Low sidelobe multi-beam lossless feed networks for array antennas
First Claim
1. A multi-beam antenna feed network with more aperture ports than beam ports, to enable low sidelobe lossless operation, comprising:
- five aperture ports, referenced as ports I, II, III, IV and V;
four beam ports, referenced as ports A, B, C and D; and
a feed arrangement comprising directional coupler elements and phase shift elements intercoupled between said beam ports and said aperture ports and responsive to beam port signal inputs to provide relative signal value outputs at said aperture ports as follows;
beam port A input, aperture port outputs;
I=0.7;
II=1;
III=1;
IV=1;
V=0.7;
beam port B input, aperture port outputs;
I=0.7;
II=-1;
III=1;
IV=-1;
V=0.7;
beam port C input, aperture port outputs;
I=0.7;
II=j;
III=-1;
IV=-j;
V=0.7;
beam port D input, aperture port outputs;
I=0.7;
, II=-j;
III=-1;
IV=j;
V=0.7;
said signal value outputs at the aperture ports representing orthogonal excitations having phase gradients effective to provide a four beam radiation pattern.
1 Assignment
0 Petitions
Accused Products
Abstract
Multi-beam antenna feed networks employ more aperture ports (e.g., ports I, II, III, IV and V) than beam ports (e.g., ports A, B, C and D) to achieve low sidelobe lossless operation, particularly for cellular communications. With five aperture ports, signal value outputs at the aperture ports represent orthogonal outputs having phase gradients effective to provide a four beam radiation pattern. The feed arrangement includes directional couplers (e.g., C11, C21) and phase shifters (e.g., P22, P23) intercoupled between the beam ports and aperture ports to provide the desired orthogonal aperture excitation. An example of specific directional coupler and phase shifter circuit values for a matrix network for a four beam port to five aperture port feed network configuration is provided.
6 Citations
8 Claims
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1. A multi-beam antenna feed network with more aperture ports than beam ports, to enable low sidelobe lossless operation, comprising:
-
five aperture ports, referenced as ports I, II, III, IV and V; four beam ports, referenced as ports A, B, C and D; and a feed arrangement comprising directional coupler elements and phase shift elements intercoupled between said beam ports and said aperture ports and responsive to beam port signal inputs to provide relative signal value outputs at said aperture ports as follows; beam port A input, aperture port outputs;
I=0.7;
II=1;
III=1;
IV=1;
V=0.7;beam port B input, aperture port outputs;
I=0.7;
II=-1;
III=1;
IV=-1;
V=0.7;beam port C input, aperture port outputs;
I=0.7;
II=j;
III=-1;
IV=-j;
V=0.7;beam port D input, aperture port outputs;
I=0.7;
, II=-j;
III=-1;
IV=j;
V=0.7;said signal value outputs at the aperture ports representing orthogonal excitations having phase gradients effective to provide a four beam radiation pattern. - View Dependent Claims (2, 3, 4)
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5. A multi-beam feed network with more aperture ports than beam ports, to enable low sidelobe lossless operation, comprising:
-
five aperture ports, each for coupling to a radiating element; a plurality of directional couplers; a first beam port coupled in series to a first rank of four of said directional couplers none of which is resistively terminated, and coupled via directional couplers of said first rank to each of said five aperture ports; a second beam port coupled in series to a second rank of three of said directional couplers none of which is resistively terminated, and coupled via directional couplers of said second rank to said first rank of directional couplers; a third beam port coupled in series to a third rank of two of said directional couplers none of which is resistively terminated, and coupled via directional couplers of said third rank to said second rank of directional couplers; a fourth beam port coupled to a fourth rank of a single one of said directional couplers which is resistively terminated, and coupled via the directional coupler of said fourth rank to said third rank of directional couplers; and a plurality of phase shift elements positioned in selected signal paths coupled to said ranks of directional couplers, said phase shift elements configured to provide predetermined phase shifts. - View Dependent Claims (6, 7, 8)
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Specification