A tunable electrically small antenna (ESA) designed to be naturally resonant at 100 MHz is evaluated for its range of tuning and feasibility for use in a mobile ionospheric heating (MIH) setup. The overarching goal is to match the ionospheric heating performance of the 180 element array at the high frequency active auroral research program (HAARP), which occupies approximately 1.2×105 m2 of land in Gakona, Alaska. While each HAARP crossed dipole element occupies 440 m2 of land and is tunable in the range of 2.7-10 MHz using automatic matching networks, the presented ESA approach is aimed toward enabling the fabrication of a transportable MIH array platform capable of high continuous wave (cw) power, albeit with a linear dimension five to ten times smaller than that of an equivalent dipole antenna. It is elucidated that the capacitively tuned ESA is continuously tunable to a frequency about 50% lower than that of the ESA's base frequency, albeit the resonant antenna structure carries a fractional bandwidth of merely 1%-2%.
- Antenna efficiency
- Electrically small antennas (ESAs)
- Inductive feed
- Loop antennas
- Reconfigurable antennas