Patent Publication Number: US-7903033-B2

Title: Antennas incorporated in a fitted accessory of a mobile unit

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to two antennas incorporated in a fitted accessory such as an end cap or an add-on of a mobile unit. Specifically, the antennas are radio frequency identification antennas that are part of an overall housing design of the mobile unit. 
     BACKGROUND 
     A mobile unit (MU) may include a variety of different functionalities. For example, the MU may include a radio frequency identification (RFID) functionality. The RFID functionality requires an antenna to transmit and/or receive RFID signals. However, in many instances, the MU is initially sold without the RFID functionality. The RFID functionality is an accessory that may or may not be used with the MU. Therefore, the RFID functionality is often sold as an accessory for the MU. For example, the RFID functionality may be an add-on that includes components (e.g., an antenna, an RFID transceiver, etc.) connected externally to the MU. However, this add-on RFID technology makes an overall size of the MU increase, creates an inconvenient obstruction to an overall design of the MU, requires an intrusive operation for incorporation, etc. 
     SUMMARY OF THE INVENTION 
     The present invention relates to antennas incorporated into a fitted accessory of a mobile unit. The mobile unit comprises a main housing, an end cap, and two antennas. The end cap couples to the main housing creating an overall housing for the mobile unit. The two antennas are incorporated within the end cap. 
     The present invention relates to a fitted accessory for a housing of a mobile unit. The fitted accessory comprises two antennas incorporated within the fitted accessory. The fitted accessory also comprises an electrical contact coupling to a corresponding electrical contact disposed on the housing so that an electrical connection is established between the components of the fitted accessory and components in the housing. The fitted accessory couples to the housing. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a first exploded view of a mobile unit according to an exemplary embodiment of the present invention. 
         FIG. 2  shows a second exploded view of the mobile unit of  FIG. 1  according to an exemplary embodiment of the present invention. 
         FIG. 3  shows an assembled view of the mobile unit of  FIG. 1  according to an exemplary embodiment of the present invention. 
         FIG. 4  shows first exemplary antennas incorporated into an end cap of the mobile unit of  FIG. 1  according to an exemplary embodiment of the present invention. 
         FIG. 5  shows a perspective view of the first exemplary antennas of  FIG. 4  according to an exemplary embodiment of the present invention. 
         FIG. 6  shows second exemplary antennas incorporated into an end cap of the mobile unit of  FIG. 1  according to an exemplary embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     The exemplary embodiments of the present invention may be further understood with reference to the following description and the appended drawings, wherein like elements are referred to with the same reference numerals. The exemplary embodiments of the present invention describe two antennas incorporated in a fitted accessory of a mobile unit (MU). Specifically, in a first embodiment, the MU of the exemplary embodiments of the present invention may include a housing that utilizes an end cap on the housing. In a second embodiment, the MU of the exemplary embodiments of the present invention may include a housing configured to receive an add-on. The end cap or the add-on may include at least the antennas to execute radio frequency identification (RFID) functionalities. Thus, according to the exemplary embodiments of the present invention, components capable of executing the RFID functionalities may be incorporated into the MU without requiring an intrusive operation or creating an inconvenient obstruction to an overall design of the MU. The housing, the end cap, and the antennas will be discussed in more detail below. 
     Those skilled in the art will understand that while the exemplary embodiments describe RFID antennas, the exemplary embodiments may be modified to include an antenna or antennas that operate in other frequency spectra. In addition, the exemplary embodiments describe the fitted accessory as an end cap or an add-on. However, the fitted accessory may be designed to be located in other portions of the MU housing (e.g., the back or sides). 
       FIG. 1  shows a first exploded view of an MU  100  according to an exemplary embodiment of the present invention. The MU  100  may be any portable electronic device that utilizes a portable power supply (e.g., battery, capacitor, super capacitor, etc.). In particular, the MU  100  may be an RFID reading device. However, the MU  100  being an RFID device is only exemplary. That is, the MU  100  may also be a handheld terminal, a laptop, a pager, a cell phone, a scanner, etc. It should be noted that the use of the MU  100  is only exemplary. That is, the exemplary embodiments of the present invention may apply to any electronic device that utilizes an antenna. The MU  100  may include a main housing  105 , a display  110 , a data input arrangement  115 , an input/output (I/O) port  120 , an audio input  125 , an audio output  130 , an end cap  150 , a scanner window  155 , locking mechanisms  160 , corresponding electrical contacts  165 , and antennas  170 . The scanner window  155 , the locking mechanisms  160 , and the corresponding electrical contacts  165  will be discussed in detail below with reference to  FIG. 2 . 
