Jianglin Du

• Doctor of Philosophy
• PhD at University College Dublin

Over the past two decades, all-digital techniques for RF frequency synthesis have gained significant interest. In this chapter, we will review the all-digital phase-locked loop (ADPLL) architecture (also known as the phase-domain ADPLL and retrospectively classified as the counter-based ADPLL) followed by new techniques that help push the jitter pe...

This article proposes a mm-wave fractional-N ADPLL employing a reference-waveform oversampling (ROS) phase detector (PD) that increases its effective rate four times, consequently improving jitter at lower power consumption while using a low-frequency reference of 50 MHz. The passive over-sampling PD utilizes a zero-forcing technique for voltage-do...

In this article, we propose a digital-to-time conversion technique operating entirely in the sinusoidal waveform voltage domain of a crystal oscillator (XO) before the signal’s final slicing into the time domain of a programmably delayed clock. Precise timing delay is obtained simply by adjusting the dc offset of the sine signal. A low-complexity s...

In this article, we present a low phase noise (PN) mm-wave quadrature digitally controlled oscillator (DCO) exploiting transformers for class-F operation and harmonic extraction. A third transformer coil is added for the inter-core coupling with the source terminals of the switching transistors. We identify that the inter-core coupling in quadratur...

We introduce a new mode of oscillation in an LC -tank: an inverse class-F <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">23</sub> . In contrast to the conventional class-F oscillators, in which a high value of the real impedance (i.e., resistance) is presented to the third (in class-F <sub xmlns:mml...

This paper presents a millimeter-wave (mmW) frequency synthesizer based on a new charge-sharing locking (CSL) technique. A charge-preset capacitor is introduced for charge sharing with a resonant LC-tank for phase correction, while the resulting charge residue on the sharing capacitor is processed by a digital frequency-tracking loop (FTL) against...

This article presents a wide-band suppression technique of flicker phase noise (PN) by means of a gate-drain phase shift in a transformer-based complementary oscillator. We identify that after naturally canceling its second-harmonic voltage by the complementary operation itself, third-harmonic current entering the capacitive path is now the main ca...

This letter proposes a mm-wave fractional-N reference-oversampling (ROS) ADPLL for 5G applications utilizing a relatively low but standard reference frequency. The 4× ROS phase detector (PD) increases the phase detection rate 4× in a power-efficient manner in order to reduce the in-band phase noise contributed from the PD. This improves the overall...

Transient features of graphene oxide (GO), graphene oxide nanoribbon (GOR) and graphene quantum dot (GQD) have been investigated by femtosecond transient absorption (TA) spectroscopy. It is found that for pristine GO and HNO3-/NaOH-treated GO, a hybrid sp²/sp³ state at about 430 nm (∼2.88 eV) always appears. However, this hybrid state becomes less...

This article presents a low-power fractional-N all-digital phase-locked loop (ADPLL) employing a reference-waveform oversampling (ROS) phase detector (PD) that increases its effective rate four times, thus leading to lower jitter and settling time. The proposed ROS-PD adopts a bottom-plate sampling with a voltage zero-forcing technique, which yield...

This paper proposes a mm-wave all-digital PLL (ADPLL) employing a 4×reference oversampling (ROS) phase detector (PD). The fractional-N operation is assisted by two capacitive DACs embedded in the ROS-PD. Exploiting the benefits of all-digital implementation, differential/offset mismatches can be compensated by CDAC and zeroed out through a 4-tap mo...

This paper demonstrates a digitally friendly time-based analog-to-digital converter (ADC) exploiting Dickson charge-pump (CP) as part of a voltage-to-time conversion (VTC) implemented in 28-nm CMOS. In the proposed technique, the Dickson CP generates a ramp signal that is compared with the input voltage to generate a pulse of commensurable widths,...

We present a new analog-to-digital converter (ADC)-based architecture of a phase-tracking receiver (PT-RX) optimized for ultra-low-power (ULP) and ultra-low-voltage (ULV) operations for the Internet of Things (IoT). The RX employs a type-II loop configuration that offers improved stability compared with the previous type-I PT-RX solutions. In addit...

The letter presents a triple-8-shaped transformer-based complementary oscillator. It features tiny area, wide tuning range, electromagnetic compatibility (EMC), and low flicker phase noise (PN), combining the merits of both LC-tank and ring oscillators. We identify that after suppressing the 2nd harmonic voltage by the complementary operation itsel...

We present a sub-mW ultra-low-voltage (ULV) digitally controlled oscillator (DCO) in which all electronic devices (amplifying transistors and switched-capacitor banks) are vertically embedded within the inductor coils. A special arrangement of a native layer (NTN) diminishes any adverse effects on the inductors. To suppress flicker noise upconversi...

We have prepared random lasers with conjugated polymer(MEH-PPV) coated on TiO2 nanoparticle films. The threshold of the lasing based on random TiO2 nanoparticle film is significantly reduced by a factor of 9 in comparison with the amplified spontaneous emission(ASE) threshold of the flat MEH-PPV film, which is caused by multiple scattering induced...

Graphene quantum dots (GQDs) with a variety of functional groups are studied with adjusting the pH of the solvents and reducing by chemical methods. Our study suggests that the -CO-OH and -CO-N(CH3)2 groups could contribute to the green fluorescent emission (peak at 500-520 nm), and -CO-N(CH3)2 group could form the green fluorescent emission state...

Solution-processed thin-film solar cells based on aqueous nanocrystals (NCs) are attractive due to their environmental friendliness and cost effectiveness. Furthermore, nanoscale heterostructures can be formed upon annealing which is beneficial for prolonged carrier lifetime and effective carrier transport. Herein, we demonstrate that the carrier d...

The emitting properties of fluorophores can be tailored by surface plasmon polaritons (SPPs), which offers the potential to understand the light-matter interactions at the nanoscale, and lays the groundwork for many future applications. As one of the useful features in SPPs—surface plasmon-coupled emission (SPCE) based on the metal gratings; howeve...

A universal route to GQDs is developed based on “solution phase-based scissor” methods. The PL center of the GQDs is systematically studied and is proved to be the surface state, which is formed by the hybridization structure of edge groups and the connected partial graphene core. Through experiment and analysis, it preliminarily proves the efficie...

The understanding of strong coupling between local restricted electromagnetic field of cavity and surface-plasmon (SP) on the metal surface lays the groundwork for many photonic applications. However, much of the fundamental photophysical properties underlying this performance such as how this strong coupling is induced by these two components, nam...