Search Results (46)

This study presents a sample isolation bridge readout integrated circuit (ROIC) specifically designed for intracranial pressure (ICP) monitoring systems. The ROIC consists of an instrumentation amplifier (IA) and a successive approximation register (SAR) analog-to-digital converter (ADC). Additionally, the output of the IA is isolated to protect against output spikes that could compromise the linearity and stability of the ROIC. Both traditional and proposed ROIC circuits are fabricated using 0.18 µm complementary metal-oxide-semiconductor (CMOS) technology. The peak signal-to-noise ratio (SNR) for the traditional ROIC is 40.9 dB, while the peak signal-to-noise and distortion ratio (SNDR) is measured at 40.1 dB. In contrast, the proposed ROIC, which incorporates the SAR ADC, achieves a peak SNR of 54.6 dB and a peak SNDR of 51.8 dB, demonstrating a significant improvement in linearity. The new ROIC consumes 39.5 µA of current from a 1.8 V power supply and occupies a chip core area of only 0.27 mm². Full article

A new radio frequency (RF) probe using pogo pin tips for integrated chip (IC) measurement up to 50 GHz is proposed. It offers high durability due to the pogo pins and meets three key design criteria for general IC measurement: (1) a 45° tilted shape with a 70 μm tip protrusion for easy microscope inspection, (2) linear pogo pin alignment for commercial chip pad contact, and (3) a 250 μm pitch compatible with standard IC pad pitches. This design is distinct from traditional pogo pin probe cards which place pogo pins in vertical form, in a diagonal arrangement, and at wide intervals. The probe exhibits a low insertion loss of 1.6 dB at 45 GHz. A printed circuit board (PCB)-based calibration standard for the calibration of the designed probe is constructed, which is adjusted to inductance and capacitance values using a simulation to form the Vector Network Analyzer (VNA) calibration set. The measurements of a commercial amplifier IC using this probe show a nearly identical performance to commercial RF probes, confirming its accuracy and reliability. Full article

The implementation of quantum gates by means of microwave cryo-RFICs controlling qubits is a promising path toward scalable quantum processors. Quantum gate fidelity quantifies how well an actual quantum gate produces a quantum state close to the desired ideal one. Regrettably, the literature usually reports on quantum gate fidelity in a highly theoretical way, making it hard for RFIC designers to understand. This paper explains quantum gate fidelity by moving from Shannon’s concept of fidelity and proposing a detailed mathematical proof of a valuable integral formulation of quantum gate fidelity. Shannon’s information theory and the simple mathematics adopted for the proof are both expected to be in the background of electronics engineers. By using Shannon’s fidelity, this paper rationalizes the integral formulation of quantum gate fidelity. Because of the simple mathematics adopted, this paper also demystifies to electronics engineers how this integral formulation can be reduced to a more practical algebraic product matrix. This paper makes evident the practical utility of this matrix formulation by applying it to the specific examples of one- and two-qubit quantum gates. Moreover, this paper also compares mixed states, entanglement fidelity, and the error rate’s upper bound. Full article

The design of transformers, a key component of radio frequency integrated circuits (RFICs), is traditionally carried out through an iterative process involving extensive electromagnetic simulations. While process design kits (PDKs) offer tools based on interpolation or fitting equations to simplify parameter estimation, these tools are restricted to standard geometries, leaving designers to manually simulate and optimize custom designs. This approach is inefficient and resource intensive. This paper proposes an automated process to generate a database containing the physical and electrical parameters of a wide range of transformers. This database is part of a tool designed to efficiently identify the desired transformer. To evaluate the tool’s effectiveness in reducing the time required for design, a millimeter-wave (mm-Wave) 69.4–74.2 GHz differential low-noise amplifier (LNA) is designed using GlobalFoundries 45 nm silicon-on-insulator (SOI) technology. This circuit demonstrates a noise figure (NF) of 4.1 dB, a gain of 10.1 dB, an input third-order intercept point (IIP3) of −10.78 dBm, and a power consumption of 4.7 mW from a 0.406 V DC supply. Moreover, the simulated performance achieves these specifications within a highly compact area of 0.12 mm². The transformer selection process for the circuit takes only a few seconds, whereas the conventional method of manual transformer design and electromagnetic simulation would require a significantly greater amount of time. Full article

