KR100420546B1 - Battery Antenna for portable Wireless Communication Terminal - Google Patents

Abstract

The basic type of the battery antenna for a portable wireless communication terminal of the present invention is a plate-shaped reverse F (F) shape in which the feeder and the finger surface formed at the design position on the back plate surface of the portable wireless communication terminal and the battery for the portable wireless communication terminal are improved. Radiation structure configured to match the location designed by the antenna. The structure of the improved plate-shaped F-shaped antenna is added to the short-circuit plate of the conventional plate-shaped F-shaped antenna by adding an inverse L-shaped radiation structure symmetrically extended from the short-circuit plate. With this structure, the frequency band used can be increased up to three times. This prevents the efficiency from being reduced by more than 25% within the use frequency band due to the small structure of the existing internal antenna, and eliminates the volume of the conventional internal antenna, thereby greatly increasing the volume of the wireless communication terminal. In addition, by greatly reducing the electromagnetic wave in the human brain direction, the SAR (bio-electromagnetic absorption rate), which represents the electromagnetic wave effect on the human body, is significantly reduced.

Description

Battery antenna for portable wireless communication terminal {Battery Antenna for portable Wireless Communication Terminal}

The present invention relates to an antenna for a wireless communication terminal (FIG. 1) for use in a portable radiotelephone or a portable terminal. In particular, the present invention relates to a portable radio communication terminal by a conventional method of reducing SAR, which regulates the effect of electromagnetic waves on the human body. Incorporating a flat panel antenna (FIG. 2) on the back side of the present invention, there is shown an extreme reduction in radiation efficiency caused by fabricating a small flat antenna (FIG. 2) in order to minimize the volume of the portable wireless terminal while being built therein. Battery antenna for a portable wireless communication terminal of the portable wireless communication terminal by using a battery for the portable wireless communication terminal as an antenna, while minimizing the volume of the portable wireless communication terminal, while maintaining the radiation efficiency, to reduce the electromagnetic wave in the human body direction It is about.

The conventional monopole antenna for a wireless communication terminal as shown in FIG. 1 is an isotropic antenna and emits electromagnetic waves equivalent to the communication direction even in the direction of the human body, causing high SAR (biowave absorption rate). In order to solve such a problem, a built-in small antenna used in a conventional portable wireless communication terminal, for example, a small loop antenna as described in Patent Publication No. 1997-0068163 has a frequency band of 3% or less, PIFAs (plate inverted-F antennas) of the type described in No. 2000-0045787 reduce the radiation efficiency by up to 75% (= -6 dB) in the frequency band used. In this case, a radio wave shield is used between the radiating surface and the fingerboard surface to block radio waves flowing through the fingerboard surface so that the standing wave ratio (VSWR), which generally indicates the efficiency of the antenna, is set to be 2: 1 or less within the frequency band used. In practice, the maximum frequency of 1% to 4% when the distance between the fingerboard surface (2) and the radiation surface (3) of the PIFA (plate-shaped inverted F-shaped antenna) of FIG. 2 is 0.01-0.03 wavelengths apart In general, when a high dielectric constant of 10 or more is used to make a microminiature, a maximum frequency band of 0.5% to 2% is used. In such a state, when the radio wave group is used as in the above patent, it only blocks the radio wave to the standing wave but does not emit the radiation, and thus shows the same radiation efficiency. 2 is a structural diagram of a conventional plate-shaped inverted F (F) -shaped antenna, Figure 3 is a standing wave ratio of 2: 1 according to the height of the radiation surface on the fingerboard surface of the PIFA (plate-shaped inverted F-shaped antenna) Is a diagram illustrating a maximum used frequency band ratio satisfying Figure 3 is a reference K. Tsunoda, et al. "Analysis of Palanar Inverted F Antenna Using Spatial Network Method" IEEE 1990, symbol L1 shown in Figure 3 is the length of the antenna L, L2 is the radiation surface (patch) The widths W and H are the heights, and the number at the top of each data line is the ratio of the width of the shorting plate to the width of the radiating surface.

In order to obtain the efficiency by standing wave ratio (VSWR) from the standing wave ratio of 2: 1 frequency band, the following equations are listed.

Equation 1 for calculating the ratio of the used frequency band to the specific standing wave ratio (VSWR) of the antenna is shown in Equation 1.

Where BW is the ratio to the center frequency of the frequency band used, VSWR is the standing wave ratio, and Q is the resonance performance of the antenna.

By canceling Q from Equation 1, a frequency band ratio for another standing wave ratio is obtained from the frequency band ratio for a specific standing wave ratio of the same antenna.

However, BW1 is a known frequency band ratio and VSWR1 is a known standing wave ratio as a reference for the previous frequency band ratio.

