PATENT DOCUMENT

Publication Number: US-9965052-B2
Application Number: US-201414307257-A
Country: US
Kind Code: B2

Title: Antenna for computer stylus

Abstract:
A computer stylus may have an elongated body with a metal tube that serves as an antenna ground for an antenna. An antenna resonating element for the antenna may be formed from metal traces that wrap around a longitudinal axis for the elongated body. The antenna may be an inverted-F antenna. A ground antenna feed terminal for the inverted-F antenna may be coupled to the metal tube with a sheet metal member, conductive fabric, and solder. A clip may run along a side of the elongated body at a location that does not overlap the metal traces of the antenna resonating element. The antenna may be fed at a location on an opposing side of the elongated body from the clip. Antenna signals from the inverted-F antenna may be reflected towards the tip by metal structures at the end of the elongated body opposing the tip.

Claims:
What is claimed is: 
     
       1. A computer stylus, comprising:
 an elongated body having a tip and an opposing end coupled by a shaft that is formed from a metal tube that extends along a longitudinal axis, wherein the elongated body includes a region devoid of the metal tube that extends around the longitudinal axis; and 
 an antenna adjacent to the opposing end and mounted within the region of the elongated body devoid of the metal tube, wherein the antenna comprises an antenna resonating element formed from metal traces on a dielectric substrate having a circumference, an antenna ground that includes the metal tube, a positive antenna feed terminal coupled to the antenna resonating element, and a ground antenna feed terminal coupled to the antenna ground, the metal traces comprising a first portion that extends perpendicular to the longitudinal axis and along the circumference of the dielectric substrate and a second portion that extends parallel to the longitudinal axis and that is coupled between and end of the first portion and the antenna ground. 
 
     
     
       2. The computer stylus defined in  claim 1  wherein the opposing end includes metal structures that reflect antenna signals associated with the antenna towards the tip. 
     
     
       3. The computer stylus defined in  claim 2  wherein the antenna resonating element comprises an inverted-F antenna resonating element. 
     
     
       4. The computer stylus defined in  claim 3  wherein the computer stylus further comprises a clip and the clip and the positive antenna feed terminal are located on opposing sides of the elongated body. 
     
     
       5. The computer stylus defined in  claim 4  further comprising a plastic layer that covers the metal tube and the dielectric substrate. 
     
     
       6. The computer stylus defined in  claim 5  further comprising a sheet metal member that shorts the ground antenna feed terminal to the metal tube. 
     
     
       7. The computer stylus defined in  claim 6  further comprising conductive material that couples the sheet metal member to the metal tube. 
     
     
       8. The computer stylus defined in  claim 7  wherein the conductive material comprises conductive fabric. 
     
     
       9. The computer stylus defined in  claim 8  further comprising solder that couples the ground antenna feed terminal to the sheet metal member. 
     
     
       10. The computer stylus defined in  claim 9  further comprising a force sensor in the tip and an accelerometer. 
     
     
       11. The computer stylus defined in  claim 1  further comprising a sheet metal member coupled between the ground antenna feed terminal and the metal tube. 
     
     
       12. The computer stylus defined in  claim 11  further comprising solder that couples the return path to the sheet metal member. 
     
     
       13. The computer stylus defined in  claim 12  further comprising metal structures that reflect antenna signals from the antenna towards the tip, wherein the metal structures and the tip are located at opposing ends of the elongated body. 
     
     
       14. The computer stylus defined in  claim 1 ,
 wherein the dielectric substrate comprises a cylindrical plastic tube that encloses the longitudinal axis. 
 
     
     
       15. The computer stylus defined in  claim 14 , wherein the metal traces are patterned directly onto the cylindrical plastic tube. 
     
     
       16. The computer stylus defined in  claim 15 , wherein the metal traces are patterned directly onto the cylindrical plastic tube using laser-based patterning. 
     
     
       17. The computer stylus defined in  claim 1 , wherein the region devoid of the metal tube is interposed between the metal tube and the opposing end. 
     
