Binboga Siddik Yarman

Computer-aided double matching via parametric representation of Brune functions

A new computer-aided broadband matching technique, the so-called parametric approach, is applied to double-matching problems. The technique takes less computation time and yields superior gain performance over the other available brute-force CAD techniques. Examples are presented to exhibit the practical use of the parametric approach. The results obtained are compared with those obtained via the real-frequency-direct-computational technique, which offers superior design performance with simple equalizer structures. The real-frequency techniques of broadbanding are implemented with several computational phases in which data-fitting processes, explicit factorization of real polynomials, and solution of a set of linear equations are required. The proposed parametric approach is a reformulation of the real-frequency techniques that eliminates the laborious numerical computations of the latter. The approach involves the parametric representation of Brune functions. Neither the use of explicit factorization of polynomials nor the solution of linear equation systems is necessary. Thus, the parametric method of broadband matching requires less computation with improved numerical stability. >

Design of Practical Matching Networks With Lumped Elements Via Modeling

It is a common practice to utilize commercially available software tools to design matching networks for wireless communication systems. Most of these tools require a properly selected matching network topology with good initial element values. Therefore, in this paper, a practical method is presented to generate matching networks with initial element values. In the implementation process of the proposed method first, the driving point immitance data for the matching network is obtained in a straight forward manner without optimization. Then, it is modeled as a realizable bounded-real input reflection coefficient which in turn yields the desired matching network with reasonable element values. Eventually, the initial design is improved by optimizing the performance of the matched system employing the commercially available computer-aided design (CAD) packages. An example is given to illustrate the utilization of the proposed method. It is shown that new method provides excellent results as a front-end when utilized together with CAD tools.

An integrated design tool to construct lossless matching networks with mixed lumped and distributed elements

A design tool that combines the simplified real frequency technique of broadbanding with an appropriate application of algebraic network decomposition and replacement techniques is presented. The method incorporates the outstanding merits of modern single-variable broadbanding techniques, i.e. during the course of the design, there is no need to choose a circuit topology with mixed elements in advance, nor is it necessary to invent a realizable transfer function in two variables to measure the system performance. Examples are presented to exhibit the application of the tool, which is expected to be useful for constructing practical MMIC matching networks, since the fringing lumped element parasitics which arise due to the physical implementation can easily be adsorbed within the mixed element network structure. >

Design of ultra-wideband antenna matching networks

In this review paper, modern methods, so called the real frequency techniques to design broadband matching network are covered, a design roadmap is given with relevant recommendations. Measured performances of the recently designed and manufactured ultra-wideband matching circuits are outlined for various applications.

High Precision LC Ladder Synthesis Part I: Lowpass Ladder Synthesis via Parametric Approach

In this paper, a novel, high precision lowpass LC ladder synthesis algorithm is presented. The new algorithm directly works on the driving point input immitance function which describes the lowpass LC ladder in resistive termination. The crux of the idea is that, at each step of the proposed method, a simple pole at infinity is removed then, the remaining immitance function is corrected using the parametric method. Parametric method warrants the exact lowpass LC ladder nature of the remaining immitance function. Thus, at the end of the synthesis process, a lowpass LC ladder is obtained with high numerical precision. Examples are presented to exhibit the implementation of the synthesis algorithm. A randomly generated driving point input immitance is synthesized with 19 elements yielding a relative error less than 10-6. Furthermore, numerical robustness of the novel synthesis method is tested. Based on the tests, we can confidently state that, proposed synthesis algorithm can safely extract more than 40 elements from the original immitance function with a relative error less than 10-2. Newly developed synthesis algorithm is coded on MatLab environment and it is successfully combined with the “Real Frequency-Direct Computational Technique” to construct practical impedance matching networks.

Opportunistic source-pair selection for multi-user two-way amplify-and-forward wireless relaying networks

This study investigates the opportunistic source-pair selection (OSPS) strategy for the intercell interference (ICI) challenge in multi-user amplify-and-forward-based bi-directional wireless relaying networks. The method relies on selection of an appropriate SP node among N available SP nodes based on each SPs maximum sum capacity (SC). According to analytical, asymptotic and Monte Carlo simulation results, the OSPS strategy, besides achieving the near-optimal solution for the ICI challenge, if the number of the user-pair increases, also achieves multi-user diversity gain by selecting the maximum SC user-pair in each time slot. Moreover, the SC-based user-pair selection method outperforms the simultaneous transmission model and the max–min-based user-pair selection method in such a system model.

EEG signal compression based on Classified Signature and Envelope Vector Sets

In this paper, a novel method to compress electroencephalogram (EEG) signal is proposed. The proposed method is based on the generation classified signature and envelope vector sets (CSEVS) by using an effective k-means clustering algorithm. In this work, on a frame basis, any EEG signal is modeled by multiplying three parameters as called the classified signature vector, classified envelope vector, and frame-scaling coefficient. In this case, EEG signal for each frame is described in terms of the two indices R and K of CSEVS and the frame-scaling coefficient. The proposed method is assessed through the use of root-mean-square error (RMSE) and visual inspection measures. The proposed method achieves good compression ratios with low level reconstruction error while preserving diagnostic information in the reconstructed EEG signal.

Construction of some classes of two-variable lossless ladder networks with simple lumped elements and uniform transmission lines

In this paper, explicit two-variable description of some classes of ladder networks of high-pass, band-pass and band-reject types are presented. Up to a certain complexity, for two-element kinds of these types of regular structures, explicit expressions describing the two-variable scattering functions are obtained.

A novel biometric authentication approach using electrocardiogram signals

In this work, we present a novel biometric authentication approach based on combination of AC/DCT features, MFCC features, and QRS beat information of the ECG signals. The proposed approach is tested on a subset of 30 subjects selected from the PTB database. This subset consists of 13 healthy and 17 non-healthy subjects who have two ECG records. The proposed biometric authentication approach achieves average frame recognition rate of %97.31 on the selected subset. Our experimental results imply that the frame recognition rate of the proposed authentication approach is better than that of ACDCT and MFCC based biometric authentication systems, individually.

A novel method to design wideband power amplifier for wireless communication

A new approach is presented to design microwave amplifiers to deliver maximum output power using Simplified Real Frequency Technique (SRFT). Proposed method tracks the maximum stable gain (MSG) curve of the active device (BJT, FET etc.) under consideration. Maximum Stable Gain Amplifier (MSGA) possesses higher gain than that of the constant or Flat Gain Amplifier (FGA) along the operating frequency band. Compared to FGA, it is this feature that makes MSGA high efficiency and low DC power consumption amplifier. Employing the proposed design method, a MSG power amplifier is constructed over the frequency band of 800-5200 MHz which can be utilized for GSM, UMTS, Wi-Fi and Wi-MAX applications.