KR20040081595A - Built-in Loop Antenna with Multi-band Characteristic - Google Patents

Abstract

PURPOSE: An internal loop antenna having a multiple band characteristic is provided to realize an internal antenna for a multiple band terminal including a GPS(Global Positioning System) by combining a loop antenna and an inverse F-type antenna. CONSTITUTION: A power feed element is connected with a terminal PCB(Printed Circuit Board) to supply a current to an antenna. A ground element is connected with the terminal PCB to ground the antenna. A first radiating element(34) has one end connected with the power feed element and the other end connected with the ground element, operates in half-wavelength of dynamic frequency, and is formed of a loop structure. A second radiating element(35) has one end connected with the ground element, and the other end is open in a direction of the power feed element, operates a quarter-wavelength of the dynamic frequency, and is formed of an inverse F-structure that the power feed element and the ground element are changed in position. A housing part(37) is formed to install the first and second radiating elements(34,35).

Description

Built-in Loop Antenna with Multi-band Characteristic

The present invention relates to a built-in loop antenna having a multi-band characteristic, and more particularly, to a built-in loop antenna having a multi-band characteristic by combining a first radiator having a loop structure and a second radiator having a modified inverted-F structure. It is about.

Conventional loop antennas have been widely used as reception antennas for home TV receivers or as reception loop antennas such as pagers in the wireless paging market. In addition, such antennas have a lower radiation resistance than loss resistors, so that the radiation efficiency of the antenna is generally low. Accordingly, the signal-to-noise ratio (S / N) characteristic of the antenna is not particularly serious. The antenna has been widely used as a structure for the VHF (Very High Frequency) or UHF (Ultra High Frequency) band.

The conventional basic structure of such an antenna is designed as a circular loop type when the system appearance is not greatly restricted, or when the appearance is limited according to the environment of each system, while maintaining the loop shape basically according to each environment. Most of them have a closed curve structure such as a rectangle or a triangle. In one embodiment, a loop antenna for use in a pager is shown in FIG. As shown in FIG. 1, the loop antenna 11 has a rectangular loop structure according to the shape of the pager 10. However, such a structure has a problem in that it is mostly used for a single band of single resonance characteristic due to a single closed curve of a loop.

Recently, dual loop and multi-loop antenna structures have also been reported. However, most of these structures have implemented multiple loops to satisfy the miniaturization by increasing the turn number of the loops. In most cases, it is a single band loop antenna structure having only one input and output terminal. As an embodiment thereof, an antenna is disclosed in which two loops of approximately the same size are spaced apart in parallel to each other so that currents flowing from each antenna cancel each other (Publication No. 2001-0106513, Multiple). Loop antenna). These antennas are antennas for short-range sensors that allow the fields to cancel each other at distances greater than one wavelength.As the current flows in two opposite loops in opposite directions, they are insensitive at long distances and used for the purpose of sensors at close ranges. Since it is a near antenna used, there is a problem that it is not suitable for long distance.

In addition, in recent years, a structure in which a single loop antenna is mounted on a folder cover of a terminal for a mobile communication terminal has been disclosed (Original Application Publication 2002-0044089, "Mobile communication terminal having various electronic money functions"). This creates a large loop near the top liquid crystal display (LCD) of the folder, so it's too close to the human ear when actually talking on it, which causes serious SAR (Specific Absorption Rate) problems. Antenna characteristic deterioration occurs due to magnetic field characteristics, and there is a problem in that a single band characteristic is basically obtained by using a single loop.

The present invention has been proposed to solve the above problems, and provides an integrated loop antenna having a multi-band characteristic by combining a first radiating portion having a loop structure and a second radiating portion having a modified inverted-F structure. have.

1 is an exemplary configuration diagram of a conventional loop antenna.

Figure 2 is a detailed configuration diagram of an embodiment of a built-in loop antenna having a multi-band characteristics according to the present invention.

Figure 3 is a detailed configuration diagram of an embodiment of a modified internal loop antenna having a multi-band characteristics according to the present invention.

4 is a detailed block diagram of another embodiment of a modified internal loop antenna having multi-band characteristics according to the present invention.

5 is a diagram illustrating a PCS band radiation pattern of a terminal to which a built-in loop antenna having a multi-band characteristic according to the present invention is applied.

6 is a diagram illustrating a GPS band radiation pattern of a terminal to which a built-in loop antenna having a multi-band characteristic according to the present invention is applied.

