Remote Antenna Impedance Measurement

Abstract

Due to the comparable size of the feeding cable to the original device and the induced current on the outer surface of the cable, the electrically small antenna (ESA) input impedance measurement using a network analyzer is a debatable technique. A remote impedance measurement technique is therefore implemented using an electrostatic discharge (ESD) to excite the ESA and remotely measure the ESA's terminated impulse response to three standard loads, short - open - matched load. The ESA's input impedance is evaluated based on three corresponding impulse responses, treating the measurement system as a three-port network and incorporating the advantage of microwave network analysis and the impulse responses resulting from the derived complex natural resonances (CNRs). To confirm the proposed technique, the input impedance of different antennas is directly measured via a network analyzer as well as a remote measurement technique, and the results are compared.