     The main housing  105  may be a first portion of an overall housing for the MU  100 . The main housing  105  may also be an entire housing of the MU  100  that is configured to receive additional components. The main housing  105  may provide a casing in which components of the MU  100  may be at least partially disposed. That is, the components of the MU  100  may be wholly or partially within the main housing  105 . For example, the display  110 , the data input arrangement  115 , the I/O port  120 , the audio input  125 , and the audio output  130 , etc. may be disposed partially within the housing  105  so that a portion of these components are disposed on a periphery of the main housing  105 . It should also be noted that other components of the MU  100  such as a processor, a memory, etc. may be disposed wholly within the main housing  105 . 
     The display  110  may provide a user interface. Specifically, the user interface may be a graphical user interface (GUI). The data input arrangement  115  may be a keypad in which a user may enter various inputs. The inputs may correspond to at least one installed program or functionality of the MU  100 . It should be noted that the display  110  may be a touch screen that enables a user to enter inputs thereon. That is, the data input arrangement  115  being a separate component is only exemplary. Thus, the MU  100  may include the display  110  and the data input arrangement  115 , the display  110  with touch screen capabilities, or a combination thereof. It should also be noted that the data input arrangement  115  may include further keypads disposed on other peripheral areas of the housing  105  such as a side data input arrangement. 
     The I/O port  120  may be an access port in which other hardware components may electrically connect to the MU  100 . For example, the I/O port  120  may be a universal serial bus (USB) port. In another example, the I/O port  120  may be an infrared (IR) port that is capable of exchanging data wirelessly. 
     The audio input  125  may be, for example, a microphone while the audio output  130  may be, for example, a speaker. The microphone and speaker may be disposed wholly within the main housing  105 . 
     The end cap  150  may be a second portion of the overall housing of the MU  100 . Specifically, the end cap  150  may be an end cap that is a complementary portion to the main housing  105 . That is, the main housing  105  may be manufactured with an opening in which the end cap  150  provides a lid. For example, the overall housing of the MU  100  may be a clamshell design, a monocoque design, etc. The end cap  150  may also be an add-on that is received by the main housing  105 . That is, as discussed above, the main housing  105  may be configured to receive the end cap  150 . The end cap  150  may include the scanner window  155 , the locking mechanisms  160 , the corresponding contacts  165 , and the antennas  170 . As will be discussed in further detail below, the antennas  170  may be incorporated with the end cap  150 . 
     According to the exemplary embodiments of the present invention, the antennas  170  may be wholly disposed within the end cap  150  toward an inner side. That is, the antennas  170  may not include any part that is exposed externally to the overall housing of the MU  100 . The antennas  170  may also be configured so that the other components near the antennas  170  such as the scanner window  155  may still be disposed. For example, the antennas  170  may be shaped around the scanner window  155  so that a line of sight is not disrupted from a scanning component disposed behind the scanner window  155 . The antennas  170  will be discussed in further detail below, particularly with reference to  FIGS. 4-6 . 
       FIG. 2  shows a second exploded view of the MU  100  of  FIG. 1  according to an exemplary embodiment of the present invention. Specifically, the second exploded view of the MU  100  shows a top side of the main housing  105  prior to assembly with the end cap  150 . The second exploded view shows the main housing  105 , the display  110 , the data input arrangement  115 , the audio input  125 , the audio output  130 , the end cap  150 , the scanner window  155 , and the locking mechanisms  160 . In addition, the second exploded view shows corresponding locking mechanisms  135 , a scanning engine  140 , and electrical contacts  145 . 
