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This article designs and analyzes LC injection-locked frequency dividers (ILFDs) using dual-resonance LC resonator. The ILFD consists of two single-resonance LC-tank capacitive cross-coupled sub-ILFDs operating at 3.7 and 5.1 GHz, respectively, and the two sub-ILFDs are coupled by the electric field through a pair of metal–insulator–metal (MIM) capacitors. The die area in the Taiwan Semiconductor Manufacturing Corporation (TSMC) 0.18- $\mu \text{m}$ CMOS is $0.65\times1.023$ mm2. By controlling the gate voltages of the switching transistors, the ILFD has three different operational modes—high-band dominant mode, low-band dominant mode, and concurrent oscillation mode. Overlapped locking range is demonstrated for the first time in the designed electric-field coupling resonator ILFD. Non-overlapped locking range is found for the ILFD manifesting an effect of the dual-resonance resonator. [ABSTRACT FROM AUTHOR]

This article presents and analyzes a wide-locking range divide-by-5 injection-locked frequency divider (ILFD) manufactured in the TSMC 0.18- $\mu \text{m}$ processes. The ILFD uses the balanced injection method and uses the pure harmonic mixing approach at low injection power, and it is designed with an RLC dual-resonance resonator. The harmonic mixer relies on the self-generated second harmonic, which increases with injection power. Because of no narrowband filter as used in the linear mixer counterpart, the divide-by-5 ILFD uses a wideband design method. In addition, the ILFD enhances the divide-by-5 locking range via the overlapped dual-band locking ranges as verified by both experiment and simulation. At the drain–source bias ${V} _{\text{DD}}$ of 0.8 V and at the incident power of 0 dBm, the locking range of the divide-by-5 ILFD is 3.6 GHz, from the incident frequency 13.0–16.6 GHz with the percentage 24.3%. The core power consumption is 4.09 mW, and the die area is $1.02\times0.93$ mm2. [ABSTRACT FROM AUTHOR]

This article designs and analyzes wide locking range (LR) high even-modulus LC-tank injection-locked frequency dividers (ILFDs) with current-reused topologies. The current-reused LC ILFD uses two stacked LC sub-ILFDs sharing the same dc current. The current-reused ILFD becomes a divide-by-4 ($\div 4$) ILFD, when both sub-ILFDs are used $\div 2$ ILFDs, and it is used as a divide-by-8 ($\div 8$) ILFD when one sub-ILFD is used a $\div 4$ ILFD. Both sub-ILFDs use nMOSFETs as linear injection mixers for high conversion gain. For the $\div 8$ LC ILFD designed in the TSMC 0.18- $\mu \text{m}$ CMOS process, the circuit uses one high-frequency $\div 4$ sub-ILFD and one low-frequency $\div 2$ sub-ILFD, at the supply of 1.6 V, and at the incident power of 0 dBm, the LR is 4 GHz (38.835%), from the incident frequency 8.3 to 12.3 GHz. The $\div 8$ ILFD core power consumption is 13.98 mW, and the die size is $1.2 \times 1.2$ mm2. Both the $\div 8$ LC ILFD and the $\div 4$ sub-ILFD have nonoverlapped and overlapped LRs, which are due to a dual-resonance resonator used in the varactor-free n-core sub-ILFD. The LC dual-resonance resonator is due to parasitic capacitors in active FETs and on-chip spiral inductors and inductive elements, and it is used to get wide overlapped LR. Two $\div 4$ LC ILFDs inherent in the designed circuit are also studied. [ABSTRACT FROM AUTHOR]

A varactorless divide-by-4 injection-locked frequency divider (ILFD) with LC resonator is designed. The ILFD uses the parasitic capacitors and the inductor architecture to construct a dual-resonance resonator. The ILFD has two locking ranges associated with the dual-resonance resonator. The locking range of the ÷4 ILFD is wider than conventional single-band ÷4 LC-tank ILFD because of overlapped locking ranges. The designed single-stage ÷4 ILFD was fabricated in the TSMC 0.18 μm 1P6M CMOS process. At the incident power of 0 dBm, the locking range is 6.6 GHz from 7.3 to 13.9 GHz at the power consumption of 5.59 mW. [ABSTRACT FROM AUTHOR]