Electronic devices with capacitive proximity sensors

Abstract

An electronic device may have a housing in which an antenna is mounted. An antenna window may be mounted in the housing to allow radio-frequency signals to be transmitted from the antenna and to allow the antenna to receive radio-frequency signals. Near-field radiation limits may be satisfied by reducing transmit power when an external object is detected in the vicinity of the dielectric antenna window and the antenna. A capacitive proximity sensor may be used in detecting external objects in the vicinity of the antenna. The proximity sensor may have conductive layers separated by a dielectric. A capacitancc-to-digital converter may be coupled to the proximity sensor by inductors. The capacitive proximity sensor may be interposed between an antenna resonating element and the antenna window. The capacitive proximity sensor may serve as a parasitic antenna resonating element and may be coupled to the housing by a capacitor.

Description

[0001] This application is a divisional application of an invention patent application with an application date of July 9, 2010, an application number of 201010229675.5, and an invention title of "electronic equipment with a capacitive proximity sensor". [0002] This application claims priority to U.S. Provisional Patent Application No. 61 / 226,683, filed July 17, 2009, and U.S. Patent Application No. 12 / 632,695, filed December 7, 2009, the entire contents of which are hereby incorporated by reference . technical field [0003] The present invention relates generally to antennas, and more particularly to antennas for electronic devices. Background technique [0004] Electronic devices such as portable computers and handheld electronic devices are becoming increasingly popular. Devices such as these often have wireless communication capabilities. For example, an electronic device may use long-range wireless communication circuitry, such as cellular telephone circuitry, to c...

AI Technical Summary

Problems solved by technology

This can make it difficult to implement antennas in electronic devices that contain conductive housing walls or other conductive structures that could block RF signals

Regulators may place limits on RF transmit power

These limitations pose challenges when operating electronic device antennas at elevated power levels

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