Proximity sensor and antenna system arrangement for metal housing

摘要

A unified proximity sensor including multiple physically separated radio antenna structure for mobile electronic devices that senses proximity of a person to the antennae. Changes in capacitances of the antennae are detected based on a low frequency signal output by a single capacitance sensor. As a human body approaches any of the antennae, this capacitance increases. Based on the increase in capacitance, the transmission powers of radio signals emitted by the antennae are reduced.

主权项

1. A device, comprising:
a first antenna; a second antenna, physically separate and electrically insulated from the first antenna; a first radio frequency (RF) transmitter electrically coupled to the first antenna via a first RF feed and configured to transmit a first RF signal at a first frequency; a second radio frequency (RF) transmitter electrically coupled to the second antenna via a second RF feed and configured to transmit a second RF signal at a second frequency; a capacitance sensor configured to determine a capacitance attached to an electrode of the capacitance sensor using a sensing signal output by the capacitance sensor via the electrode, the sensing signal having a lower frequency than the first RF signal and the second RF signal, the capacitance sensor to determine a capacitance value that is proportional to the capacitance; a first inductor electrically connecting the first antenna to the electrode of the capacitance sensor, the first inductor being configured to (i) pass the sensing signal between the electrode and the first antenna, and (ii) block transmission of the first RF signal from the first antenna into the capacitance sensor; a second inductor electrically connecting the first antenna to the second antenna, the second inductor being configured to (i) pass the sensing signal between the first antenna and the second antenna, (ii) block transmission of the first RF signal from the first antenna to the second antenna, and (iii) block transmission of the second RF signal from the second antenna to the first antenna; a first capacitor arranged between the first RF transmitter and the first antenna, the first capacitor to (i) pass the first RF signal from the first RF transmitter to the first antenna, and (ii) block transmission of the sensing signal into the first RF transmitter; a second capacitor arranged between the second RF transmitter and the second antenna, the second capacitor to (i) pass the second RF signal from the second RF transmitter to the second antenna, and (ii) block transmission of the sensing signal into the first RF transmitter; and a digital comparator, wherein:
the digital comparator determines that the capacitance value is greater than a threshold value, andthe first RF transmitter reduces a first transmission power of the first RF signal, and the second RF transmitter to reduce a second transmission power of the second RF signal, in response to the capacitance value being greater than the threshold value, and wherein the capacitance value increases as a human body approaches either the first or second antennae.