Analysis of Coupling between DR and Microstrip

The coupling between dielectric resonator (DR) and microstrip is theoretically analyzed in thispaper.The equivalent circuit and corresponding components' expression are achieved.Also,the formula of thecoupling ratio is deduced,which is the critical parameter to calculate the values of components.The analysis of thepaper can be used in modeling and strict design in DR applications such as dielectric resonator oscillators(DROs)and DR filters.At the end of the paper,an example of DRO design based on the analysis above is given.Thecoincidence between modulation and measure shows the significance of the paper.     

Design of Unequal Thickness Interference Filters with Quarter Wavelength Stack

A system of unequal thickness interference filters with quarter wavelength stack which consists of a spacer surrounded by two multiplayer stacks is designed, and the examples of the filter design are given.This kind of filters are not only characterized by high-transparency, but also by high-reflection, therefore, it is superior to the common equal thickness interference system with quarter wavelength.it is easier to control the manufacturing techniques of the new design as compared with that of interference filter of non-quarter wavelength.     

Microstrip Antenna–Oscillators Integrated with a Waveguide Built in a Dielectric Substrate

The design of a microwave oscillator based on a microstrip log-periodic antenna integrated with a field effect transistor and a waveguide built in a dielectric substrate has been developed and analyzed. The waveguide geometry provides the possibility of propagation and radiation at both the fundamental frequency of the log-periodic antenna and harmonics. Computer simulation of the oscillator design in a frequency range near resonance frequencies of the log-periodic antenna is conducted. The possibility of summation of powers of several antenna–oscillators arranged ias a linear phased array is investigated.     

Mosaic Structure of (001)YBa2Cu3O7-δ/(10.2)Al2O3 Epitaxial Films and Millimeter Waveband Properties of Microstrip Resonators

The c-axis single-phase YBa₂Cu₃O_7-δ films (δ = 0-0.15) on sapphire substrates prepared by the laser ablation technique and the band-pass stripline resonators for 34 GHz-range have been investigated. Increasing disorientation of mosaic block structure of YBa₂Cu₃O_7-δ films is related to increasing surface resistance R_s at 135 GHz-range and decreasing unloaded quality factor Q_o of linear stripline resonators. The linear dependence between the YBa₂Cu₃O_7-δ film mosaicity (M) and half-width B_α1 of 00.13 reflecting component is determined. The reflection spreading is due to microstrains resulted mainly from the coherent adjustment of the YBa₂Cu₃O_7-δ film lattice to GdBa₂Cu₃O_7-δ sub-layer and sapphire substrate. Increasing number of the block characterized by a weak radial lattice adjustment (ΔΨ) is demonstrated by spreading of 00.13 reflection. It is found out that ΔΨ depends on the Bragg angle of reflection due to inhomogenity of YBa₂Cu₃O_7-δ mosaic structure, which resulted from the gradual mosaicity decreasing with the depth.     

Dual and tri-band bandpass filters based on novel Π-shaped resonator

A novel Π-shaped resonator is proposed, and compact dual-band and tri-band bandpass filters that meet IEEE 802.11 application requirements by using the new resonator are designed. The dual-band bandpass filter centres at 2.45 and 5.6 GHz with a simulated passband insertion loss of no more than 0.8 dB, and the tri-band bandpass filter which is got by two-path coupling achieves simulated passband insertion loss of no more than 1.1 dB. The new designs are demonstrated by experiment. The new filters have advantages of simple and compact structures, low passband insertion losses, good frequency selectivity and miniature circuit sizes. All these have prospect to be applied in future wireless communication systems.     

Performance Study of 90° Bend Substrate Integrated Waveguide Band-Pass Filter with Multi-transmission Zeroes for MIC Applications

Wireless Personal Communications - In wireless sensor networks, the privacy of an event is critical to its safety. The location privacy of the sensor node that reports the event is imperative to...     

Synthesis of Wideband Linear-Phase FIR Filters with a Piecewise-Polynomial-Sinusoidal Impulse Response

A method is presented to synthesize wideband linear-phase finite-impulse-response (FIR) filters with a piecewise-polynomial-sinusoidal impulse response. The method is based on merging the earlier synthesis scheme proposed by the authors to design piecewise-polynomial filters with the method proposed by Chu and Burrus. The method uses an arbitrary number of separately generated center coefficients instead of only one or none as used in the method by Chu–Burrus. The desired impulse response is created by using a parallel connection of several filter branches and by adding an arbitrary number of center coefficients to form it. This method is especially effective for designing Hilbert transformers by using Type 4 linear-phase FIR filters, where only real-valued multipliers are needed in the implementation. The arithmetic complexity is proportional to the number of branches, the common polynomial order for each branch, and the number of separate center coefficients. For other linear-phase FIR filter types the arithmetic complexity depends additionally on the number of complex multipliers. Examples are given to illustrate the benefits of this method compared to the frequency-response masking (FRM) technique with regard to reducing the number of coefficients as well as arithmetic complexity.     

