Abstract: An optical signal transmission apparatus (1) for a rotating antenna comprising a plurality of optical modulators (6) arranged for receiving a respective plurality of analog RF signals (5) and for modulating a respective plurality of optical signals therewith to produce a plurality of modulated analog optical signals (8). A plurality of opto-electrical converters (14) each converts a respective modulated analog optical signal (13) into an analog electrical signal. The plurality of optical modulators (6) are rotationally coupled in optical communication with the plurality of opto-electrical converters (14) via an optical rotary joint (10) including a reversion prism.

Abstract: An antenna sub-array for use in an antenna array having a plurality of such sub-arrays includes a stripline for signal distribution, the stripline defining a plurality of signal pathways from a common feed point to a plurality of radiating elements, wherein the stripline is housed in a first support structure located a distance away from a first surface of a ground plane structure.

Abstract: A method for calibrating an antenna system (1) including a antenna elements (3) connected to signal receiver units (4) at an RF signal input port thereof comprising, generating an RF calibration signal (62), applying the RF calibration signal to the RF signal input port of the signal receiver units without applying the calibration signal via the antenna elements (3). The response of the antenna system to the calibration signal is measured, and a signal correction is calculated according to the measured response. The signal correction is applied to the response of the antenna system to signals subsequently received at the signal receiver units via the antenna elements of the antenna system.

Abstract: An antenna comprising two or more substantially identical antenna sub-arrays (3A, 3B) each comprising a plurality of separate antenna radiating elements (6A, 6B) connected to a common radio frequency (RF) signal input/output port (4A, 4B). The separate antenna elements are connected to the RF signal input/output port via respective RF signal power dividers (8A, 8B). A variance in values of the power splitting ratio, and/or of the input RF signal reflectivity, and/or of the phase balance of corresponding signal power dividers of the two or more antenna sub-arrays is sufficient to provide a cancellation ratio exceeding 40 dB. Alternatively, the separate antenna elements are connected to the RF signal input/output port via respective transmission paths (7A, 7B) and a variance in values of the transmission path lengths of corresponding signal transmission paths of the two or more antenna sub-arrays is sufficient to provide a cancellation ratio exceeding 40 dB.

Abstract: An optical signal transmission apparatus (1) for a rotating antenna comprising a plurality of optical modulators (6) arranged for receiving a respective plurality of analogue RF signals (5) and for modulating a respective plurality of optical signals therewith to produce a plurality of modulated analogue optical signals (8). A plurality of opto-electrical converters (14) each converts a respective modulated analogue optical signal (13) into an analogue electrical signal. The plurality of optical modulators (6) are rotationally coupled in optical communication with the plurality of opto-electrical converters (14) via an optical rotary joint (10) including a reversion prism.

Abstract: Disclosed is antenna sub-array for use in an antenna array comprising a plurality of such sub-arrays, comprising: a stripline for signal distribution, the stripline defining a plurality of signal pathways from a common feed point to a plurality of radiating elements, wherein the stripline is housed in a first support structure located a distance away from a first surface of a ground plane structure.

Abstract: A method for calibrating an antenna system (1) including a antenna elements (3) connected to signal receiver units (4) at an RF signal input port thereof comprising, generating an RF calibration signal (62), applying the RF calibration signal to the RF signal input port of the signal receiver units without applying the calibration signal via the antenna elements (3). The response of the antenna system to the calibration signal is measured, and a signal correction is calculated according to the measured response. The signal correction is applied to the response of the antenna system to signals subsequently received at the signal receiver units via the antenna elements of the antenna system.

Abstract: An optical signal transmission apparatus (1) for a rotating antenna comprising a plurality of optical modulators (6) arranged for receiving a respective plurality of analogue RF signals (5) and for modulating a respective plurality of optical signals therewith to produce a plurality of modulated analogue optical signals (8). A plurality of opto-electrical converters (14) each converts a respective modulated analogue optical signal (13) into an analogue electrical signal. The plurality of optical modulators (6) are rotationally coupled in optical communication with the plurality of opto-electrical converters (14) via an optical rotary joint (10) including a reversion prism.

