LAUSR

An antenna sensor is proposed to play dual role of a functional antenna and a sensor in a wireless sensor system, in an effort to reduce data loss and to increase transmission rate by eliminating a certain interface. A function of protractor was implemented on the coil antenna, working at radio frequency, to demonstrate the antenna sensor. The coil antenna was made of a copper wire with a wire diameter of 1 mm and had a coil diameter of 60 mm. With the impedance matching for the antenna designed at a resonant frequency of 43 MHz, a signal composed of multiple waves at shifted frequencies was transmitted from a mixer to the bent coil sensor, which acts as the emitting antenna. Upon received at the receiver coil, the signal was analyzed using the fast Fourier transform (FFT) algorithm. The received frequency‐domain signals were used to establish the characteristic matrix for the antenna sensor during a calibration process. The characteristic matrix becomes the fingerprint pattern to identify test angle of the bent coil sensor through the calculation of the Euclidean distance based upon the k nearest neighbor (kNN) classifier of the machine learning. The results showed that all the 16 test angles were identified accurately in the correct angle range.