In this study, one kind of novel co-designed defected ground structure (DGS) filter with slot antenna is proposed to realize bandpass reflection coefficient and gain performance. This antenna consists of two parts: 1) a 50 Ω feeding line and 2) a modified stepped slot with additional narrow slot and defected ground structure. The extra narrow slot, which can effectively prolong the current path of low frequency and generate reflection zero, is introduced to improve the lower band-edge selectivity. DGS is used to improve the upper band-edge selectivity, which can produce transmission zeros in certain frequencies and provides excellent stopband characteristics. In addition, the modified stepped slot with DGS can produce additional resonance frequency, which is helpful to improve the in-band impedance characteristics and radiation efficiency of the antenna. Measured results show that not only the band-edge selectivity of the antenna is improved, but also the in-band impedance matching and radiation efficiency are improved. The experimental results show that the proposed design could be a good candidate for UWB applications.
As the mainstream technology of the next generation chip design, to ensure the information security of three dimensional integrated circuits (3DIC) is very necessary, however, the existing hardware security technology is still not suitable for 3DIC’s unique stack structure and interconnection technology. This paper proposes a novel Physical Unclonable Functions (PUF) circuit technology based on 3DIC. The new scheme exploits the process variation of both CMOS devices and TSVs (Through Silicon Vias) available on TSV-based 3DIC, for secure data generation resistant to physical attacks. In the six layers of the 3DIC, the TSV-based ring oscillator PUF Circuit and independent arbiter PUF circuit are designed. The TSV is introduced as additional sources of process variation, and the same 100 3DIC-PUF chips are simulated through HSPICE under the process variation pre-set. The simulation results show that the TSV-based PUF circuit has good unique and reliability, and can be directly applied to the field of 3DIC security authentication.
Single-phase three-level grid-connected inverter is widely used in high-voltage applications, which can be connected to the grid through a single inductor (L filter) or an LCL filter. The control schemes for an LCL-based grid-connected inverter are more complex than those for an L-based one to damp the resonance of the LCL filter. In this paper, a robust nonlinear direct adaptive fuzzy control scheme is proposed to control both the L- and LCL-based inverters. The principle of the inverter is introduced, especially the space vector pulse width modulation method for the single-phase three-level inverters. Then, the theory of the direct adaptive fuzzy control is described. Based on the theory, the current controller for both types of grid-connected inverters is designed. The closed-loop stability is proved based on the Lyapunov theory. Finally, simulations are conducted to verify the effectiveness of the controller. The results show that both the L- and LCL-based grid-connected inverters operate well with strong robustness under the same controller.
This study aims to propose a method for adjusting loss peak in the spectrum of long period fiber grating fabricated with CO2 laser by applying tension with some weight to make the loss peak suitable for a multi-point temperature sensor under a high temperature environment. This method could achieve an increase of 5.3 dB in the value of loss peak by loading the fiber with a weight of 150 g. Furthermore, it was found that the method had a minimal influence on the temperature sensitivity of the long period fiber grating in the range varying from room temperature to 800°C.
We used ab initio calculations to clarify the atomistic origin of memory state switching in SiN based ReRAMs. The results of our calculations indicate that a N vacancy with a H atom acts as the high resistance state (HRS) and a N vacancy without a H atom is low resistive state (LRS). Moreover, we find that HRS and LRS can be switched by charge injection and removal. These results indicate that having N vacancies in the SiN layer can enable SiN based ReRAMs with high program/erace cycle endurance.
The aging effect due to the electromigration (EM) may result in faulty Through-silicon vias (TSVs) and affect the three-dimensional integrated circuits (3D ICs) lifetime. To design a flexible and efficient structure, in this paper, we enhance the region-based design for latent TSV faults, which can adjust the size of the TSV block and TSV redundancy. Experimental results demonstrate that the design can achieve 11.27% and 20.79% reduction of additional delay overhead as compared with router-based design and ring-based scheme, respectively. More importantly, when the target year is 3 years, the design can achieve above 99% reparability for all sizes of TSV blocks. After a given 5-year lifetime, the reparability of the proposed region-based design can still achieve 99% reparability when the TSV size is lower than 16 * 16, which is the best choice by considering RTSV area and delay overhead.
An integrated potentiostat designed for amperometric electrochemical sensors is presented in this paper. The analog input current is digitized using an A/D converter which employs a current-mode, first-order single-bit sigma-delta (ΣΔ) A/D architecture. Compared with traditional potentiostat, the new potentiostat topology consumes very low power, occupies a very small die area, and has potentially very low noise. These characteristics make the new topology very suitable for portable applications. The potentiostat circuit is implemented in a 0.18 um CMOS process. The circuit converts the sensor current to digital code and the results indicated that the potentiostat can measure the current as low as several nA, and the digital output has a good linearity.
