A 35 GHz mm-Wave Pulse Radar with Pulse Width Modulated by SDM Realizing Sub-mm Resolution for 3D Imaging System

This paper describes a novel fully integrated mm-wave pulse radar chip with pulse width modulated by sigma-delta modulation (SDM) realizing sub-millimeter resolution for 3D imaging system. The carrier frequency is 35 GHz. For pulse radar system, the distance resolution is highly related to the pulse width. In this paper, the pulse widths of transmitted signals are modulated by SDM. The proposed pulse radar is composed of 35 GHz transmitter and receiver. The pulse generator consists of a 35 GHz phase-locked loop (PLL), a delay-locked loop (DLL) and a SDM. The receiver consists of low noise amplifier (LNA), envelope detector and time to voltage converter with calibration. The transmitter circuit consumes 61 mW with 10 dBm output power and receiver circuits consume 21 mW with -91.5 dBm sensitivity. The chip is fabricated in 65 nm CMOS process, the measurement results show the proposed radar chip can realize 0.2 mm distance resolution.