Phased array antenna and its phase calibration method
First Claim
1. A phase calibration method for a phased array antenna,the phased array antenna comprising:
- an oscillator that generates radio waves;
a plurality of antenna elements;
a plurality of phase shifters, each of which is connected to each of the plurality of antenna elements and changes a phase of radio waves radiated by the plurality of antenna elements;
means for distributing radio waves generated by the oscillator to the plurality of antenna elements via the plurality of phase shifters;
means for controlling the plurality of phase shifters and the distributing means; and
a signal input part that inputs received signals outputted from a receiver that detects power of radio waves radiated by the plurality of antenna elements; and
the phase calibration method comprising;
at the controlling means,calibrating a phase of each of the phase shifters for each pair of antenna elements located at a pair of positions symmetric with respect to a central axis of an array of the phased array antenna, among the plurality of antenna elements; and
subsequently performing, with respect to an antenna element located at a position of the central axis of the array and all pairs of antenna elements located at positions symmetric with respect to the central axis of the array, the steps of;
supplying radio waves from the oscillator via the distributing means to an antenna element located at a position of the central axis of the array and a pair of antenna elements located at positions symmetric with respect to the central axis of the array, among the plurality of antenna elements;
obtaining a directivity pattern formed by the antenna element and the pair of antenna elements from a distribution in a received power of the radio waves, received at the receiver via the signal input part, along a horizontal direction with respect to an array direction of the plurality of antenna elements, while changing a phase of each of the phase shifters connected to the pair of antenna elements in the same manner; and
setting a value of the phase of each of the phase shifters in such a manner that a level of side lobes, which occur in the directivity pattern obtained, becomes a predetermined value.
1 Assignment
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Accused Products
Abstract
A phased array antenna includes an oscillator, a plurality of antenna elements, a phase shifter, a distributor, a receiver, and a control processor. The control processor performs a first calibration process to calibrate a phase of the phase shifter connected to a pair of antenna elements that is selected from the antenna elements and are located at a pair of positions symmetric with respect to a central axis of an array formed by the phased array antenna, and a second calibration process to calibrate a phase of the phase shifter connected to a pair of target antenna elements with respect to a phase of the phase shifter connected to a reference antenna elements located at a central portion of the array. The pair of target antenna elements are located at a pair of positions that are symmetric with respect to the central axis of the array.
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Citations
2 Claims
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1. A phase calibration method for a phased array antenna,
the phased array antenna comprising: -
an oscillator that generates radio waves; a plurality of antenna elements; a plurality of phase shifters, each of which is connected to each of the plurality of antenna elements and changes a phase of radio waves radiated by the plurality of antenna elements; means for distributing radio waves generated by the oscillator to the plurality of antenna elements via the plurality of phase shifters; means for controlling the plurality of phase shifters and the distributing means; and a signal input part that inputs received signals outputted from a receiver that detects power of radio waves radiated by the plurality of antenna elements; and the phase calibration method comprising; at the controlling means, calibrating a phase of each of the phase shifters for each pair of antenna elements located at a pair of positions symmetric with respect to a central axis of an array of the phased array antenna, among the plurality of antenna elements; and subsequently performing, with respect to an antenna element located at a position of the central axis of the array and all pairs of antenna elements located at positions symmetric with respect to the central axis of the array, the steps of; supplying radio waves from the oscillator via the distributing means to an antenna element located at a position of the central axis of the array and a pair of antenna elements located at positions symmetric with respect to the central axis of the array, among the plurality of antenna elements; obtaining a directivity pattern formed by the antenna element and the pair of antenna elements from a distribution in a received power of the radio waves, received at the receiver via the signal input part, along a horizontal direction with respect to an array direction of the plurality of antenna elements, while changing a phase of each of the phase shifters connected to the pair of antenna elements in the same manner; and setting a value of the phase of each of the phase shifters in such a manner that a level of side lobes, which occur in the directivity pattern obtained, becomes a predetermined value.
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2. A phased array antenna, comprising:
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an oscillator that generates radio waves; a plurality of antenna elements; a plurality of phase shifters, each of which is connected to each of the plurality of antenna elements and changes a phase of radio waves radiated by the plurality of antenna elements; means for distributing radio waves generated by the oscillator to the plurality of antenna elements via the plurality of phase shifters; means for supplying radio waves from the oscillator via the distributing means to, among the plurality of antenna elements, an antenna element located at a position of the central axis of the array and a pair of antenna elements located at positions symmetric with respect to the central axis of the array, when a phase of the plurality of antenna elements are calibrated; a signal input part that inputs received signals outputted from a receiver that detects power of radio waves radiated by the plurality of antenna elements; and a calibrating unit configured to; calibrate a phase of each of the phase shifters for each pair of antenna elements located at a pair of positions symmetric with respect to a central axis of an array of the phased array antenna, among the plurality of antenna elements; and subsequently perform, with respect to an antenna element located at a position of the central axis of the array and all pairs of antenna elements located at positions symmetric with respect to the central axis of the array, a process to; supply, when a phase of the plurality of antenna elements are calibrated, radio waves from the oscillator via the distributing means to an antenna element located at a position of the central axis of the array and a pair of antenna elements located at positions symmetric with respect to the central axis of the array, among the plurality of antenna elements; obtain a directivity pattern formed by the antenna element and the pair of antenna elements from a distribution in a received power of the radio waves, received at the receiver via the signal input part, along a horizontal direction with respect to an array direction of the plurality of antenna elements, while changing a phase of each of the phase shifters connected to the pair of antenna elements in the same manner; and set a value of the phase of each of the phase shifters in such a manner that a level of side lobes, which occur in the directivity pattern obtained, becomes a predetermined value.
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Specification