FIG. 4 is a calculation diagram of a used frequency band standing wave ratio for obtaining a standing wave ratio VSWR of a desired frequency band BW from a frequency band BW1 having a standing wave ratio VSWR1 of 2: 1 or less from Equation 2. FIG.

FIG. 5 is a calculation diagram for converting standing wave efficiency from standing wave ratios obtained from FIG. 4.

As an example of calculating the efficiency of a conventional small internal antenna, the frequency band ratio BW = 120 ÷ 1810 = 0.07 with the PCS frequency band, which is the mobile communication frequency band, from 1.75 GHz to 1.87 GHz, with a bandwidth of 120 MHz and an intermediate frequency of 1.81 GHz. to be.

Table 1 shows the standing wave efficiency of the antenna according to the height of the radiating plane with respect to the fingerboard at the 0.07 frequency band ratio obtained in the figure of the micro antenna.

Radiation Height Radiation Height medium BW of VSWR 2: 1 0.07 / BW VSWR of BW 0.07 VSWR efficiency 1 mm 0.006 wavelength High dielectric constant 0.005 14 100 5% 1 mm 0.006 wavelength Low dielectric constant 0.01 7 27 15% 2 mm 0.012 wavelength High dielectric constant 0.01 7 27 15% 2 mm 0.012 wavelength Low dielectric constant 0.02 3.5 8 40% 3 mm 0.018 wavelength High dielectric constant 0.02 3.5 8 40% 3 mm 0.018 wavelength Low dielectric constant 0.03 2.3 4.5 60%

In the above table, the height of the radiating surface is the distance between the fingerboard surface 2 and the storage antenna 6, and also the height of the shorting plate 4. Since the wavelength of the electromagnetic wave at 1810 MHz is 165.7 mm, the height of the radiation surface of 1 mm is 1 / 165.7 = 0.006.

In Table 1, the result of standing wave ratio (VSWR) efficiency according to the radiation height of the micro antenna is shown to be 5% to 60% efficiency. There is no room on the surface of the phone. At 1810 MHz, the proper length as an antenna is at least 1 / 4mm, which is 41mm long. 41mm / 10mm = 4.1, and the permittivity of the medium is 16.8. In FIG. 2, if the dielectric constant of the medium between the fingerboard surface 2 and the radiation surface 3 is 16.8, it corresponds to a high dielectric constant. VSWR) efficiency. In FIG. 5, the efficiency is reduced by six times compared to 90% of the efficiency at the standing wave ratio (VSWR) 2: 1.

In addition, since the monopole antenna (FIG. 1), which is the antenna used most frequently, is an isotropic antenna, a large number of electromagnetic waves are radiated toward the human body during communication, thereby increasing the SAR (bio-electromagnetic absorption rate) value of the electromagnetic wave. FIG. 6 is a diagram showing electromagnetic radiation of a horizontal plane of a monopole antenna in a free space, and FIG. 7 is a diagram showing electromagnetic radiation of a horizontal plane of a monopole antenna when it is in close contact with an ear to talk a wireless communication terminal. In FIG. 7, the electromagnetic wave of the human body is reduced by up to 20 dB, which is reduced by more than 99% in terms of 20 dB. The reduced amount of electromagnetic waves is reflected from some surfaces of the human body, and the other is absorbed by the human body, especially the head. . FIG. 8 is a diagram illustrating a cross section in which electromagnetic waves radiated from a monopole antenna are absorbed by a human body, and it can be seen that the electromagnetic waves rapidly decrease step by step within the head. In particular, it can be seen that the electromagnetic waves penetrate deeply through the ear. have.

An object of the present invention is to reduce the emission of electromagnetic waves to the human body in the conventional monopole antenna for portable wireless communication terminal to improve the SAR (biological electromagnetic absorption rate), and recently to improve the SAR of the method of embedding on the back of the wireless communication terminal It improves the radiation efficiency of the micro built-in antenna, and improves aesthetics by eliminating the conventional monopole antenna for wireless communication terminal, improves the distance when carrying, and also eliminates the space of the built-in antenna for the existing wireless communication terminal. There is a technical problem to miniaturize a wireless communication terminal.

1 is a block diagram of a conventional monopole antenna for a wireless communication terminal.

2 is a block diagram of a conventional plate-shaped inverted F (F) shape antenna

3 is a diagram showing the frequency bandwidth of a conventional plate-shaped inverted F antenna

4 is a calculation diagram for converting a frequency band ratio to a standing wave ratio VSWR.

5 is a calculation diagram for converting standing wave ratio (VSWR) into efficiency.

6 is a free space synthesized polarization horizontal radiation of a conventional monopole antenna for a wireless communication terminal.

7 is a composite polarization horizontal radiation diagram when the conventional monopole antenna for wireless communication in close contact with the human body.

