Antenna system, calibration unit, and calibration method

An calibration unit comprising:

• a reference signal generator configured to generate a reference signal having high auto-correlation;
• a delay unit configured to delay the reference signal to generate delayed reference signals having delay amounts different from each other and to respectively output the reference signal and the delayed reference signals to transmission units, the transmission units respectively modulating input signals and output the modulated signals as output signals to the antenna elements;
• a calibration network configured to combines the output signals of the transmission units;
• and
• an analyzer configured to analyze a correlation between a signal obtained by demodulating a combined signal output from the calibration network and the reference signal to determine variations of timing, amplitude and a phase of the output signal of each transmission unit, and to notify the transmission units of determination results, wherein
• each transmission unit calibrates the timing, amplitude and phase of the output signal based on a corresponding determination result.

A calibration method comprising:

• generating a reference signal having high auto-correlation;
• delaying the reference signal to generate delayed reference signals having delay amounts different from each other;
• outputting the reference signal and the delayed reference signals to transmission units, respectively, the transmission units respectively modulating input signals and output the modulated signals as output signals to the antenna elements;
• combining the output signals of the transmission units to generate a combined signal;
• and
• analyzing a correlation between a signal obtained by demodulating the combined signal and the reference signal to determine variations of timing, amplitude and a phase of the output signal of each transmission unit;
• notifying the transmission units of determination results, wherein
• each transmission unit calibrates the timing, amplitude and phase of the output signal based on a corresponding determination result.