0.13 K NETD D-Band CMOS Passive Imager With Noise Suppression Analysis

This article presents a new system design and in-depth analysis of a wideband, low-power passive imaging receiver based on a Dicke-switch architecture, implemented in 28 nm CMOS technology. The proposed structure employs a three-coil gm-boosting technique for the low-noise amplifier (LNA). This approach reduces the LNA’s noise figure (NF) and expands the input matching bandwidth (BW). Furthermore, it allows for the co-design of a three-coil transformer Dicke switch with low insertion loss, ultimately lowering the system’s total NF. Recognizing the critical role of Dicke switches and chopper modulation in radiometric systems, this work investigates and compares two distinct chopper configurations and evaluates their effectiveness in flicker noise suppression. A combination of theoretical analysis, circuit-level simulations, and measurement results (for one of the configurations) is used to assess the noise performance of the architecture. The analysis quantifies the critical impact of the chopper clock’s duty cycle on the noise suppression. Additionally, the effect of mismatch between the signal and reference paths is also analyzed in detail. The proposed receiver demonstrates a noise equivalent temperature difference (NETD) of 0.13 K, making it well suited for high-resolution passive imaging applications. To the best of the authors’ knowledge, this is the first reported Dicke-switch-based passive imager that provides quantitative analysis and validation of noise suppression. The receiver achieves a measured noise suppression of 21 dB, with a noise equivalent power (NEP) of 13.96 fW/$\surd $Hz, a peak responsivity of 2.1 MV/W, a 3-dB BW of 30 GHz, and a total power consumption of 28.4 mW.