Bifilar Helical Antenna for High Power Electromagnetic Applications

This paper introduces a bifilar helical antenna design tailored for integration with high-power electromagnetic (HPEM) sources working in differential mode. A turn-to-turn voltage hold-off of 200 kV has been engineered by replacing air with sulfur hexafluoride gas (SF 6) as the antenna medium, leveraging its superior dielectric properties. The antenna features a cylindrical geometry with a compact ground structure, which effectively reduces backfire radiation and enhances overall performance. The introduced antenna presents an impressive impedance bandwidth of 47% in the UHF band and achieves a gain of 10.1 dBi at 433 MHz. A fabricated prototype has been characterized showing good agreement with simulations. The antenna's characteristics, along with the robust design and optimized performance parameters, enables its integration of the proposed antennainto compact HPEM applications.