Experimental Study of VHF Band Electrically Small Antenna with Modified Wheeler Method

The aim of the research was experimental study of radiation characteristics of VHF band electrically small omnidirectional antenna. The main point of research was radiation efficiency of the antenna. Given the existing theoretical limitation on the bandwidth of the small antennas, the paper considers and experimentally studies methods for increasing the bandwidth using the example of modifications to the shape of the inverted F-antenna, as well as the inclusion of additional ohmic losses in the antenna structure. Measurements of the antenna radiation efficiency was done with the Wheeler Cap method using additional processing of the impedance measurement results, as well as additional measurement of the frequency trend of the efficiency using a reference antenna. An additional measurement can be performed in a laboratory environment without strict requirements for the anechoic coefficient in the frequency range under study.