, two currents with a phase difference of 180 degrees can be generated on the first section 110 and the second section 120 The flow direction of the first section 110 in FIG. 1A is from the right to the left, and the flow direction of the second section 120 is from the left to the right), thereby canceling the energy with each other and achieving the effect of reducing the SAR value. Of course, the orientation of the floating element 100 and the form of the floating element 100 are not limited thereto.

It is worth mentioning that, in this embodiment, the floating element 100 only shields the portion of the first radiator 16 near the feeding end 15, and does not shield the open end 18 of the first radiator 16. In other embodiments, the size of the floating element 100 may be increased while shielding more parts of the first radiator 16, as long as at least 1/3 of the portion of the first radiator 16 from the open end 18 is not left by the floating element 100 Just cover it.

The following will introduce other forms of floating elements. Elements that are the same as or similar to the previous embodiment are denoted by the same or similar symbols, and will not be described in detail, only illustrating the main differences.

2 is a schematic side view of an antenna unit and a floating element of an antenna module according to another embodiment of the present disclosure. Please refer to FIG. 2 first. The main difference between the antenna module 5′ of FIG. 2 and the antenna module 5 of FIG. 1A is that, in this embodiment, the antenna module 5′ further includes another floating element 150 attached to the back cover 2 On the inner edge 22. The floating element 150 is separated from the antenna unit 10 by a distance D2. The floating element 150 shields the feeding end 15 of the antenna unit 10 and is coupled to the antenna unit 10. In this embodiment, the projection of the feeding end 15 on the plane of the floating element 150 will be within the range of the floating element 150. Similarly, when the antenna unit 10 excites a resonance frequency mode, the energy of the feed end 15 of the antenna unit 10 will be coupled to the floating element 150, and the floating element 150 may at least act as a reflector to reduce the inside of the back cover 2 The effect of the SAR value near edge 22.

In addition, in an embodiment not shown, the floating element 150 may be connected to the ground plane element 12 through a conducting bar (not shown). In this embodiment, the length of the conducting bar may be the extra frequency mode The 1/4 wavelength of the state can make the antenna module 5'have a frequency mode more than the antenna module 5 of FIG. 1A and become a dual-frequency antenna. Of course, the form of the floating element 150 is not limited thereto.

3 to 8 are schematic diagrams of various floating elements according to other embodiments of the present disclosure. Please refer to FIG. 3 first. The main difference between the floating element 100a of FIG. 3 and the floating element 100 of FIG. 1A is that, in this embodiment, a part of the floating element 100a is U-shaped. The floating element 100a further includes an extension section 112a connected to the first section 110a and extending away from the second section 120a. The extension section 112a shields the feeding end 15 of the antenna unit 10.

Please refer to FIG. 4. The main difference between the floating element 100 b of FIG. 4 and the floating element 100 a of FIG. 3 is that, in this embodiment, the opening direction of the U-shaped portion of the floating element 100 b is opposite to that of the floating element 100 a of FIG. 3. The opening direction of the part of the type.

In the embodiments of FIG. 3 and FIG. 4, when the energy of the feeding end 15 is coupled to the floating elements 100a, 100b, since the floating elements 100a, 100b have parallel first sections 110a, 110b and second sections 120a , 120b, the first section 110a, 110b and the second section 120a, 120b can also generate two currents with a phase difference of 180 degrees, and then cancel each other's energy to achieve the effect of reducing the SAR value.

Please continue to refer to FIGS. 5-7. The main difference between the floating elements 100c, 100d, 100e of FIGS. 5-7 and the floating element 100 of FIG. 1A is that in FIG. 1A, the opening direction of the floating element 100 faces the right side of the drawing. square. In FIG. 5, the opening direction of the floating element 100c faces upward in the drawing. In FIG. 6, the opening direction of the floating element 100d faces downward in the drawing. In FIG. 7, the opening direction of the floating element 100e is toward the left in the drawing.

In the embodiments of FIGS. 5-7, although the opening directions of the floating elements 100c, 100d, 100e are different, when the energy of the feeding end 15 is coupled to the floating elements 100c, 100d, 100e, the floating elements 100c, 100d, 100e The first section 110c, 110d, 110e and the second section 120, 120c, 120d, 120e can also generate two currents with a phase difference of 180 degrees, thereby canceling each other's energy to achieve the effect of reducing the SAR value.

Next, please refer to FIG. 8. In this embodiment, the floating element 100 f is polygonal, such as rectangular, but not limited to this. In this embodiment, the floating element 100 f shields the feeding end 15 of the antenna unit 10 and is coupled to the antenna unit 10. The floating element 100f can be used as a reflecting plate to achieve the effect of reducing the SAR value. In other embodiments, the floating element may also be triangular, pentagonal, hexagonal, or the like. Alternatively, in other embodiments, the floating element may also be circular, oval, egg-shaped, or irregular.

