KR19980023441A - Dual helical antenna of dual band radiotelephone - Google Patents

Abstract

An object of the present invention is to provide an antenna structure of a dual band radiotelephone which can obtain a uniform standing wave ratio and antenna gain in both frequency bands.

The antenna structure of the dual band wireless telephone according to the present invention has a coupling means which can be fixed to the main body of the wireless telephone 1, and an external housing 32 having an empty interior, and inserted into the external housing 32 to a high frequency band. A coil-shaped first helical 33 having a length at which resonance can occur, an inner housing 38 inserted into the outer housing 32 and empty inside, and inserted into the inner housing 38. When connected to the first helical 33, a coil-shaped second helical 34 having a length in which resonance may occur in a low frequency band, and the first helical 33 and the second helical 34 are used frequency bands. It includes a connecting means 36 for connecting when changing.

This ensures uniform standing wave ratios and antenna gains in both frequency bands to maintain optimal antenna performance.

Description

Dual helical antenna of dual band radiotelephone

The present invention relates to a radiotelephone, and more particularly, to an antenna structure of a radiotelephone for use in a dual band.

1 is a view showing a state of use of a conventional radiotelephone antenna, FIG. 1A is a state diagram when using a helical as an antenna, and FIG. 1B is a state diagram when using a helical and a whip as an antenna. 1A and 2, there is shown an antenna 11 coupled to one end of a rectangular cordless telephone body 1, the antenna 11 having an empty interior and a screw 16 formed at the bottom thereof. A housing 12, a coil-shaped helical 13 inserted into the housing 12, and a knob 14 formed thereon with a size that can be caught on an upper portion of the housing 12. The lower portion includes a whip 17 having a whip contact terminal 15 formed thereon. The housing 12 is coupled to the cordless phone body 1 by a screw 16 formed at the bottom thereof, and the helical 13 is brought into contact with the board contact terminal 2 formed on the cordless phone body 1. The top of the whip 17 penetrates the helical 13 inserted into the housing 12, and the bottom of the whip 17 is inserted into the radiotelephone.

1A and 1B, when the whip 17 is placed inside the radiotelephone body 1 and the housing 12, only the helical 13 contacts the board contact terminal 2. Therefore, when the helical 13 acts as an antenna in both frequency bands f1 and f2, and the lower part of the whip 17 is taken out of the main body of the radiotelephone 1, the helical 13 and the whip contact terminal 15 In contact with the board contact terminal 2, the whip 17 and the helical 13 act as antennas in both frequency bands of the frequencies f1 and f2.

FIG. 2 is a diagram showing a standing voltage ratio of an antenna of a conventional radiotelephone, FIG. 2a is a standing wave ratio when a helical is used as an antenna, and FIG. 2b is a helical and whip when an antenna is used. The standing wave ratio of In the figure, Rx denotes a reception state, Tx denotes a transmission state, f1 is 800 MHz, and f2 is 1.8 GHz. The whip acting as an antenna shows better performance than the helical acting as an antenna.

In the structure of the dual band radiotelephone antenna, it is desirable to obtain a uniform standing wave ratio and antenna gain by generating resonance in both frequency bands. In the conventional dual band radiotelephone antenna structure, the helical or helical and whip are physically applied to both frequency bands. As a function of the same type of antenna, resonance cannot occur in each of the two frequency bands, and thus there is a problem that the standing wave ratio and the gain of the antenna are different in both frequency bands.

SUMMARY OF THE INVENTION An object of the present invention is to provide an antenna structure of a dual band wireless telephone which can obtain a uniform standing wave ratio and antenna gain in both frequency bands.

1 is a view showing a state of use of a conventional radiotelephone antenna

Figure 1a is a state diagram when using a helical as an antenna

Figure 1b is a state diagram when using the helical and whip as the antenna

2 is a view showing the standing wave ratio of the antenna of the conventional wireless telephone.

Fig. 2A is a view showing the standing wave ratio when using helical as an antenna

Fig. 2B shows standing wave ratios when using helical and whip as antennas

3 is a view showing a state of use of a radiotelephone antenna according to the present invention;

Figure 3a is a state diagram used in the high frequency band

Figure 3b is a state diagram used in the high frequency band

Figure 4 is a detailed view of the connecting means of the first helical and the second helical according to the embodiment of the present invention

5 is a view showing the standing wave ratio of the antenna of the radiotelephone according to the embodiment of the present invention;

Fig. 5A is a view showing the standing wave ratio when using the high frequency band (1.8 GHz)

Fig. 5B shows standing wave ratios when using a high frequency band (800 MHz).

