Mobile wireless communications device with NFC coupling circuit and related methods
View Patent ↗A mobile wireless communications device may include a housing, a wireless transceiver carried by the housing, a processor carried by the housing and coupled to the wireless transceiver, and an NFC IC carried by the housing and coupled to the processor. The mobile wireless communications device may also include an NFC antenna carried by the housing, and a coupling circuit between the NFC IC and the NFC antenna. The coupling circuit may include a capacitive network including capacitors coupled in series with each other and in parallel with the NFC antenna, a transmit branch coupled between the NFC IC and a first node between a first pair of capacitors, and a receive branch coupled between the NFC IC and the first node between the first pair of capacitors.
1. An electronic device comprising:
a near field communication (NFC) antenna;
an NFC circuit;
a capacitive network comprising a plurality of capacitors coupled in series with each other and in parallel with said NFC antenna;
a transmit branch coupled between said NFC circuit and a first node between a first pair of capacitors of said plurality thereof; and
a receive branch coupled between said NFC circuit and the first node between the first pair of capacitors of said plurality thereof.
2. The electronic device of claim 1 further comprising at least one tuning branch coupled between said NFC circuit and a second node between a second pair of capacitors of said plurality thereof.
3. The electronic device of claim 2 wherein said at least one tuning branch comprises a pair thereof.
4. The electronic device of claim 3 wherein said pair of tuning branches comprises a first tuning branch comprising a first capacitor, and a second tuning branch comprising a second capacitor, and a diode coupled thereto.
5. The electronic device of claim 1 wherein said transmit branch comprises an inductor and a capacitor coupled thereto.
6. The electronic device of claim 5 wherein said transmit branch further comprises another capacitor coupled at a node between said inductor and said capacitor and a voltage reference.
7. The electronic device of claim 1 wherein said receive branch comprises a resistor and a capacitor coupled thereto.
8. The electronic device of claim 1 wherein said NFC circuit is configured to operate in an IC card emulation mode or a reader/writer mode.
9. A electronic device comprising:
a near field communication (NFC) antenna;
an NFC circuit configured to operate in an IC card emulation mode or a reader/writer mode;
a capacitive network comprising a plurality of capacitors coupled in series with each other and in parallel with said NFC antenna;
a transmit branch coupled between said NFC circuit and a first node between a first pair of capacitors of said plurality thereof;
a receive branch coupled between said NFC circuit and the first node between the first pair of capacitors of said plurality thereof; and
at least one tuning branch coupled between said NFC circuit and a second node between a second pair of capacitors of said plurality thereof.
10. The electronic device of claim 9 wherein said at least one tuning branch comprises a pair thereof.
11. The electronic device of claim 10 wherein said pair of tuning branches comprises a first tuning branch comprising a first capacitor, and a second tuning branch comprising a second capacitor, and a diode coupled thereto.
12. The electronic device of claim 9 wherein said transmit branch comprises an inductor and a capacitor coupled thereto.
13. The electronic device of claim 12 wherein said transmit branch further comprises another capacitor coupled at a node between said inductor and said capacitor and a voltage reference.
14. The electronic device of claim 9 wherein said receive branch comprises a resistor and a capacitor coupled thereto.
15. A method for making an electronic device comprising a near field communication (NFC) antenna and an NFC circuit, the method comprising:
coupling the NFC circuit and the NFC antenna together using a capacitive network comprising a plurality of capacitors in series with each other and in parallel with the NFC antenna by at least
coupling a transmit branch between the NFC circuit and a first node between a first pair of capacitors of the plurality thereof, and
coupling a receive branch between the NFC circuit and the first node between the first pair of capacitors of the plurality thereof.
16. The method of claim 15 further comprising coupling at least one tuning branch between the NFC circuit and a second node between a second pair of capacitors of the plurality thereof.
17. The method of claim 16 wherein the at least one tuning branch comprises a pair thereof.
18. The method of claim 17 wherein the pair of tuning branches comprises a first tuning branch comprising a first capacitor, and a second tuning branch comprising a second capacitor, and a diode coupled thereto.
19. The method of claim 15 wherein the transmit branch comprises an inductor and a capacitor coupled thereto.
20. The method of claim 19 wherein the transmit branch further comprises another capacitor coupled at a node between the inductor and the capacitor and a voltage reference.