Millimeter-wave (mm-Wave) technology is a promising solution to meet ever-increasing demand in wireless data transmission capacity thanks to the availability of large bandwidths at mm-Wave frequencies, where the choice of dielectric materials is one of important issues because the high water absorption at mm-Wave frequencies restricts remarkably the choice. Liquid crystal polymer (LCP) is one of materials available for mm-Wave applications and is able to provide cost-effective solution. In this paper, features of LCP will be introduced for applications at V-band (60 GHz) and E-band (70 GHz, 80 GHz) in terms of dielectric constant, feasible structure, process and reliability. Some LCP-based devices such as transmission line, mode transition between different transmission-lines, antenna and filter will be reviewed. It is demonstrated that LCP-based devices actually have shown good performance and LCP is especially suitable for consumer applications that require high reliability and cost-effectiveness.
This paper describes the application of organic photonic devices including organic light-emitting and photodetector devices to integrated photonic devices for the realization of flexible optical link and sensor devices. Fundamentals and future prospects in printed optoelectronic devices for high-speed modulation are discussed and reviewed.
This paper presents flexible electronics with a bio-compatible material interface for bio-signal monitoring applications. Organic thin-film transistors (TFT) are integrated with the bio-compatible gel interface in a 1.2-µm-thick film substrate. An electrocardiogram (ECG) of a rat is amplified by an organic TFT amplifier circuit that is mounted directly on the surface of the heart. In addition to the flexible electronics implantation, an implantable wireless sensor is introduced in this report. Integration between the flexible organic electronics and the silicon devices produces a promising technology for next-generation internet-of-things (IoT) sensors.
A high efficiency frequency doubler is realized based on a single embedded gate (EG) graphene field effect transistor (GFET) with natural Al oxidation dielectrics. Due to elimination of the step of depositing gate dielectrics, the fabrication process of the EG-GFET is improved compared to conventional EG-GFETs. The capacitive efficiency of the EG-GFET is improved up to 80 times compared to the conventional silicon back gate (BG) GFET with 300 nm thick SiO2, which is higher than that of most conventional EG-GFETs. Thanks to the high capacitive efficiency, the conversion gain of the frequency doubler is 14 times higher than that of the BG-GFET based frequency doubler.
A reconfigurable U-shaped tunnel field-effect transistor (RUTFET) is proposed as a low-power dynamically programmable logic device. It has several advantages over conventional reconfigurable TFETs: 1) Excellent scalability without any degradation of subthreshold swing (SS) and drain-induced barrier thinning (DIBT) with recessed channel structure. 2) High current drivability with increased band-to-band tunneling junction 3) Scaling of SS with tunneling barrier width defined by geometrical parameters. In this manuscript, its electrical characteristics are examined by technology computer-aided design (TCAD) simulation. It shows ∼30× higher ON-state current than control devices and 41.8 mV/dec-SS during drain current increase by five orders magnitude. The reconfigurable operations for n- and p-type FETs are also discussed.
This paper presents a force touch technology that uses strain gauge sensors for next-generation 3D touch screens. We developed a force measurement module using strain gauges, and configured a system that was identifiable according to touch pressure, and tested the force measurement module. We found that the thickness of the base pad in the force measurement module is very important for touch sensitivity, and carried out thickness optimization of the base pad. We successfully conducted an experiment to display touch signals on a screen with various touch pressure and multi-touch testing. This study confirmed the possibility of applying to the force touch screen using the force measurement module.
A number of critical load applications depend on a UPS system to uphold the normal operation. As soon as any disruption happens on the utility, an off-line UPS system starts supplying the power to the load to prevent blackout. Nonetheless, during this process, a substantial inrush current can be observed for the transformer-coupled loads. To avoid this inrush current, we propose an off-line UPS system based on a current regulated voltage source inverter. The inverter of the proposed UPS system uses a current control scheme executed in a stationary frame to regulate the load current and eliminates the likelihood of the inrush current. To endorse the performance of the proposed UPS system, we constructed a small prototype to obtain the experimental results.
Based on the self-biased current-reuse complementary structure and interposed network, a low power LC voltage controlled oscillator (VCO) is presented, which can simultaneously achieve ultra-low power consumption and low phase noise. Firstly, thanks to the self-biased voltage-diving technique, the LC-VCO consumes ultra-low power consumption. Secondly, the novel interposed network can greatly improve the VCO’s phase noise performance. The proposed VCO is implemented in SMIC 180 nm CMOS process with a small area of 0.15 mm2, which exhibits phase noise of −118.3 dBc/Hz at 1 MHz offset from the 2.5 GHz carrier at 0.8 V supply voltage while the power dissipation is only 0.23 mW.
