KR20100065445A

KR20100065445A - Multi-band loop antenna

Info

Publication number: KR20100065445A
Application number: KR1020080123775A
Authority: KR
Inventors: 박정숙; 신천우
Original assignee: 박정숙
Priority date: 2008-12-08
Filing date: 2008-12-08
Publication date: 2010-06-17

Abstract

PURPOSE: A multi-band built-in loop antenna with a vertically symmetrical structure is provided to expand the fundamental frequency and the bandwidth of high frequency band by adjusting the spaces among a plurality of open loops. CONSTITUTION: An upper loop(11) and a lower loop(12) are formed to be vertically symmetrical in the upper side and the lower side of a dielectric substrate of a preset size. An open loop pattern forms one or more open loops(13,14) by forming one or more bending points in the center between the upper loop and the lower loop. A turnaround unit(15) is formed on one end of the open loop pattern. A through hole connects the upper loop pattern and the lower loop pattern which are formed near the open loop pattern. A power feeding unit(25) feeds power to the upper loop pattern. A grounding unit(26) grounds the lower loop pattern.

Description

Multi-Band Loop Antenna with vertically symmetrical structure

The present invention relates to a multiband embedded loop antenna (intenna) having a vertically symmetrical structure.

In general, the antenna is provided in a wireless communication terminal (mobile communication terminal, personal digital communication terminal (PCS), personal digital terminal (PDA), satellite reception terminal (GPS), wireless LAN terminal (smartphone, etc.) from the outside A device that receives a received signal and radiates a transmitted signal to the outside.

As such, the wireless communication terminal has an antenna for receiving a signal transmitted from the other party or transmitting a signal to the other party in place inside and outside the main body of the wireless communication terminal to communicate with the other party through a wireless communication network.

In recent years, as the wireless communication terminal becomes smaller and lighter, the antenna, which is one of the largest components of the wireless communication terminal, is being designed as an increasingly smaller antenna in consideration of reception sensitivity and harmfulness of electromagnetic waves.

Generally, the antenna of the PIFA type antenna of FIG. 1 (a) is most used as an antenna of a small wireless communication terminal, but this is one of the antennas of a miniaturized monopole antenna. However, when the PIFA type antenna of FIG. 1 (a) is used, a space where the electric field of the monopole antenna is radiated to the outside is required, and the thickness of the antenna is required to be larger than a certain size. If so, the resonance frequency and radiation characteristics are affected by the field radiation, so that the gain is lowered and the directivity is changed.

Therefore, recently, in order to improve the problems of the PIFA antenna as described above, as shown in FIG. It has reached the stage of miniaturization and improving transmission and reception characteristics.

However, even in the case of the planar loop antenna of FIG. 1 (b), a loop having a length corresponding to a resonance frequency must be formed, which causes a problem in that it is difficult to be applied to a small terminal.

The present invention can reduce the size of the built-in antenna by stacking the loop antennas vertically, and by folding the loops of the antennas so that the arrangement between the loops serves as a stub, the broadband characteristics can be obtained in a high frequency band, and the arrangement of loop antennas It is possible to reduce the electromagnetic absorption rate (SAR) and obtain an omnidirectional radiation pattern while forming a miniaturized structure by forming a vertically symmetric structure, and to provide a small multiband internal antenna by folding the loop pattern of the vertically symmetric structure. There is this.

The present invention has been proposed to solve the above problems, by reducing the size of the antenna by configuring a loop antenna in a thin film dielectric substrate or film stacked up and down, and implementing a plurality of bending points before returning the loop pattern to a plurality of By forming an open loop and realizing an antenna that resonates to a plurality of frequencies, it is further miniaturized by further reducing the area of the loop pattern of the loop antenna, and vertically symmetrical structure that can obtain wideband characteristics in the high frequency band by adjusting the interval between the plurality of open loops. Its purpose is to provide a multiband embedded loop antenna for.

In addition, the present invention by forming the antenna loop pattern in a vertically symmetrical structure to distribute the current density evenly up and down symmetrical to reduce the electromagnetic absorption rate (SAR) and to obtain an omnidirectional radiation pattern, the antenna gain is high and the radiation efficiency is high It is an object of the present invention to provide a multi-band internal loop antenna having a vertically symmetric structure that is high and resonant in a multi-band.

The objects and advantages of the present invention can be understood by the following description, and will be more clearly understood by the embodiments of the present invention. Also, it will be readily appreciated that the objects and advantages of the present invention may be realized by the means and combinations thereof indicated in the claims.

