A method of producing a helical antenna and the helical antenna apparatus

摘要

The invention provides a helical antenna capable of covering a plurality of frequency bands and using commonly a feeder system for antenna elements adjusted to the respective frequency bands. First and second antenna elements adjusted in length to wavelengths of the frequency bands to be used are arranged helically at a specified pitch angle with a spacing between each other in the circumferential direction of a cylindrical body on the surface of a dielectric sheet wound around the outer circumferential surface of said cylindrical body. Coupling lines to be electromagnetically coupled to one-side ends of the antenna elements being adjacent to one another are formed on the surface of the dielectric sheet. Signal is fed from a common feeder circuit through the coupling lines to the respective antenna elements.