An improved feedline configuration for dual-mode resonator filter is investigated in this paper. Based on the introduced topology, a dual-mode dual-band bandpass filter with center frequencies of 1.8 and 2.4 GHz is optimally designed, fabricated and tested. The introduced dual-band bandpass filter has simple structure and enables high selectivity to be realized due to two pairs of transmission zeros located near to the lower and upper passband, respectively. Both measured and simulated performances are presented with good consistency.
To explore the application of plan–do–check–action (PDCA) cycle in the management of the naked medicine dispensing about the automatic package and to analyze the practice improved in the quality of naked medicine dispensing medicine management.
The PDCA theory was used to analyze the data, to find out the causes of the problem, and to formulate the corresponding countermeasures to intervene. The data of the naked medicine/adverse drug events satisfaction degree of the inpatients in 18 inpatient departments given for the adoption of PDCA cycle in January 2017 were set as the observation group. The number of the naked medicine/adverse drug events satisfaction degree of patients in 18 inpatient departments before adoption of PDCA cycle in December 2016 was set as the control group. The number of the naked medicine/adverse drug events satisfaction degree of patients in 18 inpatient departments before and after adoption of PDCA cycle was observed and analyzed.
The number of the naked medicine/adverse drug events after implementing the method of PDCA cycle management rate was significantly lower than before the implementation method of PDCA cycle management, and the difference had statistical significance (P < 0.05). The satisfaction degree of the inpatients after implementing the method of PDCA cycle management rate was significantly higher than that before the implementation method of PDCA cycle management, and the difference had statistical significance (P < 0.05).
Application of PDCA cycle in the management of the naked medicine dispensing about the automatic package can help to reduce the adverse drug events, to improve the safety of drug treatment, and to increase the patients’ satisfaction degree.
A lumped-LC equivalent circuit to model a novel rectangular bracket shaped defected ground structure (DGS) is presented in this paper. The presented equivalent circuit can accurately predicate the frequency responses, in terms of the magnitude and phase responses of S parameters, of the studied DGS. The lumped LC parameters of the presented model are extracted based on a unit cell of the DGS. Further, the model is found to be applicable in microwave engineering, including microwave filter designs. Some design examples are presented and examined. The studied DGS based microwave filters characterize maximum passband flatness, sharp skirt between the passband and stopband and wide stopband. The studied equivalent circuit model can accurately predicate the frequency responses including the magnitude and phase of S parameters.
Bowtie antenna-based time reversal mirror (TRM), incorporating with randomly distributed and arbitrarily shaped wire metamaterials medium, is proposed to realize super-resolution target detection. The achieved performance for standard and scatterer bowtie antenna TRM is compared and discussed. The dual-band bowtie antennas resonate at 2.45 GHz and 5.2 GHz and a super-resolution of 0.0817 of the free-space wavelength at 2.45 GHz has been achieved. For the first time, studies show that the TRM with microstructure perturbations (namely scatterers) can enhance the resolution in some cases. Proposing a method of super-resolving transmission of electromagnetic waves is very important to realize multi-independent channels in a compact space for the related applications.
A four-way network with 45 deg output phase shifts for feeding antenna array is studied in this work. To widen the phase imbalance, quarter wavelength short stubs with suitable characteristic impedances are introduced and numerically analyzed. Meanwhile, the wideband magnitude imbalance is also discussed by extending the inter-stage transmission line with proper electric length. The study is further confirmed by developing a prototype feeding network centered at 3 GHz. Results from the fabricated prototype network exhibit wideband good performance, both from numerical evaluations and experimental demonstrations.
A wideband transition from the coaxial TEM mode to the TM01 mode of the circular waveguide with in-line input-output architecture is proposed in this paper. The transition employs multi-stage stepped impedance transformer to achieve wideband responses. Both mode transition and impedance matching characteristics are discussed in the paper. A demonstrator is developed and validated experimentally. As compared with some recently published reports, a better performance is observed. Moreover, the developed transition could facilitate the mechanical fabrication more easily. It can be found wide applications such as the circular waveguide based slot array antenna, the nondestructive detection, cracks inside the conductive pipes, and so on.
The design and implementation of planar multi-way differential power dividers remain a challenge in terms of the compactness and especially, for the achievable characteristic impedance of the quarter-wavelength transformer when considering large number of outputs. In this work, the double-sided parallel stripline is recommended to realize such a power divider with out-of-phase outputs, and explicit design methods are provided. The proposed multi-way power divider was developed without the use of lump elements on a single substrate. For system applications, a prototype operating at 41.6 MHz with 12 pairs of out-of-phase outputs that utilize the microstrip line as the output interfaces was fabricated and examined. At the center frequency of 41.6MHz, the developed prototype measured insertion losses akin to 14.3 dB as compared with the theoretical data of 13.8 dB. The attainable impedance bandwidth ranges from 10 MHz to 80 MHz under a magnitude imbalance of ±0.3 dB. The isolations of the adjacent outputs are about 13.1 dB as compared with the theoretical values of 14.428 dB, and are better than 34 dB for more distant ones. Parameter measurements are in good agreement with the numerical predications, thus demonstrating the realization of the proposed multi-way power divider.
This contribution presents, for the first time, the design of microwave lowpass filter with ultrawide stopband and low insertion loss based on the log-periodic zig-zag defected ground structure (DGS); the design is specifically evolved from the principle of the log-periodic line antenna and the slotline based DGS. Based on the log-periodic property, studies show that ultra-wideband suppression can be realized by increasing the flare angle or the angle subtended by each element of the slotline DGS. The developed filter therefore shows low insertion loss of 0.7 dB within the passband, sharp transition between the passband and the stopband and ultra-wide suppression band from 2.61-26.5 GHz with a 20 dB suppression level. The DGS architecture is simple and easy to realize, and the design is thus useful in many microwave applications. The fabricated prototype filter validates the study, both from simulations and from measurements.