An assessment of the potential improvement in radiation efficiency of an aircraft HF antenna system using high temperature superconductors

Estimates are made of the improvements which might be achieved to the efficiency of an aircraft HF antenna system at the bottom of the band by the use of high temperature superconductors (HTS). The particular system considered is that of a `long-wire´ antenna mounted upon a BAC1-11 aircraft. Because it is rather difficult to see how the antenna itself can be cooled to the required temperatures, attention is concentrated upon the antenna tuning unit inductor. A combination of calculation and measurement is adopted to derive the equivalent circuit for the system which is then used to assess the effect upon radiation efficiency and bandwidth of eliminating the inductor losses. It is found that improvements to efficiency may be possible whilst maintaining adequate bandwidth