Contactless Impedance and Far-Field Characterization of Electrically Small Antennas

Due to their small size and versatility, electrically small antennas (ESAs) must be precisely characterized in modern wireless communication systems. Traditional direct cable connection methods are susceptible to induced currents, resulting in imprecise input impedance and far-field radiation pattern measurements. This paper presents a novel contactless measurement technique that employs an oscilloscope to capture the time-domain impulse response of ESAs, mitigating induced current issues and enabling precise impedance measurement. In addition, we present an indirect method for characterizing far-field patterns and polarization, thereby enhancing the ESA's characterization. Our contactless method is adaptable to various ESA designs and frequencies and offers versatility and non-intrusiveness. Experimental results validate the efficacy of our approach, which represents a significant advance in ESA characterization for wireless system design optimization.