A Design and Analysis of Dolph-Chebyshev Microstrip Planar Array Using Butler Matrix Beamforming Networks

1　IntroductionInrecentyears,personalandmobilecellularcommunicationhasexperiencedanoverwhelmingin creaseinthenumberofusers,leadingtothehugeexpansionofcellularcommunicationsystems.Theproblemsassociatedwiththeearlyusedomnidirec tionalantennasincellularcommunicationbasesta tionsarepartlysolvedbyusingsectoredantennasorcellsectorization ;thatissplittingupa 360°areainto3or 6individualsectorsormore .Thetransmittedpowerisstillnotefficientlyutilizedbecausethean tennabeamsarestillfixedindirectionanddon…     

Morphological Filters and Wavelet-based Histogram Equalization Image Enhancement for Weak Target Detection

1　IntroductionInrecentdecades ,infrared (IR)andvisualimagesensorshavebeenusedinmanyapplications .Thesensorper formancedependsonitsworkcondition .Insomecasesthesensorperformancewoulddegenerateandimagequalitydescend ,makingtheweakincontrastandgray levelsda…     

Morphological Filters and Wavelet—based Histogram Equalization Image Enhancement for Weak Target Detection

Image enhancement methods are typically aimed at improvement of the overall visibility of features. Though histogram equalization can enhance the contrast by redistributing the gray levels, it has the drawback that it reduces the information in the processed image. In this paper, we present a new image enhancement algorithm. After histogram equalization is carried out, morphological filters and wavelet-based enhancement algorithm is used to clean out the unwanted details and further enhance the image and compensate for the information loss during histogram equalization. Experimental results show that the morphological filters and wavelet-based histogram equalization algorithm can significantly enhance the contrast and increase the information entropy of the image.     

Design of Multilayered K-Band and Ka-Band Slot-Coupled Microstrip 90° Hybrid Couplers Employing Circular Ring Patch Shapes

Numerical analysis and design of millimeter-wave (mmWave) slot-coupled microstrip 90° hybrid couplers employing circular ring patches, which is operating between 18 and 40 GHz frequency range for K-Band and Ka-Band radar applications, is presented in this paper. The proposed design uses multilayer printed circuit board (PCB) technology that allows having a compact and broad bandwidth coupler. The proposed couplers use broadside coupling between microstrip patches at the top and the bottom layers via an elliptical-shaped slot in the common ground plane (mid-layer). The design uses circular ring shaped broadside coupled patches and an elliptical-shaped slot created in a common ground plane between two identical dielectric substrates. The 3 dB coupler prototype has been fabricated on two 0.127 mm thick Rogers Duroid RT5880 substrates. The circuit occupies the dimensions of less than 5 mm × 5 mm without the extension that is required to insert the connectors. Extensive parametric studies are performed to address the effect of varying the coupler parameters on the coupling values, return losses, isolations, transmission magnitudes and phases through the operational frequency bandwidth. A 3 dB/90° hybrid coupler prototype is fabricated and then tested experimentally using Agilent E8364B PNA Network Analyzer. The simulation and experimental results show a good performance in terms of bandwidth, which covers the entire desired frequency range. In addition, detailed design for different coupling values of the proposed coupler is presented in this paper. The proposed coupler can achieve different coupling values range from 3 up to 9 dB that can be used for switched beam antenna array systems.     

Novel Cascadable All-Pass/Notch Filters Using a?Single?FDCCII and Grounded Capacitors

Four new second-order voltage-mode cascadable all-pass/notch filters are proposed using only a single active element and four passive components. The active element used is a fully differential current conveyor. All the circuits possess high-input and low-output impedance, which is a desirable feature for voltage-mode circuits. A non-ideal and parasitic study is also performed. The proposed circuits are verified through PSPICE simulation results.     

A Control-Theoretic Approach for Efficient Design of?Filters in DAC and Digital Audio Amplifiers

A control-theoretic approach in designing Digital-to-Analogue Converters and Digital Amplifiers which leads to improved performance in Audio and Multimedia applications is presented in this paper. The design involves an over-sampling and a pulse modulation component which is driven by a pulse generation algorithm based on the characteristics of the output filter. The theoretical model results in a family of digital circuits whose operation is verified by computer simulations achieving a performance of Signal-to-Noise Ratio of 147 dB at a switching rate of 90 MHz. Implementation and hardware complexity issues are discussed based on a FPGA realization of the algorithm.     

Reduced-Order H ∞ Filters for Uncertain 2-D Continuous Systems,Via LMIs and Polynomial Matrices

This paper deals with designing H _∞ filters of reduced order for two dimensional (2-D) continuous systems described by Roesser models, with uncertain state space matrices. These filters are characterized in terms of linear matrix inequalities (LMI), to minimize a bound on the H _∞ noise attenuation, by using homogeneous polynomially parameter-dependent matrices of arbitrary degree. The methodology is also particularized for full order and zero order (static) filters, where more simple LMI conditions are derived. Numerical examples are presented to illustrate the proposed methodology.     

Novel Multimode Interference Optical Filters in GeSi/Si for λ=1.3μm and 1.55μm

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Waveguide Bandstop Filters Based on Microwave Photonic Crystals with Parameters Controlled by n–i–p–i–n Diodes

Journal of Communications Technology and Electronics - A feasible design of a system with an allowed band with near-unity frequency-independent transmission utilizing the reflective properties of...     

Problems with Mobile IP and Their Solutions

The Mobile IP technologyis the core technology toimplement NGNapplications in traditionalnetworks.It is a newdomain for thedevelopment of IPtechnologies and theconvergence of wirelesscommunication and IPtechnologies.This paperdiscusses the mainproblems of Mobile IP intriangle routing,handoff,micro-movement andQoS,and gives theirsolutions respectively.Italso analyzes Mobile IPapplications for mobilecommunications,andconcludes that the MobileIP technology will play animportant role in mobilecommunications andprovide new opportunitiesto develop novelapplications in the future.     

Novel IGBT SPICE Model with Non-destructive Parameter Extraction and Comparison with Measurements

A subcircuit-based model for the insulated gate bipolar transistor(IGBT) is proposed and optimized. The IGBT wide base conductivity modulated resistor is effectively equivalent by using a voltage controlled resistor. Based on analytical equation describing the semiconductor physics, the model parameters are extracted accurately via measured data without device destruction. Employing the MOS-level-8 SPICE model, the proposed IGBT subcircuit model gives more simulation accuracy and easy convergence, the simulation results are verified by comparison with measured results.