Gain-Enhanced Wideband Antenna Sensor Integrated with CMOS-Based Transceiver Chip for Human Respiratory Monitoring in Telemedicine Diagnosis

A compact gain-enhanced antenna sensor integrated with 65-nm CMOS based transceiver chip is proposed for respiratory monitoring in telemedicine diagnosis with a wide bandwidth, high gain. To enhance the gain, a metasurface lens and| U-shaped slot are loaded on the Vivaldi antenna, which increases the forward gain. The antenna properties have a contribution to improving the detection capability of the respiration radar ranging from 14 to 16 GHz. The simulation and measurement have been performed to evaluate its characteristics and its performance in supporting respiration radar operation. As a proof of concept, a prototype is designed, fabricated, and tested. A good agreement is observed between measurement and simulation results. It achieves an impedance bandwidth from 11.5 to 21.3 GHz (59.76% FBW) for a −10-dB reflection coefficient with port isolation higher than 24.92 dB. The realized gain is up to 10.5 dBi, the radiation efficiency is 88.01-90.02%, and the envelope correlation coefficient (ECC) is less than 0.00122 among antenna elements. Integrated with the designed and fabricated transceiver based on the 65 nm CMOS processing, the test circuit and system are built up. The experiment is conducted by using the respiration radar. The extracted phase information from the raw data shows that the proposed wideband antenna sensor can be used to identify the reflected signal from the chest wall at inhaling and exhaling phase of respiration activity.