* Explanation of symbols for the main parts of the drawings

10: pager 11: built-in loop antenna

20: top cover of the terminal 21: multi-band loop antenna

22: folder terminal body 23: folder terminal battery pack

30: feed point pad 31: ground point pad

32: probe pin for power supply 33: probe pin for grounding

34: Modified loop radiator that is the first radiator

35: modified inverted-F emitter that is a second emitter

36: fixing hole

37: housing part (Printed Circuit Board (PCB) or plastic frame)

38: main printed circuit board 40: first radiator

41: second radiator 42: feeder line

The apparatus of the present invention for achieving the above object, in a built-in loop antenna of a mobile terminal having a multi-band characteristics, is connected to a terminal printed circuit board (PCB), feeding means for supplying a current to the antenna A grounding means connected to the terminal PCB for grounding the antenna; A first radiating means having one end connected to the feeding means and the other end connected to the grounding means, operating at a half-wavelength length of an operating frequency, having a loop structure, one end connected to the grounding means and the other end directed to the feeding means And a second radiation means and a dielectric material having a modified inverted-F structure having reversed positions of the power supply means and the grounding means, operating at a quarter-wavelength of the operating frequency, the first radiation A housing means in which the means and the second radiating means are installed.

In addition, the present invention is a built-in loop antenna of a mobile terminal having a multi-band characteristics, the power supply means connected to the terminal PCB, for supplying current to the antenna: connected to the terminal PCB, the grounding means for grounding the antenna; Each loop structure has a different size, and one end of each loop structure is connected to the power supply means and the other end is connected to the ground means, and a plurality of loops are arranged with a certain distance offset. Spinning means; And a housing means composed of a dielectric material, said housing means being provided with said plurality of radiating means.

The above objects, features and advantages will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Figure 2 is a detailed configuration diagram of an embodiment of a multi-band internal antenna according to the present invention, mounted on the battery 23 of the clamshell terminal. As shown in FIG. 2, the built-in loop antenna 21 according to the present invention is embedded in the main body 22 of the terminal.

3 is a detailed configuration diagram of an embodiment of a multi-band internal antenna according to the present invention mounted on a battery of a clamshell terminal. As shown in FIG. 3, the built-in loop antenna according to the present invention includes a housing part (such as a PCB or a plastic frame) 37 in which the antenna is implemented, a feed point pad 30 for supplying current to the antenna, and a feeding probe. Probe pin 32, grounding point pad 31 for grounding the antenna and probe pin 33 for grounding, first radiator 34 and second radiator 35 and antenna for radiating multi-band radio waves It consists of a fixing hole 36 for fixing with the rear cover of the terminal, the built-in antenna is mounted on the main PCB 38 of the terminal. At this time, the housing 37 may be implemented as a PCB or a plastic frame.

The structure of the built-in loop antenna shown in FIG. 3 and its operation principle will be described in detail as follows. In the built-in loop antenna structure according to the present invention, the first radiator 34 and the second radiator 35 are installed on the housing part 37 formed of a PCB or a plastic frame, thereby providing a dielectric effect of the housing part 37. In this case, the first resonance can be generated with a small size, and a stripline for the second radiator 35 generating the second frequency is arranged in parallel near the first radiator 34. In particular, referring to the structure of the second radiator 35 shown in FIG. 3, one end is connected to the grounding point pad 31 while the other end is different from the loop of the first radiator 34. It is.

In the present invention, since the one-way antenna 34 is coupled to the structure surrounding the other antenna 35, the total length of the antenna can operate at about half-wavelength, so the horizontal length of the antenna is about half-wavelength or the total length of the antenna. Can be reduced to half the size compared to a typical horizontal rectangular loop antenna operating with a length of about one wavelength.

The first radiator 34 embodied in the FR-4 PCB board, which is one embodiment of the housing part 37, is one wavelength, which is the operating length (circumference) in the air of an electrically large loop antenna generally operated. It operates in the US-PCS band with an electrical length corresponding to about 0.45 times the wavelength rather than the length, and the position of the feed point 30 and the ground point 31 is different from that of a general loop antenna. It operates as a modified loop antenna that is slightly offset spatially.

Meanwhile, in the case of the second radiator 35, the stripline from the feed point 30 to the ground point 31 is used as a signal transmission line of the first radiator 34, and the remaining stripline has an electrical length of about 0.25 times the wavelength. It operates as a built-in antenna radiator for the GPS band. In particular, the structure of the second radiator 35 is a modified internal antenna structure in which the positions of the feed point and the ground point are reversed compared to the general inverted-F antenna, and the second radiator 35 stripline is a loop strip of the first radiator 34. It is a structure that is enclosed or enclosed by, and operates while reducing the size of the antenna to about 1/2 of the general antenna by increasing the mutual coupling characteristics between each antenna.