The rapid pace of innovation in non-volatile memory technologies such as 3D Xpoint , NVDIMM , and zSSD  is set to transform how we build, deploy, and manage data service platforms. In particular, the emergence of a byte-addressable and persistent type of memory changes the landscape of the current storage architecture, consolidating different functionalities of memory and storage into a single layer . To take full advantage of this advanced technology, this letter presents a crash-resilient skip list (CRAST) which serves as an in-memory data management module in a key-value store to support crash-consistency from a system failure when running on non-volatile memory. By maintaining the persistent in-memory data in a consistent manner, the proposed skip list provides strong reliability and high performance simultaneously in modern data service platforms. We demonstrate the efficacy of CRAST by implementing its prototype in LevelDB. We experimentally show that CRAST provides excellent performance across various workloads, compared to the original key-value store without any compromise on reliability.
This paper presents an ultra-low temperature coefficient sub-threshold voltage reference, which is based on a novel compensation principle without using any resistors or operational amplifiers. Being implemented on a 0.18 µm standard CMOS process, the post-layout simulation results show that the proposed design achieves a minimum temperature coefficient (TC) of 2.1 ppm/°C over the temperature range of −40 °C to 100 °C with a 1.2 V supply voltage. This proposed design also shows the worst line regulation of 0.034%/V at room temperature, when the supply voltage varies from 1.2 V to 1.8 V. Due to the elimination of resistors and amplifiers, the circuit area is at least 91% less than existing designs.
A high-performance inductorless ring VCO with wide tuning range and extended monotonic tuning voltage range (MTVR) is proposed and fabricated in standard 0.18 µm CMOS technology. By combining the crossing-strength-tuning and load-resistance-tuning techniques with opposite tuning characteristics, the MTVR for the proposed VCO can be widened significantly. The dual-delay path technique is employed to improve the oscillating frequency. The cross-coupled pair is added to reduce phase noise and guarantee reliable differential-mode oscillation over the wide tuning voltage range. With an occupied area of 475 µm × 275 µm and a single supply voltage of 1.8 V, measurement results show the proposed VCO can oscillate with a frequency range from 1.57 to 2.76 GHz, phase noise of −91.12 dBc/Hz @ 1 MHz and FOMT of 164.5 dBc/Hz @ 1 MHz and extended MTVR.
A high linearity full differential 8 GSa/s track-and-hold amplifier (THA) is presented in this paper. The proposed THA is designed and implemented using 2-µm GaAs HBT technology to be targeted for faster operation in sampling systems at a clock frequency of GHz. In this THA, an alternative switch emitter follower (SEF) is used as a switching stage with a Schottky diode for hold-mode isolation enhancement and high-speed operation. In conjunction with well-designed input buffer allows us to achieve high linearity and comparable dynamic performance. Measured small signal −3 dB bandwidth, and hold-mode isolation are better than 3.6 GHz and 40 dB, respectively. The prototype achieves a spurious-free dynamic range (SFDR) of 43.9 dB at 0.5 GHz and an average total harmonic distortion (THD) below −40 dBc up to a first Nyquist frequency of 4 GHz. This work has the potential for wideband, high speed and low distortion analog to digital converter (ADC) used in the future direct sampling systems.
Wireless power transfer (WPT) systems can be used in various situations such as electric vehicles and electronic equipments. This paper developed a mobile WPT system with a LCCL resonance structure and a parameter configuration method to develop favorable transmission characteristics. Using the circuit equivalence principle, the formula for output power and transmission efficiency of the system was obtained. The system parameters were determined and the transmission characteristics of the system were analyzed by simulation. The experimental platform was built according to the determined parameters and was used to analyze the transmission characteristics of the system. The experimental results show that the developed system can acquire favorable transmission characteristics and provide an effective means for 1.5 kW WPT application.
This letter presents a pico-ampere level voltage reference with ultra-high performance of line regulation and power supply rejection ratio (PSRR) based on a self-regulation technique for Internet-of-Things (IoT) systems. Post-layout simulation results show that it achieves a minimum temperature coefficient (TC) of 18.9 ppm/°C over the temperature range from 0 °C to 120 °C with a 1.2 V supply voltage. At 27 °C, its current consumption is 98 pA. The line regulation is 0.17 ppm/V over the supply voltage range from 1.2 V to 3.0 V and the PSRR is −72 dB@100 Hz.
This paper presents a Ku-band compact Wilkinson power divider (WPD). The proposed WPD is realized by a multi-tap inductor with shunt capacitors to achieve low insertion loss, broadband isolation while minimizing chip area. Occupying only 188 × 116 µm2, the proposed WPD achieves a measured insertion loss of less than 1 dB from 1 to 16 GHz. From 11 to 16 GHz, the measured isolation is better than 20 dB with input and output return losses higher than 16 and 21 dB, respectively.