     
       18. The computer stylus defined in  claim 1  wherein the region devoid of the metal tube extends completely around the longitudinal axis and the first portion of the metal traces extend around at least 180 degrees of the circumference. 
     
     
       19. The computer stylus defined in  claim 1 , further comprising:
 a sensor at the opposing end of the elongated body. 
 
     
     
       20. The computer stylus defined in  claim 19 , further comprising an additional sensor in the tip. 
     
     
       21. The computer stylus defined in  claim 20 , wherein the sensor comprises a force sensor. 
     
     
       22. The computer stylus defined in  claim 1 , wherein the metal traces further comprise a third portion that extends from the ground antenna feed terminal to the second portion of the metal traces, the third portion extending parallel to the first portion of the of the metal traces.

Description:
BACKGROUND 
     This relates generally to wireless communications circuitry and, more particularly, to wireless communications circuitry for elongated wireless devices such as computer styluses. 
     It can be challenging to form wireless circuitry for electronic equipment. For example, it can be difficult to incorporate wireless components such as antennas into compact portable devices such as tablet computer styluses. If care is not taken, the presence of conductive structures will adversely affect antenna performance. Poor antenna performance can lead to the use of increased transceiver power and reduced battery life. Poor antenna performance can also degrade wireless functionality. 
     It would therefore be desirable to be able to provide improved wireless circuitry for wireless devices such as computer styluses. 
     SUMMARY 
     A computer stylus may have an elongated body. A tip may be located at one end of the elongated body and may be configured to supply input to a capacitive touch screen. A metal connector and other metal structures may be located at an opposing end of the elongated body. 
     A metal tube in the elongated body may serve as an antenna ground for an antenna. An antenna resonating element for the antenna may be formed from metal traces that wrap around the elongated body at a location between the metal structures at the end of the elongated body and the metal tube. 
     The antenna may be an inverted-F antenna and may have a positive antenna feed terminal coupled to a resonating element arm in the metal traces and a ground antenna feed terminal. The ground antenna feed terminal may be coupled to the metal tube using a sheet metal member, conductive fabric, and solder. 
     A clip may run along part of the length of the elongated body at a location that does not overlap the metal traces of the antenna resonating element. The positive and ground antenna feed terminals may be located on an opposing side of the elongated body from the clip. Antenna signals from the inverted-F antenna may be reflected towards the tip by the metal structures at the end of the elongated body. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an illustrative computer and associated computer stylus in accordance with an embodiment. 
         FIG. 2  is a schematic diagram of an illustrative stylus with wireless communications circuitry in accordance with an embodiment. 
         FIG. 3  is a diagram of illustrative wireless circuitry for use in a stylus in accordance with an embodiment. 
         FIG. 4  is a diagram of an illustrative antenna for a stylus in accordance with an embodiment. 
         FIG. 5  is a cross-sectional side view of a portion of the elongated body of a stylus in accordance with an embodiment. 
         FIG. 6  is a side view of the upper end of a stylus in accordance with an embodiment. 
         FIG. 7  is a perspective view of an illustrative antenna resonating element formed from a metal trace on a hollow plastic tube in accordance with an embodiment. 
         FIG. 8  is a perspective view of an illustrative antenna formed from a length of flexible printed circuit that has been wrapped around a plastic tube in a helix in accordance with an embodiment. 
         FIG. 9  is a perspective view of an illustrative antenna formed from a flexible printed circuit that has been wrapped around the circumference of a hollow plastic tube in accordance with an embodiment. 
         FIG. 10  is a cross-sectional view of an illustrative antenna formed from a flexible printed circuit that has been wrapped around the circumference of a hollow plastic tube in accordance with an embodiment. 