Wireless sensor networks often rely on battery power, which incurs high costs, considerable volume, and a limited lifespan. Additionally, the communication range of existing passive sensor tags remains short, which challenges their suitability for evolving Internet of Things (IoT) applications. This paper, therefore, presents a long-distance passive RFID sensing tag that integrates multi-source energy harvesting and reflection amplification. Multi-source energy harvesting enhances tag receiving sensitivity and extends the system’s downlink communication distance, while reflection amplification increases tag reflection power and improves the uplink communication distance, thereby significantly expanding the overall communication range. The test results show that the tag achieves a receiving sensitivity of −45 dBm, a reflection gain of 44 dB, and a communication distance of up to 96 m. Full article

This paper presents a 5G new radio (NR) FR2 beamforming system with an integrated transceiver module. A real-time operating module providing enhanced flexibility and capability has been proposed. The integrated RF beamforming system with an integrated transceiver module can be operated in 8Tx-8Rx mode configuration simultaneously. A series-fed structure 8 × 7 microstrip antenna array for compact size and improved directivity is employed in the RF beamforming module. The RF beamforming module incorporates a custom 28 GHz, eight-channel fully differential beamforming IC (BFIC). An eight-channel BFIC in a phased-array beamforming system offers advantages in terms of increased antenna density and improved beam steering precision. The RF beamforming module is integrated with an RF transceiver module that enables the simultaneous up-conversion and down-conversion of the baseband signal. The RF transmitter module consists of a transmitter, a receiver, a signal generator, a power supply, and a control unit. The RF beamforming system can scan horizontally from −50° to +50° with a step of 10°. To achieve an optimized beam pattern, a calibration was conducted. The transmit and receive conversion gain of around 20 dB is achieved with the transceiver module. To verify the communication performance of the manufactured integrated RF beamforming system, a real-time wireless video transmission/reception test was performed at a frequency of 28 GHz, and the video file was transmitted smoothly in real time without interruption within a range of ±50°. Full article

A balise is a specialized device utilized for train communication and control. However, existing balises are composed of separate components, resulting in high production costs, low integration, and significant room for improvement in stability. We propose an integrated solution, to enhance the integration of balises, reducing the number of discrete components. Additionally, we propose a feedback-enabled energy extraction circuit with a limiter-based startup circuit, to enhance the stability of the balise system. The prototype was fabricated using 180 nm high voltage(HV) complementary metal oxide semiconductor(CMOS) technology. Once implemented in the balise, the number of discrete components in the system is reduced by 25%, and the system can start up within 20 ms and operate stably. The mean data rate (MDR) deviation of the balise is only 62 ppm, which is 69% lower than that specified in the test specification for the Eurobalise form–fit–function interface specification (FFFIS), and the maximum time interval error (MTIE) is less than 250 ns. Full article

Broadband millimeter-wave power amplifiers have attracted much attention and have wide applications for 5G communication, satellite communication, radar, sensing, etc. Yet, it is challenging to design a power amplifier with broadband small-signal gain and power performance simultaneously. In this study, a transformer-based symmetrical magnetically coupled resonator (MCR) matching network for broadband output matching and stagger-tuned MCRs are used to achieve both broadband small- and large-signal performance. Also, to enhance the gain for the power amplifier, a three-stage common-source pseudo-differential structure is adopted to mitigate the low-gain issue due to stagger tuning, and the shunt resistors aimed to decrease the Q factor of the MCRs. We used the in-phase two-way current combined with microstrip transmission lines to increase the output power. Designed in 65 nm bulky CMOS technology, the power amplifier presents a 3 dB small-signal gain bandwidth from 25.8 GHz to 36.9 GHz, indicating a peak gain of 25.87 dB at 30.5 GHz. The power amplifier demonstrates a 17.84 dBm saturated output power ($P_{sat}$) at 31 GHz and a 24.37% peak power added efficiency ($PA{E}_{max}$) at 28 GHz. The power amplifier achieves a flat $P_{sat}$ of 17.44 ± 0.4 dBm, a $PA{E}_{max}$ of 22.59 ± 1.78%, and an $O{P}_{1dB}$ of 13.78 ± 0.31 dBm from 26 GHz to 36 GHz. Full article

