Search

To establish ubiquitous and energy-efficient wireless sensor networks (WSNs), short-range Internet of Things (IoT) devices require Bluetooth low energy (BLE) technology, which functions at 2.4 GHz. This study presents a novel approach as follows: a fully integrated all-digital phase-locked loop (ADPLL)-based Gaussian frequency shift keying (GFSK) modulator incorporating two-point modulation (TPM). The modulator aims to enhance the efficiency of BLE communication in these networks. The design includes a time-to-digital converter (TDC) with the following three key features to improve linearity and time resolution: fast settling time, low dropout regulators (LDOs) that adapt to process, voltage, and temperature (PVT) variations, and interpolation assisted by an analog-to-digital converter (ADC). It features a digital controlled oscillator (DCO) with two key enhancements as follows: ΔΣ modulator dithering and hierarchical capacitive banks, which expand the frequency tuning range and improve linearity, and an integrated, fast-converging least-mean-square (LMS) algorithm for DCO gain calibration, which ensures compliance with BLE 5.0 stable modulation index (SMI) requirements. Implemented in a 28 nm CMOS process, occupying an active area of 0.33 mm2, the modulator demonstrates a wide frequency tuning range of from 2.21 to 2.58 GHz, in-band phase noise of −102.1 dBc/Hz, and FSK error of 1.42% while consuming 1.6 mW. [ABSTRACT FROM AUTHOR]

This article comprehensively reviews and studies CMOS transformer tank voltage‐controlled oscillators (VCOs) designed to improve the frequency tuning range (FTR) and minimize phase noise (PN) across a broad frequency range, particularly for mm‐wave and fifth‐generation applications. The study focuses on enhancing the performance of the oscillators to meet the demanding requirements of these advanced applications. This study thoroughly investigates and compares various strategies to increase the FTR, minimize PN, and reduce power dissipation in transformer tank VCOs. The aim is to establish fundamental guidelines for implementing transformer‐based tank VCOs. The study comprehensively reviews and analyzes the overall architecture of transformer‐based tank VCOs, presenting a detailed examination of the methods employed to enhance VCO performance. Additionally, the study illustrates the impact of the coupling factor on the VCO's performance parameters, detailing and demonstrating the overall tank circuit quality factor (Q) and resonator coupling factor (κ). A thorough understanding of PN methodology and the limitations of FTR has led to the development of innovative architectures. These include transformer‐based capacitive feedback (FB) oscillators with resistively adjusted variable inductors, as well as class‐F and inverse class‐F VCOs. These novel architectures contribute significantly to the improvement of oscillator performance. [ABSTRACT FROM AUTHOR]

Summary: This paper presents more compatible three‐stage inverter‐based ring voltage controlled oscillators (VCOs) by modifying the current‐starved delay cell to oscillate with high tuning range. Unlike some ring structures in which extra transistors are used as current boosting to enhance the frequency tuning range, no extra elements are used in the proposed three‐stage VCOs for increasing the tuning range. Besides, a new method is introduced to couple two proposed ring VCOs for designing a six‐phase ring VCO. The coupling method can be generalized to some other ring VCOs to generate multiphase signals. The proposed circuits have wide frequency tuning ranges and show good noise performances. The proposed six‐phase VCO can oscillate from 1.62 GHz to 3.45 GHz, which illustrates 72.2% tuning range. The phase noise of the proposed VCO is −97.5 dBc/Hz at 1 MHz offset frequency. The circuit figure of merit is −181.5 dBc/Hz. The post‐layout simulation results of the proposed six‐phase VCO are provided based on the TSMC 0.18 μm CMOS process. [ABSTRACT FROM AUTHOR]

To establish ubiquitous and energy-efficient wireless sensor networks (WSNs), short-range Internet of Things (IoT) devices require Bluetooth low energy (BLE) technology, which functions at 2.4 GHz. This study presents a novel approach as follows: a fully integrated all-digital phase-locked loop (ADPLL)-based Gaussian frequency shift keying (GFSK) modulator incorporating two-point modulation (TPM). The modulator aims to enhance the efficiency of BLE communication in these networks. The design includes a time-to-digital converter (TDC) with the following three key features to improve linearity and time resolution: fast settling time, low dropout regulators (LDOs) that adapt to process, voltage, and temperature (PVT) variations, and interpolation assisted by an analog-to-digital converter (ADC). It features a digital controlled oscillator (DCO) with two key enhancements as follows: ΔΣ modulator dithering and hierarchical capacitive banks, which expand the frequency tuning range and improve linearity, and an integrated, fast-converging least-mean-square (LMS) algorithm for DCO gain calibration, which ensures compliance with BLE 5.0 stable modulation index (SMI) requirements. Implemented in a 28 nm CMOS process, occupying an active area of 0.33 mm2, the modulator demonstrates a wide frequency tuning range of from 2.21 to 2.58 GHz, in-band phase noise of −102.1 dBc/Hz, and FSK error of 1.42% while consuming 1.6 mW.

