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A ferrite-loaded dipole antenna with wideband and low profile is proposed for VHF/UHF applications. The ferrite used in this paper is a kind of novel magneto-dielectric material with high and matched permittivity and permeability. Through the material loading, the interference of ground plane is effectively suppressed, and thus the antenna profile is reduced significantly. Furthermore, the antenna bandwidth is expanded to lower frequency band due to the high magneto-dielectric property of the ferrite. The optimized antenna obtains a profile of $0.08 \lambda_{0}$ , a −10 dB impedance bandwidth of 107.7% (150–500 MHz), and a peak gain of 6.2 dBi.

In the teaching of electronic engineering, some practical projects need to be added in order to connect various courses together. To strengthen the connections between courses, the project-based teaching method proposed in this paper advocates linking the knowledge of different courses through the combination of theory and practice. With this as a guide, projects have been set up for students. One of them is about designing and making a managed ethernet switch. In the process of making and completing this project, the students' ability has been significantly improved, which fully proves the benefits of the teaching method.

This paper presents a fast-transient radiation-hardened low-dropout (LDO) voltage regulator integrated in a standard CSMC 0.6 μm BiCMOS technology for space and other harsh radiation environments applications. The fabricated LDO consumes 150 μA quiescent current at 6 A maximum output current. A low dropout voltage of 300 mV which corresponds to an ultra-low RDS(ON) resistance of 50 mΩ is realized by accurate modeling. A separate fast-transient response circuit under narrow-bandwidth condition is proposed to improve the output voltage transient speed. It operates from an input voltage range of 2.8 V to 5.5 V and provides for output voltage of 2.5 V, with output voltage accuracy of ±2%. The proposed LDO achieves a successful line regulation of 1 mV/V, and a load regulation of 2.16 mV/A. Novel radiation-hardened layout techniques are applied to realise high area-efficient LDO chip, whose total area including pads is 5.35 mm2, only about one-third area of similar radiationhardened products. Total ionising dose (TID) experiments were conducted at China Academy of Engineering Physics, Mianyang of Sichuan province. Furthermore, a special set of single event latch-up (SEL) experiments were performed at the Heavy Ion Research Facility in Lanzhou (HIRFL), Institute of Modern Physics, Chinese Academy of Sciences, the most advanced heavy ion accelerator of China. The measurement results show that the LDO can tolerate up to a total ionising dose (TID) of 150 krad (Si) and SEL immunity at a linear energy transfer (LET) of 99.8 MeV/(mg/cm2) with proposed novel layout design.

This brief presents an external capacitor-less nMOS low-dropout (LDO) voltage regulator integrated with a standard CSMC 0.6- ${\mu }\text{m}$ BiCMOS technology. Over a −55 °C to +125 °C temperature range, the fabricated LDO provides a stable and considerable amount of 3 A output current over wide ranges of output capacitance $C_{\mathrm {OUT}}$ (from zero to hundreds of ${\mu }\text{F}$ ) and effective-series-resistance (ESR) (from tens of milliohms to several ohms). A LDO voltage of 200 mV has been realized by accurate modeling. Operating with an input voltage ranging from 2.2 to 5.5 V provides a scalable output voltage from 0.8 to 3.6 V. When the load current jumps from 100 mA to 3 A within 3 ${\mu }\text{s}$ , the output voltage overshoot remains as low as 50 mV without output capacitance, $C_{\mathrm {OUT}}$ . The system bandwidth is about 2 MHz, and hardly changes with load altering to ensure system stability. To improve the load transient response and driving capacity of the nMOS power transistor, a buffer with high input impedance and low output impedance is applied between the transconductance amplifier and the nMOS power transistor. The total area of fabricated LDO voltage regulator chip including pads is 2.1 mm $\times $ 2.2 mm.

