Dual frequency band quadrifilar helix antenna systems and methods
First Claim
1. A half-duplex antenna system for providing electrical signals to a receiver and for transmitting electrical signals from a transmitter, comprising:
- a receive quadrifilar helix antenna comprising two bifilar helices arranged orthogonally and excited in phase quadrature;
a transmit quadrifilar helix antenna comprising two bifilar helices arranged orthogonally and excited in phase quadrature, positioned concentrically with said receive quadrifilar helix antenna;
first coupling means for coupling the signal from said receive quadrifilar helix antenna to said receiver;
first disconnecting means for electrically isolating the bifilar helices of said transmit quadrifilar helix antenna from said receiver during periods of transmission;
second coupling means for coupling the signal from said transmitter to said transmit quadrifilar helix antenna; and
second disconnecting means for electrically isolating the bifilar helices of said receive quadrifilar helix antenna from said transmitter when the antenna system is operating in the receive mode; and
wherein one of said transmit quadrifilar helix antenna and said receive quadrifilar helix antenna is disposed within the cylinder defined by the other of said transmit quadrifilar helix antenna and said receive quadrifilar helix antenna.
3 Assignments
0 Petitions
Accused Products
Abstract
A quadrifilar helix antenna system capable of providing a positive gain, quasi-hemispherical antenna pattern over widely separate transmit and receive frequency bands. This new antenna system comprises concentrically arranged, but electrically isolated, transmit and receive quadrifilar helix antennas, each of which comprises two bifilar helices arranged orthogonally and excited in phase quadrature. In the preferred embodiment, the antenna elements forming each bifilar helix are short-circuited at their distal ends, and energy is induced from the receive antenna and coupled to the transmit antenna via receive and transmit 90° hybrid couplers which are electrically connected to the bifilar loops of the respective receive and transmit antennas. Also provided are switches or other disconnection means which are used to electrically isolate the transmit antenna during periods when the antenna is receiving a signal and to electrically isolate the receive antenna during periods of transmission. In the preferred embodiments, these disconnecting means are implemented as PIN diodes or radio frequency Gallium arsenide field effect transistor switches.
81 Citations
23 Claims
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1. A half-duplex antenna system for providing electrical signals to a receiver and for transmitting electrical signals from a transmitter, comprising:
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a receive quadrifilar helix antenna comprising two bifilar helices arranged orthogonally and excited in phase quadrature; a transmit quadrifilar helix antenna comprising two bifilar helices arranged orthogonally and excited in phase quadrature, positioned concentrically with said receive quadrifilar helix antenna; first coupling means for coupling the signal from said receive quadrifilar helix antenna to said receiver; first disconnecting means for electrically isolating the bifilar helices of said transmit quadrifilar helix antenna from said receiver during periods of transmission; second coupling means for coupling the signal from said transmitter to said transmit quadrifilar helix antenna; and second disconnecting means for electrically isolating the bifilar helices of said receive quadrifilar helix antenna from said transmitter when the antenna system is operating in the receive mode; and wherein one of said transmit quadrifilar helix antenna and said receive quadrifilar helix antenna is disposed within the cylinder defined by the other of said transmit quadrifilar helix antenna and said receive quadrifilar helix antenna. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A half-duplex antenna system for providing electrical signals to a receiver and for transmitting electric signals from a transmitter, comprising:
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a transmit 90°
hybrid coupler having two output ports fed by said transmitter;a receive 90°
hybrid coupler having two input ports feeding said receiver;concentric transmit and receive quadrifilar helix antennas, each comprising two bifilar helices arranged orthogonally and excited in phase quadrature; wherein one of said transmit quadrifilar helix antenna and said receive quadrifilar helix antenna is disposed within the cylinder defined by the other of said transmit quadrifilar helix antenna and said receive quadrifilar helix antenna; wherein the bifilar helices comprising said transmit quadrifilar helix antenna each comprise a first filar coupled at its origin to one of the output ports on said transmit 90°
hybrid coupler and a second filar coupled at its origin to ground, and wherein said first and second filar helices are electrically connected at their distal ends, andwherein the bifilar helices comprising said receive quadrifilar helix antenna each comprise a first filar coupled at its origin to one of the input ports on said receive 90°
hybrid coupler and a second filar coupled at its origin to ground, and wherein said first and second filar helices are electrically connected at their distal ends;first disconnecting means for electrically isolating the bifilar helices of said transmit quadrifilar helix antenna from said receiver; and second disconnecting means for electrically isolating the bifilar helices of said receive quadrifilar helix antenna from said transmitter. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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19. A half duplex antenna system comprising:
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a receive quadrifilar helix antenna for receiving radio frequency signals in the 1525 MHz to 1559 MHz frequency band with a directivity in excess of 3 dBi for all elevation angles exceeding 45°
, having four helical filars of less than 10 centimeters in length, said filars arranged orthogonally and excited in phase quadrature;a transmit quadrifilar helix antenna for transmitting electrical signals in the 1626.5 MHz to 1660.5 MHz frequency band with a directivity in excess of 3 dBi for all elevation angles exceeding 45°
, comprising four helical filars of less than 10 centimeters in length, said filars arranged orthogonally and excited in phase quadrature;first coupling means for electrically connecting the signal from said receive quadrifilar helix antenna to said receiver; second coupling means for electrically connecting the signal from said transmitter to said transmit quadrifilar helix antenna; first disconnecting means for electrically isolating the bifilar helices of said transmit quadrifilar antenna from said receiver during periods of transmission; and second disconnecting means for electrically isolating the bifilar helices of said receive quadrifilar helix antenna from said transmitter when the antenna system is operating in the receive mode; and wherein one of said transmit quadrifilar helix antenna and said receive quadrifilar helix antenna is disposed within the cylinder defined by the other of said transmit quadrifilar helix antenna and said receive quadrifilar helix antenna. - View Dependent Claims (20, 21, 22, 23)
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Specification