Communications: radio wave antennas – Antennas – With radio cabinet
Reexamination Certificate
2002-03-14
2003-09-02
Wimer, Michael C. (Department: 2821)
Communications: radio wave antennas
Antennas
With radio cabinet
C343S846000
Reexamination Certificate
active
06614401
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a communication apparatus such as a portable telephone and an antenna-electrode structure provided in the communication apparatus.
2. Description of the Related Art
Recently, the size communication apparatuses, such as portable telephones have been decreasing rapidly. In association with such miniaturization of communication apparatuses, a built-in antenna is required to further reduce the size of the communication apparatus.
However, when the size of an antenna is reduced, the frequency bandwidth of electric waves transmitted and received by the antenna is reduced. Antennas having various structures are proposed to obtain a miniaturized antenna having an increased bandwidth. However, an antenna has not yet been produced in which miniaturization, increased bandwidth and a simplified structure are achieved.
SUMMARY OF THE INVENTION
In order to overcome the above-described problems, preferred embodiments of the present invention provide an antenna-electrode structure and a communication apparatus including the antenna-electrode structure in which miniaturization, increased bandwidth and a simplified structure are achieved.
An antenna-electrode structure according to preferred embodiments of the present invention includes a substrate, a grounded portion provided on the substrate, a non-grounded portion on which an antenna is mounted, a feeding radiant-electrode into which a signal is supplied from a signal supply source, a non-feeding radiant-electrode provided adjacent to the feeding radiant electrode and spaced from the grounded portion via a spacing therebetween for producing a dual-frequency resonance state by electromagnetic coupling with the feeding radiant-electrode, and a dielectric base substance surface-mounted on the substrate and having the feeding radiant-electrode mounted thereon in a substantially U-shaped configuration, wherein one end of the feeding radiant-electrode is open so as to produce a capacitance to the grounded portion therebetween, and wherein the non-feeding radiant-electrode is provided on the dielectric base substance in a substantially L-shaped configuration along the feeding radiant-electrode and one end of the non-feeding radiant-electrode is connected to the grounded portion while the other end is open, the open end of the non-feeding radiant electrode is a capacity-loaded electrode defining a capacitance to the grounded portion therebetween at a position close to a capacity portion provided between the open-end of the feeding radiant-electrode and the grounded portion.
Preferably, the antenna-electrode structure further includes an insulating member, wherein the feeding radiant-electrode and the non-feeding radiant-electrode are arranged with the insulating member provided therebetween.
Preferably, the feeding radiant-electrode and the non-feeding radiant-electrode are provided directly on the non-grounded portion on the substrate by pattern forming, instead of forming the feeding radiant-electrode and the non-feeding radiant-electrode on the dielectric base substance.
Preferably, the antenna-electrode structure further includes a feeding electrode electrically connected to the signal supply source, wherein the feeding radiant-electrode communicates and connects to the feeding electrode so as to define a direct-feeding-type feeding radiant-electrode in which a signal is directly supplied from the signal supply source via the feeding electrode.
Preferably, the antenna-electrode structure further includes a feeding electrode that is electrically connected to the signal supply source, wherein the feeding radiant-electrode is arranged at a position that is spaced from the feeding electrode so as to define a capacity-feeding-type feeding radiant-electrode in which a signal from the signal supply source is supplied by capacitively coupling from the feeding electrode.
A communication apparatus according to preferred embodiments of the present invention includes an antenna-electrode structure according to one of the configurations described above.
According to preferred embodiments of the present invention having the configurations described above, when a signal is supplied to the feeding radiant-electrode from the signal-supply source, the signal is transmitted from the feeding radiant-electrode to the non-feeding radiant electrode by electromagnetic coupling. With such signal supply, the feeding radiant-electrode and the non-feeding radiant electrode perform the antenna actions. Also, according to preferred embodiments of the present invention, the respective open-ends (i.e., capacity-loaded electrodes) of the feeding radiant-electrode and the non-feeding radiant electrode have capacities to the grounded portion of the substrate therebetween, such that the electric current, which is excited by the antenna actions of the feeding radiant-electrode and the non-feeding radiant electrode, flows through the grounded portion. That is, when excited by the antenna actions of the feeding radiant-electrode and the non-feeding radiant electrode, the grounded portion also performs an antenna action corresponding to the antenna actions of the feeding radiant-electrode and the non-feeding radiant electrode.
The grounded portion is provided on a circuit board of a communication apparatus, for example, and the position and size thereof can be varied such that the degree of design freedom is greatly increased. Therefore, even when the size of the feeding radiant-electrode and the non-feeding radiant-electrode is reduced (miniaturized), the transmission and reception of electric waves at a desired frequency bandwidth is performed with sufficient power by appropriately configuring the grounded portion. Moreover, the feeding radiant-electrode and the non-feeding radiant-electrode produce a dual-frequency resonance state, such that the frequency bandwidth is greatly increased as compared with a mono-resonance state where the non-feeding radiant-electrode is not provided.
Furthermore, because the feeding radiant-electrode and the non-feeding radiant-electrode are provided on the dielectric base-substance, the frequency of electric waves radiated from the feeding radiant-electrode and the non-feeding radiant-electrode is increased due to the wavelength reduction effect by the dielectric substance, enabling the size of the feeding radiant-electrode and the non-feeding radiant-electrode to be further reduced.
As described above, with the antenna-electrode structure according to preferred embodiments of the present invention, a simplified antenna-electrode structure having a greatly reduced size and an increased bandwidth is provided.
Although a direct-feeding type or a capacity-feeding type feeding radiant-electrode has outstanding characteristics, when a capacity-feeding type is provided, the feeding radiant-electrode can be provided separately from the feeding electrode, such that the feeding electrode is matched to the feeding radiant-electrode by the position of the feeding electrode, resulting in another advantage that a matching circuit is not required to be interposed between the feeding electrode and the signal-supply source.
When the feeding radiant-electrode and the non-feeding radiant-electrode are directly pattern-formed on the non-grounded portion of the substrate, manufacturing costs are reduced because the chip base-substance mentioned above is not required, and further, the manufacturing is simplified.
When the feeding radiant-electrode and the non-feeding radiant-electrode are arranged in the depositing direction via an insulating member interposing therebetween, the space between the feeding radiant-electrode and the non-feeding radiant-electrode can be more easily changed as compared with the case in which both the feeding radiant-electrode and the non-feeding radiant-electrode are provided on the top surface of the dielectric base-substance, for example, such that the amount of electromagnetic coupling between the feeding radiant-electrode and the non-feeding radiant-el
Ishihara Takashi
Kawahata Kazunari
Miyata Akira
Nagumo Shoji
Onaka Kengo
Keating & Bennett LLP
Murata Manufacturing Co. Ltd.
Wimer Michael C.
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