Enhancing the antenna radiation-bandwidth product with dual-tone temporal modulation

Electrically small antennas (ESA) are subject to fundamental bandwidth and radiation efficiency limitations due to their small size compared to the wavelength of operation. While the use of active loads has been long explored to overcome these limits, practical implementations have been hindered by unwanted instabilities and nonlinearities. Recently, various parametric phenomena have been investigated as a powerful tool to enhance the radiation properties of ESAs. However, increasing the parametric gain alone reduces the antenna bandwidth, highlighting the inherent gain-bandwidth trade-off. In this work, we overcome this challenge by designing a dual-resonant ESA, which is parametrically driven by two independent parametric pump tones oscillating at the sum and difference frequencies of tailored resonant modes of the ESA. By carefully engineering the pump power levels and frequencies, we surpass conventional limits associated with the gain-bandwidth product and demonstrate enhancement of both peak transmission and 3-dB bandwidth of ESAs, yielding tangible enhancements in data rate. Both analytical and experimental validations confirm the efficacy of this approach, underscoring its potential to transcend conventional gain-bandwidth product limitations for ESAs.