         FIG. 11  is a perspective view of a flexible printed circuit with antenna traces and associated structures of the type that may be installed within a stylus in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     A system that includes electronic equipment that communicates wirelessly is shown in  FIG. 1 . The equipment of  FIG. 1  includes electronic device  120  and electronic device  10 . Electronic equipment such as devices  120  and  10  may, in general, be computing devices such as laptop computers, computer monitors containing embedded computers, tablet computers, cellular telephones, media players, or other handheld or portable electronic devices, smaller devices such as wrist-watch devices, pendant devices, headphone or earpiece devices, devices embedded in eyeglasses or other equipment worn on a user&#39;s head, or other wearable or miniature devices, televisions, computer displays that do not contain embedded computers, gaming devices, navigation devices, embedded systems such as a systems in which electronic equipment is mounted in kiosks or automobiles, computer accessories such as touch pads, computer mice, computer styluses, or other electronic accessories, equipment that implements the functionality of two or more of these devices, or other electronic equipment. In the illustrative configuration of  FIG. 1 , which is sometimes described herein as an example, device  120  is a tablet computer or other device with a touch screen and device  10  is a computer stylus. When a drawing program is running on tablet computer  120 , a user can use stylus  10  to draw on tablet computer  120  and to provide other input to tablet computer  120 . 
     Tablet computer  120  may include a housing such as housing  124  in which display  122  is mounted. Input-output devices such as button  126  may be used to supply input to tablet computer  120 . Display  122  may be a capacitive touch screen display or a display that includes other types of touch sensor technology. The touch sensor of display  122  may be configured to receive input from stylus  10 . 
     Stylus  10  may have a cylindrical shape or other elongated body that extends along longitudinal axis  26 . The body of stylus  10  may be formed from metal and/or plastic tubes and other elongated structures. Stylus  10  and tablet computer  120  may contain wireless circuitry for supporting wireless communications via wireless communications link  28 . As an example, stylus  10  may supply wireless input to tablet computer  120  via link  28  (e.g., information on settings in a drawing program or other software running on tablet computer  120 , input to select a desired on-screen option, input to supply tablet computer  120  with a touch gesture such as a stylus flick, input to draw a line or other object on display  122 , input to move or otherwise manipulate images displayed on display  122 , etc.). 
     Stylus  10  may have a tip such as tip  14 . Tip  14  may contain a conductive elastomeric member that is detected by the capacitive touch sensor of display  122 . If desired, tip  14  may contain active electronics (e.g., circuitry that transmits signals that are capacitively coupled into the touch sensor of display  122  and that are detected as touch input on the touch sensor). 
     Shaft portion  16  of stylus  10  may couple tip  14  of stylus  10  to opposing end  22  of stylus  10 . End  22  may contain a conductive elastomeric member, active electronics (e.g., circuitry that transmits signals that are capacitively coupled into the touch sensor of display  122  and that are detected as touch input on the touch sensor), buttons, a metal connector that mates with an external plug, or other input-output components. The structures of end  22  may be formed from metal. 
     A force sensor may be incorporated into tip  14  and/or opposing end  22  of stylus  10 . A force sensor may be used to measure how forcefully a user is pressing stylus  10  against the outer surface of display  122 . Force data may then be wirelessly transmitted from stylus  10  to tablet  120  so that the thickness of a line that is being drawn on display  122  can be adjusted accordingly or so that tablet  120  may take other suitable action. 
     A clip such as clip  24  may be used to attach stylus  10  to a user&#39;s shirt pocket or other object. Clip  24  may run along the side of the elongated body of stylus  10 . Clip  24  may be formed from a strip of flexible material such as springy metal and may be attached to stylus  10  at end  22 . End  22  may have a removable cap, a data port connector to receive a cable (e.g., a cable that supplies power signals for charging a battery in stylus  10  and/or that supplies digital data), input-output devices (e.g., a button and/or a light-emitting diode or other light-based output device), or other components (e.g., metal structures). 
