Parallel fed collinear antenna array

摘要

An antenna comprises a coaxial dipole antenna, including an outer radiating cylinder 10 one quarterwave length long at its operating center frequency. A quarterwave radiating/quarterwave non-radiating inner cylinder 20 one halfwave length long at the operating center frequency coaxially is positioned within outer radiating cylinder 10 with an end of inner cylinder 20 aligned with an end of outer radiating cylinder 10. Means 12 (eg studs) is for electrically connecting the aligned ends of outer radiating cylinder 10 and non-radiating quarterwave of inner cylinder 20. Means 30 (may be a mast) is for grounding the midpoint of the halfwave inner cylinder 20 whereby inner cylinder 20 is transformed electrically into two one quarterwave length long cylinders.