Design of matching network for HF vehicular antennas

High frequency (HF) communications are regaining interest in large part due to their robustness for establishing long haul (beyond the line of sight) links over 2 to 30 MHz frequency range. However, the conventional 3 kHz channel bandwidths are not sufficient for the amount of information that needs to be communicated, so hardware and software solutions that enable wider bandwidths (24 kHz or more) are being sought. The bandwidth requirements are particularly challenging for antennas aimed to be integrated on vehicles where small physical size (relative to the vehicles´ profile) is needed. The small physical size also leads to the small electrical size, especially at the lower portion of the HF band, where the features of electrically small antennas make their development extremely difficult. In that light, tunable matching networks able to support wider bandwidths with hopping RF carriers at HF at the reduced loss are also desired.