This article presents a wide-range and high-precision analog front-end circuit for multi-parameter sensors that can handle sensor outputs of different types (R, C, V). A rail-to-rail baseline compensation method has been proposed, which further incorporates a fine offset elimination of 0.6 mV/step. Additionally, self-zeroing and correlated double-sampling techniques are integrated to reduce low-frequency noise and offset, prevent sensor signal saturation, and enhance the precision of the analog front-end circuit. By incorporating variable components in the sensor signal acquisition circuit and integrating them with the baseline compensation circuit, the applicability range of the sensor has been expanded (R: 7 $\mathsf{\Omega }$–1.7 M$\mathsf{\Omega }$, C: 50 fF–35 pF, V: 0.05–1.7 V). Test results show all interface circuits exhibit significant total conversion gains (C: 45 mV/fF, R: 14.5 mV/$\mathsf{\Omega }$, V: 144 V/V), achieving high precision. Meanwhile, a coefficient of determination ($R^2$) greater than 0.998 indicates high conversion linearity of the circuit. Full article

Layout stitching is a repetitive and tedious task of the radio frequency integrated circuit (RFIC) design process. While academic research on layout splicing algorithms mainly focuses on analog and digital circuits, there is still a lack of well-developed algorithms for RFICs. An RFIC system usually has a symmetrical layout, such as transmitter and receiver components, low-noise amplifier (LNA), an SPDT switch, etc. This paper aims to address this gap by proposing an automated procedure for the layout of RFICs by relying on the basic device/PCell structure based on the interconnection among circuit topologies. This approach makes the in-series generation of layouts and automatic splicing based on circuit logic possible, resulting in superior stitching performance compared with related modules in Advanced Design System. To demonstrate the physical application possibilities, we implemented our algorithm on an LNA and a switch circuit. Full article

Due to the current limitations of three-dimensional (3D) simulation graphics technology, mind wandering commonly occurs in virtual reality tasks, which has impeded it being applied more extensively. The right ventrolateral prefrontal cortex (rVLPFC) plays a vital role in executing continuous two-dimensional (2D) mental paradigms, and transcranial direct current stimulation (tDCS) over this cortical region has been shown to successfully modulate sustained 2D attention. Accordingly, we further explored the effects of electrical activation of the rVLPFC on 3D attentional tasks using anodal high-definition (HD)-tDCS. A 3D Go/No-go (GNG) task was developed to compare the after effects of real and sham brain stimulation. Specifically, GNG tasks were periodically interrupted to assess the subjective perception of attentional level, behavioral reactions were tracked and decomposed into an underlying decision cognition process, and electroencephalography data were recorded to calculate event-related potentials (ERPs) in rVLPFC. The p-values statistically indicated that HD-tDCS improved the subjective mentality, led to more cautious decisions, and enhanced neuronal discharging in rVLPFC. Additionally, the neurophysiological P300 ERP component and stimulation being active or sham could effectively predict several objective outcomes. These findings indicate that the comprehensive approach including brain stimulation, 3D mental paradigm, and cross-examined performance could significantly lengthen and robustly compare sustained 3D attention. Full article

A novel adaptive mesh generation technique for efficient electromagnetic simulation of radio-frequency integrated circuits (RFICs) is herein presented. By exploring the geometrical and physical characteristics of RFICs, some adaptive mesh treatments, such as mesh projection, edge refinement, via polymerization, etc., are utilized to improve the accuracy and efficiency of electromagnetic computations. For strong coupling structures, such as two conductors in close proximity for a relatively large area, a projection-based mesh scheme is introduced to improve the accuracy of numerical integration. Moreover, the current most likely concentrates near the edges of conductors due to the edge effect. To better model the edge effect, an edge refinement scheme is applied. For via arrays that appear common in RFICs, an automatic via aggregation approach is adopted to improve computational efficiency yet still keep good computational accuracy. Finally, some numerical examples are given to validate the computational accuracy and efficiency of the novel adaptive mesh generation technique. Full article

