In order to put Radio Frequency Identification (RFID) and Wireless Sensor Network (WSN) in a hybrid system, this paper presents the design and implementation of a RFID reader/router that can obtain information of both RFID tags and WSN sensor nodes and transmit the information through the WSN to the PC server. The RFID reader and WSN router are combined with both hardware and software. In hardware structure, CC2530 is used as micro controller and RF module for ZigBee wireless communication, and MF RC522 is used as reader RF chip. The software deals with both identity and sensing information and controls the routing. Experiment results show that the RFID reader/router achieves long distance identification, flexibility, scalability, and low cost. It also provides reliable and secured data transmission and broadens the communication range and application scope of RFID readers.

A wideband filter with a notched band is presented. The proposed filter is formed by cascading three coupling units, and each coupling unit is composed of two curved T-shaped microstrip patches at the top and bottom layers and a circular coupling slot at the mid layer. Overlapping three coupling units could result in a wideband filter with a tunable notched band. To analyse the resonance characteristics, the equivalent circuit model is presented. The notched frequency is 5.8 GHz, and within the passband, the insertion and return losses are better than −2 dB and −15 dB, respectively. The group delays are 0.08 ns and 0.12 ns correspondingly, and the upper stopband reaches 15 GHz. The multi-layer structure leads to a compact size and tight coupling characteristics, and the feasibility and excellent performance of the design is verified.

This filter has the advantages of compact size, low insertion loss in the passband, and sharp rejection in the stopband. Moreover, without coupling gaps, this novel bandpass filter can reduce the fabrication uncertainty. One transmission zero is realized in the low stopband. The simulated and measured results were found to be in good agreement. TEMPORAL ACCELERATION OF TIME-DOMAIN INTEGRAL-EQUATION SOLVERS FOR ELECTROMAGNETIC SCATTERING FROM OBJECTS RESIDING IN LOSSY MEDIA

The paper presents a dual‐wideband bandpass filter using multilayer broadside‐coupled microstrip‐coplanar waveguide (CPW) structure. The half‐wavelength stepped‐impedance resonators at the top and bottom layers are broadside coupled in the vertical direction through a CPW‐multimode resonator (CPW‐MMR) at the mid layer, which forms a mixed MMR. The ultra‐wideband obtained from tight coupling is split into two passbands by introducing extra transmission zeros, good impedance matching is achieved by adopting open‐ended microstrip stubs on the input and output microstrip feed lines, and the dual‐wideband characteristic is realized. The proposed filter is small in size, and its operation bands and the bandwidth of the stopband are adjustable. Both experiments and computer simulations were conducted, and the measured results are in good agreement with the simulation results.

This paper describes the design of a compact stripline ceramic filter, using short‐circuit stepped‐impedance resonators (SIRs) to enhance the harmonic stop‐band response. Moreover, this filter has a very small size of 3.6 mm × 3.0 mm × 0.5 mm and a low insertion loss of 0.6 dB in the passband. The filter's response, with a design center frequency of 2390 MHz and 3‐dB bandwidth at 250 MHz (10.4%), shows an increase in the first harmonic frequency to 9004 MHz. At three times the fundamental passband frequency (7160 MHz), stop‐band attenuation is better than −40 dB. The results demonstrate the usefulness of SIRs for improving the stop‐band performance of bandpass filters. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 380–383, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11224

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We Use Ansoft HFSS to simulate coplanar waveguide (CPW) feeding butterfly slot antenna(CPW-Fed Bow-Tie-Slot) . Through the control of the parameter variation, the thickness of the substrate , width of the slit , length of CPW , frequency, etc ,we compared and analyzed return loss and obtained the change rules of the antenna performance. Based on the study results, this paper proposed a method to obtain reasonable set parameters and simple optimization.

In this paper, the resonant frequency of a dual-mode dielectric resonator is calculated using a finite difference time-domain method. A new type of bandpass filter is designed with the calculated coupling coefficient. The filter designed in this paper has reached the design goal, verified by simulation with Ansoft HFSS.