Abstract:
An antenna for a communications device with a design to minimize human exposure to emitted electromagnetic energy. The antenna incorporates a shield wall and directing buds having the property of reflecting, deflecting or absorbing RF frequency waves. The shield wall and directing buds direct transmitted communication signals away from the immediate user and other bystanders in the vicinity of the communications device while simultaneously directing a stronger signal towards a receiver. Alternative embodiments of the antenna include the ability to extend or swivel. These features allow the antenna to be positioned to maximize transmission/reception while simultaneously minimizing human exposure.

Description:
FIELD OF THE INVENTION 
     This invention relates to antennas used on portable devices. More specifically, the invention involves the design of an antenna for a portable transceiver device to reduce the exposure of its user and bystanders to electromagnetic transmissions emitted from the device. 
     BACKGROUND OF THE INVENTION 
     Technological progress in the field of electronics has broadened the availability of affordable yet sophisticated portable communication devices. For example, consider the cell or wireless phone. Such transceiver devices provide users with the convenient ability to talk with associates, family and friends even while on the move. More recently, these devices have offered users the ability to send and receive digital information including electronic mail and even surf the Internet from almost any location. Thus, it is no surprise that the devices are widely used. Moreover, while the number of present users of such devices is staggering, with new advancements and improvements, the numbers will only continue to grow. 
     However, increased convenience should not come at the cost of personal safety. In recent years, the proliferation of such devices has generated some cause for concern. Since each transceiver device requires the ability to transmit information to some external location without the use of a physical channel or wire, each device must be equipped with a radio-frequency (RF) transmitter. Typically, these RF transmitters generate Ultra High Frequency (UHF) electromagnetic carrier waves in the region of 300 to 3000 MHz. Since these waves emanate from these devices in close proximity to their users and bystanders, the potential negative health effects of UHF radiation exposure has entered the public arena. For example, the effect of UHF radiation as a cause of cancer is addressed in JE Moulder et al: Cell Phones and Cancer: What Is the Evidence for a Connection? Radiation Research 151(5):513-531, May 1999; see also KR Foster and JE Moulder: Are mobile phones safe? IEEE Spectrum, August 2000, p. 23-28. 
     At least one prior art antenna has attempted to minimize the risks of cancer due to the exposure to RF radiation transmitted from a hand-held communications device. In the patent to Chang, U.S. Pat. No. 6,097,340, an antenna with a semi-cylindrical shield is used to limit the direction of radiating RF waves of a cell phone. The shield is intended to cover the side of the core of the antenna that faces the cell phone user. However, the antenna has an important shortfall. The antenna provides only limited protection. As designed, the antenna provides no shielding for non-users of the phone who are still in close proximity to the RF radiation from the side of the core opposite the shield. 
     BRIEF DESCRIPTION OF THE INVENTION 
     An objective of the present invention is to provide an antenna for a portable communications device that reduces the user&#39;s exposure to RF radiation emitted from the device. 
     A further objective of the present invention is to provide an antenna for a portable communications device that reduces bystanders&#39; exposure to RF radiation emitted from the device. 
     A still further objective of the present invention is to provide such an antenna while maintaining the antenna&#39;s effectiveness. 
     An additional objective is to provide an antenna with improved signal transmission capabilities. 
     Additional objectives will be apparent from the description of the invention as contained herein. 
     In its broadest aspects, the present invention involves an antenna for hand-held communications devices such as a cell phone, beeper, portable computer/organizer with RF transmission capabilities, portable Internet access device or other transmitter emitting RF radiation. In its preferred embodiment, the antenna utilizes a unique directing shield with a design intended to minimize RF radiation exposure by users and bystanders in close proximity to the device while simultaneously maximizing directional transmission toward the intended receiver of the signal. In general, the directing shield combines a concave shield wall with one or more semi-conic buds. The shield wall and semi-conic buds are treated with or molded from a transmission blocking/reflecting material. The directing shield is positioned over a linear cylindrical rod or conducting member of the antenna. The combined directing shield and conducting member are encased by a resin or plastic shell. The conducting member extends from the encasing for connection to RF transmission circuitry of a communications device. 
