Achieving Omnidirectional Dual-Polarized Sensing with Additively Manufactured Antennas

A monolithic, additively manufactured circular array of curved inverted-F antennas (CIFA) is made dual-polarized by incorporating a discone antenna similarly produced in monolithic fashion by digital light processing. The discone is carefully designed to have minimal impact on the CIFA array characteristics inclusive of impedance bandwidth and radiation patterns, while itself providing omnidirectional sensing and transmitting capability over nearly the same bandwidth. The design of the discone and the mating solution between antenna elements is discussed, highlighting the considerations necessary to make the one-piece 3D-printed fabrication possible. The resulting dual-polarized system exhibits return loss of 10 dB or greater over most of the 2–3 GHz band while maintaining gain of at least 0 dBi at horizon (θ = 90°). Measured results for the fabricated prototype show some disagreement with initial simulations due to effects associated with the stray currents on the cables needed for metrology. Methods to mitigate these issues in future design iterations are suggested and demonstrated in simulation.