*Article* **An 18.8–33.9 GHz, 2.26 mW Current-Reuse Injection-Locked Frequency Divider for Radar Sensor Applications**

**Kwang-Il Oh 1, Goo-Han Ko 1, Jeong-Geun Kim 2 and Donghyun Baek 1,\***


**Abstract:** An 18.8–33.9 GHz, 2.26 mW current-reuse (CR) injection-locked frequency divider (ILFD) for radar sensor applications is presented in this paper. A fourth-order resonator is designed using a transformer with a distributed inductor for wideband operating of the ILFD. The CR core is employed to reduce the power consumption compared to conventional cross-coupled pair ILFDs. The targeted input center frequency is 24 GHz for radar application. The self-oscillated frequency of the proposed CR-ILFD is 14.08 GHz. The input frequency locking range is from 18.8 to 33.8 GHz (57%) at an injection power of 0 dBm without a capacitor bank or varactors. The proposed CR-ILFD consumes 2.26 mW of power froma1V supply voltage. The entire die size is 0.75 mm × 0.45 mm. This CR-ILFD is implemented in a 65 nm complementary metal-oxide semiconductor (CMOS) technology.

**Keywords:** current-reuse; injection-locked frequency divider; radar sensor; wideband

**Citation:** Oh, K.-I.; Ko, G.-H.; Kim, J.-G.; Baek, D. An 18.8–33.9 GHz, 2.26 mW Current-Reuse Injection-Locked Frequency Divider for Radar Sensor Applications. *Sensors* **2021**, *21*, 2551. https:// doi.org/10.3390/s21072551

Academic Editor: Federico Alimenti

Received: 17 February 2021 Accepted: 2 April 2021 Published: 6 April 2021

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