     In one embodiment of the invention, the antenna is configured with a bend angle to maximize transmission in the desired direction and away from its user and bystanders. while the portable device is in use. In another embodiment, the antenna has a collapsible/extendible portion to allow the antenna to be raised and lowered. In a further embodiment, the antenna can swivel at its base so that the directional alignment of the bud or buds may be adjusted when the portable device is used in alternative positions. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The figures are presented with this disclosure are for illustrative purposes only and are not drawn to scale. As such, they are not intended as a limitation on the scope of the invention as specified in the following detailed description. 
     FIG. 1 is a plan view of the side profile of an antenna of the present invention; 
     FIG. 1A is a cross-section of the antenna of FIG. 1 taken along the line  1 A— 1 A. 
     FIG. 2 is an exploded elevational view of the antenna of FIG. 1; 
     FIG. 3 is an elevational view of a directing shield with a single semi-conic bud taken from a point of view above and in front; 
     FIG. 4 is a plan view of the left side of the shield of FIG. 3; 
     FIG. 4A shows a cross-section of the single bud directing shield of FIG. 3 taken along line  4 A— 4 A of FIG. 4; 
     FIG. 5 is a front plan view of the shield of FIG. 3; 
     FIG. 6 is a top plan view of the shield of FIG. 3; 
     FIG. 7 is an elevational view of a directing shield with multiple buds taken from the point of view above and in front; 
     FIG. 8 is a front view of the shield of FIG. 7 with a conducting rod; 
     FIG. 8A shows a the directing shield of FIG. 8 taken along line  8 A— 8 A of FIG. 8; 
     FIG. 9 is a side view of the shield of FIG. 7 with a conducting rod; 
     FIG. 10 is a front view of a communications device with an alternative embodiment of the antenna of FIG. 1; 
     FIG. 11 is a top view of the communications device of FIG.  10 . 
     FIG. 12 shows a communications device with an alternative embodiment of the antenna of FIG. 1; 
     FIG. 13 is a side view of the communications device of FIG. 10; 
     FIG. 14 is a top view showing the positions of a user and bystanders in relation to a directing shield; 
     FIG. 15 shows an embodiment of the shield wall with a receiver member; 
     FIG. 16 shows one embodiment of the antenna within a communications device; 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIGS. 1 and 2, an antenna A made in accordance with the present invention can be generally described as having three parts. The antenna A has an outer shell  6 , a directing shield  4  and a conducting rod  2 . 
     The conducting rod  2  serves the purpose of sending an RF signal from the communications device. The rod  2  may also serve as the means for receiving externally transmitted RF signals. Although the conductor used in the antenna is referred to as a rod  2 , any conducting member of an alternative shape may be used if it can be placed within the directing shield  4 . Generally, the rod  2  has a tip portion  7  and a base portion  9 . The rod  2  is connected to the circuit of the communications device typically at the base portion  9 . In the embodiment depicted in FIG. 1, the base portion  9  of the rod uses. a threaded connector  9 A to attach to the circuit. The connector will allow the transfer of current between the rod  2  and the transmitter/receiver circuit of the communications device. To this end, there are many alternative means for connecting the rod  2  to a communications device, which will be obvious to one skilled in the field. In one embodiment of the invention, seen in FIG. 16, the rod  2  and the directing shield  4  may extend into the shell or casing of the communications device D. 
     FIGS. 2 through 9 show two embodiments of a directing shield  4  constructed in accordance with the present invention. FIGS. 3 through 6 show the single bud version and FIGS. 2 and 7 through  9  show a multi-bud version. The directing shield  4  provides a means to reduce user and bystander exposure to generated electromagnetic waves. The directing shield  4  includes a shield wall  12  and one or more semi-conic buds  10 . The shield wall  12  serves as the means for reducing radiation of RF waves in the immediate direction of the user of a portable communications device equipped with the antenna. The shield wall  12  is desirably formed of a section of a cylinder having a concave curve relative to the conducting rod  2  and is generally straight along its length. The shield wall  12  has a length and a width that are sufficient to extend beyond the length and width of the conducting rod  2  to form a protective barrier. 
