Information handling system proximity sensing

1. A portable information handling system comprising:

a planar housing;

a processor disposed in the planar housing and operable to execute instructions to process information;

a memory disposed in the planar housing and interfaced with the processor, the memory operable to store the information;

a display disposed in the planar housing and interfaced with the processor and memory, the display operable to present the information as visual images;

a radio disposed in the planar housing and interfaced with the processor, the radio operable to transmit wireless signals at selectable signal strengths with conductive effects;

a near field communication (NFC) transceiver disposed in the planar housing and interfaced with the processor, the NFC transceiver operable to transmit wireless signals;

an NFC antenna disposed in the planar housing and interfaced with the NFC transceiver to support NFC wireless signal communication with inductive effects; and

a proximity processor disposed in the planar housing and interfaced with the NFC antenna, the proximity detector operable to detect proximity of objects to the NFC antenna with capacitive effects, the proximity detector providing the proximity of objects to the radio for selecting signal strength.

2. The portable information handling system of claim 1 further comprising a matching circuit disposed between the NFC transceiver and the NFC antenna, the matching circuit having only capacitive elements.

3. The portable information handling system of claim 1 wherein the NFC antenna is disposed at a back side of the planar housing opposite a front side having the display.

4. The portable information handling system of claim 1 further comprising:

a conductive antenna interfaced with the radio and operable to communicate the wireless signals; and

a proximity sensor disposed proximate the conductive antenna and operable to detect proximity of objects relative to the conductive antenna, the proximity sensor providing the proximity of objects to the radio for selecting signal strength.

5. The portable information handling system of claim 4 further comprising an object analyzer interfaced with the radio and operable to compare proximity of objects from the proximity processor and the proximity sensor to select the signal strength.

6. The portable information handling system of claim 5 wherein detection of an object proximate the NFC antenna without detection of an object proximate the conductive antenna selects full signal strength.

7. The portable information handling system of claim 5 wherein detection of a constant object proximate the NFC detection with detection of a variable object proximate the conductive antenna selects signal strength based upon proximity of the object to the conductive antenna.

8. The portable information handling system of claim 5 wherein the conductive antenna comprises a wireless wide area network (WWAN) antenna.

9. A method for selecting radio signal strength at a portable information handling system, the method comprising:

interfacing a proximity processor with a near field communication (NFC) antenna;

monitoring electrostatic charge at the NFC antenna with the proximity processor to sense proximate objects by changes in capacitive effects at the NFC antenna; and

providing the sensed proximate objects to a radio to select signal strength transmitted by the radio, the radio sending wireless signals with conductive effects.

10. The method of claim 9 further comprising:

interfacing the NFC antenna with an NFC transceiver; and

isolating the NFC transceiver from the capacitive effects with a capacitive matching circuit disposed between the NFC antenna and the NFC transceiver.

11. The method of claim 10 further comprising:

monitoring proximity of objects to a conductive antenna that sends that radio signals at the radio signal strength with a proximity sensor disposed proximate the conductive antenna; and

selecting the radio signal strength at least in part by comparing the proximity of objects to the NFC antenna and the conductive antenna.

12. The method of claim 11 wherein the conductive antenna comprises a wireless local area network antenna.

13. The method of claim 11 wherein the conductive antenna comprises a wireless wide area network antenna.

14. The method of claim 11 wherein selecting the radio signal strength by comparing the proximity of objects further comprises comparing changes in proximity of objects to the NFC antenna and the conductive antenna as the proximity of objects changes over time.

15. A portable information handling system proximity detector comprising:

a near field communication (NFC) antenna;

an NFC transceiver interfaced with the NFC antenna and operable to perform NFC communications through the NFC antenna with inductive effects associated with the NFC antenna;

a proximity processor interfaced with the NFC antenna and operable to perform proximity detection of objects proximate the NFC antenna with electrostatic effects associated with the NFC antenna;

a capacitive matching circuit disposed between the NFC antenna and the NFC transceiver, the capacitive matching circuit isolating the NFC transceiver from the electrostatic effects;

a radio operable to communicate wireless signals with conductive effects;

a radio antenna disposed distal the NFC antenna and interfaced with the radio, the radio antenna operable to transmit and receive the wireless signals with the conductive effects; and

a proximity sensor disposed proximate the radio antenna and interfaced with the radio, the radio operable to alter wireless signal strength based at least in part on objects detected by the proximity sensor.

16. The portable information handling system proximity detector of claim 15 wherein the radio interfaces with the proximity processor to alter wireless signal strength based at least in part on a comparison of objects detected proximate the NFC antenna.

17. The portable information handling system proximity detector of claim 16 wherein the radio comprises a wireless local area network radio.

18. The portable information handling system proximity detector of claim 16 wherein the radio comprises a wireless wide area network radio.