# US 9,520,638 B2 · Hybrid radio frequency / inductive loop antenna > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,520,638 B2 - Document ID: US9520638B2 - Status: Granted - Kind: B2 - Application number: 14/290,906 - Filed: 2014-05-29 - Published: 2014-09-18 - Granted: 2016-12-13 - Earliest claimed: 2013-01-15 - Assignees: Fitbit, Inc. - Applicants: Fitbit, Inc. - Inventors: William B. Baringer; Mark Manuel Martinez - Web page: https://patentgrep.com/patent/US9520638B2 ## CPC - H01Q 21/28: Combinations of substantially independent non-interacting antenna units or systems {(multiple beam H01Q25/00)} - A61B 5/0002: {Remote monitoring of patients using telemetry, e.g. transmission of vital signals via a communication network (endoradiosondes A61B5/07)} - A61B 5/02416: {using photoplethysmograph signals, e.g. generated by infrared radiation (A61B5/14552 takes precedence)} - A61B 5/02427: {Details of sensor} - A61B 5/02433: {for infrared radiation} - A61B 5/02438: {with portable devices, e.g. worn by the patient} - A61B 5/1123: {Discriminating type of movement, e.g. walking or running (A61B5/1116, A61B5/112 take precedence)} - A61B 5/4812: {Detecting sleep stages or cycles} - H01Q 1/22: by structural association with other equipment or articles - H01Q 1/2291: {used in Bluetooth® or Wi-Fi® devices of Wireless Local Area Networks [WLAN] (H01Q1/241 takes precedence; WLAN in general H04W)} - H01Q 1/273: {Adaptation for carrying or wearing by persons or animals} - H01Q 1/38: formed by a conductive layer on an insulating support {(patch antennas H01Q9/0407; microstrip dipole antennas H01Q9/065; microstrip slot antennas H01Q13/106; transmission line microstrip antennas H01Q13/206; manufacturing reflecting surfaces using insulating material for supporting the reflecting surface H01Q15/142)} - H01Q 1/48: Earthing means; Earth screens; Counterpoises - H01Q 7/00: Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop - H01Q 9/0421: {with a shorting wall or a shorting pin at one end of the element (H01Q9/0414 takes precedence)} - H02J 50/10: using inductive coupling - H04B 5/26: using coils - H04W 4/027: {using movement velocity, acceleration information} - H02J 7/345: {using capacitors as storage or buffering devices} - H04L 67/12: specially adapted for proprietary or special-purpose networking environments, e.g. medical networks, sensor networks, networks in vehicles or remote metering networks - H04W 4/80: Services using short range communication, e.g. near-field communication [NFC], radio-frequency identification [RFID] or low energy communication - Y10T 29/49016: Antenna or wave energy "plumbing" making - H01Q: ANTENNAS, i.e. RADIO AERIALS (radiators or antennas for microwave heating H05B6/72) - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) - H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY - H04B: TRANSMISSION - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract Biometric monitoring devices, including various technologies that may be implemented in such devices, are discussed herein. Additionally, techniques, systems, and apparatuses are discussed herein for providing a hybrid antenna including an RF radiator and an electrically coupled inductive loop. The hybrid antenna is capable of providing both RF and induction functionality, e.g., radio frequency transmission/reception capabilities for Bluetooth as well as near-field-communications (NFC) functionality via the inductive loop. The inductive loop may be in conductive contact with the RF radiator or may be inductively coupled with the RF radiator and not in conductive contact with the RF radiator. The inductive loop may act as a planar element of a planar inverted-F antenna (PIFA). ## Claims ### Claim 1 An apparatus comprising: a ground plane; a radio-frequency radiator; a feed post conductively connected to the radio-frequency radiator; a shorting post, wherein the shorting post is connected to the radio-frequency radiator; and a near-field communications (NFC) tag including an NFC circuit and a multi-turn inductive loop configured to couple electrically with the radio-frequency radiator, the multi-turn inductive loop either in conductive contact with the radio-frequency radiator or not in conductive contact with the radio-frequency radiator, the radio-frequency radiator at least partially overlapping the turns in the multi-turn inductive loop, wherein: the multi-turn inductive loop is conductively connected with the NFC integrated circuit and configured to inductively couple with a near-field magnetic field to provide power to the NFC circuit, the NFC circuit, when powered, is configured to broadcast information stored within the NFC circuit, and the multi-turn inductive loop of the NFC tag, the radio-frequency radiator, the ground plane, and the feed post together form a planar inverted-F antenna configured to produce and receive electro-magnetic radio-frequency signals, wherein the multi-turn inductive loop of the NFC tag serves as a radiator extension to the radio-frequency radiator when producing and receiving the electro-magnetic radio-frequency signals. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein the turns of the multi-turn inductive loop of the NFC tag at least partially overlap the ground plane. ### Claim 3 (depends on 1) The apparatus of claim 1, wherein the radio-frequency radiator at least partially overlaps less than 20% of the turns in the multi-turn inductive loop of the NFC tag. ### Claim 4 (depends on 1) The apparatus of claim 1, wherein the turns in the multi-turn inductive loop of the NFC tag that the radio-frequency radiator at least partially overlaps are outermost turns of the multi-turn inductive loop of the NFC tag. ### Claim 5 (depends on 1) The apparatus of claim 1, wherein the radio-frequency radiator follows a path that is substantially aligned with paths followed by the turns of the multi-turn inductive loop of the NFC tag with which the radio-frequency radiator at least partially overlaps. ### Claim 6 (depends on 1) The apparatus of claim 1, wherein the turns in the multi-turn inductive loop of the NFC tag follow a path that defines a major surface that faces towards the radio-frequency radiator. ### Claim 7 (depends on 1) The apparatus of claim 1, wherein the multi-turn inductive loop of the NFC tag is separated from the radio-frequency radiator by a first gap. ### Claim 8 (depends on 7) The apparatus of claim 7, wherein the NFC tag includes an insulating layer that is interposed between the radio-frequency radiator and the multi-turn inductive loop in the first gap. ### Claim 9 (depends on 7) The apparatus of claim 7, further comprising: a first housing portion; and a second housing portion, wherein: the radio-frequency radiator is supported by the first housing portion, the NFC tag is supported by the second housing portion, and the first housing portion is mated to the second housing portion such that the NFC tag and the radio-frequency radiator are separated by the first gap. ### Claim 10 (depends on 7) The apparatus of claim 7, further comprising: a plastic carrier; and a substrate with a printed circuit, wherein: the radio-frequency radiator is supported by the plastic carrier, the plastic carrier is supported by the substrate with the printed circuit, the substrate with the printed circuit acts as the ground plane, and the NFC tag is also supported by the plastic carrier. ### Claim 11 (depends on 7) The apparatus of claim 7, further comprising: a housing having a first surface and a second surface, wherein: the first surface and the second surface are nominally on opposing sides of a portion of the housing and define the first gap, the radio-frequency radiator is formed by a metallization layer deposited on the first surface, the NFC tag is located on or adjacent to the second surface such that the second surface is interposed between the first surface and the NFC tag. ### Claim 12 (depends on 7) The apparatus of claim 7, further comprising: a housing having a first surface and a second surface, wherein: the first surface and the second surface are nominally on opposing sides of a portion of the housing and define the first gap, the radio-frequency radiator is formed by a metallization layer deposited on the second surface, the NFC tag is located on or adjacent to the second surface such that the radio-frequency radiator is interposed between the second surface and the NFC tag. ### Claim 13 (depends on 7) The apparatus of claim 7, wherein the ground plane is provided by a structure located on an opposite side of the first housing portion from the radio-frequency radiator. ### Claim 14 (depends on 13) The apparatus of claim 13, wherein the structure is selected from the group consisting of: a printed circuit board, a flexible circuit board, a metal plate contained within the apparatus, and a metal plate at least partially providing an exterior surface of the apparatus. ### Claim 15 (depends on 7) The apparatus of claim 7, wherein: the radio-frequency radiator has a nominal width of between about 0.5 mm and 1.5 mm and an average length of between about 10 mm and 25 mm, and the multi-turn inductive loop of the NFC tag has an average path length of about 500 mm to 600 mm. ### Claim 16 (depends on 7) The apparatus of claim 7, wherein the radio-frequency radiator is substantially the shape of a rectangle having a length-to-width aspect ratio of at least 10:1. ### Claim 17 (depends on 7) The apparatus of claim 7, wherein the radio-frequency radiator is L-shaped. ### Claim 18 (depends on 7) The apparatus of claim 7, wherein the radio-frequency radiator is U-shaped or C-shaped. ### Claim 19 (depends on 1) The apparatus of claim 1, wherein the multi-turn