     The shield wall  12  and the bud  10  are formed from a metal, ceramic or other material that has the property of reflecting/deflecting or absorbing the RF radiation or electromagnetic energy transmitted by communications devices. Alternatively, the shield wall  12  and the bud  10  can be made from any material that is then coated or treated with a reflective/deflective or absorbing substance. Such materials or substances are well known and will be obvious to one skilled in the field. The shield wall  12  and bud(s)  10  can be molded as a single unit or they can be made separately and bonded together with an adhesive or by any other appropriate bonding process. 
     The bud  10  portion of the directing shield  4  is also depicted in FIGS. 2 through 9. One or more buds  10  serve as a means for reducing RF radiation emitted from a communications device in the direction of a near bystander. Referring to the directing shield of FIG. 3, a bud  10 , coupled with the shield wall  12 , form a semi-conic channel having a large upper aperture  14  and smaller lower aperture  16 . A cross-section of the bud  10 , taken along line  8 A— 8 A of FIG. 8, is shown in FIG.  8 A. 
     With regard to the semi-conic channel, the side of the bud  10  proximate to the shield wall  12  forms a posterior arc  18  that is concave with respect to the channel  8  within the bud  10 . The side of the bud  10  opposite the shield wall  12  forms an anterior arc  20  that is also concave with respect to the channel  8 . The anterior arc  20  relative to the smaller lower aperture  16  has a radius that is smaller than the anterior arc  20  relative to the large upper aperture  14 . In addition, the radius of the anterior arc  20  relative to the large upper aperture  14  is smaller than the radius of the posterior arc  18 . In the preferred embodiment, the posterior arc  18  is formed by the concave curve of the shield wall  12 . 
     In general, the shield wall  12  is parallel to the rod  2  along the shield wall  12 . In addition, the relative sizes of the large upper aperture  14  and smaller lower aperture  16  of the bud  10  structure form a bud angle  22  (see FIG. 9) between the exterior surface of the bud  10  relative to the central longitudinal axis of the rod  2  in the channel  8 . Preferably, the bud angle  22  formed is in a range between 10 and 60 degrees. 
     FIGS. 2 and 7 through  9  depict a directing shield  4  having multiple buds  10 . As shown, the buds are arranged in a cascade fashion so that each predecessor bud  10 P partially overlaps a successor bud  10 S such that the successor bud&#39;s  10 S smaller lower aperture  16  is within the channel  8  of the predecessor bud  10 P through the large upper aperture  14  of the predecessor bud  10 P. 
     In the preferred embodiment of the device, the shield wall  12  extends above the posterior arc  18  of the outer most bud  10 M or the only bud  10  for a single bud  10  design to form a shield wall extension  24 . The shield wall extension  24  provides additional protection for the user from RF radiation reflecting from the outer most bud  10 M. 
     The preferred embodiment of the invention also has an outer shell  6  which serves as a means to protect, bind, and insulate the directing shield  4  and rod  2 . Essentially, the rod  2  resides within the channel  8  of the directing shield  4  with the tip  7  of the rod  2  between the smaller lower aperture  16  and large upper aperture  14  of the outer most bud  10 . In the channel  8 , the rod  2  is offset from the shield wall  12  and directing bud  10  and thus, does not contact either. This arrangement is then encased within the outer shell  6  such that the material of the outer shell  6  fills the space between the directing shield  4  and rod  2  and insulates the directing shield  4  from the rod  2 . One method to make such an embodiment includes the placement of the rod  2  and directing shield  4  into a holder member that holds the positions of the rod  2  and directing shield  4  respectively. The rod  2  and directing shield  4  are then placed into a mold with the material for the outer shell  6  in a fluid state and removed when the material has solidified. 