     Components such as components  18  may be formed on stylus  10  (e.g., on shaft  16  or elsewhere). Components  18  may include buttons, touch sensors, and other components for gathering input, light-emitting diodes or other components for producing output, etc. 
     Stylus  10  may include a metal tube or other conductive components in shaft portion  16 . The metal tube or other structures in stylus  10  may serve as an antenna ground for an antenna. An antenna resonating element for the antenna may be formed from metal traces on a printed circuit or other conductive structures. The antenna resonating element may be located in region  20  of stylus  10  between the metal tube and the metal structures of end  22  or may be located in another suitable portion of stylus  10 . 
     A schematic diagram showing illustrative components that may be used in stylus  10  is shown in  FIG. 2 . As shown in  FIG. 2 , stylus  10  may include control circuitry such as storage and processing circuitry  30 . Storage and processing circuitry  30  may include storage such as nonvolatile memory (e.g., flash memory or other electrically-programmable-read-only memory configured to form a solid state drive), volatile memory (e.g., static or dynamic random-access-memory), etc. Processing circuitry in storage and processing circuitry  30  may be used to control the operation of stylus  10 . This processing circuitry may be based on one or more microprocessors, microcontrollers, digital signal processors, baseband processor integrated circuits, application specific integrated circuits, etc. 
     Storage and processing circuitry  30  may be used to run software on stylus  10 . The software may process input from buttons, sensors, and other input components. The software may also be used to provide output to a user (e.g., using light-emitting-diodes or other output components such as components  18  of  FIG. 1 ). To support interactions with external equipment such as tablet computer  120 , storage and processing circuitry  30  and other circuitry in stylus  10  may be used in implementing communications protocols. Communications protocols that may be implemented in stylus  10  include protocols for short-range wireless communications links such as the Bluetooth® protocol. If desired, other types of wireless communications links may be supported. The use of Bluetooth communications is merely illustrative. 
     Stylus  10  may include input-output circuitry  44 . Input-output circuitry  44  may include input-output devices  32 . Input-output devices  32  may be used to allow data to be supplied to stylus  10  and to allow data to be provided from stylus  10  to external devices such as tablet computer  120 . Input-output devices  32  may include user interface devices, data port devices, and other input-output components. For example, input-output devices  32  may include touch screens, displays without touch sensor capabilities, buttons, joysticks, scrolling wheels, touch pads, microphones, cameras, speakers, status indicators, light sources, audio jacks and other audio port components, digital data port devices, light sensors, accelerometers or other components that can detect motion and stylus orientation relative to the Earth, capacitance sensors, proximity sensors (e.g., a capacitive proximity sensor and/or an infrared proximity sensor), magnetic sensors, and other sensors and input-output components. 
     Input-output circuitry  44  may include wireless communications circuitry  34  for communicating wirelessly with external equipment. Wireless communications circuitry  34  may include radio-frequency (RF) transceiver circuitry formed from one or more integrated circuits, power amplifier circuitry, low-noise input amplifiers, passive RF components, one or more antennas  40 , transmission lines, and other circuitry for handling RF wireless signals. 
     Wireless communications circuitry  34  may include radio-frequency transceiver circuitry  90  for handling wireless communications in the 2.4 GHz Bluetooth® communications band or other suitable communications bands. Bluetooth signals or other wireless signals may be transmitted and/or received by transceiver circuitry  90  using one or more antennas such as antenna  40 . Antennas in wireless communications circuitry  34  may be formed using any suitable antenna types. For example, antennas for stylus  10  may include antennas with resonating elements that are formed from loop antenna structures, patch antenna structures, inverted-F antenna structures, slot antenna structures, planar inverted-F antenna structures, helical antenna structures, hybrids of these designs, etc. If desired, one or more of the antennas in stylus  10  may be cavity-backed antennas. 