Copyright of Electronic Components & Materials is the property of Electronic Components & Materials and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This letter presents a fully-integrated 2-bit CMOS voltage-controlled oscillator (VCO) along with a 2-bit buffer, which delivers the highest RF output power among recently reported state-of-the-art to the best of the authors’ knowledge. The proposed 2-bit VCO is designed and fabricated in a $0.18-\mu \text{m}$ CMOS process with a die size of 1.2 mm $\times$ 1.2 mm, which covers four frequency bands of interest. Fine-tuning at each of the four frequency bands is also obtained by utilizing two varactors. The proposed 2-bit VCO delivers a single-ended output power of 6.5/6.8/10.6/12.5 dBm at 0.930/1.157/1.436/1.917 GHz, respectively. This 2-bit VCO can cover frequency ranges of 930–1005, 1046–1157, 1248–1436, and 1540–1917 MHz, thus providing a total frequency bandwidth of 751 MHz. The proposed 2-bit VCO at each frequency band demonstrates −99, −93, −90, and −86 dBc/Hz for phase noise, and −150, −150, −160, and −168 dBc/Hz for figure-of-merit (FOM), respectively. [ABSTRACT FROM AUTHOR]

This paper presents a wide tuning-range LC-tank voltage controlled oscillator (VCO). To perform large frequency tuning range, the proposed circuit topology uses a tunable active inductor (TAI) for the coarse frequency tuning, while the fine-tuning is controlled only by a MOS varactor. The TAI design is based on toggling varactor arrays by which four channels are able to be selected for multi-band applications. The proposed VCO is designed in 90-nm CMOS process. Simulation results show that the VCO can operate from 760 MHz to 4.370 GHz representing an FTR of 140.74%, with a tuning gain Kvco from 654 to 1882 MHz/V. The achieved phase noise is lower than − 105 dBc/Hz at an offset frequency of 1 MHz from the carrier tuned to 2.52 GHz. The VCO core circuit draws 3.3 mA from a 1V voltage supply and occupies a small active area of (45 × 37) μm2. The fully implemented VCO provides excellent performances such as attractive FOMA value of − 196 dBc/Hz. [ABSTRACT FROM AUTHOR]

Here, a new design of a variable micro electromechanical system (MEMS) capacitor is introduced to use in telecommunication systems. For the first time, an on‐chip MEMS component has been used in the substrate integrated waveguide (SIW) structures to avoid discrete and non‐integrated connection problems and high noise levels and affects the operating frequency of telecommunication systems. The behaviour of two capacitors with the fixed–fixed and supported membrane by special spiral arms is analysed and simulated using the finite element method. The MEMS bridges are implemented by a 6 μm gold layer and an air gap of 3 μm. It can be seen that using the new special arms, the movement of the membrane is more uniform than the clamped while the actuation voltage is up to 1.32 V and the tuning range of the capacitor is 29%. Then both the capacitors are placed on half‐mode SIW structure and the electromagnetic simulation is done. Finally, the results comparison shows that the frequency tuning range of the MEMS variable capacitor is more significant than the other. [ABSTRACT FROM AUTHOR]

This paper presents a quadrature-clock generator based on a novel low-power ring oscillator with a wide frequency tuning range and low temperature variations. The proposed ring oscillator consists of two differential delay cells with a new controllable capacitive load of an MOS transistor. The wide tuning range is achieved due to transistor utilization in different regions and considering its resistance not to narrow down the frequency range. Delay cells are biased with a minimum possible value of a proportion to absolute temperature current to decrease frequency variations to temperature while the power consumption is kept low. The validation of the proposed methods is proved by circuit analysis. Post-layout simulation results of the proposed clock generator in 180 nm CMOS technology are also presented. It exhibits a wide tuning range of 807 MHz to 2.66 GHz. The phase noise of the output signal is about − 1 1 1 dBc/Hz at 10 MHz offset frequency. Frequency changes less than 1 1 3. 0 6 ppm ∕ ∘ C in the temperature range of − 4 0 ∘ C– 1 0 0 ∘ C. The clock generator consumes 0.657 mW of power. Results show improvement in comparison to the previous works. [ABSTRACT FROM AUTHOR]