The present invention provides a multi-band internal antenna, comprising: forming a loop pattern of the antenna on a dielectric substrate or a dielectric film in up-down symmetry; Folding to form a plurality of open loops having a bending point several times before the return portion of the loop for the purpose of reducing the length of the vertically symmetric loop pattern of the antenna; Adjusting an interval between the plurality of open loops to extend a resonance of a high frequency band and a bandwidth of a resonance frequency among operating frequencies of the antenna; A plurality of through holes connected to a return portion of a loop symmetrically formed above and below the dielectric film; A feeding part for feeding the upper loop of the vertically symmetric loop; And a grounding part for grounding the lower loop.

The present invention can reduce the size of the antenna as much as possible by implementing the loop-type antenna in a vertical stack structure and an open loop structure.

In addition, the present invention has the effect of greatly expanding the bandwidth of the fundamental frequency and the high frequency band of the antenna operating frequency by adjusting the interval between the open loop by making a plurality of open loops.

In addition, the present invention by forming the antenna loop pattern in the up-down symmetry and left-right symmetry structure, to evenly distribute the current density to reduce the electromagnetic wave absorption rate (SAR), and to the entire operating frequency (base frequency band and high frequency band) of the antenna The omnidirectional radiation pattern can be obtained.

A multi-band internal antenna, comprising: an upper loop pattern positioned on an upper portion of the antenna and formed in a loop form from a feeding part to a returning part; A first open loop and a second open loop formed through a bending point inserted in the middle of the loop pattern to widen the bandwidth of the high frequency band among the operating frequencies of the antenna while reducing the area of the loop pattern; A lower loop formed in an upper symmetry with an upper loop in a return part and connected to a ground part; A plurality of through holes to which the upper loop and the lower loop are connected before the return unit; The feeding part for feeding the upper loop; And a grounding part for grounding the lower loop.

The foregoing and other objects, features and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings, in which: There will be. In addition, in describing the present invention, when it is determined that the detailed description of the known technology related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

2 is a diagram illustrating an embodiment of a multi-band internal antenna having a symmetrical structure including a stub according to the present invention.

As shown in FIG. 2, the multi-band internal antenna according to the present invention includes an upper loop 11, a lower loop 12, a primary open loop 13, a secondary open loop 14, and a return unit 15. And a through hole 16 for return part connection, bending points 17, 18, 19, 20, 21, 22, 23, and 24, a feed part 25, and a ground part 26.

The upper loop 11 and the lower loop 12 are positioned on the upper and lower surfaces of the dielectric substrate to finally radiate a signal received from the feeder 25 to the outside of the loop. Here, the loop pattern of the feed end of the upper loop and the opposite end is short-circuited. In the present invention, the part is referred to as a return part, and the upper loop is formed by processing a through hole connecting the lower loop at a predetermined distance from the return part. 11) and the lower loop 12 are connected to form an entire loop as a closed loop.

In addition, in order to further reduce the length of the loop pattern, the first bent point 17 and the second bent point 18 are inserted in the middle of the loop pattern to change the direction of the loop pattern to form the first open loop 13 as a whole. . In order to further reduce the length of the next loop pattern, the loop pattern is inserted by inserting a third bending point 19, a fourth bending point 20, a fifth bending point 21, and a sixth bending point 22 in the middle of the loop pattern. The secondary open loop 14 used is formed. As a result, the length of the loop pattern can be reduced to 1/8 or more than the original loop length.

The shape of the multi-band internal loop antenna of the basic vertically symmetric structure as shown above is shown in FIG. 2. In addition, as shown in FIG. 3 (a), the basic type of FIG. 2 may be modified to form a multiband internal loop antenna having two vertically symmetrical structures on a single dielectric substrate, and may be operated only with a first open loop antenna. As shown in FIG. 3B, the primary open loop 13, the secondary open loop 14, and the tertiary open loop 28 may be formed together to be further miniaturized. In order to improve the characteristics of an arbitrary band, as shown in FIG. 3, an open stub 27 may be formed at an arbitrary point of a loop to improve characteristics.

Meanwhile, the upper loop 11 is formed on the dielectric substrate 10 or the film having a predetermined thickness between the upper loop 11 and the lower loop 12. At this time, the thickness of the dielectric substrate 10 or the film does not affect the operation as an antenna.

The signal from the feeder 25 of the antenna is transferred to the return unit 15 through the plurality of bending points 17, 18, 19, 20, 21, 22 by the upper loop 11. The upper loop 11 is transferred through the lower loop 12 which is symmetrical with the upper loop 11 to form a complete loop connected to the ground portion 26. At this time, the loop pattern is designed to have a constant line width.

