Parametric Enhancement of Radiation from Electrically Small Antennas

Electrically small antennas are characterized by large quality factors, which yield limited gainbandwidth products, as a result of the Bode-Fano limit. This bound implies a trade-off between the antenna's footprint and radiation features, hindering wireless applications that require compact, broadband, and efficient antennas. Here, building on a previous theoretical analysis of parametric matching networks [H. Li, A. Mekawy, and A. Al & ugrave;, Phys. Rev. Lett. 123, 164102 (2019)], we demonstrate how parametric phenomena can overcome this trade-off, offering a pathway to realize stable non-Foster wideband antennas that go beyond the restrictions of passive systems. We demonstrate our approach in a planar small loop antenna loaded by a time-varying capacitor that oscillates around twice the radiation frequency, showing that it can result in wideband radiation enhancement, exceeding the limitations of passive scenarios.

Automated summary

Electrically small antennas have large quality factors and limited gain-bandwidth products due to the Bode-Fano limit, leading to a trade-off between antenna footprint and radiation characteristics. However, research shows that parametric phenomena can overcome this trade-off, allowing the realization of stable non-Foster wideband antennas that go beyond the limitations of passive systems. This study demonstrates this approach in a planar small loop antenna loaded with a time-varying capacitor, showing wideband radiation enhancement beyond passive scenarios.