EP0520564A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Circularly-polarized antenna and phase shift stripline device for such an antenna
Assignee: The AT&T MVPD Group LLC
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Filing: 1992-06-19
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Granted: —
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Expires: 2012-06-19
Abstract
Abstract The invention relates to an antenna system for sending and receiving circularly-polarized signals and to a phase shift stripline device for circularly-polarized signals for use with such an antenna, in particular to receiving circularly-polarized signals from a satellite Global Positioning System. Prior art antenna systems for GPS comprise quadrifilar elements driven from the top of the antenna assembly, resulting in relatively complex and high cost systems. Also, such systems are difficult to tune, i.e. high precision is difficult to achieve. According to the present invention a very small, high precision, low cost antenna system (110) is provided, in its preferred form comprising a quadrifilar antenna, having four helical elements (112) in volute form attached to a phase shift network comprising bifilar modules on separate substrates.
Inventors
- 👤 Miroslaw Balodis
- 👤 Hassan Zamat
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 07:01
CPC Classifications
H; H01; H01Q; H01Q11/00; H01Q11/02; H01Q11/08
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
160 words
A circularly polarized antenna system comprising a phase shift network for phase shifting signals between two or more antenna elements of an antenna an a radio comprising: signal transmission paths extending between a terminal for connection to a radio and each of a plurality of terminals for connection to each of two antenna elements; the transmission paths each having progressively equally different effective electrical lengths to provide a predetermined equal phase shift of the signal progressively through the transmission paths; the transmission paths commencing separately from the point of connection at each antenna element, the transmission paths having adjacent path pairs being progressively joined at combiner nodes of equal power division by shunt connection of combiner line segments such that the power at each antenna terminal is equal to the power at the radio connector terminal divided by the number of antenna terminals; the transmission paths being impedance matched between the antenna element connection points and the radio connection point.
Claim 2
Dependent Claim
25 words
The antenna system of claim 1 wherein the combiner line segments connect to form a combiner node having equal impedance and equal effective electrical length.
Claim 3
Dependent Claim
37 words
The antenna system of claim 1 or 2 wherein the combiner line segments define branched pairs and all branched pairs are equally phased relative to their respective antenna terminals have equal impedance and equal effective electrical length.
Claim 4
Dependent Claim
56 words
The antenna system of Claim 1, 2 or 3 wherein the transmission paths define one path arbitrarily as being at a zero degree reference phase and each successive path is phase shifted progressively by an equal phase shift amount such that the sum of all phase shifts is N times 360 where N is an integer.
Claim 5
Dependent Claim
181 words
The antenna system of claim 1, 2, 3 or 4 wherein a second antenna is used, each antenna being designed for operation at a different frequency, the phase shift network having a second set of said signal transmission paths extending from said point of connection to a radio to points of connection to each of two or more second antenna elements: the second set of transmission paths each having progressively equally different effective electrical lengths to provide a predetermined equal phase shift of the signal progressively through the transmission paths; the transmission paths commencing separately from the point of connection at each of said second antenna elements, the second set of transmission paths pairs being progressively joined at combiner nodes of equal power division by shunt connection of combiner line segments such that the power at each antenna terminal is equal to the power at the radio connection terminal divided by the number of antenna connection terminals; and the second set of transmission paths being impedance matched between the antenna elements of the second antenna and a radio connection point antenna.
Claim 6
Dependent Claim
128 words
A phase shift stripline device for use between a multi-element antenna and a radio comprising: a plurality of dielectric substrates each substrate having first and second faces formed into a multi-layer structure, a phase shifting network of circuit lines made by a printed circuit method having portions thereof on at least some of the surfaces of the dielectric substrates defining signal transmission paths between a radio connection terminal and each of a plurality of antenna element connection terminals each transmission path being phase shifted relative to an adjacent transmission path being phase shifted relative to an adjacent transmission path by a predetermined amount by each path having progressively equally different effective electrical length to provide a predetermined equal phase shift of the signal progressively through the transmission paths.
Claim 7
Dependent Claim
25 words
The phase shift stripline device of claim 6 further comprising a groundplane on surfaces of the substrates to enclose each circuit line between two groundplanes.
Claim 8
Dependent Claim
51 words
The phase shift stripline device of claim 6 or 7 wherein the transmission paths define a quadrifllar module having three bifilar modules and each bifilar module is on a separate one of the layers and the layers are stacked and the bifilar modules are connected together to form the quadrifilar module.
Claim 9
Dependent Claim
23 words
The phase shift stripline device of claim 8 wherein the surface of each layer opposite each bifilar module has a ground plane thereon.
Claim 10
Dependent Claim
46 words
The phase shift stripline device of claim 7, 8 or 9 wherein the thickness of each dielectric substrate is selected according to a predetermined Z₀ for each of the lines on each layer such that the impedance ratio between the antenna and the radio is matched.
References Cited (Backward Citations)
No citation records indexed.
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