8 is a diagram illustrating a phenomenon in which electromagnetic waves are absorbed by a human body during a call;

9 is a configuration and layout view of a battery antenna for a wireless communication terminal according to the first embodiment of the present invention

10 is a standing wave ratio characteristic diagram of the battery antenna for a wireless communication terminal according to the first embodiment of the present invention.

11 is a free space composite polarization horizontal radiation diagram of a battery antenna for a wireless communication terminal according to the first embodiment of the present invention.

12 is a side view of Embodiment 2 of a battery antenna for a wireless communication terminal of the present invention.

13 is a side view of Embodiment 2 of a battery antenna for a wireless communication terminal of the present invention.

14 is a side view of Embodiment 2 of a battery antenna for a wireless communication terminal of the present invention.

15 is a side view of Embodiment 2 of a battery antenna for a wireless communication terminal of the present invention.

Fig. 16 is a side view of Embodiment 3 of a battery antenna for wireless communication terminal of the present invention.

Figure 17 is a side view of Embodiment 3 of a battery antenna for a wireless communication terminal of the present invention.

18 is a side view of Embodiment 3 of a battery antenna for a wireless communication terminal of the present invention.

19 is a front view of Embodiment 4 of a battery antenna for wireless communication terminal of the present invention.

1: Monopole antenna for conventional wireless communication terminal

2: fingerboard of wireless communication terminal

3: Radiation plane of conventional plate-shaped inverted F antenna

4: short circuit

5: feeder

6: battery antenna

7: Structure for adding capacitive reactance

8: Structure for extending the electrical length of battery antenna

The basic configuration of the present invention is a plate-shaped feed unit 5 and the battery 6 for transmitting and receiving a signal from the bottom finger surface 2 of the battery insertion groove of the portable wireless communication terminal to the battery antenna 6 as shown in FIG. And a shorting plate 4 for use as an inverted F antenna. The position of the short circuit board 4 is determined so that the width of the short circuit board 4 may be smaller than the width of the battery antenna 6 so as to have a desired frequency F in equation (3).

Where F is the frequency, C is the speed of light, S is the width of the shorting plate, W is the width of the battery antenna 6, L is the distance from the upper end of the battery antenna 6 to the shorting plate 4, and H is a short circuit. It is the height of the plate 4.

In order to maximize the use frequency band of the battery antenna 6, S = W should be substituted. When S / W = 1, Equation 3 is expressed by Equation 4.

If the position of the short-circuit board 4 is simply obtained from Equation 4, Equation 5 is obtained.

Is the wavelength, C / F.

In practice, due to the size and material of the wireless communication terminal, it is close to 0.95 x L / (dielectric constant of material)-(thickness function of battery antenna) in actual production.

After determining the top of the battery antenna 6 and the length of the shorting plate 4 specified by the above method, another antenna for increasing the frequency band of the antenna by double resonating the portion under the shorting plate 4 as well. Be made to play a role. The distance from the short-circuit plate 4 to the lower end of the battery antenna 6 to be a double resonant antenna is made 2% to 3% shorter than the length L of the top to resonate at a slightly separated frequency to increase the use frequency bandwidth. To do that. The position of the feed section 5 is 50 ohms of radiation resistance at the upper end of the short-circuit board 4, and the frequency band used is adjusted to the widest point. The antenna of this structure is called an inverted F (F) shaped antenna having an inverted L-shaped short-plate shared double resonant structure and is an important technical structure of the present invention. In addition, the antenna of the present invention has a structure of increasing the bandwidth according to the thickness.

The above and other objects, features, aspects, advantages, and the like of the present invention will become more apparent from the following detailed embodiments described with reference to the accompanying drawings.

Best Mode for Carrying Out the Invention Embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

(Example 1)

Table 1 shows the approximate design dimensions of the battery antenna of the structure according to the present invention for use in the frequency band 1.75 GHz to 1.87 GHz, and the frequency bandwidth performance that satisfies the standing wave ratio (VSWR) 2: 1.

Battery thickness (mm) Height H (mm) Top L (mm) Bottom L (mm) Frequency Max Bandwidth (MHz) Frequency band ratio 0.1 2 37.7 37.4 75 0.04 3 2 36 35 100 0.055 4 2 35.8 33.5 120 0.066 5 2 35.7 33.3 130 0.07 6 2 34.5 33.5 140 0.077

The antenna of the above-described structure

The standing wave ratio (VSWR) for the battery thickness of 6 mm in Table 1 satisfies 2: 1 from 1.74 GHz to 1.88 GHz in the frequency band as shown in FIG. 10. It can be seen that the standing wave ratio (VSWR) efficiency of FIG. 5 satisfies 90%. As shown in Table 1, the efficiency of the plate-shaped inverse F (F) antenna using a 2 mm dielectric for embedding into a microminiature is 15%. It can be seen that the efficiency is six times compared to that.