     One appropriate material for the outer shell  6  includes plastic or resin. Any other appropriate material may be used. However, since the outer shell  6  contains the rod  2 , the material must not have a property that would reflect or impede the transmission of RF radiation. In addition, if no separate insulator is used on the rod  2 , the material for the outer shell  6  must have the property of insulating the rod from making electrical contact with the directing shield  4 . This property would not be necessary if the material for the directing shield  4  is made from a non-conductor. There are many other means for protecting or binding the directing shield  4  and the rod  2 , which will be obvious to one skilled in the field. 
     While the outer shell  6  generally encloses the rod  2 , the outer shell  6  must allow for a connection between the rod  2  and the circuitry of the communications device. There are many ways to so encase the conducting rod  2 , which will be obvious to one skilled in the field. In the embodiment depicted in FIG. 1, the rod  2  extends out from the outer shell  6 . Consistent with the objectives of the present invention, the threaded connector would be shielded within the communications device to prevent it from emitting RF radiation. 
     In an alternative embodiment, a separate receiver member  40 , shown in FIG. 15, is added to the antenna A on the side of the shield wall  12  opposite the rod  2 . Thus, the receiver member is outside the channel  8  (not shown). Consistent with the principles of the invention, the receiver member  40 , which is a conductor that may have various configurations, is used as a conductor for receiving RF signals. The receiver member  40  is not used to transmit RF signals. 
     In FIG. 14, the relative positioning of the antenna A with respect to a user&#39;s head and bystander&#39;s head is shown. In general, when on a communications device D in use, the antenna A is arranged adjacent to the user face ( 30 ) of the device D so that the shield wall  12  within the antenna A is positioned between the user head UH and the rod  2 . In this way, the anterior arc  20  of the bud(s)  10  on the opposing side of the rod  2  is adjacent to a second face of the device D and is between a bystander head BH and the rod  2 . Furthermore, the antenna A should be positioned so that a central longitudinal antenna axis C through the rod  2  is approximately vertical during use. In this configuration, the transmission of RF radiation is directed vertically minimizing exposure of the user UH and any bystander head BH near the device. 
     FIGS. 10 through 13 show various embodiments of the invention attached to a communications device D. Consistent with the invention&#39;s principles, in FIGS. 10 and 11, the antenna A is positioned at a bend angle  26  to promote vertical use when the communications device D is used. In FIG. 10, the antenna is approximately vertical with respect to the horizon line H—H. FIG. 10 also shows a central longitudinal axis of the communications device CD with a perpendicular axis PD thereto. The bend angle  26  formed by the angle between the perpendicular axis PD and the antenna axis C is in the range of 45 to 75 degrees with the preferred bend angle  26  being set at 60 degrees. 
     When antenna A has a bend angle such as that depicted in FIG. 10, the antenna A must be configured for either left hand or right hand users. In this regard, the antenna A of FIG. 10 is a left hand antenna. This ensures that the shield wall  12  within the antenna A will remain between the user and rod  2 . 
     FIG. 12 shows an extendible antenna A. The outer shell  6  with encased directing shield  4  and rod  2  can extend away from the communications device D. When extended, the antenna A has an antenna extension  28 . The antenna extension houses the means for connection between the circuitry of the communications device D and the rod  2  of the antenna A. The antenna extension  28  is treated or made from a reflective/deflective or absorptive material to prevent transmission of RF energy outward from it. 
     FIG. 13 depicts the antenna A of FIG. 10 with a swivel feature used on a display-only communications device D. With the assistance of the swivel, the antenna A can be positioned to maintain a vertical alignment of the rod  2  while the communications device D is used as, for example, an internet access device. The swivel permits the shield wall  12  to remain between the user and the rod  2  when the communication device D is used in a horizontal position. The arc of the swivel in one embodiment may be limited to restrict the antenna to about a 90 degree turn and may lock in various positions within the arc. 
     Although the invention has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of an application of the principles of the invention. Numerous modifications, in addition to the illustrative embodiments of the invention discussed herein may be made and other arrangements may be devised without departing from the spirit and scope of the invention.