NFC Antenna Switch

An electronic device comprising:

• a controller configured to transmit and, receive signals from a first contactless antenna and a second contactless antenna, the controller further configured to generate a first control signal and a second control signal;
• the first contactless antenna coupled to the controller, the first contactless antenna normally disabled and coupled to a reference voltage, the first contactless antenna enabled in response to the controller generating the first control signal;
• and
• the second contactless antenna normally enabled, the second contactless antenna disabled in response to the controller generating the second control signal, the second contactless antenna enabled in response to the first contactless antenna being disabled, the second contactless antenna disabled in response to the first contactless antenna being enabled, the first contactless antenna and the second contactless antenna having a different resonant frequency, the first contactless antenna and the second contactless antenna connected to a same input port and output port of the controller.

An antenna circuit comprising:

• a first contactless antenna and a second contactless antenna;
• a first matching circuit comprising a first switch, a first capacitor, a second capacitor, and a third capacitor, a first terminal of the first capacitor coupled to a first terminal of the first contactless antenna and to a first terminal of the second capacitor, a second terminal of the first capacitor coupled to a second terminal of the first contactless antenna, a second terminal of the second capacitor coupled to a first terminal of the third capacitor and to an input terminal of the first switch, and an output terminal of the first switch coupled to a reference ground (Vref);
• a second matching circuit comprising a second switch, a fourth capacitor, a fifth capacitor, and a sixth capacitor, a first terminal of the fourth capacitor coupled to a first terminal of the second contactless antenna and to a first terminal of the fifth capacitor, a second terminal of the fourth capacitor coupled to a second terminal of the second contactless antenna, a second terminal of the fifth capacitor coupled to a first terminal of the sixth capacitor and to an input terminal of the second switch, and an output terminal of the second switch coupled to the reference ground;
• and
• a controller comprising an input terminal, an output terminal, and one or more control terminals, each of the input terminal and the output terminal of the controller coupled to a second terminal of the third capacitor and to a second terminal of the sixth capacitor, the one or more control terminals of the controller coupled to a control terminal of the first switch and the second switch.

A method comprising:

• having a shared controller coupled to a first contactless antenna and a second contactless antenna in an antenna circuit, the shared controller configured to transmit and receive signals from a first contactless antenna and a second contactless antenna;
• coupling the first contactless antenna to the shared controller and decoupling the second contactless antenna from the shared controller in a first configuration state of the antenna circuit, the first contactless antenna coupled to the shared controller using a first matching circuit and a first filter;
• and
• operating a controllable activation component to define a second configuration state of the antenna circuit formed by decoupling the first contactless antenna from the shared controller, coupling the second contactless antenna to the shared controller, the second contactless antenna coupled to the shared controller using a second matching circuit and a second filter, at least one capacitor of the first matching circuit is used in the second filter, at least one capacitor of the second matching circuit is used in the first filter.