Wireless Electronic Device With Calibrated Reflectometer

摘要

An electronic device may have control circuitry that uses a reflectometer to measure antenna impedance during operation. The reflectometer may have a directional coupler that is coupled between radio-frequency transceiver circuitry and an antenna. A calibration circuit may be coupled between the directional coupler and the antenna. The calibration circuit may have a first port coupled to the antenna, a second port coupled to the directional coupler, and a third port that is coupled to a calibration resistance. The reflectometer may have terminations of identical impedance that are coupled to ground. Switching circuitry in the reflectometer may be used to route signals from the directional coupler to a feedback receiver for measurement by the control circuitry or to ground through the terminations. Calibrated antenna reflection coefficient measurements may be used in dynamically adjusting the antenna.

主权项

1. An electronic device, comprising:
radio-frequency transceiver circuitry; an antenna; a transmission line path that couples the antenna to the radio-frequency transceiver circuitry; a reflectometer coupled in the transmission line path between the antenna and the radio-frequency transceiver circuitry; and a calibration circuit coupled between the reflectometer and the antenna.