In this paper, we present a new architecture for implementation of millimeter-wave (mm-wave) and terahertz (THz) radiator arrays based on standing-wave properties. This structure is a continuous distributed coherent array that avoids lossy and parasitic coupling networks. Moreover, it can be scaled simply by extending the size of the structure and replicating the unit cell. The absence of coupling parasitics in addition to the unique characteristics of standing waves allows us to extend the tuning range without using varactors. The 0.34-THz four-element radiator array is designed and fabricated in a 130-nm SiGe BiCMOS process using microstrip transmission lines as the standing-wave mediums and on-chip patch antennas to radiate the desired fourth harmonic of the oscillation. The circuit was measured with no post processing or silicon lens and has 5.9% frequency tuning range (332.5–352.8 GHz) with less than 6-dB output power variation across the band. It consumes 425-mW power from 1.8-V supply and the radiated power is −10.5 dBm at center frequency with −98.2 dBc/Hz phase noise at 10-MHz offset frequency. [ABSTRACT FROM PUBLISHER]

A quasi‐lumped dual‐mode reconfigurable eight‐way filtering power divider (FPD) is presented. Two operating modes are one eight‐way tunable FPD and one all stopband filter (ASF) with high suppression. The measured eight‐way FPD can be tuned from 1.0 to 2.15 GHz, corresponding to the frequency tuning range (FTR) of 73%. The ASF is obtained by misaligning resonant frequencies of LC resonators and weakening their coupling. The proposed dual‐mode FPD has the advantage of wide FTR, compact size, high isolation, ultra‐wide isolation BW, and high suppression. [ABSTRACT FROM AUTHOR]

ABSTRACT This letter presents CMOS voltage controlled oscillator (VCO) circuit, as a part of Automatic Dependent Surveillance-Broadcast (ADS-B) transmitter, operating at the center frequency of 980 MHz, delivers highest output power with highest efficiency ever reported to the best of authors' knowledge. The 0.713 mm × 0.638 mm VCO chip fabricated using 0.18 μm CMOS technology exhibits the single-ended peak output power of 1.4 dBm and the differential peak output power of 4.4 dBm at the frequency of 1.097 GHz, with the frequency tuning range from 980 MHz to 1.1 GHz, and phase noise of −125 dBc/Hz at 1 MHz offset centered at the frequency of 980 MHz, consuming 48-mW power from 1.8-V supply, thus showing state-of-the-art performances. This promising result shows a path toward realizing high-power single-chip CMOS ADS-B transmitter. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:2437-2441, 2015 [ABSTRACT FROM AUTHOR]

In this paper, the operation of rotary traveling wave oscillators is analyzed, the general oscillation condition is derived, and analytical formula for the oscillator loss is presented. Based on this analysis, switched transmission line is employed to extend the output frequency tuning range. Post-layout simulation shows a frequency tuning range of 3.1 GHz in the vicinity of 30 GHz. The proposed half-quadrature VCO exhibits a phase noise better than −102.2 dBc/Hz at 1 MHz offset frequency. The VCO provides an output power level ranging from −6 to −2.5 dBm with drawing 15.2 mA of dc current from a 1.8 V power supply. [ABSTRACT FROM AUTHOR]

In this paper, a new class-C voltage-controlled oscillator (VCO) is presented. In the proposed VCO, the tail capacitor of the conventional class-C oscillator is dislocated from the source of the cross-coupled transistors to their gate to achieve a rail-to-rail output swing. This improves the phase noise by 2.9 dB compared to the conventional class-C one. Besides, a new switching scheme is presented in the switched capacitor bank used for coarse tuning of the proposed VCO to lower the on resistance of the switches as well as to reduce the parasitic capacitors. This wide tuning range class-C VCO is designed in a 0.18 μm CMOS technology. It achieves a -125.3 dBc/Hz phase noise at 1 MHz offset from a 2.2 GHz carrier frequency while covering a wide tuning range from 1.82 to 2.65 GHz and consuming 3.5 mW power from a single 0.9 V power supply. [ABSTRACT FROM AUTHOR]

In this article, a novel voltage-controlled oscillator (VCO) using the output matching network based on the novel harmonic control circuit is presented for reducing the phase noise without the reduction of the frequency tuning range. The phase noise suppression is achieved by the harmonic control circuit having the short impedances for the second- and third-harmonic components. The high-Q resonator has been used for reducing the phase noise but has the problem that the frequency tuning range has been also reduced by the increase of the Q value of the resonator. However, the frequency tuning range of the proposed VCO has not been reduced because the phase noise has been reduced without the high-Q resonator. The microstrip square open loop multiple split ring resonator has been used with the proposed harmonic control circuit for better phase noise property. The phase noise of this VCO has been -127.5 to -126.33 dBc/Hz @ 100 kHz in the tuning range, 5.744–5.865 GHz. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1838–1842, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24510 [ABSTRACT FROM AUTHOR]

