Dual frequency antenna system
A dual-frequency conformal multi-filiar helical antenna system ( 20 ) provides a low-profile, low drag antenna useable in flying equipment. This antenna system ( 20 ) securely holds within its shell ( 22 ) signal distribution circuitry ( 64 ), signal combining circuitry ( 68 ), and any other circuit components necessary for antenna system ( 20 ) to communicate with other stations or devices. Antenna system ( 20 ) has radiating conductors ( 24, 32 ) tuned to two different frequencies such that simultaneous transmission and reception of signals is possible in the same and opposite directions.
1. An antenna system comprising:
a shell having an exterior surface and an interior surface;
a first antenna having a first radiating conductor wrapped around said exterior surface, tuned to a first frequency and having a transmit signal pattern;
a second antenna having a second radiating conductor wrapped around said exterior surface, tuned to a second frequency and having a receive signal pattern;
a ground plate substantially covering said interior surface of said shell, said ground plate being configured to be a ground plane against which said first and second radiating conductors operate in order to form microstrip patch antenna elements;
a signal distribution circuit connected to said first antenna; and
a signal combining circuit connected to said second antenna;
wherein said shell is configured to move in a direction substantially coincident with an axis of said antenna system and one of said transmit signal pattern and said receive signal pattern favors said direction.
2. An antenna system comprising:
a shell having an exterior surface and an interior surface;
a first antenna having a first radiating conductor wrapped around said exterior surface and tuned to a first frequency;
a second antenna having a second radiating conductor wrapped around said exterior surface and tuned to a second frequency;
a ground plate substantially covering said interior surface of said shell, said ground plate being configured to be a ground plane against which said first and second radiating conductors operate in order to form microstrip patch antenna elements;
a signal distribution circuit connected to said first antenna; and
a signal combining circuit connected to said second antenna;
wherein said first antenna , said second antenna , said signal distribution circuit and said signal combining circuit are mutually configured such that transmission and reception take place simultaneously.
3. The antenna system of claim 2 wherein:
said shell is configured to move along an axis of motion; and
said first antenna and said second antenna are configured to have a greater gain along said axis of motion than transverse to said axis of motion.
4. An antenna system comprising:
a shell having an exterior surface and an interior surface;
a first antenna having a first radiating conductor wrapped around said exterior surface and tuned to a first frequency;
a second antenna having a second radiating conductor wrapped around said exterior surface and tuned to a second frequency; and
a ground plate substantially covering said interior surface of said shell, said ground plate being configured to be a ground plane against which said first and second radiating conductors operate in order to form microstrip patch antenna elements;
wherein said shell has a front end and is configured to move along an axis of motion; and
said antenna system further comprises a cone joined to said front end of said shell and aligned with said axis of motion.
5. An antenna system comprising:
a shell having an interior surface, an exterior surface and an interior cavity;
a first antenna having a first radiating conductor wrapped around said exterior surface;
a second antenna having a second radiating conductor wrapped around said exterior surface;
a ground plate substantially covering said interior surface of said shell, said ground plate being configured to be a ground plane against which said first and second radiating conductors operate in order to form microstrip patch antenna elements;
a signal distribution circuit held within said interior cavity and connected to said first antenna; and
a signal combining circuit held within said interior cavity and connected to said second antenna.
6. An antenna system comprising:
a shell having an interior surface and an exterior surface;
a first multi-filar antenna having a plurality of helical radiating conductors wrapped around said exterior surface and tuned to a first frequency;
a second multi-filar antenna having a plurality of helical radiating conductors wrapped around said exterior surface and tuned to a second frequency;
a ground plate substantially covering said interior surface, said ground plate being configured to be a ground plane against which said radiating conductors of said first and second multi-filar antennas operate in order to form microstrip patch antenna elements;
a signal distribution circuit held within said interior cavity and connected to said first antenna; and
a signal combining circuit held within said interior cavity and connected to said second antenna;
wherein said plurality of helical radiating conductors of said first multi-filar antenna are interleaved between said plurality of helical radiating conductors of said second multi-filar antenna.