Apparatus and method for measuring and tuning circularly polarized antennas
First Claim
1. A test and measurement system for antennas comprising:
- a means to support a plurality of linear polarized antenna probes in an orthogonal and planar arrangement attached to conductive ground planes located in the far-field of the antenna under test (AUT);
a means to align the AUT and antenna probe reference axes;
a network analyzer capable of measuring amplitude and phase of a radiated wave; and
a means to provide signal coupling to or from the AUT, antenna probes, and network analyzer.
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Abstract
An apparatus and method is disclosed for measuring and tuning circularly polarized antennas to simultaneously optimize axial ratio, resonant frequency, and impedance match. The antenna under test is mounted within the test apparatus. Located in the zenith and far field of the antenna are two rigidly mounted, orthogonal, and planar probes. The amplitude and phase developed by the antenna is measured at each probe. The computer calculates the zenith axial ratio from the measured amplitude and phase difference between the probes. The method further includes the steps to determine sense-of-rotation of the circular polarized wave, impedance match, and resonant frequency. This apparatus and method is an elegant, simple, and cost effective design that is applicable to any isolated circular polarized radiating element.
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Citations
20 Claims
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1. A test and measurement system for antennas comprising:
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a means to support a plurality of linear polarized antenna probes in an orthogonal and planar arrangement attached to conductive ground planes located in the far-field of the antenna under test (AUT);
a means to align the AUT and antenna probe reference axes;
a network analyzer capable of measuring amplitude and phase of a radiated wave; and
a means to provide signal coupling to or from the AUT, antenna probes, and network analyzer. - View Dependent Claims (2, 3, 4)
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5. A method for simultaneously measuring multiple circular polarized antenna performance parameters, which comprises;
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positioning an antenna to be tested in the test and measurement system;
aligning the coordinate axes of the AUT and antenna probes;
providing test signals to be radiated from the network analyzer;
recording of test signals;
determining sense-of-rotation for the AUT;
calculating amplitude and phase difference among antenna probes; and
translating measured data into antenna performance parameters. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. An antenna test fixture assembly, having a plurality of units, each unit comprising:
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a base component;
a vertical plane component, coupled in a perpendicular fashion to said base member;
a ground plane component, coupled to said vertical plane member at a distal region of the vertical plane opposite to the vertical plane and base component coupling;
radio frequency absorption material affixed to the primary surfaces of the vertical and ground plane components;
an electric field probe, affixed to and protruding away from a primary surface of the ground plane component; and
a signal cable connector coupled to the electric field probe for the transmission of a detected radiated signal from an antenna unit under test to a signal analyzer;
wherein the electric field probes are in the far-field of an antenna unit under test and in an orthogonal relationship to each other and the antenna under test. - View Dependent Claims (17, 18, 19, 20)
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Specification