This letter presents an approach to design two-pole source-load coupling and four-pole cross-coupling substrate integrated waveguide (SIW) bandpass filters based on multilayer process. Utilizing the field distribution, the vertical magnetic and electric coupling of fundamental mode is designed by suppressing the first spurious mode. Then, source-load and cross-coupling schemes are realized with controllable features in two-pole and four-pole filters, respectively. The harmonic passband produced by TE102 mode can be suppressed by proper coupling technique enabling the connection with TE102 mode in two- and four-pole filter designs, respectively. Three transmission zeros, which are derived from source-load coupling, are introduced around the passband of two-pole filter to improve its selectivity. In the four-pole filter design, a six-order cross-coupling scheme including source and load produces four transmission zeros around the passband, leading to a sharp selectivity. In addition, another transmission zero is generated at the adjacent location of the passband to improve the out-of-band rejection. Compared with conventional horizontally coupled filters made of single layer, the proposed filters show a compact size. To demonstrate the proposed design method, a two-pole and a four-pole double-layered SIW bandpass filters are fabricated and measured. Measured results show that the proposed filters exhibit high selectivity and good out-of-band rejection, as well as a good agreement between simulated and measured results.

An integrated 3rd-order pseudocombline bandpass filter with pre-designed second to fundamental harmonic ratio is designed based on 0.25 μm GaAs (Gallium Arsenide) process. λ0/4 microstrip loaded wi...

A size-minimized low-insertion-loss reflectionless bandpass filter with four notches is presented in this paper. The insertion loss of two quasi-elliptic-type filters is studied and optimized by a new approach based on cascade resonators branches. Parameters extraction procedure for the desired position of notches is illustrated. The inband performance, bandwidth and notch width are studied. This novel approach brings lower insertion loss. It can be extended to reflectionless bandpass filters with arbitrary number of notches. The size of filter is also minimized. This filter is designed, simulated, fabricated and measured. It is centered at 3.481 GHz with a 3-dB bandwidth of 276 MHz. The minimum measured in-band insertion loss, including the loss of SMA interface, is 1.239 dB. Four notches are located at 2.827, 3.238, 3.825 and 4.306 GHz, respectively. S11 of this filter is less than −10 dB during 2–5 GHz.

In this paper, a series of NiZnCo spinel ferrites with the co-doping of CaO and SiO2 (CaO–SiO2) were studied for their potential application as high-frequency magneto-dielectric materials. The effects of CaO–SiO2 on the crystalline phase composition, microstructure, and magnetic and dielectric properties over a wide frequency range of 0.1–5 GHz were systematically investigated. The results reveal that CaO–SiO2 addition reduces the closed pores in NiZnCo ferrite and helps to enhance the permeability. With increasing CaO–SiO2 content ( $x = 0$ –0.6 wt%), the permeability $\mu ^{\prime }$ increases from ~7 to ~7.5 at 0.1 GHz. For permittivity $\varepsilon ^{\prime }$ , however, it declines evidently from ~9 to ~7.8 on account of the decreased grain size and density. Consequently, $\mu ^{\prime }$ and $\varepsilon ^{\prime }$ are balanced to the matching and high values over a wide frequency range of 0.1–1 GHz in the samples with $x = 0.3$ and 0.6 wt%, accompanied with low loss characteristics that the magnetic loss tan $\delta _{\mu }$ and dielectric loss tan $\delta _{\varepsilon }$ are on the order of 10−2 and 10−3, respectively.

Hall Magnetic sensors for particles detection have been explored over the past decades. It has been mentioned that the detection has the potential in the applications of biomedicine and environmental monitor. In biomedicine, numerical researches of Hall sensor have been achieved for detecting bio-markers magnetic nanoparticles (MNPs). On the contrary, Hall sensor for environmental monitor is seldom investigated. This paper carries out a pioneering investigation on Hall sensors for air quality detection. A modelling base on finite element method (FEM) software COMSOL is established to quantify the ability of Hall sensors in the measurement of micrometer-sized magnetite particles distributed in the air. Meanwhile, as the development of environmental magnetism in recent years, the modelling has the potential to provide the first protype of portable sensors for the detection of microsized magnetite particles in the air in the future.

