Method and system for propagation time measurement and calibration using mutual coupling in a radio frequency transmit/receive system

Abstract

A method and system use the mutual coupling property of multiple antenna elements for measuring differences in propagation time among various signal paths involving antenna elements in a radio frequency transmit / receive system. The method and system alleviate the need for external test equipment by using the same hardware used in standard operation of the transmit / receive system for performing propagation time measurement through the generation, mutual coupling, and acquisition of a specially selected reference signal. In an embodiment involving calibration of various signal paths to realize matched propagation times, the signal energy returned through these various paths during standard system operation arrives for acquisition more closely coincident in time, increasing the instantaneous bandwidth of the system.

Description

BACKGROUND OF THE INVENTION[0001]Emerging applications for radio frequency transmit / receive systems are demanding increased instantaneous bandwidth. Such applications include high-data-rate communications, low-probability-of-detection communications, simultaneous occupancy of radio frequency spectrum by multiple users, high-resolution imaging radar, low-probability-of-detection radar, wide-bandwidth electronic signals surveillance, and wide-bandwidth jamming of signals. In all these applications, it is essential for energy from the entire desired spectrum bandwidth to arrive at the receiver. In systems featuring multiple antenna elements associated with multiple signal paths in parallel, maximal energy transfer requires that the signals propagating through these multiple paths arrive at the receiver simultaneously, or as near simultaneously as possible. This does not necessarily occur naturally in a system, because various signal paths associated with various antenna elements may fe...

AI Technical Summary

Benefits of technology

The present invention is a method and system for measuring and calibrating the propagation time of signals in a radio frequency transmit / receive system. The invention takes advantage of the mutual coupling phenomenon, which is commonly observed in systems using ESA antennas and other systems. The invention uses a specially selected reference signal and a mutual coupling field to determine the difference in signal propagation time through various signal paths. This difference is measured without the need for dedicated external test equipment. The invention can calibrate the system by adjusting the propagation time of signals through one or more of the signal paths. The invention achieves improved instantaneous bandwidth performance and increased bandwidth energy transfer by calibrating the system to match the propagation time of the signal paths. The invention can be used in a radio frequency transmit / receive system with multiple antenna elements and can adjust the propagation time for signals through the system's signal paths.

Problems solved by technology

Moreover, propagation time measurement and calibration using these approaches have required additional circuitry that bypasses the normal operating signal paths and feeds signals specially between different portions of the system for measurement.

Such special bypassing and feeding leads to measurements for only a portion of the system signal paths, rather than for the entire lengths of the relevant operational signal paths, and so may leave unmeasured and uncalibrated those propagation time mismatches arising in other portions of the signal paths.

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