Multi-band antenna feed with switchably shared I/O port

A tri-band antenna feed for transmitting/receiving electromagnetic waves in the C, Ku and X frequency bands, comprising:

• an inner metal tube which lies along a central axis, and an outer metal tube which surrounds and is coaxial with said inner metal tube:
• said inner tube having an inner passageway which passes electromagnetic waves in said Ku and X bands but rejects electromagnetic waves in said C band;
• said outer tube together with said inner tube defining an outer passageway therebetween which passes electromagnetic waves in said C band;
• said inner tube having a first end, and said outer tube having a corresponding first end which lies proximate to but not past said first end of said inner tube such that said C, Ku and X bands all have a common phase center located with respect to said antenna feed;
• a solid dielectric which is attached to and covers said first end of said inner tube to thereby provide an I/O port for said Ku and X band;
• a hollow metal cone which is attached to said first end of said outer tube to thereby provide an I/O port for said low frequency waves;
• and,
• a switch which is coupled to a second end of said inner tube and which has:
• a) a first moveable passageway that selectively aligns with said inner passageway and passes both said Ku and X bands;
• and b) a second moveable passageway that selectively aligns with said inner passageway and passes said Ku band but rejects said X band.