Facing the requirements of advancing the strategy of training elite talents, optimizing the talent training system and building first-class undergraduate education, the training of elite talents not only emphasizes problem – solvingl “how to do it?”, but also emphasizes thinking about problemsl “what to do?” to help students view and solve problems from a broader perspective, interdisciplinary and systematic thinking. In the teaching process of “electronic circuits”, we have clearly realized that with the rapid development of electronic circuit technology, electronic equipment has become increasingly integrated, electronic design automation (EDA) and the rapid development of various circuit simulation software have greatly simplified the complex circuit analysis and calculations. Because the world is analog, the signals in nature are analog signals, and analog circuits are inseparable from real life. Therefore, we have proposed a comparative teaching strategy of electronic circuit technology with “analogous thinking method”. The so-called analogy thinking refers to the logical reasoning method that transfers the knowledge of one special thing to another special thing based on the similarity or similarity in some aspects between two or two kinds of things. When two types of things are the same or similar in one or some aspects, analogy thinking can be used. In this paper, application of analogy as well as inspiring methodology in teaching feedback amplifier circuit have been given as a case study.

In this paper, a low drop-out (LDO) linear regulator with high power supply rejection ratio(PSR) and fast transient response is proposed for various applications. To achieve fast transient response, this work employs variable bias and transient-boost capacitance. The variable bias structure enhance the slew rate and PSR of LDO. The transient-boost capacitance (TBC) is set in a proper location, using its voltage characteristic to enhance transient response without consuming quiescent current, and it also improves circuit's stability. This circuit is designed based on TSMC 65nm CMOS Technology and verified by Cadence simulation environment. According to the simulation results, the LDO achieves a PSR of 68.3dB and 51.4dB at 10kHz and 1MHz. Undershoot and overshoot of Vout are 190mV and 143mV under a varying load current from 20mA to 80mA with edge time of 1ns.

This paper presents "Truth from Practice, Learning beyond Teaching", a new teaching model of engineering circuit courses. It is proposed to use experimental learning to drive theoretical study, which make students better fit the company’s work, transform the traditional test score based final examination to the process evaluation, which is consistent with the proposed teaching model. This paper presents a curriculum framework that establishes the combination of higher education and social production used in the supply power circuit course. The syllabus of the reform includes lectures, laboratories, projects and the procedure for evaluation focuses on process. In the contest of higher engineering education, autonomous learning and innovation are seen at the key factors of knowledge-based society, adapt the proposed education approach to cope with ongoing and future problems. The use of this teaching model to significantly motivates students to broaden their knowledge widely and to improve the quality of the course, enable scientific research techniques to solve practical problems more effectively, and avoid the blindness of talent cultivation.

This paper proposes a new capacitor recombination calibration method to compensate the capacitor mismatch of successive approximation register analog-to-digital converter (SAR ADC). This method focuses on automatically calibrating the mismatch of the SAR ADC capacitors to improve the static performance (Integral Non-Linearity, INL; Differential NonLinearity, DNL) and dynamic performance (Spur Free Dynamic Range, SFDR; Signal to Noise and Distortion Ratio, SNDR). The Monte Carlo method is used to verify the calibration of 14-bit, 16- bit, and 18-bit SAR ADC. The results show that this method can make the SAR ADC obtain more stable and better performance parameters.

With the continuous shrink of IC manufacturing process, how to accurately predict the routing violations before detailed routing is becoming more and more important to improve the placement quality. In this paper, we propose a detailed routing short violations prediction model based on the Graph Convolutional Network (GCN). Based on the key features extracted from the placement and detailed routing stage separately, we train a GCN model to build a map relationship between these two stages. Through this model, we can predict the detailed routing short violations at placement stage successfully. Experiments show that the average prediction accuracy of our model is 94% which is higher than existing method based on machine learning.

Layer assignment, which is a part of global routing, aims to assign the flat nets to 3D distribution and decrease the via count without violating edge or via constraint. Negotiation-based method is used to obtain good result but bring too much time complexity, this work presents a net partition technology to reduce the problem complexity, and develops enhanced heuristic methods of effective layer shifting and rip-up procedure which could control the via count without multiple iteration process. Experimental results show that this method could bring inspiring improvement than LAVA.

