Low-profile inverted-L aircraft antenna with one folding using ground edge current

A low-profile inverted-L antenna with one folding at 20-90 MHz bands for aircraft applications is presented. The designed antenna is installed on the top of the vertical stabiliser of an aircraft to increase the gain at 20 MHz using the ground edge current and to reduce air drag. The gain of the designed antenna is increased by 3 dB at 20 MHz, and the antenna length is reduced by 41% compared with the reference antenna, which is a folded monopole antenna coupled with a parasitic element. The measured 3 dB return loss bandwidth is 342.9 MHz (51.5%) and the peak gain at 200 MHz is -11.5 dBi for the 1/10 scaled sub-model. In addition, the omnidirectional radiation pattern was observed in the operating frequency.