inductive loop is offset from the ground plane in a direction normal to the ground plane. ### Claim 20 (depends on 1) The apparatus of claim 1, wherein the radio-frequency radiator is offset from the ground plane by a first distance. ### Claim 21 (depends on 1) The apparatus of claim 1, wherein the ground plane is a non-planar surface. ### Claim 22 (depends on 1) The apparatus of claim 1, wherein the radio-frequency radiator and the multi-turn inductive loop of the NFC tag are in electrically-conductive contact with one another. ### Claim 23 (depends on 1) The apparatus of claim 1, wherein the radio-frequency radiator and the multi-turn inductive loop of the NFC tag are formed from the same electrically-conductive trace. ### Claim 24 (depends on 1) The apparatus of claim 1, further comprising: a shorting post conductively connecting the radio-frequency radiator to the ground plane, wherein: the multi-turn inductive loop of the NFC tag, the radio-frequency radiator, the ground plane, the shorting post, and the feed post together form a planar inverted-F antenna (PIFA) configured to produce and receive electro-magnetic radio-frequency signals in a Bluetooth-compatible frequency band, wherein the multi-turn inductive loop of the NFC tag serves as a radiator extension to the radio-frequency radiator when producing and receiving the electro-magnetic radio-frequency signals in the Bluetooth-compatible frequency band. ### Claim 25 (depends on 24) The apparatus of claim 24, wherein: the radio-frequency radiator, the ground plane, and the multi-turn inductive loop of the NFC tag are formed from a common conductive trace. ### Claim 26 (depends on 1) The apparatus of claim 1, further comprising: a shorting post conductively connecting the radio-frequency radiator to the ground plane, wherein: the multi-turn inductive loop of the NFC tag, the radio-frequency radiator, the ground plane, the shorting post, and the feed post together form a planar inverted-F antenna (PIFA) configured to produce and receive electro-magnetic radio-frequency signals in a GPS-compatible frequency band, wherein the multi-turn inductive loop of the NFC tag serves as a radiator extension to the radio-frequency radiator when producing and receiving the electro-magnetic radio-frequency signals in the GPS-compatible frequency band. ### Claim 27 (depends on 1) The apparatus of claim 1, wherein: the radio-frequency radiator, the ground plane, and the multi-turn inductive loop of the NFC tag are located on a common, non-recurvate reference surface. ### Claim 28 (depends on 1) The apparatus of claim 1, wherein a path length of the multi-turn inductive loop of the NFC tag is at least 20 to 50 times greater than nominal dimensions of the NFC tag. ### Claim 29 (depends on 1) The apparatus of claim 1, wherein the multi-turn inductive loop of the NFC tag is configured to inductively couple with a near-field magnetic field at a range of about 10 cm or less. ### Claim 30 (depends on 1) The apparatus of claim 1, wherein the multi-turn inductive loop comprises a plurality of turns of decreasing size. ### Claim 31 (depends on 1) The apparatus of claim 1, wherein the turns in the multi-turn inductive loop of the NFC tag follow a path that defines a major surface that is parallel to the radio-frequency radiator. ### Claim 32 A method comprising: a) providing a radio-frequency radiator; b) mounting the radio-frequency radiator to a first surface of a first housing component; c) providing a near-field communications (NFC) tag, wherein the NFC tag includes a multi-turn inductive loop and an NFC integrated circuit; d) placing the multi-turn inductive loop such that the multi-turn inductive loop is configured to couple electrically with the radiator, the radio-frequency radiator at least partially overlapping the turns in the multi-turn inductive loop, the multi-turn inductive loop being conductively connected with the NFC integrated circuit and configured to inductively couple with a near-field magnetic field to provide power to the NFC circuit. ### Claim 33 (depends on 32) The method of claim 32, wherein the turns in the multi-turn inductive loop of the NFC tag follows a path that defines a major surface that faces towards the radio-frequency radiator. ### Claim 34 (depends on 32) The method of claim 32, wherein the NFC tag is bonded to the first surface and the radio-frequency radiator is interposed between the NFC tag and the first surface. ### Claim 35 (depends on 32) The method of claim 32, wherein a path length of the multi-turn inductive loop of the NFC tag is at least 20 to 50 times greater than nominal dimensions of the NFC tag. ### Claim 36 (depends on 32) The method of claim 32, wherein the multi-turn inductive loop of the NFC tag is configured to inductively couple with a near-field magnetic field at a range of about 10 cm or less.