     When the end cap  150  is assembled with the main housing  105 , the end cap  150  may be affixed using the locking mechanisms  160 . The locking mechanisms  160  may be a stand alone device that performs the locking feature. For example, the locking mechanisms  160  may be an adhesive. However, in another embodiment, the locking mechanisms  160  may be coupled with the corresponding locking mechanisms  135 . For example, the locking mechanisms  160  may be screws while the corresponding locking mechanisms  135  may be screw holes. In another example, the locking mechanisms  160  may be clips while the corresponding locking mechanism  135  may be mating slots or vice versa. In yet another example, the locking mechanisms  160  and the corresponding locking mechanisms may be a solenoid device. That is, the locking mechanisms  160  with the corresponding locking mechanisms  135  may be any type of attachment device that performs a locking through means that are mechanical, electrical, or a combination thereof. 
     The scanner window  155  may provide a transparent, protective via in which the scanning engine  140  may take scans. As discussed above, the scanning engine  140  may require a line of sight to an object to be scanned. For example, the scanning engine  140  may be a barcode (e.g., one-dimensional, two-dimensional) scanner. Thus, lasers from the scanning engine  140  may be produced and emitted through the scanner window  155  to the object. In other examples, the scanning engine  140  may be an imager, a camera, etc. Therefore, when the end cap  150  is assembled with the main housing  105 , the scanner window  155  may be aligned with the scanning engine  140 . 
     The electrical contacts  145  of the main housing  105  may couple to the corresponding electrical contacts  165  of the end cap  150 . The coupling may establish an electrical connection for any components of the end cap  150  to, for example, the processor housed within the main housing  105 . Because the antennas  170  are incorporated within the end cap  150 , the antennas  170  require an electrical connection. That is, signals received or transmitted by the antennas  170  are sent to or originate from a source such as a transceiver or radio. According to the exemplary embodiments of the present invention, the transceiver or radio may be disposed in the main housing  105  or in the end cap  150 . In a first embodiment where the transceiver/radio is disposed as part of the main housing  105  (e.g., part of a printed circuit board), the electrical contacts  145  may be a connector in which one end is connected to the transceiver/radio. In this embodiment, the transceiver/radio may already be connected to the processor. The corresponding electrical contacts  165  may be a connector in which one end is connected to the antennas  170 . Therefore, when the electrical contacts  145  are coupled to the corresponding electrical contacts  165 , an electrical connection may be established between the antennas  170  and the transceiver/radio. In a second embodiment where the transceiver/radio is disposed in the end cap  150 , the electrical contacts  145  may be a connector in which one end is connected to the processor. The corresponding electrical contacts  165  may be a connector in which one end is connected to the transceiver/radio. In this embodiment, the antennas  170  may already be connected to the transceiver/radio. Therefore, when the electrical contacts  145  are coupled to the corresponding electrical contacts  165 , an electrical connection may be established between the transceiver/radio and the processor. It should be noted that the electrical contacts  145  and the corresponding electrical contacts  165  may be coupled in a variety of manners. For example, the electrical contacts  145  may be conducting extensions that are received by the corresponding electrical contacts  165  that are conducting recesses. In another example, the electrical contacts  145  and the corresponding electrical contacts  165  may include conducting pads that contact each other. 
     As discussed above, the antennas  170  may be incorporated within the end cap  150 . Specifically, the antennas  170  may conform to an inner side of the end cap  150 . The antennas  170  may be used for the RFID functionalities. Because the antennas  170  and possibly the transceiver/radio in which the antennas  170  are connected (e.g., directly or indirectly) are incorporated in the end cap  150 , the RFID functionalities may be provided to the MU  100  through replacement of an end cap without an incorporated antenna with the end cap  150  according to the exemplary embodiments of the present invention. In this manner, neither an intrusive operation is necessary nor an obtrusive protuberance is created. In addition, RFID functionalities may be provided to the MU  100  with no end cap through the addition of the end cap  150  according to the exemplary embodiments of the present invention. 
     Ultra high frequency (UHF) RFID functionalities generally operate between 902 MHz and 928 MHz. Thus, a single sine wave of the RFID wave is between 1.103×10 −9  seconds and 1.078×10 −9  seconds, respectively. Half a wavelength for the RFID wave at the UHF band is thus between 5.543×10 −10  seconds and 5.388×10 −10  seconds, respectively. Because the waves are measured against the speed of light, an optimal length for these operating parameters is between 6.54 inches and 6.36 inches, respectively. It should be noted that the half a wavelength being a first optimal length is only exemplary. Other exemplary optimal lengths may include a quarter wavelength and a three-quarters wavelength. The quarter wavelength may correspond to 3.27 inches to 3.18 inches while the three-quarters wavelength may correspond to 9.81 inches to 9.54 inches. Thus, the antennas  170  may exhibit any predetermined length corresponding to an appropriate wavelength for the RFID functionality (e.g., half wavelength, quarter wavelength, three-quarters wavelength). 