This paper addresses the design of a hybrid beamforming system considering the circuit parameter of six-bit millimeter-wave phase shifters based on the process design kit. The phase shifter design adopts 45 nm CMOS silicon on insulator (SOI) technology at 28-GHz. Various circuit topologies are utilized, and in particular, a design is presented based on switched LC components, connected in a cascode manner. The phase shifter configuration is connected in a cascading manner to get the 6-bit phase controls. Six different phase shifters are obtained, which are 180°, 90°, 45°, 22.5°, 11.25°, and 5.6°, with a minimum number of LC components. The circuit parameters of the designed phase shifters are then incorporated in a simulation model of hybrid beamforming for a multiuser MIMO system. The number of OFDM data symbols used in the simulation is ten for eight users, 16 QAM modulation schemes, −25 dB SNR, 120 simulation runs, and around 170 h runtime. Simulation results are obtained considering four and eight users, assuming accurate technology-based models of RFIC components of the phase shifter as well as ideal phase shifter parameters. The results indicate that the performance of the multiuser MIMO system is affected by the accuracy level of the phase shifter RF component models. The outcomes also reveal the performance tradeoff based on user data streams and the number of BS antennas. By optimizing the amount of parallel data streams per user, higher data transmission rates are achieved, while maintaining acceptable error vector magnitude (EVM) values. In addition, stochastic analysis is conducted to investigate the distribution of the RMS EVM. The outcomes show that the best fitting of RMS EVM distribution of the actual and ideal phase shifters agreed with the log-logistic and logistic distributions, respectively. The obtained (mean, variance) values of the actual phase shifters based on accurate library models are (46.997, 481.36), and for ideal components the values are (36.47, 10.44). Full article

Humidity-sensing devices are widely utilized in various fields, including the environment, industries, food processing, agriculture, and medical processes. In the past few years, the development of noncontact sensors based on moisture detection has increased rapidly due to the COVID-19 pandemic. Moisture-detection, noncontact and breath-monitoring sensors have promising applications in various fields. In this study, we proposed a rapid-response graphene oxide (GO)-doped P(VDF-TrFE)/LiCl nanocomposite-based moisture sensor fabricated on an interdigitated electrode. The synthesis of GO/P(VDF-TrFE)/LiCl resulted in a porous structure with nano-sized holes due to the effect of LiCl. Moreover, doped GO improved the conductivity of the sensing film. The created nanoporous structure improved the recovery time better than the response time, with the times being 4.8 s and 7.8 s, respectively. Not only did our sensor exhibit rapid response and recovery times, it also exhibited a high sensitivity of 1708.8 pF/%RH at 25% to 93%RH. We also presented a real-time breath-monitoring system for noncontact sensing applications based on GO-doped P(VDF-TrFE)/LiCl composites. The results revealed that GO-doped P(VDF-TrFE)/LiCl is a good candidate for fabricating real-time moisture-detection noncontact sensing devices. Full article

The development of radio-frequency integrated circuits (RF-IC) necessitates higher requirements for the size of microtransformers. This paper describes millimeter-scale 3D transformers in millimeter-scale, solenoidal, and toroidal transformers manufactured using Micro-electromechanical Systems (MEMS). Two through-silicon via (TSV) copper coils with a high aspect ratio are precisely interleaved on a reserved air core (magnet core cavity) with a vertical height of over 1 mm because of the thickness of the substrate, which increases the performance while reducing the footprint. The effects of the wire width, coil turns, magnetic core, and substrate on the performance of the two transformers are discussed through numerical simulations. When an air core is present, solenoidal transformers are better than toroidal transformers in terms of performance and footprint; however, the gap decreases when the size is reduced. Additionally, the magnetic core significantly improves the performance of the toroidal transformer compared to that of the solenoid. Thus, the toroidal transformer has a higher potential for further size reduction. The two types of transformers were then manufactured completely using MEMS and electroplating. This paper discusses the influence of various parameters on millimeter-scale 3D transformers and realizes processing in silicon, which provides the foundation for integrating transformers in a chip. Full article