Patent Grant
7388544
1. Field of Invention
The present invention relates to an antenna and a communication device that includes the antenna. More particularly, the present invention pertains to a Global Positioning System (GPS) antenna in a communication device.
2. Description Related Art
In recent years, portable communication devices have become very popular. In view of their ubiquity, such devices may be very useful in contacting emergency personnel, as it is likely that a person owning such a unit will be present at the scene of an accident or crime. As such, the Federal Communications Commission (FCC) has mandated certain standards for reliable operation of GPS applications in portable communications devices.
Although almost all portable communications devices meet or will meet the FCC standards, the reception associated with most GPS antenna is sometimes poor. In many cases, the problem is caused by difficulties associated with synthesizing an antenna pattern optimized for GPS satellite reception. In particular, many portable communications devices rely on the main subscriber antenna to capture GPS signals. Unfortunately, if the communication device is in a typical vertical position, such as clam-shell cellular phone, the main lobe of the GPS radiation pattern is generally pointed downward, which reduces the link margin with GPS satellites transmitting from the upper hemisphere. In fact, in many cases, the GPS radiation pattern features a null pointing upward towards the GPS satellites. Radio frequency (RF) currents flowing on the phone chassis, particularly the lower portion of a clam-shell handset, are generally seen as the root of this problem.
The invention concerns an antenna and a communication device comprising the antenna.
The antenna can comprise a dielectric substance, a radiator element and at least one radio frequency feed point coupled to the radiator element. The antenna can further comprise a ground plane, which can be coupled to the dielectric substance. The radiator element can have at least a first portion and a second portion coupled to one another and folded about the dielectric substance such that the radiator element is split into a plurality of radiator branches in at least one of the first portion and the second portion of the radiator element. At least one region can be located between the plurality of radiator branches such that one or more components can be positioned in the region. The radiator element can be positioned on the dielectric substance or can also be positioned on the inside surface of a housing of a wireless communication device. The admittance of the first portion of the radiator element can be at least substantially equal to the admittance of the second portion of the radiator element.
The radio frequency feed point can be provided in the first portion or the second portion of the radiator element. The radio frequency feed point can further be conductively, magnetically or capacitively coupled to the ground plane. The radio frequency feed point can be an unbalanced feed point. In an embodiment of the present invention, the dielectric substance can be partially comprised of air. In another arrangement, the radiator element can be a self-consistent antenna, and the dielectric substance can be folded about the ground plane. Also, the radiator element can be contained within a wireless communication device having a flip portion and a base portion.
In another embodiment of the present invention, a communication device is provided. The communication device can comprise a ground plane, a dielectric substance surrounding at least a portion of the ground plane, a radiator element having a first portion and a second portion coupled to one another and a radio frequency feed point coupled to the radiator element. The radiator element can be folded about the dielectric substance, and at least one of the first portion and the second portions of the radiator elements can contain multiple segments that are separated by a distance that can permit components coupled to the ground plane to be positioned between the segments. The admittance of the first portion of the radiator element can be substantially equal to the admittance of the second portion of the radiator element. The communication device can be a wireless communication device, and at least one of the components can be a transducer. The communication device can further comprise a housing wherein the radiator element can be positioned on the dielectric substance or on an inside surface of the housing.
In an exemplary embodiment of the present invention, a wireless communication device, for example, a mobile phone, can incorporate the ground plane and the radiator element or antenna. The antenna in the wireless communication device can be such that the first portion and the second portion of the radiator element can contain multiple segments that are separated by a distance that can permit components coupled to the ground plane to be positioned between the segments.
In view of the unique design of the antenna, improved performance in certain frequencies and better use of space can be realized in wireless communication devices. In one particular arrangement, the invention can improve the signal reception for a communication device receiving GPS signals.
The features of the present invention, which are believed to be novel, are set forth with particularity in the appended claims. The invention, together with further objects and advantages thereof, may best be understood by reference to the following description, taken in conjunction with the accompanying drawings, in the several figures of which like reference numerals identify like elements.
While the specification concludes with claims defining the features of the invention that are regarded as novel, it is believed that the invention will be better understood from a consideration of the following description in conjunction with the drawing figures, in which like reference numerals are carried forward.
As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which can be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure. Further, the terms and phrases used herein are not intended to be limiting but rather to provide an understandable description of the invention.
The terms “a” or “an”, as used herein, are defined as one or more than one. The term “plurality”, as used herein, is defined as two or more than two. The term “another”, as used herein, is defined as at least a second or more. The terms “including” and/or “having”, as used herein, are defined as comprising (i.e., open language). The term “coupled”, as used herein, is defined as connected, although not necessarily directly, and not necessarily mechanically. The terms “program”, “software application”, and the like as used herein, are defined as a sequence of instructions designed for execution on a computer system. A “program”, “computer program”, or “software application” may include a subroutine, a function, a procedure, an object method, an object implementation, an executable application, an applet, a servlet, a source code, an object code, a shared library/dynamic load library and/or other sequence of instructions designed for execution on a computer system.
The present invention relates to an antenna and a communication device comprising the antenna, which can enable a user to use the communication device in various positions with uniform coverage and improved signal reception. More particularly, the present invention relates to an antenna in a communication device, which can improve GPS signal reception and quality.
