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Transceiver having retractable antenna assembly
| Details |
Inventors: Grunwell, Randall L.;
Assignee: Matsushita Communication Industrial Corp. of America (Peachtree City, GA)
Primary Examiner: Wimer; Michael C.
Assistant Examiner:
Attorney, Agent or Firm: Jones & Askew
A transceiver (10) having a retractable antenna (12) that substantially reduces interference when the antenna is in a retracted position. The transceiver (10) includes transceiver circuitry (T), operating at a predetermined frequency, electrically connected to the retractable antenna (12). The retractable antenna (12) includes two antenna elements (20, 22). A first antenna element (20) comprises a whip antenna element, movable within a conductive tube (14) housed within a cellular telephone case (C). A second antenna element (22) comprises a helical coil antenna element extending from the whip antenna element (20) and located outside the case (C). In the retracted position, a first contact assembly (76) contacts the whip antenna element (20). The first contact assembly (76) is electrically connected to the transceiver circuitry (T) through a conductor (96) which is a predetermined multiple of a quarter wavelength at the predetermined frequency. In the retracted position the whip antenna element (20) and the conductive tube (14) form a coaxial transmission line so that only the helical coil antenna element (22) is electrically active and the whip antenna element (20) does not radiate internal to the case (C). In the extended position, a second contact assembly (74) contacts the whip antenna element (20) such that the whip antenna element (20) and the helical coil antenna element (22) are both electrically active. In the extended position, the lower conductor (86), the conductive tube (14) and the first contact assembly (76) act as a predetermined multiple of a one-quarter wavelength stub and appear as an open circuit to the transceiver circuitry. |
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DETAILED DESCRIPTION Referring now in more detail to the drawings, in which like numerals refer to like parts throughout the several views, FIGS.
1A and 1B depict a radio transceiver device 10 in accordance with the present invention.
The radio transceiver device 10 includes a case C, which houses a retractable antenna assembly 11 electrically connected to transceiver circuitry T.
Those having ordinary skill in the art will understand that the transceiver circuitry T may comprise radio frequency circuitry, power supply circuitry and other circuitry for providing dialing and special feature capabilities.
The specifics of the transceiver circuitry T are well-known in the art and need not be disclosed in detail herein.
The retractable antenna assembly 11 includes an antenna 12, a conductive tube 14, an upper finger contact assembly 74, a lower finger contact assembly 76, a lower conductor 86 and an upper conductor 96.
The lower conductor 86 and the upper conductor 96 are external to the conductive tube 14.
The conductive tube 14 is maintained at ground potential with respect to the transceiver circuitry T through a ground strap or conductor 72 in a conventional manner.
If lower conductor 86, upper conductor 96, or the conductor 104 between junction 102 and the transceiver T is a coaxial cable then ground strap 72 may be implemented by the shield of such a coaxial cable.
Junction 102 and conductor 104 form a means for connecting the conductors 86 and 96, and therefore the upper and lower finger contact assemblies 74 and 76, to the transceiver circuitry T.
The antenna 12 is shown in a retracted position in FIG.
1 and in an extended position in FIG.
2.
The antenna 12 is a compound antenna which comprises two radiating elements: a first antenna element embodied as an elongate, rigid whip antenna element 20, and a second o antenna element embodied as a helical coil antenna element 22.
The helical coil antenna element 22 is attached to the whip antenna element 20 at a junction 24.
In an alternative embodiment of the retractable antenna of the present invention, the second antenna element may be embodied as a rigid second whip antenna element 22', shown in FIG
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