9 is a schematic diagram of an antenna unit and a floating element of an antenna module according to another embodiment of the present disclosure. Please refer to FIG. 9, in this embodiment, the antenna unit 10g is a multi-band antenna. The antenna unit 10g includes a ground plane element 12g, a first radiator 16g and a second radiator disposed above the ground plane element 12g 11g, a third radiator 17g and a signal feed line 14g coupled to the feed end 15g. In this embodiment, the first radiator 16g is, for example, a monopole antenna, and the feeding end 15g and the open end 18g are located at opposite ends of the first radiator 16g, respectively. The shapes of the second radiator 11g and the third radiator 17g are, for example, L-shaped, wherein the open ends of the second radiator 11g and the third radiator 17g are opposite to each other, and the other ends are coupled to each other. To the ground plane element 12g. The length of the first radiator 16g is, for example, 90 mm, and the width is, for example, 10.5 mm. The floating element 100g is arranged 6 mm above the antenna unit 10g, but the size is not limited thereto.

Similarly, in this embodiment, the floating element 100g shields the feeding end 15g of the antenna unit 10g and is coupled to the antenna unit 10g. Therefore, when the antenna unit 10g excites a resonance frequency mode, the energy of the feed end 15g of the antenna unit 10g is coupled to the floating element 100g, and the floating element 100g can at least serve as a reflector to reduce the SAR value. In addition, when the floating element 100g has a U-shaped structure, when the energy of the feeding end 15g is coupled to the floating element 100g, two currents with a phase difference of 180 degrees can be generated on the first section 110g and the second section 120g, and then Mutually offset the energy to achieve the effect of reducing SAR value.

It is worth mentioning that, in this embodiment, the second radiator 11g is used to couple high-frequency signals. The second radiator 11g has a first end 13g, which is close to the feeding end 15g and is connected to the ground plane element 12g. The first end 13g of the second radiator 11g is close to 0 ohm, which makes the first The SAR value at terminal 13g is larger. Therefore, in this embodiment, in addition to shielding the feeding end 15g of the first radiator 16g, the floating element 100g also shields the first end 13g of the second radiator 11g to reduce the overall SAR value. Of course, if the first end 13g of the second radiator 11g does not directly contact the ground plane element 12g, in other embodiments, the floating element may not shield the first end 13g of the second radiator 11g.

In addition, in this embodiment, the third radiator 17g is coupled with a low-frequency signal, and the SAR value at a second end 19g of the third radiator 17g itself is low, and it is not necessary to be shielded by the floating element 100g.

10 is a schematic diagram of the frequency-reflection loss of the antenna module and the antenna unit of FIG. 9 without floating elements. Please refer to FIG. 10, the dotted line represents the frequency-reflection loss result of the antenna unit 10g without the floating element 100g, and the solid line is the frequency of the antenna module 5g of FIG. 9 (that is, the antenna unit 10g is provided with the floating element 100g) -Reflection loss results.

It can be seen from FIG. 10 that the resonance frequency mode of the antenna module 5g of FIG. 9 is the same as the resonance frequency mode of the antenna unit 10g without the floating element 100g. That is to say, the provision of the floating element 100g on the antenna unit 10g does not generate a new resonance frequency mode. In this embodiment, the input impedance bandwidth of the antenna module 5g of FIG. 9 is based on the VSWR 4.5:1 or 4dB reflection loss as the standard, and can be operated in the LTE/C2K/EGPRS/UMTS communication system.

Furthermore, the antenna module 5g of FIG. 9 can excite four resonance frequency modes 31, 32, 33, and 34, wherein the third radiator 17g excites the resonance frequency mode 31 and the first radiator 16g excites the resonance frequency mode. In states 32 and 33, the second radiator 11g excites a resonance frequency mode 34. Since the resonance frequency modes 31 and 34 are generated by the coupling of the third radiator 17g and the second radiator 11g, they are not excited by the feed of the signal feed line 14. Therefore, the SAR values of the resonance frequency modes 31 and 34 are low. The following will test the effect of the floating element 100g on the resonance frequency modes 32 and 33 when the floating element 100g is placed above the antenna unit 10g for the modes with higher SAR values, that is, the resonance frequency modes 32 and 33.

The resonance frequency of resonance frequency mode 32 is LTE band V Channel 20525 (836.5MHz), the resonance frequency of resonance frequency mode 33 is LTE band II Channel 18900 (1880MHz), and the total antenna radiated power of resonance frequency modes 32 and 33 ( The measurement results of Total Radiated Power (TRP) and 1g electromagnetic energy specific absorption rate (SAR) values are shown in Table 1 and Table 2 below.

Table 1 shows the specific absorption rate of antenna radiated power and electromagnetic wave energy measured by resonance frequency mode 32:

It is known from the experimental data in Table 1 that in the resonance frequency mode 32, the SAR value is reduced from 2.01 w/k to 1.79 w/kg. In other words, the 1g SAR value of the antenna module 5g of FIG. 9 in the positive Z direction becomes 89%, and the antenna radiated power (TRP) is only reduced from 19.31 dBm to 19.15 dBm (a decrease of 0.16 dBm).

