A direct digital synthesis based chirp radar transmitter in 0.13 µm SiGe technology

This paper presents an X-band direct digital synthesis (DDS) based chirp radar transmitter implemented in 0.13μm SiGe BiCMOS technology. The transmitter contains a quadrature DDS, two low-pass filters, an IF IQ modulator, a programmable gain amplifier (PGA), a RF mixer and a pre-amplifier. The DDSs, built with two digital-to-analog converters (DACs), generate two-channel IQ baseband chirp signals from 62MHz to 77MHz. The IQ chirp signals are filtered by two programmable 5th-order Butterworth filters before up-converted to the IF frequency with IQ modulators. The filtered IF signal is further up-converted to the desired radio frequency by an RF mixer. The proposed transmitter thus generates a chirp signal at 8.6GHz, consuming a total power of 333 mW from 2.2V and 1.5V power supplies.