| CPC G01S 3/48 (2013.01) [G01S 3/043 (2013.01)] | 23 Claims |

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1. A zero-balance phase measurement apparatus, comprising:
a first hybrid coupler comprising a first input port configured to receive a first radio frequency (RF) signal from a first receiving element, and first and second output ports, the second output port generating a 90-degree phase shift relative to the first output port; and
a second hybrid coupler comprising a second input port configured to receive an RF signal from a second receiving element, and third and fourth output ports, the fourth output port generating a 90-degree phase shift relative to the third output port,
wherein the first output port is coupled to a first input of a first phase detector, the second output port is coupled to a second input of a second phase detector, the third output port is coupled to a first input of the second phase detector, and the fourth output port is coupled to a second input of the first phase detector, and
wherein the zero-balance phase measurement apparatus is configured to generate a zero-balance phase output signal as a function of first and second phase difference signals generated by the first and second phase detectors, respectively, the first phase difference signal being indicative of a phase difference between respective signals at the first and second inputs of the first phase detector, and the second phase difference signal being indicative of a phase difference between respective signals at the first and second inputs of the second phase detector.
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