We present a low phase noise four-core triple-band voltage controlled-oscillator (VCO) with reconfigurable oscillator cores and multi-mode resonator. By activation/deactivation of oscillator cores and change of resonator impedance in three modes of operations, the proposed VCO provides complete freedom in selecting the resonance frequency for three operation bands in the mm-wave range. Compared to VCOs using switch-capacitor-bank for multi-band operation, the proposed VCO does not use any series switches with passive components in the resonator to provide a low phase noise in all three bands of operation. As a proof of concept, the proposed four-core triple-band VCO is implemented in a 65 nm CMOS process using four class-D oscillators with tail switches and a compact high-Q triple-mode resonator. The VCO oscillation frequencies center at 19, 28, and 38 GHz while providing good phase noise and low power consumption in all bands. Measured results show the total frequency tuning range (FTR) of 38.5% while the PN at 1MHz offset varies from -100.3 dBc/Hz to -106.06dBc/Hz resulting in an excellent FoMT of 199.8 dBc/Hz.
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This content will become publicly available on January 1, 2025
A Triple-Band, High DC-to-RF Efficiency, Multicore VCO With a Dual-Path Inductor and Mode-Switching Capacitor
This article introduces an innovative four-port dual-path inductor designed to deliver two distinct inductance values to the resonator of a voltage-controlled oscillator (VCO). The switching between the inductor’s two excitation modes, even and odd, is determined by the differential excitation’s input polarity, eliminating the need for a series switch. Thus, the inductor has a high-quality factor ( Q ) in both modes. The inductances in these modes can be independently set based on desired frequencies. This inductance change achieves coarse frequency tuning, while fine-tuning is realized by a conventional 2-bit capacitor bank with a small-size varactor. This inductor is well suited for designing multiband VCOs aimed at widely spaced operation frequency bands. Apart from the inductance change, a particular case of mode-switching capacitor is employed to extend to another frequency band in between the low and middle bands, achieving triple-band oscillation. As a result, this article presents two VCOs designed using the proposed inductor: one in class-D biasing in a 65-nm CMOS process and another with class-B biasing in a 180-nm BiCMOS process. Both VCOs successfully oscillate across three distinct frequency bands, centered at 19, 28, and 36 GHz, while maintaining outstanding phase noise and minimal power consumption. Measurement results show good match with simulation, resulting in a peak figure of merit (FoM) of 185.7 dBc/Hz at 18.5 GHz, and occupy 0.088- mm2 (250 × 350 μ m) area in both processes.
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- NSF-PAR ID:
- 10538242
- Publisher / Repository:
- IEEE Microwave Theory and Techniques Society
- Date Published:
- Journal Name:
- IEEE Transactions on Microwave Theory and Techniques
- ISSN:
- 0018-9480
- Page Range / eLocation ID:
- 1 to 11
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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