An Antenna Proximity Sensor for Mobile Terminals Using Reflection Coefficient.

Area of Science:

• Electrical Engineering
• Antenna Theory
• Sensor Technology

Background:

• Mobile terminals require proximity sensing for various applications.
• Existing proximity sensors, like capacitive ones, have limitations in detection range and accuracy.
• Antenna performance can be affected by nearby objects, necessitating effective sensing mechanisms.

Purpose of the Study:

• To introduce a new antenna proximity sensor for mobile terminals.
• To utilize the antenna's reflection coefficient for proximity detection.
• To enhance the performance of proximity sensing in mobile devices.

Main Methods:

• A bidirectional coupler was integrated between the antenna and front-end module.
• Forward and reverse Long-Term Evolution (LTE) signals were coupled.
• The reflection coefficient was calculated in the base-band processor.
• Measurements were taken for different object types and distances.

Main Results:

• The measured reflection coefficients clearly differentiated between object types.
• Distinct reflection coefficients were observed at varying distances.
• The proposed sensor demonstrated a recognition distance approximately 5 mm greater than conventional capacitive sensors.

Conclusions:

• The developed antenna proximity sensor effectively detects objects using reflection coefficient measurements.
• This method offers improved detection range compared to traditional capacitive sensors.
• The sensor shows promise for enhanced proximity sensing in mobile terminals.