77 GHz waveform generator with multiple frequency shift keying modulation for multi-target detection automotive radar applications

A waveform generator for a 77 GHz automotive radar that uses multiple frequency shift keying (MFSK) modulation is presented. The use of this modulation can improve the detection ability of radar applications in multi-target situations. The proposed generator consists of a conventional 77 GHz Σ-Δ fractional-N synthesiser and MFSK modulation control logic (MMCL). The key innovation is the introduction of the MMCL, which has the ability to track the linear frequency increase while generating the frequency shift keying in each time step. Prior to realising the hardware implementation, a behavioural simulation was evaluated. In addition, a 77 GHz generator module was designed using 130 nm CMOS technology. In a chirp time of 6 ms, there were a total of 128 modulation steps. The bandwidth and frequency step of the chirp were 100 MHz and 300 kHz, respectively.