     Transmission line paths may be used to couple antenna  40  to transceiver circuitry  90 . Transmission lines in stylus  10  may include coaxial cable paths, microstrip transmission lines, stripline transmission lines, edge-coupled microstrip transmission lines, edge-coupled stripline transmission lines, transmission lines formed from combinations of transmission lines of these types, etc. Filter circuitry, switching circuitry, impedance matching circuitry, and other circuitry may be interposed within the transmission lines, if desired. 
     As shown in  FIG. 3 , transceiver circuitry  90  in wireless circuitry  34  may be coupled to antenna  40  using paths such as path  92 . Wireless circuitry  34  may be coupled to control circuitry  30 . Control circuitry  30  may be coupled to input-output devices  32 . Input-output devices  32  may supply output from stylus  10  and may receive input from sources that are external to stylus  10 . 
     To provide antenna  40  with the ability to cover communications frequencies of interest, antenna  40  may be provided with circuitry such as filter circuitry (e.g., one or more passive filters and/or one or more tunable filter circuits). Discrete components such as capacitors, inductors, and resistors may be incorporated into the filter circuitry. Capacitive structures, inductive structures, and resistive structures may also be formed from patterned metal structures (e.g., part of an antenna). If desired, antenna  40  may be provided with adjustable circuits such as tunable components  102  to tune antenna  40  over communications bands of interest. Tunable components  102  may include tunable inductors, tunable capacitors, or other tunable components. Tunable components such as these may be based on switches and networks of fixed components, distributed metal structures that produce associated distributed capacitances and inductances, variable solid state devices for producing variable capacitance and inductance values, tunable filters, or other suitable tunable structures. During operation of stylus  10 , control circuitry  30  may issue control signals on one or more paths such as path  88  that adjust inductance values, capacitance values, or other parameters associated with tunable components  102 , thereby tuning antenna  40  to cover desired communications bands. Configurations in which antenna  40  is free of tunable components may also be used. 
     Path  92  may include one or more transmission lines. As an example, signal path  92  of  FIG. 3  may be a transmission line having a positive signal conductor such as line  94  and a ground signal conductor such as line  96 . Lines  94  and  96  may form parts of a coaxial cable or a microstrip transmission line (as examples). A matching network formed from components such as inductors, resistors, and capacitors may be used in matching the impedance of antenna  40  to the impedance of transmission line  92 . Matching network components may be provided as discrete components (e.g., surface mount technology components) or may be formed from housing structures, printed circuit board structures, traces on plastic supports, etc. Components such as these may also be used in forming filter circuitry in antenna  40 . 
     Transmission line  92  may be coupled to antenna feed structures associated with antenna  40 . As an example, antenna  40  may form an inverted-F antenna, a slot antenna, a hybrid inverted-F slot antenna or other antenna having an antenna feed with a positive antenna feed terminal such as terminal  98  and a ground antenna feed terminal such as ground antenna feed terminal  100 . Positive transmission line conductor  94  may be coupled to positive antenna feed terminal  98  and ground transmission line conductor  96  may be coupled to ground antenna feed terminal  92 . Other types of antenna feed arrangements may be used if desired. The illustrative feeding configuration of  FIG. 3  is merely illustrative. 
       FIG. 4  is a diagram of illustrative inverted-F antenna structures that may be used in implementing antenna  40  for stylus  10 . Inverted-F antenna  40  of  FIG. 4  has antenna resonating element  106  and antenna ground  104 . Antenna resonating element  106  may have a main resonating element arm such as arm  108 . The length of arm  108  may be selected so that antenna  40  resonates at desired operating frequencies. For example, the length of arm  108  may be a quarter of a wavelength at a desired operating frequency for antenna  40  (e.g., 2.4 GHz). Antenna  40  may also exhibit resonances at harmonic frequencies. 
