Dual helix antenna and manufacturing methods

摘要

An dual frequency band antenna comprises an inner helical coil, and an outer helical coil disposed outside the inner coil, the coils being connected at an end remote from the end at which the outer coil is fed. The pitch of the second coil is greater than that of the first. The coils may be supported on inner and outer cylindrical bodies which have spiral grooves. The coils may alternatively be insulated from each other by encapsulation in a resin or ceramic/plastic material. Also disclosed is a method for manufacture of a dual helix antenna by forming conductive patterns on ceramic substrates which are bonded to form a laminate. Alternatively an antenna is made by forming conductive patterns on flexible substrates which are rolled into a cylindrical shape.