The radio frequency feed point 135 can be coupled to the radiator element 105 in either the first portion 110 or the second portion 115, or even both. Those skilled in the art will appreciate that the plurality of radiator branches 120 and 125 can be provided in either the first portion 110 or the second portion 115 or both the first portion 110 and the second portion 115 or any other suitable portion(s) of the radiator element 105, and the invention shall have the full scope of the claims. As another example, the branches 120, 125 may be parallel to one another, which is the configuration shown in
In one arrangement, the dielectric substance 130 can be coupled to and folded about a ground plane 145. In addition, the radio frequency feed point 135 can be conductively, magnetically or capacitively coupled to the ground plane 145. It is understood, however, that the ground plane 145 is optional in this configuration. Those of skill in the art will appreciate that the invention may include more than one radio frequency feed point 135 if no ground plane 145 is included.
The radiator element 105 may also include one or more radiating edges 148. As an example, both the first portion 110 and the second portion 115 may have radiating edges 148. Also, if the first portion 110 or the second portion 115 includes the plurality of branches 120, 125, the branches 120, 125 may also include radiating edges 148, as seen in
The radiator element 105 can be provided such that the admittance of the first portion 110 of the radiator element 105 can be at least substantially equal to the admittance of the second portion 115 of the radiator element 105. In particular, the per-unit-length (PUL) admittance of the radiating element 105 can be substantially constant along the length of the radiating element 105, such as from the radiating edge(s) 148 of the first portion 110 to the radiating edges(s) 148 of the second portion 115. This arrangement may also apply if one or both of the first portion 110 and the second portion 115 include a plurality of branches 120, 125. That is, the PUL admittance of the branches 120, 125 may be combined to form the admittance of the portion of the radiator element 105 containing the branches 120, 125. In any event, by having the admittance of the radiating element 105 substantially constant along its length can ensure that radiating currents can flow from one radiating edge 148 to another with minimal reflection along the current path.
In one arrangement, the radiator element 105 can be a self-consistent antenna, which, as is known in the art, can mean that the radiator element 105 does not necessarily rely on the ground plane 145 to resonate. As such, as those of skill in the art will appreciate, RF currents on the ground plane 145 can be relatively weak outside the projection area of the radiator element 105 and do not substantially affect the performance of the antenna 100. Those of skill in the art will also appreciate that because the ground plane 145 may be sandwiched between the dielectric substance 130, the radio frequency feed point 135 can be an unbalanced feed point, which can employ unbalanced feed lines, such as coaxial cables, striplines and microstrip lines. Using an unbalanced transmission line on the ground lane 145 to originate the radio frequency feed can eliminate the need for introducing a balun to feed the radiator element 105.
In an embodiment of the present invention, the radiator element 105 can be positioned on the dielectric substance 130. The dielectric substance 130 can comprise at least one of air, ceramic, mica, glass, plastics and oxides of various metals. The dielectric substance can also partially comprise of air. For example, the dielectric substance 130 can partially comprise ceramic and partly comprise air. To describe how the dielectric substance 130 can be air, reference is made to
Referring once again to
Referring to
The present invention presents several advantages. For example, because the radiator element 105 can be a self-consistent antenna, RF currents on the ground plane may be weak. Because they are weak, these RF currents do not substantially affect the radiation pattern of the radiator element 105. This principle also applies if a user places his or her hand on the communication device 200. Moreover, because the ground plane 145 can be sandwiched between the dielectric substance 130, an unbalanced transmission line can be used with the radio frequency feed point 135. That is, the need for a balun may be eliminated. By using an unbalanced transmission line, less space is required to implement the antenna 100 in the communication device 800 and the ground plane 145 can maintain its isolation properties.
The antenna 100 can be designed to operate in any suitable frequency or range of frequencies. In one particular arrangement, the antenna 100 can be designed to receive GPS signals for the communication device 200. As shown in
As can be seen, both radiation patterns 400, 410 are optimized for signal reception, and no nulls are present. This feature is based on the unique design of the antenna 100 and is irrespective of whether a using is holding the communication device 200. Further, the signal strength of the radiation patterns 400, 410 can be maximized for signal reception from the open sky, such as for receiving GPS signals from GPS satellites. Of course, it must be stressed that the invention is not limited to being implemented in a clam-shell handset or for receiving GPS signals.
Radiation pattern 500 can represent the radiation pattern produced if the flip portion 305 is electrically disconnected from the base portion 310, and radiation pattern 510 can represent the pattern if the flip portion 305 and the base portion 310 are electrically connected. In view of the unique design of the antenna 100, it can be seen that the performance of the antenna is not substantially affected by the electrical connection or disconnection of the flip portion 305 and the base portion 310.
In a more general embodiment of the present invention, the antenna specified in the present invention can be used not only to receive but also to transmit radio frequency signals. The radio frequency signals include but are not limited to GPS signals. The antenna specified herein can be used, in a portable communication device, wherein the portable communication device is not limited to cellular phones. Further the antenna specified herein can be mounted either on the flip portion or on the base portion of a clam-shell phone and is not only limited to the flip portion. Mounting the antenna on the base portion of a clamshell phone lies within the scope of the present invention. Skilled artisans shall appreciate the advantages of the present invention, including ease of use, quality of reception, improved radiation patterns, and the advantage of incorporating additional components such as an earpiece or speaker, as described above. The invention also offers the advantage of reduced radio frequency currents in the communication device. The invention improves the performance of a communication device and enables GPS navigation with improved quality and ease of use.
This disclosure is intended to explain how to fashion and use various embodiments in accordance with the invention rather than to limit the true, intended and fair scope and spirit thereof. The foregoing discussion is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Modifications or variations are possible in the light of the above teachings. The embodiment(s) was chosen and described to provide the best illustration of the principles of the invention and practical application, and to enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims, as may be amended during the pendency of this application for patent, and all equivalents thereof, when interpreted in accordance with the breadth to which they are fairly, legally and equitably entitled.
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