     Main resonating element arm  108  may be coupled to ground  104  by return path  110 . Antenna feed  112  may include positive antenna feed terminal  98  and ground antenna feed terminal  100  and may run parallel to return path  110  between arm  108  and ground  104 . If desired, inverted-F antennas such as illustrative antenna  40  of  FIG. 4  may have more than one resonating arm branch (e.g., to create multiple frequency resonances to support operations in multiple communications bands) or may have other antenna structures (e.g., parasitic antenna resonating elements, tunable components such as components  102  of  FIG. 3  to support antenna tuning, etc.). Antenna  40  of  FIG. 4  may be a planar inverted-F antenna (e.g., arm  108  may have planar metal structures that run into the page in the orientation of  FIG. 4 ) or may be formed from non-planar structures. In mounting antenna  40  in stylus  10 , the structures of antenna  40  may be curved. For example, ground  104  and/or resonating element  106  may be formed from metal that wraps around longitudinal axis  26  of stylus  10 . 
     The housing of stylus  10  may be formed from metal, plastic, carbon-fiber composites and other fiber composites, glass, ceramic, other materials, and combinations of these materials. A cross-sectional side view of a section of shaft  16  of the elongated body of stylus  10  is shown in  FIG. 5 . As shown in  FIG. 5 , shaft  16  may include concentric cylindrical tubes such as inner metal tube  150  and outer plastic tube  158 . Inner metal tube  150  and outer plastic tube  158  may be cylindrical tubes or other hollow shaft members (e.g., tubes with triangular or square cross-sectional shapes, etc.). Hollow interior  152  of inner tube  150  may be used to house components  156  (e.g., storage and processing circuitry  30  and input-output circuitry  44  of  FIG. 2 ). Components  156  may include integrated circuits, sensors, input-output components, a battery, and other components that have been soldered or otherwise coupled to a substrate such as substrate  154 . Substrate  154  may be a printed circuit (e.g., a flexible printed circuit such as a layer of polyimide or a sheet of other flexible polymer or a rigid printed circuit board such as a printed circuit board formed from fiberglass-filled epoxy or other rigid printed circuit board material), a plastic carrier, or other substrate. Outer tube  158  may be a plastic sheath that slides onto the outside of metal tube  150 , may be molded plastic or other plastic coating that is formed on the exterior of tube  150 , or may be other exterior plastic structures. 
     If desired, portions of stylus  10  such as region  20  between shaft portion  16  and end  22  may be devoid of metal tube  150 . An antenna resonating element for antenna  40  may be located in region  20 . An arrangement of this type is shown in  FIG. 6 . As shown in  FIG. 6 , portion  16  of stylus  10  may include metal tube  150  (outer plastic tube  158  is not shown in  FIG. 6 ). Region  20  may contain antenna structures supported by plastic inner support tube  164 . For example, region  20  may contain antenna resonating element  106 . Antenna resonating element  106  may have resonating element arm  108 , return path  110 , and feed path  112  with positive antenna feed terminal  98  and ground antenna feed terminal  100 . Ground antenna feed terminal  100  may be coupled to metal tube  150 , which may serve as antenna ground  104  for antenna  40 . 
     End portion  22  of stylus  10  may be formed from metal structures (e.g., structure  25 , which may be, for example, a metal connector that is configured to receive a mating plug). The presence of end portion  22  above antenna  40  may help reflect radio-frequency antenna signals from antenna  40  downwards in direction  160  towards tablet computer  120 . As a result, the efficiency of antenna  40  may be greatest in a cone defined by dashed lines  162  (e.g., a cone having a spread of angle A and facing in direction  160 ). The value of A may be, for example, 20-160°, more than 40°, less than 130°, or other suitable value. Because antenna efficiency is enhanced in direction  160  (i.e., towards tablet computer  120 ), wireless communications link  28  between stylus  10  and tablet computer  120  can be maintained efficiently (i.e., power consumption from the battery in stylus  10  and the battery in table computer  120  can be minimized). 
     Antenna resonating element  106  may be formed from metal traces on the surface of support structure  164 , as shown in  FIG. 7 . Traces for antenna resonating element  106  may, for example, be formed using laser-based patterning (e.g., laser-enhanced metal plating, laser etching, etc.). Traces for antenna resonating element  106  may also be deposited using ink jet printing (e.g., inkjet printing of metal paint), pad printing, screen printing, physical vapor deposition, etc. 
