An Energy-Efficient Antenna Impedance Detection Using Electrical Balance for Single-Step On-Chip Tunable Matching in Wearable/Implantable Applications.

A low-power impedance detection method using a hybrid transformer and its analysis are presented. A balun is reused for the hybrid transformer to achieve area-efficiency. The complex impedance detection enables faster optimization on a tunable matching network and its calibration technique increases the detection accuracy. The proposed impedance detection method fabricated in a 40-nm CMOS process ...