The transmission characteristics of a frequency selective surface (FSS) consisting of small resonant circular apertures with a ridge are related to the transmission cross section of a single ridged aperture, and the performance is verified experimentally. The FSS structure with a ridged circular aperture has a lower resonant frequency, enlarged fractional bandwidth, and a larger wavelength-to-periodicity ratio compared to an FSS with a conventional circular aperture. Experiment results show that the resonant frequency of the proposed FSS structure can be lowered from 13.98 GHz to 7.30 GHz (47.8%) by adding the ridge.
With the increasing high requirements for digital circuits in space application, devices with smaller feature size are put into use, which have more potential suffering from Single Event Upset (SEU) under certain radiation environment. In this paper, we propose a SEU-tolerant latch with low power-delay-product (PDP) that combines a SEU-tolerant cross-coupled structure with isolation operation of flipped state. Negative feedback paths are introduced to help recover the flipped state and can be cut off to speed up the write operation at transparent mode. Furthermore, isolation of flipped state is utilized to achieve better SEU-tolerance. The simulation results with 180 nm and 40 nm CMOS technology show that the proposed latch can achieve outstanding SEU-tolerance (Qcritical > 10 fC) and a relatively low PDP of 0.0095 fs×J for 40 nm CMOS technology.
This paper proposes a sensor data compression mechanism based on the amount of change of sensor input data and a power management scheme for various sensors used for the motion recognition application. The experimental results confirmed that the proposed compression mechanism and power management scheme reduced the wakeup count of the sensor hub core and the amount of data transmitted to the core by about 78% compared to the conventional data buffering structure, and the power consumption of the IMU (inertial measurement unit) is reduced by about 56%.
A transceiver for a 25.8 Gbps/lane with a re-timer IC has been developed for information and communication equipment. Since a 1-unit interval (UI) is very narrow at 38.8 ps at 25.8 Gbps, power integrity (PI) jitter due to power supply fluctuation cannot be ignored. In this paper, we proposed a decoupling-capacitors (Decaps) placement technique to reduce power distribution network impedance (Zpdn) and a circuit design procedure regarding power supply fluctuation. The re-timer IC adopted from the proposed procedure achieved a bit error rate (BER) lower than 1 × 10−12 on backplane transmission with an insertion loss (IL) of 40 dB.
This paper presents the design and testing of a novel rotary transformer for rotary ultrasonic machining (RUM). The transformer structure is innovatively designed for easy assembly and disassembly, which provides increased convenience to tool replacement in RUM. Circuit analysis shows the efficiency loss caused by the structure simplification is less than 5%. Also, the effect of the primary core angle and air gap length on coupling coefficient is studied for guiding the design. A rotary transformer with 90° primary core and 1.0 mm air gap is achieved. Contrast tests were carried out in simulation and experiment. Results show this novel rotary transformer transmission efficiency is 0.8972, which is agree with the theoretical value.
This paper proposed a high gain spherical dielectric resonator antenna (DRA) operating on higher-order mode excited by microstrip patch. A microstrip patch was used to excite TEn01 mode on a dielectric sphere. The excited dielectric sphere operates as higher-order mode spherical DRA with high gain. Impedance matching method for conventional microstrip patch could be applied to the proposed antenna. Size minimization method for the excitation microstrip patch was also described on this paper. A prototype antenna operating on TE301 mode at 5.8 GHz was fabricated by a ceramic dielectric material, which dielectric constant is 13, and showed the peak gain of 9.03 dBi.
We propose a new beam control method using frequency selective side reflectors (FSRs) with no help of the conventional array of multiple antennas. To control radiation directions on an H plane, we need only one feeding dipole antenna with a pair of the FSRs placed on both sides of the dipole antenna. Each FSR consists of equal-length rectangular copper patches. But, in order to obtain different reflection phase from each FSR, the lengths of the patches on each FSR are different from one another. By changing reflection behavior of each FSR, we can derive constructive interference between a direct wave from the dipole and the reflected waves from the FRS and a ground plane. Consequently, we can direct our antenna beam in any target direction with relatively high gain in a wide frequency range.
In a high speed rotor system, active balancing control is an important method to improve performance and robustness. The time-delay will significantly increase the stability of the balance control system. Based on the dynamic model of rotor system with time-delay, a strictly positive real system is built to satisfy the stability conditions of adaptive control system in this paper. Furthermore, a feed-forward gain adaptive controller is designed. To improve the balance control of rotor system under both variable speed and constant speed, an adaptive control method is proposed. The advantage of this method against traditional control strategy is validated by numerical and experimental results.
This paper proposes a X-filling method that reduces capture power during scan-based testing. The proposed method classifies scan cells for dividing the scan cells into some groups. Then, based on the divided groups, X-bits are filled simultaneously to reduce the computation time. Since the proposed method uses a novel grouping algorithm and fills X-bits based on groups, the proposed method reduces switching activity and computation time when compared with conventional X-filling methods. The simulation results show that the proposed method reduces the switching activity up to 70% and the number of simulations for the X-filling up to 52% compared with that of conventional X-filling methods.