The loop pattern starting from the feed section 25 forms an open loop with one side open in the process of passing through several bending points 17, 18, 19, 20, 21, 22 to the return section 15. It can be composed of only the primary open loop 13 or the primary open loop 13 and the secondary open loop 14, and the primary open loop 13 and the 2 in order to further reduce the loop antenna. It is possible to achieve miniaturization by implementing the primary open loop 14 and the third open loop 28 or more multiple open loops.

In addition, the opening direction of the primary open loop 13 and the secondary open loop 14 is shown in the right direction in FIG. 2, but the present invention is not limited thereto, and any position may satisfy the characteristics of the antenna. It is clear that it may be provided.

The total length of the loop pattern, which is the sum of the total lengths of the upper loop 11 and the lower loop 12, corresponds to the half-wavelength length of the low frequency band of the use band of the antenna.

3 is a view for explaining in detail a multi-band internal antenna having a vertically symmetrical structure to obtain more excellent characteristics by implementing a plurality of loop antennas including a stub according to the present invention, with reference to Figures 2 and 3 According to the detailed specifications of each part of the multi-band internal antenna of the vertically symmetric structure according to the following.

Here, the present invention is not limited to the specification of the antenna shown in FIG. 2, but it is to be noted that the specification of the antenna designed by way of example only for the purpose of understanding the present invention is described. Therefore, each material, structure, size, and position can be changed according to the operating frequency and design method of the antenna.

In the proposed method, a loop pattern having a line width of 1 mm is formed on a rectangular dielectric substrate having a width of 30 mm, a length of 10 mm, and a thickness of 0.2 mm to resonate in 4 bands (850 MHz, 1.58 GHz, 1.8 GHz, 2.1 GHz). A multiband internal antenna with a thin film vertically symmetric structure is implemented.

In this case, a FR-4 substrate having a thickness of 0.2 mm was used as the dielectric substrate, and copper, which is a kind of perfect electric conductor (PEC), was used as the upper loop 11 and the lower loop 12.

The upper loop 11 pattern starts at the left 10 mm position starting from the ground portion 26 and forms a primary bend point 17 at the left end point so that the upper loop 11 is vertically upward. ) To the right to move horizontally to form a primary open loop (13). Move downward to the 3rd bend point 19 at the right end point 5mm, and move horizontally to the left just after the 4th bend point 20 with a certain distance “d” and the 2nd bend point 18 With the spacing dd, the 5th bend point 21 is directed downwards, and then again horizontally past the 6th bend point 22 and connected to the return unit 15 so as to be constant with the first open loop 13. A secondary open loop 14 with a gap “d” is formed.

The interval “d” between the primary open loop 13 and the secondary open loop 14 is a resonance characteristic of the most fundamental frequency of the antenna, and a constant interval “dd” is a high frequency resonance characteristic of the antenna. Radiation characteristics such as gain and resonance band are adjusted.

As described above, the specifications of the antenna shown in FIG. 2 are not limited thereto, for example, because they are specifications of an antenna designed to help an understanding of the present invention, and the antenna characteristics of FIGS. Note that this is an antenna characteristic measured using an antenna designed with the specifications shown.

In this embodiment, “d” is set to 1mm, and “dd” is set to 10mm so that the reflection characteristic in the fundamental resonance frequency of 850MHz is based on the reflection coefficient whose resonance frequency is -6dB or less (standing wave ratio 3 or less). In the basic resonant frequency band (centered at 850 MHz), broadband characteristics of 50 MHz and 1.45 GHz to 2.45 GHz in the high frequency band of 1 GHz were obtained.

Herein, the radiation pattern of the radiating antenna shows that the antenna gain of about 0 dBi can be obtained in the characteristics of the 850 MHz band of FIG. 4, and as shown in FIG. 5, the antenna gain of about 0.5 dBi is obtained in the 1.58 GHz GPS band. In the PCS band, gain is obtained about 3.5 dBi as shown in FIG. 6, and in the WCDMA band of 2.12 GHz band, about 3.8 dBi is obtained as shown in FIG. 7, and the radiation pattern is well symmetrically radiated from side to side.

Actually, the antenna was fabricated by forming a printed pattern of both sides on a 30mm × 10mm dielectric substrate by etching, and the result of the measurement in the chamber of the radio darkroom is shown in FIG. 9. As shown in FIG. It was confirmed that the radiation efficiency was excellently emitted in the range of 60% to 99%, and the peak gain was also obtained at 3dBi or more, and the average gain was obtained at -1dBi or more, indicating good characteristics. In addition, it can be seen that the radiation pattern radiated from the antenna is well symmetrically radiated from side to side.

The bending direction of the loop antenna directly affects the radiation pattern, and it is possible to obtain an omnidirectional radiation pattern that is difficult to obtain in the high frequency band due to the symmetrical bending direction. It can be reduced.