This study presents a voltage-controlled oscillator (VCO) in a cross-coupled pair configuration using a multi-tapped switched inductor with two switch-loaded transformers in 0.5 µm GaN technology. Two switch-loaded transformers are placed at the inner and outer portions of the multi-tapped inductor. All the switches are turned off to obtain the lowest sub-band. The outer transformer with three pairs of switches is turned on alternately to provide three sub-band modes. A pair of switches at the inner transformer provide a high-frequency band. Two switch-loaded transformers are turned on to provide the highest sub-band. Six modes are selected to provide a wide tuning range. The frequency tuning range (FTR) of the VCO is 27.8% from 3.81 GHz to 8.04 GHz with a varactor voltage from 13 V to 22 V. At a 1 MHz frequency offset from the carrier frequency of 4.27 GHz, the peak phase noise is −119.17 dBc/Hz. At a power supply of 12 V, the output power of the carrier at 4.27 GHz is 20.9 dBm. The figure of merit is −186.93 dB because the VCO exhibits a high output power, low phase noise, and wide FTR. To the best of the author's knowledge, the FTR in VCOs made of GaN-based high electron mobility transistors is the widest reported thus far. [ABSTRACT FROM AUTHOR]

By utilizing a differential tunable active inductor for the LC-tank, a wide tuning-range CMOS voltage-controlled oscillator (VCO) is presented. In the proposed circuit topology, the coarse frequency tuning is achieved by the tunable active inductor, while the fine tuning is controlled by the varactor. Using a 0.18-μm CMOS process, a prototype VCO is implemented for demonstration. The fabricated circuit provides an output frequency from 500 MHz to 3.0 GHz, resulting in a tuning range of 143% at radio frequencies. The measured phase noise is from -101 to -118 dBc/Hz at a 1-MHz offset within the entire frequency range. Due to the absence of the spiral inductors, the fully integrated VCO occupies an active area of 150 × 300 μm2. [ABSTRACT FROM AUTHOR]

A self-mixing wide tuning range voltage-controlled oscillator (VCO), using 0.35 \mum SiGe bipolar technology, is proposed in this work. The entire circuit consists of a VCO core, a mixer and an emitter coupled differential amplifier. The fundamental and second harmonic signals from the VCO core are used as LO and RF input signals for the mixer circuit, respectively. The mixing product at the third harmonic of the VCO core is selected and amplified, while the low frequency part of the mixing product is suppressed. The simulated harmonic suppression of the third harmonic over fundamental signal is higher than 18 dB. The VCO operates from 91 to 101 GHz with 10.6% tuning range. The measured phase noise at 3 MHz offset is lower than -83 dBc/Hz over the entire frequency band. The VCO occupies 700\,\times\,500 \mum^2 die area and consumes 185 mW under 3.5 V dc power supply. [ABSTRACT FROM PUBLISHER]

In this article, a K-band push-push Voltage Controlled Oscillator (VCO) is presented using a miniaturized hairpin resonator (MHR) with a higher loaded quality factor and the reduced circuit area within 50% compared to the conventional one at 9.2 GHz.The MHR combined with the GaAs MESFET varactor shows a tuning range of 140 MHz, and this voltage tunable MHR is used to compose a push-push VCO. It provides the frequency tuning range of 71 MHz with flatness of +0.13 dB, which is increased by 31 MHz compared to the conventional VCO. The voltage controlled push-push oscillator based on the series feedback topology is implemented on 0.54 mm-thick Teflon substrate with a dielectric constant of 2.54. The measurement shows the output power of 1.18 dBm, the fundamental signal power suppression of -33 dBc, and phase noise performance of -86.78 dBc/Hz at 100 kHz offset. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 699–701, 2010; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/mop.25007 [ABSTRACT FROM AUTHOR]

A new type of silicon-based differential stacked spiral inductor (DSSI) was proposed in this letter, which was successfully implemented in the design of a cross-coupled differential voltage-controlled oscillator (VCO). The samples of DSSI and VCO were fabricated using standard CMOS 0.18 mum process. Based on the two-port S-parameters measured using standard deembedding procedure, the self-resonance frequency (fsr ) and -factor of the new and conventional DSSIs, frequency tuning range and phase noise of two VCOs are characterized and compared. It is demonstrated that, due to the reduction of parasitic capacitance in the new DSSI, its fsr is increased significantly, and further resulting in the evident increase of frequency tuning range of the VCO with smaller on-chip area occupied, as compared to the other new VCO design. [ABSTRACT FROM PUBLISHER]

A fully integrated K-band balanced voltage controlled oscillator (VCO) is presented. The VCO is realized using a commercially available InGaP/GaAs heterojunction bipolar transistor (HBT) technology with an fT of 60 GHz and an fMAX of 110 GHz. To generate negative resistance at mm-wave frequencies, common base inductive feedback topology is used. The VCO provides an oscillation frequency from 21.90 GHz to 22.33 GHz. The frequency tuning range is about 430 MHz. The peak output power is -0.3 dBm. The phase noise is -108.2 dBc/Hz at 1 MHz offset at an operating frequency of 22.33 GHz. The chip area is 0.84×1.00 mm2. [ABSTRACT FROM PUBLISHER]