Antenna for electronic device
Embodiments are disclosed for an antenna system comprising an over-resonant antenna conductor and a radio receiver electrically coupled to the over-resonant antenna conductor. The antenna system further comprises a capacitor electrically coupled to the over-resonant antenna conductor and sized to match the antenna conductor to a selected frequency.
1. A communication system of an electronic device to be worn on human skin, the communication system comprising:
a radio receiver arranged within an electrically conductive enclosure and configured to receive a communication signal at a predetermined target frequency;
electrically coupled to the radio receiver, an antenna conductor arranged outside of the electrically conductive enclosure and configured geometrically for resonance at an unmatched frequency above the predetermined target frequency, the antenna conductor being folded into multiple parallel portions; and
a shunting capacitor electrically coupled to the antenna conductor, the shunting capacitor being of such capacitance as to bring the antenna conductor into resonance at the predetermined target frequency.
2. The communication system of claim 1 , wherein the antenna conductor includes an electrically conductive trace disposed on a substrate.
3. The communication system of claim 2 , wherein the electrically conductive trace comprises an inverted-L shape to form an inverted-L antenna conductor.
4. The communication system of claim 2 , wherein the substrate is surrounded by two stacks of dielectric material.
5. The communication system of claim 1 , wherein the antenna conductor is connected to the radio receiver via a coaxial cable.
6. The communication system of claim 5 , wherein the coaxial cable is configured to traverse a pass-through structure pressed into an opening in an outer wall of the electrically conductive enclosure.
7. The communication system of claim 6 , wherein the coaxial cable is grounded at the pass-through structure.
8. The communication system of claim 1 , wherein the target frequency is selected from a range of 1560 MHz to 1605 MHz, to communicate via GPS.
9. The communication system of claim 1 , wherein the target frequency is selected from a range of 2400 MHz to 2482 MHz, to communicate via Bluetooth.
10. A wearable electronic device to be worn on human skin, the electronic device comprising:
a display-carrier module forming an electrically conductive enclosure housing a compute system and a display device;
a flexible wrist band coupled to the display-carrier module;
a communication system including a radio receiver arranged within the electrically conductive enclosure and configured to receive a communication signal at a predetermined target frequency;
electrically coupled to the radio receiver, an antenna conductor arranged outside of the electrically conductive enclosure at flexible portions of the flexible wrist band and configured geometrically for resonance at an unmatched frequency above the predetermined target frequency, the antenna conductor being folded into multiple parallel portions; and
a shunting capacitor electrically coupled to the antenna conductor, the shunting capacitor being of such capacitance as to bring the antenna conductor into resonance at the predetermined target frequency.
11. The electronic device of claim 10 , wherein the antenna conductor includes an electrically conductive trace disposed on a substrate.
12. The electronic device of claim 11 , wherein the electrically conductive trace comprises an inverted-L shape to form an inverted-L antenna conductor.
13. The electronic device of claim 10 , wherein the antenna conductor is connected to the radio receiver via a coaxial cable.
14. The electronic device of claim 13 , wherein the coaxial cable is configured to traverse a pass-through structure pressed into an opening in an outer wall of the electrically conductive enclosure.
15. The electronic device of claim 14 , wherein the coaxial cable is grounded at the pass-through structure and at substrates corresponding to each of the antenna conductor and the radio receiver.
16. The electronic device of claim 10 , wherein the antenna conductor comprises a first antenna conductor and the shunting capacitor comprises a first shunting capacitor, the electronic device further comprising a second antenna conductor coupled to a second shunting capacitor.
17. The electronic device of claim 16 , wherein the first shunting capacitor is of such capacitance as to match the first antenna conductor to a first target frequency for communicating via GPS and the second shunting capacitor is of such capacitance as to match the second antenna conductor to a second target frequency for communicating via Bluetooth.
18. The electronic device of claim 16 , wherein the first and second antenna conductors are disposed on opposite sides of the display device.
19. A communication system of an electronic device to be worn on human skin, the communication system comprising: a radio receiver arranged within an electrically conductive enclosure and configured to receive a communication signal at a predetermined target frequency; electrically coupled to the radio receiver, an antenna conductor arranged outside of the electrically conductive enclosure and configured geometrically for resonance at an unmatched frequency above the predetermined target frequency, the antenna conductor being formed with plural parallel portions on a flexible printed-circuit assembly attached to a metal armature through a plastic antenna substrate, the plastic antenna substrate maintaining a two-millimeter separation between the metal armature and the antenna conductor; and a shunting capacitor electrically coupled to the antenna conductor, the shunting capacitor being of such capacitance as to bring the antenna conductor into resonance at the predetermined target frequency.
20. The communication system of claim 19 wherein the communication signal includes one or more of a Bluetooth, Wifi, GPS, and cellular signal.