Coaxial-Collinear (‘CoCo’) antennas are known as conceptually elegant and structurally simple antennas that in theory exhibit a superior gain potential. However, the physical principles that underpin CoCo have not been well understood. This circumstance has led to an assortment of difficulties in fabrication and tuning, most often resulting in suboptimal performance realization. In this presentation, we trace these difficulties to a set of electromagnetic boundary conditions that must be satisfied if full gain potential is to be achieved. In meeting these boundary conditions, we then employ the previously reported Displaced-Feedpoint Dipole (‘DFD’) as a generic input-network for CoCo. With this modification, full CoCo gain potential is rendered in a highly convenient physical form, and with no accompanying requirement for feedpoint impedance transformation or additional shield-current suppression.
In this session, you will learn:
Attendees can expect the following take-aways; (i) review of Coaxial-Collinear (‘CoCo’) and Displaced-Feedpoint Dipole (‘DFD’) operating principles, (ii) leveraging of DFD as a CoCo building block in creation of the Displaced-Feedpoint Coaxial Collinear (‘DF/CoCo’) , (iii) MMANA/NEC2-based DF/CoCo simulation and performance prediction, (iv) DF/CoCo build-and-test.