The present invention relates generally to portable and stationary electronic devices such as mobile phones, and more particularly to electronic devices having an antenna for carrying out mobile communications.
Portable electronic devices such as mobile phones have been popular for years and yet only continue to increase in popularity. Traditionally, mobile phones had been used strictly for conventional voice communications. However, as technology has developed mobile phones are now capable not only of conventional voice communications, but also are capable of data communications, video transfer, media reproduction, commercial radio reception, etc. More and more, a user having a single electronic device is able to perform a variety of different functions.
As technology advances in the field of mobile phones and other electronic devices, the need for broadband data transmission and reception continues to increase. Consequently, the demands on the radio portion of the electronic device also increase. At the same time, however, there is a constant push for miniaturization of the electronic devices to satisfy the convenience and desires of consumers. The need for broader bandwidth coupled with reduced size creates problems insofar as providing an antenna in the electronic device that performs satisfactorily. Generally speaking, the smaller the size of the antenna, the lower the antenna performance at the various frequency bands (e.g., 880 to 960 megahertz (MHz) and 1.71 to 2.17 gigahertz (GHz)).
In view of the aforementioned shortcomings associated with conventional electronic devices, there is a strong need in the art for an electronic device having an antenna configuration that provides both small size, and good low and high band performance and increased bandwidth.
According to an aspect of the invention, a monopole antenna having multiple resonances includes a feed point; a meander element; and an electrically conductive element that couples the feed point to the meander element, the electrically conductive element including at least a portion with a width that is greater than the width of the meander element.
According to another aspect, the width of the electrically conductive element is at least 1.5 times the width of the meander element.
In accordance with another aspect, the width of the electrically conductive element is at least 2.0 times the width of the meander element.
In accordance with still another aspect, a branch element is included along at least one of the feed point and the electrically conductive element, the branch element being coupled to ground.
According to another aspect, the branch element is less than one third the width of the electrically conductive element.
In yet another aspect, the branch element is between one-third and one-fiftieth the width of the electrically conductive element.
In still another aspect, the branch element is coupled at one end to the electrically conductive element.
According to another aspect, an additional branch element is provided and is positioned between the branch element and the at least one of the feed point and the electrically conductive element, the additional branch element being coupled to either the ground point or the feed point.
In still another aspect, the additional branch element is coupled to the ground point.
According to another aspect, the additional branch element is coupled to the feed point.
In accordance with another aspect, an additional branch element is electrically coupled to the branch element, and the additional branch element is positioned on a side of the branch element opposite the side of the electrically conductive element.
According to another aspect, at least part of the electrically conductive element is located sufficiently close to the feed point such that capacitive coupling occurs between the two, thereby further enhancing bandwidth.
To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative embodiments of the invention. These embodiments are indicative, however, of but a few of the various ways in which the principles of the invention may be employed. Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the drawings.
It should be emphasized that the term “comprises/comprising” when used in this specification is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.
The present invention will now be described in detail with reference to the figures, in which like elements are referred to by like reference labels throughout.
Referring initially to
The antenna 10 is a bent monopole antenna having multiple resonances. As is shown in
The wide conductive element 18 couples the feed point 16 to a proximal end of the meander element 20. The conductive element 18 has a width w that is significantly wider than that found in conventional configurations. In the exemplary embodiment, the width w of the conductive element 18 is approximately twice the meander width wmeander of the meander element 20, and twenty-five times the trace width wtrace of the meander element 20. More broadly, the width w of the conductive element 18 is preferably greater than the meander width wmeander, more preferably greater than 1.5 times, and even more preferably greater than two times the meander width wmeander. Moreover, the width w of the conductive element 18 is preferably at least ten times the trace width wtrace of the meander element 20.
