Co‐Design of Wide Beamwidth Quadrifilar Helical Antenna Integrated With Miniaturized Monopole Based on Non‐Uniform Compression for Submersible Application

ABSTRACT An assembled antenna, based on the non‐uniform compression of two wide‐beamwidth quadrifilar helical antennas (QHA) with a miniaturized monopole, is proposed for submersible applications. Initially, the impact of each parameter of the QHA on the Half Power Beamwidth (HPBW) is analyzed. Subsequently, the structural parameters of the spiral arm's compression part are examined. Utilizing theoretical analysis, the structure of the QHA is established, and two QHAs with differing polarizations are combined with a miniaturized monopole antenna to enable the proposed antenna to operate in triple‐mode, encompassing satellite navigation, duplex communication, emergency location, and search and rescue (SAR). Finally, the antenna is constructed and evaluated. The evaluation results indicate that the left‐hand circularly polarized QHA achieves a 189° HPBW and a 208° ARBW within the B1C satellite navigation band (1575.42 ± 16.368 MHz) and a 201° HPBW and a 206° ARBW within the L satellite communication uplink band (1615.68 ± 7 MHz). The right‐hand circularly polarized QHA exhibits a 202° HPBW and a 186° ARBW in the S satellite communication downlink band (2491.75 ± 15 MHz). The monopole antenna operates effectively at 406 MHz, emitting vertically polarized waves suitable for SAR.