Silicon Hall-effect sensors have been widely used in industry and research fields due to their straightforward fabrication process and CMOS compatibility. However, as their material property limitations, technicians usually implement complex CMOS circuits to improve the sensors’ performance including temperature drift and offset compensation for fitting tough situation, but it is no doubt that it increases the design complexity and the sensor area. Gallium arsenide (GaAs) is a superior material of Hall-effect device because of its large mobility and stable temperature characteristics. Concerning there is no specified modelling of GaAs Hall-effect device, this paper investigated its modelling by using finite element method (FEM) software Silvaco TCAD® to help and guide GaAs Hall-effect device fabrication. The modeled sensor has been fabricated and its experimental results are in agreement with the simulation results. Comparing to our previous silicon Hall-effect sensor, the GaAs Hall-effect sensor demonstrates potential and reliable benchmark for the future Hall magnetic sensor developments.

Nowadays, the field of microelectronics has become the drive for the advancement of the times, which promotes new demands on the cultivation of the students in colleges and universities. In order to keep up with the trend of the global engineering educational reform, three important reforms in education have been in progress step by step, including classroom teaching, innovative training and virtual laboratories. At first, for enhancing and integrating the existing courses related to the circuit, so that the students can comprehend the existing knowledge much more effectively, an important and effective curriculum reform has been performed by combining “Circuit Analysis” and “Analog Circuit Foundation” into one course; Then, innovative training has been carried out to cultivate the team skills among the students; Finally, in consideration of the rapid development of the electrical and electronic experiment, the conventional laboratory equipment may not satisfy the demand of every student due to financial constraints, therefore, the construction of virtual simulation experiment center is an efficient way to break this bottleneck. As a result, the atmosphere of academic innovation of the pursuit of truth, advocacy of science, brave exploration, dare to practice have been formed in colleges and universities through the above innovative engineering education reform.

This paper presents a digital magnetic field detection system, which can collect and analyze the remote sensing data by using the analog-to-digital converters (ADCs). The proposed digital magnetic field detection system contains two different types of digital pulse-width modulation (PWM) ADCs by using the complementary metal-oxide-semiconductor (C-MOS) mixed-signal technology and the field-programmable gate array platform (FPGA). The 12-bit digital PWM delta-sigma ( $\Delta\Sigma$ ) ADC is implemented in 180nm CMOS mixed-signal technology and achieves the signal-to-noise-distortion ratio (SNDR), the spurious free dynamic range (SFDR) and the effective number of bits (ENOB) are 70.68dB, 92.62dB and 11.44-bit with a supply voltage of 1.2V and at a sampling rate of 58.82kS/s. The digital PWM successive approximation register (SAR) ADC is based on FPGA to reduce the interference in the workpiece magnetic field to enhance reliability. Proposed digital PWM ADCs can be combined with a Hall effect sensor to measure the magnitude of a magnetic field without using the microcontroller, which are widely used for proximity sensing, positioning, speed detection, and current sensing applications.

This article puts forward some feasible sensor related courses redesign for solving the current predicament of electronic information course education. Two practical teaching cases have been given in this work. The approach proposed in this work allows students to flexibly use what they have learned, then put theories into practice.

In this article, a novel coupling structure is proposed. The surface voltage and current distribution on this structure can be tuned by changing the ratio of the two capacitances so that the central frequency and coupling coefficient can be tuned. The coupling structure can also be tuned to change the sign of coupling coefficient, which is utilized to control the transmission zero of cross coupled tunable bandpass filter. A second order bandpass filter with tunable central frequency and bandwidth is designed and measured. The measurement shows that the central frequency tuning range is 0.768 to 1.512 GHz and the fractional bandwidth tuning range is 0.052 to 0.18 at 1.14 GHz. It shows that the filter can also be tuned with constant fractional bandwidth or constant absolute bandwidth. A tunable cascaded triple bandpass filter with tunable central frequency and bandwidth is designed and measured, as well. The cross-coupled transmission zero can be configured to locate at either high side or low side of the passband by changing the coupling type of the filter topology.