As shown in FIG. 3, a band of the fundamental resonance frequency of the 850 MHz band is obtained about 50 MHz. In order to obtain a wider bandwidth characteristic, a method of connecting two vertically symmetrical loop antennas as shown in FIG. In this case, a broadband characteristic of 100 MHz or more can be obtained, and in some cases, an antenna having a double resonance characteristic having a resonance characteristic of CDMA in the 850 MHz band and two fundamental resonance frequencies resonating in the GSM band in the 900 MHz band can be realized. do. In addition, in order to improve the characteristics of the resonance band, it is also possible to improve the resonance characteristics by attaching the open stub 27 to a specific point of the loop pattern.

4 to 7, the multi-band internal antenna of the vertical symmetry structure according to the present invention shows the omnidirectional radiation pattern in both the low frequency band and high frequency band. This is a characteristic that appears because both the upper loop and the lower loop of the antenna according to the present invention is formed in a symmetrical structure, which acts as a significant advantage in the antenna.

The present invention described above is capable of various substitutions, modifications, and changes without departing from the technical spirit of the present invention for those skilled in the art to which the present invention pertains. It is not limited by the drawings.

The present invention is used in the field of wireless communication, in particular wireless communication terminals such as mobile phones, GPS receivers, WLAN.

1 is a view for explaining a conventional built-in antenna

2 is a diagram illustrating an embodiment of a multi-band internal loop antenna having a vertically symmetric structure according to the present invention.

3 is a diagram illustrating an embodiment of an antenna modified from a multi-band internal loop antenna having a vertically symmetric structure according to the present invention.

4 is a view for comparing and explaining the reflection coefficient characteristics of a multi-band internal loop antenna having a vertically symmetric structure according to the present invention.

5 is a radiation pattern of 850MHz band of the antenna

6 is a radiation pattern of the 1.58GHz band of the antenna

7 is a radiation pattern of the 1.89GHz band of the antenna

8 is a radiation pattern of 2.13GHz band of the antenna

9 is measurement data of the fabricated antenna

* Explanation of symbols for the main parts of the drawings

10: dielectric substrate or film, 11: upper loop, 12: lower loop,

13: 1st open loop, 14: 2nd open loop, 15: Return part,

16: Through hole for return connection, 17: 1st bending point, 18: 2nd bending point,

19: 3rd bending point, 20: 4th bending point, 21: 5th bending point,

22: 6th bending point, 23: 7th bending point, 24: 8th bending point,

25: feeder, 26: ground, 27: open stub,

28: 3rd open loop, 29: circuit ground board

Claims

In a multi-band internal antenna having a vertically symmetric structure,

An upper loop and a lower loop formed on upper and lower portions of the dielectric substrate having a predetermined size and symmetrically;

An open loop pattern for forming one or two or more open loops by forming one or two bend points in the middle of the upper loop and the lower loop;

An open loop pattern having a return portion formed at one end of the open loop pattern;

A connecting through hole connecting the upper loop and the lower loop pattern formed near the return part of the open loop pattern;

A feeding unit for feeding the upper loop pattern; And

A grounding part for grounding the lower loop pattern

Multiband internal antenna of the up and down symmetric structure comprising a.

The method of claim 1,

The upper loop and the lower loop,

The multi-band internal antenna of the up and down symmetric structure, characterized in that formed in a vertical symmetry structure around the power supply and the ground.

The method according to claim 1 or 2,

And a plurality of bending points are formed in the middle of the upper loop and the lower loop to change the direction of the pattern.

The method of claim 3, wherein

And a plurality of bending points are formed in the middle of the upper loop and the lower loop to form a plurality of open loops.

The method of claim 4, wherein

The total length of the loop pattern, which is the sum of the length of the upper loop and the length of the lower loop, corresponds to the half-wavelength of the fundamental frequency of the operating frequency of the antenna, characterized in that the multi-band internal antenna of the up-down symmetry structure.

The method of claim 4, wherein

The middle portion between the upper loop and the lower loop,

A multi-band internal antenna having a vertically symmetrical structure, characterized in that the dielectric.

The method of claim 4, wherein

The pattern of the upper loop and the lower loop,

A multi-band internal antenna having a vertically symmetrical structure, characterized in that the conductor.

The method of claim 4, wherein

The connecting portion of the upper loop and the lower loop pattern,

And an up-and-down symmetrical multi-band internal antenna having a through hole in the vicinity of a return part which is one end of the upper loop pattern and the lower loop pattern.

The method of claim 4, wherein

In the method of using the multi-band internal antenna,

The multi-band internal antenna is attached to one side of the circuit board, or multi-band internal antenna of the up and down symmetric structure, characterized in that implemented by etching on the substrate extending the circuit board.