X-band ftequency generator including CHIRP modulator with phase shift for array antennas in short distance radar.

In the use of short distance FMCW radar for military applications, it is needed that the detecting signal is larger than disturbance from the environment and noise produced by the radar itself. One way to increase the detection possibilities of the radar is to increase the antenna gain, G, in the desired direction. This can he done in phased array antennas by controlling the phase and amplitude in each sending element. There are dilXcnlties to find components with qualified functions as signal generation in the X-band frequency range compared to lower frequencies. There is less components available and they are much more expensive. In this work we have shown that an X-band generator including CHIRP modulator with phase shift can be realized by using low cost commercial components. Qualified functions are realized at relatively low frequencies (less than 3 GHz) and the signal is multiplied and modulated to the desired frequency. This is the first step towards realizing a transmitter, with phase shift realized by a DDS, for phased array antennas.