In this paper, a ±45° dual-polarized differential-fed patch antenna is developed. Four symmetrical circular coupling patches is placed at the middle point of the square patch, which broadens the bandwidth of the antenna. The differential-fed network of two polarization is designed on the same layer so as to reduce total layer requirement. The bandwidth (S 11 12 is lower than −35dB and the HPBW equals about 90°. An 8-element array is also designed to show the scanning characteristics and sidelobe suppression. NSGA-II multi-objective optimization algorithm is introduced to obtain optimal sidelobe suppression. The comparison of patterns based on uniform amplitude and NSGA-II is conducted. It shows that lower sidelobe level is obtained by NSGA-II with little gain drop.

This paper presents a three-dimensional finite element method (FEM) model of horizontal Hall sensor in COMSOL Multiphysics. The model aims to simulate the sensor’s performance in a straightforward way and provides a means to simulate more complex applications with other physics modules. Compared with traditional two-dimensional models, the three-dimensional model is more flexible in designing Hall sensor and shows great significance in verifying the performance of sensors with different materials and geometries. By changing model parameters and comparing simulation results, an optimal design solution can be achieved effectively and economically. The presented Hall sensor achieves a sensitivity of 0.0669 V/(VT). Basic circuit modules of a complete sensor system are also introduced.

This paper designs a novel system, which can collect spatial magnetic field information and perform three-dimensional (3D) imaging operation by combining electromagnetic detection, sensor technology, signal processing, and microcontroller technology. The micro-system consists of Hall voltage sensor, STM32 microcontroller, stepper motor, OLED module, and driving circuits. The experimental results show that the magnetic field detection data obtained by the 3D imaging micro-system are complete and reliable, which can fully reflect the spatial vector distribution of the target magnetic field; the 3D scanning detection operates smoothly, the parameters of which are flexible and changeable; the system has stable and reliable performance and high detection efficiency, which achieves the effective detection of the magnetic field in the target area.

A method to decrease the threshold voltage and on-resistance is discussed in this paper, which is adding extra phosphorus injection into silicon. There are two ways to inject extra phosphorus without adding a mask. The first way is to inject extra phosphorus after the field oxide etching, and the second way is to inject extra phosphorus with the source region mask before the N+ implantation. Compare the results of the two ways to find their characteristics and choose the appropriate one.

At present, there are many complex and diverse bus interface standards in the field of sensor measurement and control, which leads that different sensors unable to be compatible with different field networks, thus increasing the difficulty of data acquisition and processing. In order to improve the compatibility and the intelligent level of sensors, in this work, a novel intelligent sensor interface model defined by IEEE1451.2 standard is proposed. Finally, the self-recognition, plug and play (PNP) functions are verified on FPGA platform.

This paper proposes a 16-bit 6-channel high-voltage successive approximation register (SAR) ADC with an optimized 5 + 5 + 6 segmented capacitor array. The lower 10 bits of the capacitor array are all composed of unit capacitors without any calibration unit. Without calibration, the lower 10 bits of the capacitor array can ensure 10-bit conversion accuracy. Every of the upper 6 bits of the capacitor array contains a linearity calibration unit. The linearity error of the upper 6 bits is calibrated by the linearity calibration unit. The 16-bit is manufactured by a $0.6~\mu m$ standard COMS process, and the total chip area of 6-channel ADC including pads is 6.6mm $\times6.6$ mm. As for single channel SAR ADC, the area is 0.9mm $\times2.0$ mm. The measurement results show that the effective conversion accuracy of the SAR ADC reaches 13 bits by using novel differential nonlinearity (DNL) and integral nonlinearity (INL) calibration methods. The power is 80mW, corresponding to a Figure of Merit (FOM) of 48 pJ/conv.-step.

