Retractable antenna unit for a mobile phone

Details Retractable antenna unit for a mobile phone Retractable antenna unit for a mobile phone

1999-10-25

2001-04-03

Wong, Don (Department: 2821)

Communications: radio wave antennas

Antennas

With radio cabinet

C343S895000, C343S901000

Reexamination Certificate

active

06211828

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a compact mobile phone, and more particularly a retractable antenna unit provided in a mobile phone operating in a low frequency band.
2. Description of the related art
A mobile phone, such as a cellular phone, is typically provided with a whip or helical antenna, whose length is &lgr;/4 or 3&lgr;/4, where &lgr; is the wavelength of the received signal in accordance with the operating frequency. If a whip antenna is used, it must be in a extended position to maximize efficiency during calls, making it less compact and therefore, inconvenient for the user to carry. On the other hand, a helical antenna has a short physical length, and hence does not bring about such inconvenience. However, the efficiency of a helical antenna is low when compared to that of a whip antenna, due to its short physical height. Therefore, due to the helical antenna's degraded performance when compared to the whip antenna, it is desirable to have an antenna with a relatively longer physical height, such as the whip antenna.
In this view, a retractable antenna has been developed which combines a whip and helical antenna to realize the advantages of both types of antenna. Such an antenna is well disclosed in U.S. Pat. No. 5,479,178. Referring to this patent, when a mobile phone stands by to receive a call, the whip antenna may be retracted into the casing of the mobile phone, utilizing only the helical antenna for receiving incoming calls. When communication is established, the whip antenna may be completely extended from the casing to improve communication quality for the duration of the call.
However, such a retractable antenna would only be sufficient for the end if the body of the mobile phone is long enough to fully receive the retracted length of the whip antenna. Moreover, there is a trend toward making mobile phones more compact, especially with the current state of development of VLSI (very large system integration) technology, making space in a mobile phone's casing a premium. Further, when retracting the whip antenna into the casing, it must be decoupled from the wave feeding point. However, if the space for retracting the whip antenna into the casing is lacking, it becomes impractical to achieve complete decoupling.
Consequently, space is one of the key factors limiting the design of an antenna. Therefore, a need exists for a retractable antenna unit combining a whip antenna with a helical antenna, wherein the whip antenna of length &lgr;/3 or 3&lgr;/4 can be completely
retracted into a compact mobile phone while the helical antenna remains projected outside of the casing.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a retractable antenna unit for a compact mobile phone, having a metal tube contacted with and supplementing the length of the helical antenna, the metal tube also supplementing the length of the whip antenna while extended.
It is another object of the present invention to provide a retractable antenna unit with a metal tube to increase space for housing the whip antenna in a retracted position and achieve complete decoupling of the whip antenna, for a mobile phone operated in a low frequency band.
According to an embodiment of the present invention, a retractable antenna unit for a mobile phone includes an antenna housing, a helical antenna installed in the antenna housing, a whip antenna having an upper end provided with a knob and a lower end provided with a stopper, the stopper being also provided with a feeder part, and a metal tube for supplementing the length of the helical antenna when the whip antenna is completely retracted into the antenna housing, or serving to extend the physically effective length of the whip antenna when the whip antenna is completely extended from the antenna housing, whereby the wave feed position of the whip antenna is raised when the whip antenna is completely pulled out from the antenna housing.


REFERENCES:
patent: 5635943 (1997-06-01), Grunwell
patent: 5717408 (1998-02-01), Sullivan et al.
patent: 5764191 (1998-06-01), Tsuda
patent: 5812097 (1998-09-01), Maldonado
patent: 5859617 (1999-01-01), Fujikawa
patent: 5861859 (1999-01-01), Kanayama et al.
patent: 6002372 (1999-12-01), Sullivan

Affiliated with

Also associated with

Rating

Retractable antenna unit for a mobile phone does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Retractable antenna unit for a mobile phone, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Retractable antenna unit for a mobile phone will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2553728