| 摘要 |
<p>An antenna cell system 10, or a method of signal tracking using such an antenna cell system, comprises: receiving input signals at, at least two, respective antenna cell elements 12, 14; generating an output signal from the respective antenna cell elements 12, 14 and tracking the phase of the input signal of at least one of said antenna cell elements 14 using a phase-locked-loop PLL circuit. The output signal from the other antenna cell element 12 is provided as a reference to the PLL. The system 10 allows the PLL to track phase changes as a result of relative movement between a source and a receiver, and to compensate for phase differences caused by the spacing between the respective antenna elements of the phased array. The system 10 may include a summation circuit combining device 24 to combine the respective output signals from each antenna cell. The PLL may generate an output control signal that is indicative of the difference in phase between the reference input signal and an input received signal using a variable frequency oscillator 40 and a signal mixing device 44 with a frequency down converter. The system 10 may include transmitter and receiver circuitry to effect retro-directive signal transmission.</p> |
