About radiation efficiency optimizing of a miniaturized antenna

This paper exhibits the miniaturization of a compact omnidirectional antenna while keeping a high radiation efficiency. More accurately, the structure of a monopolar wire-patch antenna is modified to optimize its radiation efficiency with a constant global dimension constraint. It is then shown that a lower operating frequency (1.8 GHz versus 2.5 GHz) can be obtained with very similar radiation efficiency but under different impedance locus. This means that the monopolar wire patch antenna developed on the optimal impedance presents the same radiation efficiency while having lower dimensions (compared to the free space operating wavelength). This technique studied by 3D electromagnetic simulation is then validated by the results obtained with a set of prototypes.