Hand grip sensor for external chassis antenna

1. An antenna system comprising:

a first antenna;

a first metal section spaced by a first gap from a first end of the first antenna;

a first ground section spaced by a third gap from the first metal section, the first ground section connected to ground;

a capacitance sensor configured to measure a first differential capacitance between the first antenna and the first metal section, when the first differential capacitance exceeds a first differential threshold the capacitance sensor provides a capacitance sense signal indicating that the first gap is being bridged by a user's touch; and

a matching circuit controller responsive to the capacitance sense signal and configured to provide an impedance control signal to a tunable antenna matching circuit to adjust an impedance between the first antenna and a transceiver based on the first gap being bridged, wherein the tunable antenna matching circuit is connected between the first antenna and the transceiver and wherein the antenna system further comprises a direct current (DC) blocking capacitor between the tunable antenna matching circuit and the first antenna, and wherein the matching circuit controller outputs a tuning signal to a second antenna matching circuit to reconfigure the second antenna matching circuit to impedance match a second antenna.

2. The antenna system of claim 1 , wherein the capacitance sensor is further configured to measure a first single ended capacitance between the first metal section and ground, when the first single ended capacitance exceeds a first capacitive threshold the capacitance sense signal provided by the capacitance sensor indicates that the third gap is being bridged by a user's touch and the matching circuit is further configured to provide the impedance control signal to the tunable antenna matching circuit to adjust the impedance between the first antenna and the transceiver based on the third gap being bridged.

3. The antenna system of claim 1 , further comprising;

a second metal section spaced by a second gap from a second end of the first antenna; and

a second ground section spaced by a fourth gap from the second metal section, the second ground section connected to ground;

wherein the capacitance sensor is further configured to measure a second differential capacitance between the first antenna and the second metal section, when the second differential capacitance exceeds a second differential threshold the capacitance sense signal provided by the capacitance sensor indicates that the second gap is being bridged by the user's touch and the matching circuit is further configured to provide the impedance control signal to the tunable antenna matching circuit to adjust the impedance between the first antenna and the transceiver based on the second gap being bridged.

4. The antenna system of claim 3 , wherein the capacitance sensor is further configured to measure a second single ended capacitance between the second metal section and ground, when the second single ended capacitance exceeds a second capacitive threshold the capacitance sense signal provided by the capacitance sensor indicates that the fourth gap is being bridged by a user's touch and the matching circuit is further configured to provide the impedance control signal to the tunable antenna matching circuit to adjust the impedance between the first antenna and the transceiver based on the fourth gap being bridged.

5. The antenna system of claim 1 , wherein the first antenna, the first metal section and the first ground section are part of a sectioned metal band about a perimeter edge of a mobile communication device.

6. The antenna system of claim 1 , wherein the DC blocking capacitor having a capacitance greater than a differential capacitance measurement range of the capacitance sensor.

7. The antenna system of claim 6 , wherein the DC blocking capacitor has a capacitance between about 20 pF and about 1000 pF.

8. A mobile communication device that is user equipment (UE) comprising:

a first antenna section on an exterior of the UE;

a first metal section spaced from and adjacent to a first end of the first antenna section;

a first ground section spaced from and adjacent to the first metal section such that the first metal section is between the first antenna section and the first ground section, the first ground section being connected to ground;

a capacitance module comprising:

a differential capacitance sensor configured to measure a first differential capacitance between the first antenna section and the first metal section; and

a capacitance sensor configured to measure a first capacitance between the first metal section and ground;

wherein the capacitance module outputs the first differential capacitance and the first capacitance as a capacitance sense signal;

a matching circuit controller configured to use the capacitance sense signal to reconfigure a tunable antenna matching circuit, wherein the antenna matching circuit is connected between a transceiver and the first antenna section, wherein the matching circuit controller outputs a tuning signal to a second antenna matching circuit to reconfigure the second antenna matching circuit to impedance match a second antenna section; and

a direct current (DC) blocking capacitor connected between the tunable antenna matching circuit and the first antenna section.

9. The UE of claim 8 , wherein the first antenna section, the first metal section and the first ground section are positioned sequentially as part of a perimeter band attached to and extending about a perimeter surface of the UE.

10. The UE of claim 8 , further comprising:

a second metal section space from and adjacent to a second end of the first antenna section; a second ground section spaced from and adjacent to the second metal section such that the second metal section is between the first antenna section and the second ground section, the second ground section being connected to ground;

the capacitance module further comprising:

the differential capacitance sensor further configured to measure a second differential capacitance between the first antenna section and the second metal section; and

the capacitance sensor further configured to measure a second capacitance between the second metal section and ground;

wherein the capacitance module further outputs the second differential capacitance and the second capacitance as part of the capacitance sense signal.

11. The UE of claim 8 , wherein the DC blocking capacitor has a capacitance that is greater than a differential capacitance measurement range of the differential capacitance sensor.

12. The UE of claim 8 wherein the first metal section has a floating electrical potential.

13. For a mobile communication device that is user equipment (UE) having an external antenna incorporated about a peripheral surface of the UE, a method of impedance matching at least a first antenna with a transceiver comprising:

measuring, by a differential capacitance sensor, a first differential capacitance between the first antenna and a first metal section, the first metal section being adjacent to a first end of the first antenna, the first metal section and the first antenna having a first gap there between;

measuring, by a capacitance sensor, a first capacitance between the first metal section and a first ground section, the first metal section being adjacent to the first ground section, and first metal section and the first ground section having a third gap there between, the first ground section being connected to ground; and

reconfiguring an antenna impedance matching circuit which is connected between the first antenna and the transceiver and where a direct current (DC) blocking capacitor is disposed between the antenna impedance matching circuit and the first antenna so as to impedance match the first antenna with the transceiver based on the combination of the first differential capacitance and the first capacitance, and reconfiguring the antenna impedance matching circuit to output a tuning signal to a second antenna matching circuit to reconfigure the second antenna matching circuit to impedance match a second antenna.

14. The method of claim 13 , wherein when the measured first differential capacitance is greater that a differential threshold, the antenna impedance matching circuit is reconfigured for a capacitance associated with a user bridging the first gap between the first antenna and the first metal section.

15. The method of claim 13 , wherein when the measured first differential capacitance is greater than a differential capacitance threshold and the measured first capacitance is greater than a capacitive threshold, the antenna impedance matching circuit is reconfigured for a capacitance associated with a user bridging both the first gap and the third gap.

16. The method of claim 13 , further comprising:

measuring by the differential capacitance sensor, a second differential capacitance between the first antenna and a second metal section, the second metal section being adjacent to a second end of the first antenna, the second metal section and the first antenna having a second gap there between;

measuring, by the capacitance sensor, a second capacitance between the second metal section and a second ground section, the second metal section being adjacent to the second ground section, the second metal section and the second ground section having a fourth gap there between, the second ground section being connected to ground; and

reconfiguring the antenna impedance matching circuit so as to impedance match the first antenna with the transceiver based on the combination of the first differential capacitance, the first capacitance, the second differential capacitance, and the second capacitance.