Further to China’s plan that was introduced in 2017 for attracting more students into engineering, many Chinese universities have started to explore new teaching methods that can be adopted into their programs. This shift was geared towards developing student-centred teaching materials rather than traditional teacher centred instruction. In this manuscript, we compare two different methods of instruction for a course on energy harvesting using embedded systems. We describe the learning materials and showcase the impact that project-based learning has had on a cohort of Chinese students that were enrolled in a joint master’s program between the University of Electronic Science and Technology of China (UESTC) and the Royal Institute of Technology (KTH). KTH has made remarkable progress in the teaching of embedded systems technology for energy harvesting applications, with great emphasis on active as well as collaborative learning. We demonstrate two examples of projects that Chinese students have completed in KTH and present evaluative data regarding their experiences. Our results show that KTH’s approach in teaching this module has had a positive impact on student learning, with an average of 80% of students think that teaching in KTH is conducive to students’ independent exploration.

In this letter, a dual-band magnetoelectric (ME) dipole antenna with wide operation bands is proposed for WiMAX and WLAN applications. A full-metal rectangular director is loaded right above the ME dipole antenna and it resonates at around 3.6 GHz due to the excitation of the long electric dipole (LE-dipole). Then, the lower operation bandwidth is extended significantly. This added director also allows our antenna to work as a quasi-Yagi antenna at specific frequencies, and thus, the proposed antenna is capable to achieve better unidirectional radiation performance and higher gain. In order to satisfy WLAN communication, a short trapezoid electric dipole is designed beneath the LE-dipole, which maintains the overall antenna dimensions as unchanged. Besides, such design strategy avoids the distortion of the radiation pattern at 5 GHz as well. As for the ground, a hornlike reflector is adopted instead of traditional planar structures. The measured results show that our proposed antenna achieves two wide bandwidths, 2.3–3.7 GHz (46.7%) and 5–6.25 GHz (22.2%), and high stable gain (8.5 ± 0.9 and 9 ± 1 dB) within these two operation bands.

A series of Ca-substituted Z-type hexaferrites having nominal composition Ba3– x Ca x Co2Fe24O41 ( $x = 0$ –1.5) was studied for their high-frequency magnetic properties, including measurement of the permeability spectra and magnetic loss over a frequency range of 0.1–10 GHz. Analyses of crystal composition and microstructure reveal that hexaferrite composites consist of the Z-type phase and increasing amounts of the W-type phase were obtained as the Ca content was increased. Correspondingly, the permeability $\mu ^\prime $ displays a near linear decrease with x varying from 0 to 1.5, from ~8 to ~4.1 at 0.1 GHz. The relationship between permeability and variations in intrinsic magnetic parameters, i.e., saturation magnetization $M_{s}$ and coercivity $H_{c}$ , follows the Globus model. Compared with the undoped Z-type hexaferrite, the sample with $x = 0.2$ has lower magnetic loss over a broad frequency range, and higher levels of Ca substitutions ( ${x} \ge 1$ ) lead to low magnetic loss at high frequencies. The dual-phase composite of Co2Z and Co2W in proper ratio is an effective technique to improve the homogeneity of grain and microstructure, and thus reduce the high-frequency magnetic loss of the sintering hexaferrites.

A novel 4th-order cross-coupled electrical tunable bandpass filter with constant absolute bandwidth and high frequency selectivity is proposed. The electric coupling coefficients and the magnetic coupling coefficients of the cross-coupled resonators and the external quality factor of the tunable filter are investigated. The design curves of coupling coefficients and external quality factor versus the resonant frequency are synthesized for the cross-coupled tunable filter. Tunable resonator with separate electric dominant and magnetic dominant coupling regions is designed to build the cross-coupled tunable filter topology. Theoretical analysis is derived to estimate the coupling coefficients and the performance of the proposed filter. A prototype is fabricated and measured. The measurement shows that the filter has a −3 dB bandwidth of 117 ± 3MHz from 0.95 to 1.48 GHz. Two cross-coupled transmission zeros beside the passband are generated, and the frequency selectivity is enhanced. The −30 dB/−3 dB bandwidth shape factor is 1.83~1.93.