＊ Description of symbols for main parts of the drawings ＊

1: Cordless Telephone Body 12, 32, 38: Housing

13, 33, 34: helical

The antenna structure of the dual band wireless telephone according to the present invention has a coupling means which can be fixed to the main body of the wireless telephone 1, and an external housing 32 having an empty interior, and inserted into the external housing 32 to a high frequency band. A coil-shaped first helical 33 having a length at which resonance can occur, an inner housing 38 inserted into the outer housing 32 and empty inside, and inserted into the inner housing 38. When connected to the first helical 33, a coil-shaped second helical 34 having a length in which resonance may occur in a low frequency band, and the first helical 33 and the second helical 34 are used frequency bands. It includes a connecting means 36 for connecting when changing.

3 is a view showing a state of use of a radiotelephone antenna according to the present invention, FIG. 3a shows a state of use in a high frequency band, and FIG. 3b shows a state of use in a low frequency band.

Referring to the operation of the antenna of Figs. 3a and 3b, the second helical 34 is not drawn out when the high frequency band of both frequency bands are used, in which case the second helical 34 is the first It is not electrically coupled with the helical 33. Therefore, only the first helical 33 operates as an antenna.

When the lower frequency band of both frequency bands is used, the second helical 34 is drawn out. In this case, the second helical (3) is connected by the connecting means 36 of the first helical 33 and the second helical 34. 34 is connected to the first helical 33, and the first helical 33 and the second helical 34 are electrically coupled to operate as one antenna.

Since the physical shape of the antenna varies depending on the frequency band used as described above, resonance can be generated in each of the two frequency bands by appropriately adjusting the lengths of the two helicals. For example, in a wireless telephone using 800Mhz and 1.8Ghz, the first helical is set so that resonance occurs at 1.8Ghz frequency, and the second helical is 1.25 times the length of the first helical (because the ratio of the wavelengths of the two frequencies is 1.8 If the length is set to be Ghz / 800Mhz = 2.25), resonance occurs in each of both frequency bands.

Figure 4 is an embodiment of the first helical and second helical connecting means according to the present invention. Referring to Fig. 4, it is composed of a disk-shaped housing side engaging portion 37 having a recess in the center and a disk-shaped helical side engaging portion 39 having protrusions formed at both ends thereof. Protrusions of the mouth and helical side engaging portions 38 are plated to reduce the contact resistance. Housing side coupling portion 37 is coupled to the upper inner surface of the outer housing 32, the helical coupling portion 38 is the lower end of the second helical 34, the housing coupling portion 37 is the first helical ( 33) is coupled to the top. When using the lower frequency of both frequency bands, when the second helical 34 is pulled out, the projection of the helical side coupling portion 38 comes into contact with the recess of the housing side coupling portion 37. It is electrically connected with one helical 33.

FIG. 5 is a view showing a standing wave ratio of the radiotelephone antenna according to the embodiment of the present invention, FIG. 5A shows a standing wave ratio when using a high frequency band, and FIG. 5B shows a standing wave ratio when using a low frequency band. In the figure, Rx denotes a reception state, Tx denotes a transmission state, f1 is 800 MHz, and f is 1.8 GHz. It can be seen that the conventional antenna structure shows better performance.

When the antenna is used at a high frequency or at a low frequency, the helical length of the antenna is changed so that resonance can occur for each of the antennas, thereby obtaining uniform standing wave ratios and antenna gains in both frequency bands, thereby maintaining optimal antenna performance. .

Claims (2)

An outer housing 32 having a coupling means which can be fixed to the radiotelephone body 1 and which is empty inside; A coil-shaped first helical 33 inserted into the outer housing 32 to have a length at which resonance may occur in a high frequency band; An inner housing 38 inserted into the outer housing 32 and empty inside; A coil-shaped second helical 34 inserted into the inner housing 38 and connected to the first helical 33 to have a length in which resonance may occur in a low frequency band; Antenna structure of a dual band wireless telephone, characterized in that it comprises a connecting means for connecting the first helical (33) and the second helical (34) when the frequency band is used. 2. The connecting means (36) according to claim 1, wherein the connecting means (36) includes a circular housing side coupling portion (37) formed at a center thereof and coupled to an inner upper end of the outer housing (32) and an upper end of the first helical (33); Protruding portions are formed at both ends, and an antenna structure of a dual band wireless telephone, characterized in that it is composed of a disk-shaped helical side coupling portion (39) coupled to a lower end of the second helical (34).