     As explained above, a proper electrical length of the antennas for RFID functionalities operating between 902 MHz and 928 MHz is between 6.54 inches and 6.36 inches, respectively. Depending on the capacitive and inductive loading of the antennas, the physical length may be greater than or less than this range. For example, the presence of an end-loading capacitor may change the necessary physical length of the antennas  170  to create functional RFID antennas. Further dimensions and styles for the antennas  170  will be discussed in detail below with reference to  FIGS. 4-6 . 
       FIG. 3  shows an assembled view of the MU  100  of  FIG. 1  according to an exemplary embodiment of the present invention. The assembled view of the MU  100  illustrates when the main housing  105  is coupled with the end cap  150 . The assembled view also shows the display  110 , the data input arrangement  115 , the I/O port  120 , the audio input  125 , and the audio output  130 . 
     As discussed above, when the main housing  105  is coupled to the end cap  150 , the locking mechanisms  160  may be coupled to the corresponding locking mechanisms  135 . Furthermore, the electrical contacts  145  may be coupled to the corresponding electrical contacts  165 . In addition, the scanner window  155  may be aligned with the scanning engine  140 . The end cap  150  may be coupled to the main housing  105  so that a flush exterior is created for the overall housing of the MU  100 . That is, the outer periphery of the end cap  150  that contacts the main housing  105  may exhibit dimensions of the outer periphery of a top side of the main housing  105 . As illustrated, the antennas  170  may be wholly disposed between the main housing  105  and the end cap  150  so that no portion of the antennas  170  is exposed. 
       FIG. 4  shows first exemplary antennas  170  incorporated into the end cap  150  of the MU  100  of  FIG. 1  according to an exemplary embodiment of the present invention. Specifically, the first exemplary antennas  170  exhibit a substantial cross configuration including a first antenna  170   a  and a second antenna  170   b . That is, the antenna design of the first exemplary antenna  170  is a dual-dipole with one vertical dipole (i.e., the first antenna  170   a ) and one horizontal dipole (i.e., the second antenna  170   b ). As illustrated, the first antenna  170   a  and the second antenna  170   b  are disposed on an inner side of the end cap  150 . Furthermore, the first antenna  170   a  and the second antenna  170   b  may conform to an inner surface of the end cap  150 . 
     According to an exemplary embodiment of the present invention, the MU  100  may include cross-sectional dimensions of, for example, three inches by one and a half inches (i.e., 3″×1.5″). Thus, the end cap  150  may also include these dimensions. As discussed above, the antennas  170  may exhibit predetermined lengths corresponding to half a wavelength for the RFID functionality. For example, either one of the antennas  170   a  or  170   b  may be approximately 6 inches long. The constraints of the size of the end cap  150  prevent linear antennas  170  from being disposed therein without a portion extending to an outer area of the MU  100 . However, the dual-dipole configuration of the first exemplary antennas  170  allows the approximately 6 inch electrically long antennas to be disposed in the end cap  150 . As illustrated, the dual-dipole includes two antennas that are substantially T-shaped. The disposition and the lengths of the first antenna  170   a  results in an antenna that is electrically approximately 6 inches. Furthermore, the disposition and the lengths of the second antenna  170   b  results in an antenna that is also electrically approximately 6 inches. As discussed above, the 6 inch length of the antenna corresponds to half a wavelength of the RFID frequency. 
       FIG. 5  shows a perspective view of the first exemplary antennas  170  of  FIG. 4  according to an exemplary embodiment of the present invention. As discussed above, the first antenna  170   a  and the second antenna  170   b  may conform to an inner surface of the end cap  150 . The perspective view of the first exemplary antennas  170  illustrates the conforming shape of the first antenna  170   a  and the second antenna  170   b . Also, as discussed above, the first antenna  170   a  and the second antenna  170   b  may be T-shaped. Thus, a first leg of the T-shape may be disposed on one of the side walls of the end cap  150 . A second leg of the T-shape may extend from a middle of the first leg toward a center of the end cap  150 . The extension of the second leg may curve (when the end cap  150  has rounded edges) or may be fitted into a corner (when the end cap  150  has sharp edges) of the end cap  150 . 
