Wideband vertically polarized omnidirectional antennas for direction finding (DF) system

In this work, wideband vertically polarized omnidirectional antenna candidates for a direction finding (DF) system are presented, which operate over frequency spectrum between 100 MHz to 1300 MHz (frequency ratio: 13:1). Two antenna solutions based on Spirograph monopole and bow-tie monopole were designed, developed and experimentally verified. To ease the design, two antennas for each of the solutions were realized: low band antenna (100 MHz and 450 MHz) and high band antenna (450 MHz to 1300 MHz) covering the full frequency range. Each of the selected antenna solution shares the same host ground platform. The radiation pattern was omnidirectional in nature throughout the desired frequency band. Both amplitude and phase of the receive fields could be processed to analyze direction of arrival of the signals from a typical target.