A 2.48 GHz class-C voltage controlled oscillator (VCO) without any dynamic back bias circuit is presented. The VCO uses three-path high Q-factor inductor as the low loss resonator and class-C crosscoupled nMOSFET pairs for high dc/RF conversion efficiency and direct cross-coupled pMOSFET for dc current reuse. At the supply voltage of 1.2 V, the core power consumption is 0.24 mW. The phase noise of the VCO is −124 dBc/Hz and the VCO figure of merit is −197.0 dBc/Hz. The VCO was implemented in the TSMC standard 0.18 μm SiGe BiCMOS process and occupies a die area of 0.799 × 0.809 mm 2 .
This letter presents a 2.1 GHz Class-C quadrature voltage-controlled oscillator (QVCO) working on coupling two identical Class-C VCOs. The class-C oscillator is used to achieve the performance of low phase noise. The QVCO uses a varactor ring to generate quadrature phase and it was implemented using the TSMC 0.18 lm CMOS 1P6M process. The output phase noise of the QVCO is 2130.34 dBc/Hz at 1 MHz offset frequency from the output carrier frequency of 1.978 GHz; the quadrature phase error is 0.338 and the figure of merit is 2190.61 dBc/Hz. Total power consumption is 3.9 mW. Tuning range is about 422 MHz (19%) between 1.978 and 2.4 GHz, while the control voltage was tuned from 0 V to 2 V. The die area is 0.528 3 1.168 mm 2 .ABSTRACT: This article outlines the theory and design of a network analyzer using a dual-band six-port junction at 0.915 GHz and 2.45 GHz. The proposed six-port comprises a five-port junction and a directional coupler. Some significant advantages of this design are the low cost (one RF source, no IF source, and no phase detector), compactness, real-time operation, and simplicity in realization.
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