Broadband HF antennas with distributed unbalanced load

This paper presents a study on two broadband HF antenna structures based on monopole with distributed resistive loading. The first structure is derived from a folded monopole with a slant wire and the second one is derived from a folded monopole with a meanderline wire. For both structures, distributed unbalanced resistive loads are used to enhance the bandwidth performance. The first proposed antenna structure is electrically small the low frequency and has broadband performance even wider than the whole HF band. The 10 dB return loss performance is from 0.1 MHz to 35 MHz. Gain improvement is attempted by using a meander line to replace the slant wire. It can increase the antenna gain in the lower band (3-7 MHz).