Abstract: The present invention relates to antenna calibration for active phased array antennas. Specifically, the present invention relates to a built-in apparatus for autonomous antenna calibration. Accordingly, the present invention provides an antenna array comprising: a plurality of antenna elements forming an array face and a plurality of calibration antennas mounted around the array face. The plurality of calibration antennas comprising one or more pairs. The calibration antennas have overlapping coverage areas such that the entire array face of the antenna array is within the coverage area of at least one calibration antenna and each pair of calibration antennas have overlapping coverage areas such that of a common area of the array face is within both coverage areas.

Abstract: The present invention relates to antenna calibration for active phased array antennas. Specifically, the present invention relates to a built in apparatus for autonomous antenna calibration Accordingly, the present invention provides a method of continuous on-line monitoring of each element in an array antenna comprising the steps of: (i) transmitting known test signals to one or more elements of the array antenna; (ii) monitoring responses of the elements to the test signals; and (iii)comparing the response with expected responses for the elements to determine an operation condition of the elements.

Abstract: The present invention relates to antenna calibration for active phased array antennas. Specifically, the present invention relates to a built in apparatus for autonomous antenna calibration Accordingly, the present invention provides a method of calibrating an antenna array comprising the steps of: (i) loading a set of correction coefficients for all or a portion of the antenna array; (ii) outputting a known test signal from all or a portion of the antenna array using said correction coefficients; (iii) measuring the performance of all or a portion of the antenna array using a plurality of calibration antennas; and (iv) generating a new set of correction coefficients to correct the performance of all or a portion of the antenna array.

Abstract: The present invention relates to antenna calibration for active phased array antennas. Specifically, the present invention relates to a built in apparatus for autonomous antenna calibration Accordingly, the present invention provides a method of self-calibration of a plurality of calibration antennas comprising the steps of: (i) selecting two calibration antennas to be calibrated that have a common area in range of both calibration antennas; (ii) selecting at least one radiating element within range of the two calibration antennas; (iii) transmitted a known test signal from the one or more selected radiating elements; (iv) measuring a received signal at each of the two calibration antennas; (v) comparing the received signals at each of the two calibration antennas; and (vi) determining a correction coefficient for each calibration antenna based on the received signals at the said calibration antennas.

Abstract: The present invention relates to antenna calibration for active phased array antennas. Specifically, the present invention relates to a built in apparatus for autonomous antenna calibration Accordingly, the present invention provides an antenna array comprising: a plurality of calibration antennas mounted around the array; wherein the calibration antennas have overlapping ranges such that the entire array face of the antenna array is within range of at least once calibration and each pair of calibration antennas is in range of a common area of the array face.

Abstract: The present invention relates to antenna calibration for active phased array antennas. Specifically, the present invention relates to a built in apparatus for autonomous antenna calibration Accordingly, the present invention provides a method of continuous on-line monitoring of each element in an array antenna comprising the steps of: (i) transmitting known test signals to one or more elements of the array antenna; (ii) monitoring responses of the elements to the test signals; and (iii)comparing the response with expected responses for the elements to determine an operation condition of the elements.

Abstract: The present invention relates to antenna calibration for active phased array antennas. Specifically, the present invention relates to a built in apparatus for autonomous antenna calibration Accordingly, the present invention provides a method of calibrating an antenna array comprising the steps of: (i) loading a set of correction coefficients for all or a portion of the antenna array; (ii) outputting a known test signal from all or a portion of the antenna array using said correction coefficients; (iii) measuring the performance of all or a portion of the antenna array using a plurality of calibration antennas; and (iv) generating a new set of correction coefficients to correct the performance of all or a portion of the antenna array.

Abstract: The present invention relates to antenna calibration for active phased array antennas. Specifically, the present invention relates to a built in apparatus for autonomous antenna calibration Accordingly, the present invention provides a method of self-calibration of a plurality of calibration antennas comprising the steps of: (i) selecting two calibration antennas to be calibrated that have a common area in range of both calibration antennas; (ii) selecting at least one radiating element within range of the two calibration antennas; (iii) transmitted a known test signal from the one or more selected radiating elements; (iv) measuring a received signal at each of the two calibration antennas; (v) comparing the received signals at each of the two calibration antennas; and (vi) determining a correction coefficient for each calibration antenna based on the received signals at the said calibration antennas.