A double-sampling highpass delta-sigma modulator (HPDSM) with inherent frequency translation is presented. The switched-capacitor highpass filter with double-sampling not only minimizes the number of capacitors required in the feedback network but also enables chopper stabilization which makes the modulator immune to 1/f noise and DC offset. A first-order prototype HPDSM with 3 bit quantization is fabricated in 0.35 um CMOS process, and the measurement shows 56.2 dB SNR. The total power consumption is 0.65 mW, and the active die area is 0.5 mm2. The proposed HPDSM can be useful in low-frequency applications such as hall-effect sensors or body area sensor network.
This work presents an electrocardiogram (ECG) compression processor for wireless sensors with configurable data lossless and lossy compression. Lifting wavelet transforms of 9/7-M and 5/3 are employed for signal decomposition instead of traditional wavelet. A hybrid encoding scheme improves compression efficiency by encoding the higher scales of decomposed coefficients with modified embedded zero-tree wavelet (EZW) and the lowest scale with Huffman encoding. Besides, a transposable register matrix for coefficients buffering during EZW encoding lowers the processing frequency without extra register resource. Implemented in SMIC 40 nm CMOS process, the processor only takes a total gate count of 10.8 K with 92 nW power consumption under 0.5 V voltage and achieves a compression ratio of 2.71 for lossless compression and 14.9 for lossy compression with PRD of 0.39%.
This paper proposes an efficient modulation in high-speed inter-chip data communication with inductive-coupling wireless connection for 3D-stacked system in package (SiP). In this modulation, signal is generated only in one polarity of the digital signal transmission. Compared with BPM and NRZ modulation, it has a 50% power reduction and better crosstalk immunity.
Special attention should be paid during the development of the driver circuitries for miniature spectrometers when using them in extreme environments, especially when the ambient temperature changes tremendously. In this study, a driver circuitry for a miniature spectrometer is developed by providing a basic control signal and ADC circuitry. Meanwhile, temperature stability and power consumption are considered. The performance of the driver circuitry is evaluated comprehensively from −50°C to 30°C. The lower boundary is below the operating range of most electronic parts adopted. Based on these examinations, temperature dependence, linearity and conversion accuracy of the ADC circuitry are quantified. And a correction algorithm is developed to correct any deviation in the driver circuitry with an uncertainty of around ±20 Counts. The practicality of the driver circuitry is also identified. This approach provides a general framework for developing driver circuitry for miniature spectrometers which will face tremendous variations in the ambient temperature.
A novel UWB-MIMO antenna with high isolation is presented. The proposed antenna consists of two identical UWB elements. Each antenna element is evolved from the off-center-fed patch antenna and its operating frequency band covers the ultra-wideband. The modified ground, as part of the antenna radiator, can improve isolation by propagating through the restraining surface. In addition, the ground stub between the two elements, changes the surface current distribution, makes the surface current truncated and drawn, and obviously reduces the coupling between the ports, so that the antenna always has good isolation in the UWB. The miniaturized MIMO antenna with a size of only 30 × 40 mm2 and measured mutual coupling lower than −18 dB, covers the 3.1–10.6 GHz UWB band, suitable for UWB wireless communication system.
This work presents a monolithic DC∼4 GHz 6-bit digital attenuator with low insertion phase shift and attenuation error. Based on GaAs E/D pHEMT process, a serial-to-parallel converter is introduced to decrease the control pads of the chip. In the 16 dB attenuation bit, a switched-path-type topology is employed in order to extend the bandwidth and achieve low insertion phase shift. The attenuator has 0.5 dB resolution and 0∼31.5 dB attenuation range. Measurement shows less-than-2.3 dB insertion loss at reference state, and larger-than-14 dB return loss at all states. An rms attenuation error of less-than-0.3 dB and phase-shift-variations less than 2 deg are achieved. The size of the chip is 2.0 mm × 1.7 mm.
Clock tree design plays a critical role in improving chip performance and affecting power. In this paper, we propose a novel symmetrical clock tree synthesis algorithm, including tree architecture planning, matching, merging, embedding and buffer insertion. Obstacle-aware placement and routing are also integrated into the algorithm flow. By using NGSPICE simulation for benchmark circuits, our skew results decrease by 17.2% while using less than 24.5% capacitance resource compared with traditional symmetrical clock tree. Further, we also validated the algorithm in ASIC design.
In this paper, a high effective demodulate algorithm based on tunable four-channel DFB (Distributed Feedback) laser array is proposed. In comparison with common algorithms which can work correctly when tunable laser have to be rapidly tuned through FBG’s (Fiber Bragg Grating) whole spectrum, the algorithm is unique in that accurate demodulation can be done by scanning only 0.4 nm bandwidth of FBG’s reflected spectrum and the scanned spectrum can be any part of the whole FBG spectrum including those regions with relatively low power. Therefore, the laser tuning time and response time of demodulation system is much more reduced which is important for most applications that need dynamic, real-time measurements. Wavelength-division multiplexing for FBG sensing network will be supported by the demodulating system and algorithm. Based on strain experiments of the FBG sensing system, excellent demodulation accuracy were demonstrated by the proposed algorithm.