The combination of the wide feed section, e.g., the conductive element 18, near the feed point at the beginning or proximal end of the meander element 20, and the high-impedance presented by the tight meander element 20, provides improved high-band bandwidth. Further, preferably at least part of the wide conductive element 18 is located sufficiently close to the feed point 16, e.g., as shown, such that capacitive coupling occurs between the two, thereby further enhancing bandwidth.
Referring to
In the exemplary embodiment, the width wbranch of the branch element 32 is approximately 1/50th the width w of the wide conductive element 18. More broadly, however, the width wbranch of the branch element 32 is preferably less than ⅓rd of the width w of the wide conductive element 18. As a result, the branch element 32 serves primarily for impedance matching. In the exemplary embodiment, the width wbranch of the branch element (32) is increased near the end of this branch (e.g., at ground point 34) in order to facilitate a contact pad which is in turn coupled to the printed circuit board substrate 14.
The addition of the ground point 34 and the narrow branch element 32 provide the following benefits: (i) the risk for electrostatic discharge (ESD) from the antenna into the radio or other device utilizing the antenna is minimized as ESD has a direct patch to ground; (ii) the low-band bandwidth and gain is improved as noted in
Generally speaking, tuning of the antenna 30 may be accomplished as follows: (i) the base antenna is constructed with the feed point 16, wide conductive element 18, meander element 20 and branch element 22. The meander element 20 is adjusted to adjust the low-band tuning of the antenna 30. The “tuning stub” presented by the branch element 22 is adjusted to further adjust the high-band frequencies. The slit length between the feed (e.g., wide conductive element 18) and ground (e.g., narrow branch element 32) is adjusted to provide the best impedance relative to the desired impedance (e.g., 50 ohms). It has been found that the slit works best when placed as close as possible to the edges of the wide conductive element 18. The line width and spacing is small for best results (e.g., about 0.3 mm). Smaller widths may be possible with some manufacturing techniques, but if the trace is too small, ohmic losses may increase and manufacturing tolerances may increase. Therefore, for practical purposes, a width of between about 0.2 mm and 1 mm may be preferred.
Referring now to
When the additional branch 42 is attached to the feed side, the frequency of the extra resonance created by branch 42 on antenna 40 will tend to be shifted upwards. Accordingly, a longer branch 42 will typically be necessary to tune the extra resonance of antenna 40 to the desired frequency.
The additional branch 42 preferably is relatively thin to allow for maximum bandwidth enhancement without gain degradation. For example, the width of the additional branch 42 is preferably ⅓rd or less compared to the width of the ground point 34 or feed point 16 to which it is attached. However, as known to those skilled in the art, this extra branch (42) may be made wider which may provide bandwidth advantages in certain applications.
An additional branch placed adjacent to the widened radiating area (e.g., wide conductive area 18) and connected to either the feed point 16 or the grounded branch element 32, which, when tuned to a certain length, creates a resonance which may be placed adjacent to the high-band resonance in order to improve the resonance bandwidth of the high-band. Additionally, this additional branch may be tuned to other frequencies either above or below the said high-band resonance. Furthermore, it is possible to use multiple branches attached either to the said impedance matching grounded branch or the radiating feed branch to create yet another resonance which may be used either to extend bandwidth or to change the radiating characteristics in yet another frequency bandwidth.
For example,
As is shown in
The term “electronic device” as referred to herein includes portable radio communication equipment. The term “portable radio communication equipment”, also referred to herein as a “mobile radio terminal”, includes all equipment such as mobile phones, pagers, communicators, e.g., electronic organizers, personal digital assistants (PDAs), smartphones or the like.
Although the invention has been shown and described with respect to certain preferred embodiments, it is obvious that equivalents and modifications will occur to others skilled in the art upon the reading and understanding of the specification. The present invention includes all such equivalents and modifications, and is limited only by the scope of the following claims.
The present application claims the benefit of U.S. Provisional Application Ser. No. 60/916,863, filed May 9, 2007, the disclosure of which is herein incorporated by reference in its entirety.
Number | Date | Country | |
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60916863 | May 2007 | US |