Elastic strain energy deployable helical antenna

An elastic strain energy deployable helical antenna comprising:

• a resiliently flexible antenna element in the form of a helix which is yieldably biassed to extend axially by elastic strain energy to a given fully extended length and is compressible axially to a contracted length;
• said antenna element comprising an electrically conductive tube of relatively flat oval cross-section in transverse planes containing the longitudinal axis of said helix;
• the major axis of said oval cross-section in any transverse plane being substantially normal to said longitudinal axis;
• a plurality of flexible tension members extending axially of and spaced circumferentially about said helix and secured to helical turns of said antenna element;
• and
• said tension members having relatively rigid portions between said turns and an overall length less than said fully extended length, whereby said members limit elastic strain energy extension of said antenna element to an operating length less than said fully extended length and said members are stressed in tension by said element at said operating length to reinforce said element against deflection laterally of said longitudinal axis.