     If desired, antenna resonating element  106  may be formed from metal traces on a printed circuit (e.g., a rigid printed circuit board or a flexible printed circuit). As shown in the illustrative configuration of  FIG. 8 , a flexible printed circuit such as flexible printed circuit  166  that contains metal traces for antenna resonating element  106  may be wrapped around support structure  164  in a helical pattern. 
     In the illustrative configuration of  FIG. 9 , flexible printed circuit  166  has been wrapped around the circumference of support structure  164  in the vicinity of metal tube  150  so that opposing ends  167  of flexible printed circuit  166  are adjacent to each other. In this configuration, metal traces in flexible printed circuit  166  may be used to from antenna resonating element  106  and metal tube  150  may be used to form antenna ground  104  ( FIG. 4 ). 
     A cross-sectional view of the structures of  FIG. 9  taken along line  168  and viewed in direction  169  is shown in  FIG. 10 . Outer plastic member  158  of  FIG. 5  is not shown in  FIG. 10 . Flexible printed circuit  166  contains metal traces patterned to form an antenna resonating element such as inverted-F antenna resonating element  106  of  FIG. 4 . Metal tube  150  may form antenna ground  104 . Feed  112  for antenna  40  may be located on the opposing side of stylus  10  from clip  24  to minimize interference between clip  24  and antenna  40 . Flexible printed circuit  166  may also be configured to form an opening or other region such as region  170  between ends  167  that is devoid of antenna traces for resonating element  106 . Interference between clip  24  and antenna  40  may be minimized by mounting clip  24  to the elongated body of stylus  10  where clip  24  overlaps region  170 . With this configuration, clip  24  does not overlap antenna resonating element  106  in flexible printed circuit  166  (i.e. clip  24  overlaps a region that is free of antenna resonating element traces). 
     In  FIG. 11 , flexible printed circuit  166  is shown in an unwrapped (flattened) state prior to wrapping around support structure  164  and installation within the tube-shaped housing of stylus  10 . As shown in  FIG. 11 , flexible printed circuit  166  includes metal traces for forming antenna resonating element arm  108 , return path  110 , and an antenna feed having positive antenna feed terminal  98  and ground antenna feed terminal  100 . A transmission line such as coaxial cable  92  may have a positive signal conductor such as line  94  that is soldered to terminal  98  and a ground signal conductor such as outer conductor  96  that is soldered to terminal  100 . Terminal  100  may be shorted to terminal  100 ′ on metal tube  150  via metal traces in printed circuit  166  (e.g., traces that form part of return path  110  and/or which are extensions to path  110 ), solder  180 , a sheet metal member such as stainless steel shim  182 , and a conductive material  184 . Conductive material  184  may be conductive fabric, conductive adhesive, solder, welded material, or other conductive material for facilitating the formation of an electrical connection between metal member  182  and the antenna ground formed by the inner surface of metal tube  150 . To assemble the structures of  FIG. 11  into a finished stylus, printed circuit  166  may be wrapped around longitudinal axis  26  and support structures  164  in directions  186 , as shown in  FIGS. 9 and 10 . Outer plastic tube  158  or other dielectric cover layer may then be used to cover printed circuit  166  and inner metal tube  150 . 
     The foregoing is merely illustrative and various modifications can be made by those skilled in the art without departing from the scope and spirit of the described embodiments. The foregoing embodiments may be implemented individually or in any combination.

Metadata:
Filing Date: 20140617
Publication Date: 20180508
Grant Date: 20180508
Priority Date: 20140617
Inventors: COUTTS, GORDON
LI, QINGXIANG
SCHLUB, ROBERT W.
JIANG, YI
Assignee: APPLE INC
CPC Classifications: [{"code": "H01Q1/44", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q9/42", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/03545", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q1/2258", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/44", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0393", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q9/42", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/44", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q9/42", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/2258", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/03545", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q1/2258", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/03545", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 54836137