Table 2 shows the specific absorption rate of antenna radiated power and electromagnetic wave energy measured at resonance frequency mode 33:

It is known from the experimental data in Table 2 that in the resonance frequency mode 33, the SAR value is reduced from 4.18w/k to 2.38w/kg. In other words, the 1g SAR value of the antenna module 5g of FIG. 9 in the positive Z direction becomes the original 56.9%, and the antenna radiated power (TRP) is only reduced from 19.46 dBm to 19.37 dBm (a decrease of 0.09 dBm). It can be seen that the floating element 100g can effectively reduce the SAR value, and the antenna radiated power (TRP) will only be reduced very little, so that the antenna module 5g can still have good transmission performance.

In summary, the antenna module of the present disclosure places the floating element above the antenna unit and is separated from the antenna unit by a distance. The floating element shields the feed end of the antenna unit and is coupled to the antenna unit. When the resonance frequency mode is excited by the antenna unit, the energy at the feeding end is coupled to the floating element. The floating element can at least act as a reflector to reduce the SAR value. It can avoid the human body approaching the antenna unit. Electromagnetic waves are absorbed by the human body. In an embodiment, the floating element includes a parallel first section and a second section. When the energy at the feeding end is coupled to the floating element, the first section and the second section can produce two 180 degrees difference The phase currents, which in turn cancel each other's energy, achieve the effect of reducing the SAR value.

Although this disclosure has been disclosed as above with examples, it is not intended to limit this disclosure. Anyone who has ordinary knowledge in the technical field can make some changes without departing from the spirit and scope of this disclosure. Retouching, so the scope of protection of this disclosure shall be subject to the scope defined in the appended patent application.

D1, D2: distance 2: back cover 5, 5’, 5g: antenna module 10, 10g: antenna unit 11g: second radiation 12, 12g: ground plane component 13g: the first end 14: signal feed line 15, 15g: feeding end 16, 16g: the first shot 17g: third shot 18, 18g: open end 19g: the second end 21: inner bottom 22: inner side 31, 32, 33, 34: resonance frequency mode 100, 100a, 100b, 100c, 100d, 100e, 100f: floating element 110, 110a, 110b, 110c, 110d, 110e: the first section 112a, 112b: extended section 120, 120a, 120b, 120c, 120d, 120e: second section 130, 130a, 130b, 130c, 130d, 130e: the third section

FIG. 1A is a schematic diagram of an antenna unit and a floating element of an antenna module according to an embodiment of the present disclosure. FIG. 1B is a schematic side view of FIG. 1A disposed on the back cover. 2 is a schematic diagram of an antenna unit and a floating element of an antenna module according to another embodiment of the present disclosure. 3 to 8 are schematic diagrams of various floating elements according to other embodiments of the present disclosure. 9 is a schematic diagram of an antenna unit and a floating element of an antenna module according to another embodiment of the present disclosure. 10 is a schematic diagram of the frequency-reflection loss of the antenna module and the antenna unit of FIG. 9 without floating elements.

5: Antenna module

10: Antenna unit

12: ground plane component

14: signal feed line

15: feeding end

16: The first shot

18: Open circuit

100: floating element

110: Section 1

120: Second section

130: third section

Claims (9)

An antenna module includes: an antenna unit including a feed-in end; and a floating element disposed above the antenna unit and spaced apart from the antenna unit, wherein the floating element includes a parallel first area A second section and a third section connecting the first section and the second section, the first section of the floating element shields the feed end of the antenna unit, and the antenna unit Coupling to the floating element. The antenna module as described in item 1 of the patent application scope, wherein the floating element is arranged in parallel above the antenna unit, and the floating element is U-shaped. The antenna module as described in item 1 of the patent application scope, wherein the floating element is arranged in parallel above the antenna unit, and a part of the floating element is U-shaped. The antenna module as described in item 1 of the patent application range, wherein the floating element includes a first section and a second section in parallel and is connected to the first section and extends away from the second section An extension section of the antenna, the extension section shields the feed end of the antenna unit. The antenna module as described in item 1 of the patent application scope, wherein the floating element is arranged in parallel above the antenna unit, and the floating element is polygonal. The antenna module according to item 1 of the patent application scope, wherein the antenna unit includes a ground plane element and a first radiator coupled to the ground plane element, the first radiator has the feed end and With respect to an open end of the feed-in end, the floating element does not cover the open end of the first radiator. An antenna module as described in item 6 of the patent application range, wherein at least 1/3 of the first radiator from the open end is not covered by the floating element. The antenna module according to item 6 of the patent application scope, wherein the antenna unit further includes a second radiator, the second radiator has a first end, the first end is close to the feed end and is coupled In the ground plane element, the floating element shields the first end of the second radiator. The antenna module according to item 1 of the patent application scope, wherein the antenna unit at least includes a monopole antenna, a dipole antenna, a planar inverted-F antenna, a loop antenna, a coupling antenna, or a slot antenna.

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