Communications: radio wave antennas – Antennas – Spiral or helical type
Reexamination Certificate
1999-05-03
2001-07-17
Ho, Tan (Department: 2821)
Communications: radio wave antennas
Antennas
Spiral or helical type
C343S702000, C343S872000
Reexamination Certificate
active
06262693
ABSTRACT:
FIELD OF THE INVENTION
The present invention generally concerns antennas for a portable communicator. The present invention also concerns multiple band antennas.
BACKGROUND OF THE INVENTION
Portable communicators, such as cell phones, sometimes use antennas with multiple radiators to enable phones to receive two different signal bands. These phones are compatible then with multiple cellular networks or different frequency services of a single cellular network. Such an antenna includes a first frequency radiator and second radiator which are alternately utilized through mechanical switching methods in typical devices. Frequently, one radiator might be active in a retracted position and another in an extended position.
Known techniques for connecting radiators to phone circuit contacts in such antennas include soldering and crimping to electrically connect radiators to electrodes or similar means which electrically couple to circuits of the portable communicators. A problem exists in that techniques such as soldering and crimping change the electrical characteristics of the antenna in a manner which may vary from one manufactured antenna to the next. For example, the process of adding solder to the antenna is an inherently imprecise venture since the solder adds variable amounts materials to the radiators which change the electrical characteristics of one manufactured antenna to the next. Additionally, crimping is not a desired technique since crimping can cause the radiator to deform, thus adversely affecting the electrical characteristics of the antenna. The latter problem is typically experienced when the pitch of a helical radiator is altered due to mechanical deformation during attachment.
Compensation for these variances is often achieved through additional processing, such as testing and trimming to tune the antenna to a desired frequency. Obviously, this increases both the cost and difficulty of manufacturing the antennas. In addition, operations such as soldering and crimping require assembly technicians skilled enough to perform the delicate and time-consuming techniques. Additionally, performance tolerances must be generous enough to accommodate the variances experienced in those antennas which are still suitable for use. Even so, a significant percentage of manufactured antennas may be unsuitable for use.
Related difficulties relate to high part counts and overall device complexity. It is generally desirable to reduce part counts because of the obvious benefits that such reduction has on manufacturing. In typical multiple band antennas, high part counts are often associated with the switching and connecting mechanisms to activate separate radiators for operation in separate bands.
Operation of known multiple band antennas is also limited since their structure typically requires some operator movement of the antenna to activate one radiator for one band of operation and deactive its other radiator for another band of operation. This conflicts with a trend in the art towards small fixed antennas, referred to as “stubbies”. It also limits usefulness of the antennas since one band's operation is mutually exclusive of the other band's operation.
There is therefore a need for an improved portable communicator antenna which addresses problems in such known antennas. It is an object of the invention to provide an antenna which meets this need.
SUMMARY OF THE INVENTION
This object is met or exceeded by the present multiple band, unitary radiator antenna. The present antenna for portable communicators radiates and receives two frequency bands through the use of the unitary, i.e., one piece, radiator. Separate portions of the radiator correspond to separate frequency bands, with the separate portions being electrically parallel and reacting with each other.
Preferred structures of the present invention provide such desirable multiple band operation while also separately demonstrating advantageous manufacturing characteristics. Low part counts and low sophistication assembly result from the present structure. In addition, preferred structures of the invention provide reliable manufacturing tolerances facilitating consistent electrical performance from one manufactured antenna to the next.
More specifically, a preferred antenna structure incorporating the unitary radiator of the present invention or another radiator includes a compression housing. The compression housing compresses the unitary radiator to ensure electrical contact between the unitary radiator and an electrical contact, such as a ferrule. Upon assembly, the compression housing is preferably snap fit to the ferrule.
Snap fitting is most preferred because of its repeatability, reliability, and ease. Thus, the ferrule, compression housing and portable communicator are constructed so that the compression housing snap fits to the ferrule, and then the ferrule snap fits onto the portable communicator. Preferably, to accommodate snap fit construction, an end of the ferrule includes at least one detent that corresponds to at least one projection on the compression housing. Moreover, another end of the ferrule includes at least one projection that corresponds to at least one detent on the portable communicator. Artisans will appreciate, however, that the ferrule, compression housing, and portable communicator can be constructed so that the arrangement of projections and detents are reversed.
To accommodate two bands, the unitary radiator has a generally helical shape formed by an outer portion thereof and a center portion disposed within the outer portion. Spring force from the compression of the unitary radiator guarantees an electrical connection between the unitary radiator and the ferrule without resort to crimping, soldering or similar techniques. The contact point between the ferrule (or other type of electrical contact) and the unitary radiator is a parallel electrical feed which, when transmitting, excites both portions of the radiator to interact in parallel. When receiving, both portions of the radiator similarly pass signals to the ferrule in parallel. This structure including the unitary radiator permits application of the antenna to stubby mounts, as well as retractable mounts or any mount which can accommodate the compression housing.
REFERENCES:
patent: 5436633 (1995-07-01), Liu
patent: 5742259 (1998-04-01), Annamaa
patent: 5945964 (1999-08-01), DeGroot et al.
patent: 5963170 (1999-10-01), Garner et al.
patent: 6016130 (2000-01-01), Annamaa
patent: 6052088 (2000-04-01), Simmons et al.
patent: 6075488 (2000-06-01), Hope
patent: 6100847 (2000-06-01), Sonitula
Navsariwala Umesh
Repplinger Dan
Sutter Rob
Alemu Ephrem
Greer Burns & Crain Ltd.
Ho Tan
T&M Antennas
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