       FIG. 6  shows second exemplary antennas  170  incorporated into the end cap  150  of the MU  100  of  FIG. 1  according to an exemplary embodiment of the present invention. Specifically, the second exemplary antennas  170  may include a vertically polarized loop antenna  170   c  and a horizontally polarized chip antenna  170   d . The antenna  170   c  may conform to an inner side area of the end cap  150 . That is, the antenna design of the loop antenna  170   c  covers substantially an entire side surface of an inner side of the end cap  150 . It should be noted that the loop antenna  170   c  may not cover predetermined areas of the inner side of the end cap  150 . For example, the loop antenna  170   c  may circumscribe an area in which the scanner window  155  is disposed. 
     Furthermore, the parameters of the loop antenna  170   c  (e.g., length, shape, thickness, conductivity, etc.) may be constructed so that the loop antenna  170   c  may exhibit various parameters relating to RFID functionalities and optimized performance thereof. The chip antenna  170   d  may be mounted in the end cap  150  to provide a polarization orthogonal to the loop antenna  170   c . According to the exemplary embodiment of the second exemplary antennas  170 , the loop antenna  170   c  may exhibit a vertical polarity. Thus, the chip antenna  170   d  may exhibit a horizontal polarity. 
     It should be noted that the terms horizontally polarized and vertically polarized are exemplary. According to the exemplary embodiments of the present invention, the antennas  170  in the end cap  150  are substantially orthogonal to each other. Those skilled in the art will understand that one embodiment that satisfies antenna orthogonality is a horizontally polarized antenna with a vertically polarized antenna. However, if both antennas were rotated 45 degrees, the terms “horizontally polarized” and “vertically polarized” may not be used, but the antennas  170  would still be orthogonal. 
     According to the exemplary embodiments of the present invention, the loop antenna  170   c  may be manufactured of a copper tape or a flex. However, it should be noted that other materials may be used that exhibit substantially similar signal propagation/reception properties as copper. The loop antenna  170   c  may be disposed along the inner side wall of the end cap  150  so that an overall electrical length may also be optimized. It should be noted that certain regions of the loop antenna  170   c  may be wider or narrower to properly load the antenna  170  with capacitance and/or inductance so that the loop antenna  170   c  may properly execute the RFID functionalities. 
     It should be noted that the antennas  170  being dual-dipole antennas or a loop antenna with a chip antenna are only exemplary. Other types of antennas  170  may also be used such as monopole antennas, slot antennas, or any combination thereof. That is, the horizontally polarized antenna and the vertically polarized antenna may be any combination of antenna styles and may be substantially orthogonal to each other. Other antennas may be configured using substantially similar parameters as the dual-dipole antenna, the loop antenna, or the chip antenna. That is, a physical length may vary depending on a capacitive and/or inductive loading of the antennas. However, an electrical length may always be optimized for a specific style of antennas that are employed. 
     Because the exemplary embodiments of the present invention utilizes two antennas that are orthogonal to each other, the MU  100  may switch between the two antennas for the RFID functionalities. The switching of the antennas  170  may entail utilizing a first antenna (e.g., antenna  170   a  or antenna  170   c ) while keeping a second antenna (e.g., antenna  170   b  or antenna  170   d ) idle. Subsequently, the second antenna may be utilized while the first antenna is idle. This process may repeat as necessary for the RFID functionality. The use of two antennas and the switching thereof may provide a user with orthogonal diversity. The user of the MU  100  may read RFID tags regardless of an orientation of the MU  100 . For example, if an RFID tag is oriented vertically, the vertically polarized antenna may read the tag while a horizontally oriented RFID tag may be read by the horizontally polarized antenna. Those skilled in the art will understand that if only one polarized antenna is disposed, the MU  100  may require to be properly oriented (e.g., physically rotating the MU  100 ) in order to read the RFID tag. The antennas  170  of the exemplary embodiments of the present invention eliminate the need for the MU  100  to be properly oriented. 
     It will be apparent to those skilled in the art that various modifications may be made in the present invention, without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.