4 is a detailed block diagram of another embodiment of a modified internal loop antenna having a multi-band characteristic according to the present invention, mounted on a PCB of a terminal according to another embodiment of the present invention. The built-in loop antenna shown in FIG. 4 provides an antenna having a multi band characteristic.

While the built-in loop antenna shown in FIG. 4 includes all the features of the embodiment of FIG. 3, unlike the conventional antenna at a single frequency using a plurality of loop antennas of the same size, loops of different sizes are sequentially By arranging, it operates as a multi-band antenna of each different band. In this case, currents in the same direction flow through the loops of the first radiator 40 and the second radiator 41 to operate as independent antennas even at a long distance.

In addition, by implementing the loop plane of the first radiator 40 and the second radiator 41 in the shape of 'B' rather than a single plane, it is possible to radiate more power in the upward direction, thereby improving three-dimensional radiation characteristics. Can be.

The embodiment of the present invention described above has been described with respect to the built-in loop antenna consisting of the first radiator and the second radiator, but by arranging by adding another radiator loop other than the first radiator and the second radiator according to the band of the terminal The loop can be operated as an independent antenna, thereby implementing an embedded loop antenna having multi-band characteristics such as PCS, cellular and GPS frequency bands.

5 and 6 are the results of measuring the PCS band radiation pattern of the terminal to which the multi-band internal loop antenna according to the present invention and the GPS band radiation pattern of the terminal to which the multi-band internal loop antenna according to the present invention is applied. As shown in FIGS. 5 and 6, the radiation pattern of the internal loop antenna according to the present invention is uniform at all positions, and the same band characteristics as the conventional external antenna may be seen.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications, and changes are possible in the art without departing from the technical spirit of the present invention. It will be clear to those of ordinary knowledge.

The present invention as described above, there is an effect that can provide a built-in antenna for a multi-band terminal including a Global Positioning System (GPS) by combining the loop antenna and the modified inverted F antenna structure.

In addition, the present invention, by mounting the antenna on the main printed circuit board (PCB) board of the terminal can reduce the antenna performance degradation due to the speaker and flexible printed circuit board (FPCB), the human body It is further separated from and has the effect of improving SAR (Specific Absorption Rate).

In addition, there is an effect that can improve the call quality of the portable terminal by mounting the built-in antenna in a portion where the influence of the hand is minimized.

Claims (8)

In the built-in loop antenna of a mobile terminal having a multi-band characteristics, A power supply unit connected to the terminal PCB (Printed Circuit Board) and supplying a current to the antenna; A grounding means connected to the terminal PCB for grounding the antenna; First radiating means connected at one end to the feeding means and at the other end to the grounding means, operating at a half-wavelength of an operating frequency and having a loop structure; One end is connected to the grounding means, the other end is open in the direction of the power supply means, operates at a quarter wavelength length of the operating frequency, and made of a modified inverted F-type structure in which the positions of the power supply means and the grounding means are reversed. 2 spinning means; And A housing means composed of a dielectric material, on which said first and second radiating means are installed Modified built-in loop antenna having a multi-band characteristics including a. The method of claim 1, The power supply means and the grounding means, 10. A modified internal loop antenna with multi-band characteristics, characterized in that positioned at spatially constant offsets. The method of claim 1, The first spinning means, A modified internal loop antenna with multiband characteristics, characterized in that it operates at a length of 0.45 times the operating frequency. The method of claim 1, The second spinning means, A modified internal loop antenna having multiband characteristics, characterized by being wrapped by the first radiating means. The method according to claim 1 or 2, The second spinning means, And a strip line from the feed point to the ground point is used as the signal transmission line of the first radiating means and the strip line from the ground point to the end is the actual operating length of the antenna. In the built-in loop antenna of a mobile terminal having a multi-band characteristics, Feeding means connected to the terminal PCB, for supplying current to the antenna: A grounding means connected to the terminal PCB for grounding the antenna; Each loop structure has a different size, and one end of each loop structure is connected to the power supply means and the other end is connected to the ground means, and a plurality of loops are arranged with a certain distance offset. Spinning means; And Housing means composed of dielectric material, said plurality of radiating means installed Modified built-in loop antenna having a multi-band characteristics including a. The method of claim 4, wherein The plurality of spinning means, A modified internal loop antenna having multi-band characteristics, characterized in that each loop consists of first and second radiating means through which currents flow in the same direction. The method according to claim 4 or 5, The first spinning means and the second spinning means, A modified internal loop antenna having multi-band characteristics, wherein each loop plane has a '-' shape.