11 is a free space electromagnetic polarization composite horizontal radiation diagram of the antenna for the battery thickness of 6mm in Table 1. In FIG. 11, the 0-degree direction is the human body direction. Compared to the free space electromagnetic polarization-synthesized horizontal radiation of the conventional monopole antenna of FIG. 6, the intensity of the electromagnetic wave radiated toward the human body is less than 15 dB. Able to know.

(Example 2)

In the case of Embodiment 1, the size of the antenna can be said to be an ideal embodiment to design and manufacture only for the performance of the antenna. However, in the case of an antenna combined battery according to the present invention, a large range of the size is determined according to the function of the battery. In addition, the size of the battery is determined by the size and needs of the terminal for wireless communication. Therefore, if the frequency used is smaller than the length of the required antenna, it must be electrically compensated. 12, 13 and 14 are side views in which capacitive reactance is added between the fingerboard surface and the antenna at the bottom of the antenna to extend the length of the antenna. 15 is a side view extending the length of the antenna. In this way, the structure that extends the antenna length implements excellent performance for the purpose of improving radiation efficiency and reducing electromagnetic waves for the human body according to the present invention.

(Example 3)

In the third embodiment according to the present invention, if the length of the battery is longer than the length of the required antenna, the efficiency as an antenna is greatly reduced if it is not compensated for. To solve this problem, adding a capacitive reactance between the fingerboard surface and the antenna near the short circuit board at the bottom of the short circuit board as shown in FIGS. 16, 17, and 18 shows an effect of shortening the electrical length of the antenna at a desired frequency. By double resonating, the use frequency bandwidth is increased to maximize the efficiency of the antenna. As such, the structure of shortening the antenna length by adding capacitive reactance also implements excellent performance for the purpose of improving radiation efficiency and reducing electromagnetic waves for a human body according to the present invention.

(Example 4)

In the case of an inverted F (F) shape antenna having a reverse L (L) shape short circuit plate shared double resonant structure and a battery combined antenna using the same, it is necessary to separate two or more short circuit boards for two purposes. have. One is to increase the used frequency bandwidth by dispersing the standing wave ratio (VSWR) according to the frequency, and the other is to short-circuit between the battery antenna and the fingerboard existing in the wireless communication terminal while maintaining the original frequency bandwidth. However, since the wireless communication terminal and the storage battery are detachable structures, structurally separated into two or more short-circuit plates as shown in FIG. 19 so as to be a structure suitable for the removable structure.

As such, the structure in which the shorting plate is separated into two or more implements excellent performance for the purpose of improving radiation efficiency and reducing electromagnetic waves for a human body according to the present invention.

As apparent from the above description, the battery antenna for a portable radio communication terminal of the present invention has a strength in which a conventional monopole antenna radiates electromagnetic waves in a human body direction at an intensity equivalent to that radiating electromagnetic waves for communication. The large SAR (absorption rate of living electromagnetic waves) allows the use of a battery disposed on the opposite side of the human body of a portable wireless communication terminal as an antenna, and the effect of reducing SAR by reducing electromagnetic waves by at least 15 dB in the direction of the human body. There is an effect of maximizing the efficiency of the antenna to be inevitably reduced by the limited size and structure of the conventional micro-miniature antenna manufactured for the same purpose.

As mentioned above, although the invention made by this inventor was demonstrated concretely according to the said Example, this invention is not limited to the said Example, Of course, a various change is possible in the range which does not deviate from the summary.

Claims (6)

In the antenna for a wireless communication terminal, A battery antenna using a storage battery of the wireless communication terminal as a radiating plate of a plate-shaped inverse F-shaped antenna; A short plate connecting the bottom finger surface of the battery insertion groove of the wireless communication terminal to the battery antenna to ground the battery antenna; A power supply unit connecting the wireless communication terminal and the battery antenna to feed the battery antenna; Including; The length from the bottom of the battery antenna to the shorting plate is shorter than the length from the top of the battery antenna to the shorting plate. An antenna, characterized in that. In the antenna, An antenna having a dual frequency resonant structure in which an inverted L-shaped antenna connected to a short circuit plate symmetrically is added to a short circuit board, characterized in that the frequency band of the inverted F-shaped antenna is improved or radiation efficiency is improved. The method according to claim 1 or 2, Increasing the thickness of the radiating plate of the antenna to improve the frequency band or improve the radiation efficiency. The method of claim 3, And extending the electrical length of the radiating plate of the antenna. The method of claim 3, And an electrical length of the radiating plate of the antenna is shortened. The method of claim 3, And separating the shorting plate into two or more.