Hyeong-Seok Kim

Optimum Design of Wideband Bandpass Filter With CSRR-Loaded Transmission Line Using Evolution Strategy

In this paper, a planar wideband bandpass filter with complementary split-ring resonator (CSRR)-loaded transmission line is optimally designed taking into account a multi-regional objective function. Eight physical dimensions are set to be design parameters of the filter structure, and the Evolution Strategy (ES) algorithm is adopted to optimize the multi-parameter problem. The result shows that a simple gap capacitance model can make wideband bandpass filter and accomplish the design goal well with smaller size by the proposed optimization technique.

Robust design of dual band/polarization patch antenna using sensitivity analysis and Taguchi's method

In this paper, sensitivity analysis and Taguchis method are applied to the design of dual band patch antenna using gap coupling. The proposed structure uses T-slotted aperture coupling between patch and feed line of ground plane. Using sensitivity analysis, optimum dimensions of patch and coplanar waveguide (CPW) feed line are first sought. Then the optimized values are modified by Taguchis method in order to obtain robustness against the change of material constant and gap between patch and feed line. Moreover, the validity of the robust design has been tested with two antennas manufactured according to the final design. From the numerical and experimental results, it is confirmed that the final design is insensitive to noise factors.

A Practical Approach to Robust Design of a RFID Triple-Band PIFA Structure

This paper presents a practical methodology of obtaining a robust optimal solution for a multi U-slot PIFA (Planar Inverted F-Antenna) structure with triple bands of 433 MHz, 912 MHz and 2.45 GHz. Using evolutionary strategy, a global optimum is first sought out in terms of the dimensions of the slots and shorting strip. Then, starting with the optimized values, Taguchi quality method is carried out in order to obtain a robust design of the antenna against the changes of uncontrollable factors such as material property and feed position. To prove the validity of the proposed method, the performance of the antenna is predicted by general-purpose electromagnetic software and also compared to experimental results.

System Design Considerations for a ZigBee RF Receiver with regard to Coexistence with Wireless Devices in the 2.4GHz ISM-band

At the present time the task of designing a highly integrated ZigBee radio frequency (RF) receiver with an excellent coexistence performance is still very demanding and challenging. This paper presents a number of system issues and design considerations for a ZigBee RF receiver, namely IEEE 802.15.4, for coexistence with wireless devices in the 2.4-GHz ISM-band. With regard to IEEE 802.15.4, the paper analyzes receiver performance requirements for; system noise figure (NF), system third-order intercept point (system-IIP3), local oscillator phase noise and selectivity. Based on some assumptions, the paper illustrates the relationship between minimum detectable signal (MDS) and various situations that involve the effects of electromagnetic interference generated by other wireless devices. We infer the necessity of much more stringent specification requirements than the published standard for various wireless communication field environments

Application of the Sensitivity Analysis to the Optimal Design of the Microstrip Low-Pass Filter With Defected Ground Structure

This paper shows applied sensitivity analysis for easier design and practical application of a planar half-wavelength low-pass filter (LPF) using defected ground structure (DGS). Typically, it is difficult to deploy planar half-wavelength low-pass filters when high power durability is required because of the very narrow line-widths of high impedance transmission line. Here, we propose a new configuration for the high impedance microstrip line using DGS structure to allow broader line width and high power handling capability. The sensitivity of the scattering parameters was calculated using the self-adjoint sensitivity formula in order to determine the proposed filters dimension. The paper also highlights the validity of the proposed LPF optimization with its measured performance.

Optimal Design of a Compact Filter for UWB Applications Using an Improved Particle Swarm Optimization

This paper proposes an improved particle swarm optimization (PSO) process to design a high-performance compact ultrawideband (UWB) filter. The filter consists of one-cell composite right- and left-handed-transmission line (CRLH-TL) resonator, a stepped impedance (SI), and two spurlines. The one-cell CRLH-TL resonator has compact size but performs wide passband filtering. One SI and two spurlines are employed to reject both the harmonics outside the UWB and the wireless local area network (WLAN) (5.15-5.825 GHz) band. The improved PSO consists of the conventional PSO with the sensitivity analysis, and the process for checking the ripple. The improved PSO suppresses the ripple and accelerates the optimization. During the improved PSO, the objective function converges from the 116th iteration. In addition, the characteristic of the filter is optimized to get acceptable results. The proposed filter has the overall size of 14×15 mm2 (0.63λg ×0.53λg) only, a 105% bandwidth for a return loss >10 dB, a flat insertion loss <;1.4 dB, and stopbands on 11.5~22 GHz and WLAN band. In particular, the ripple in the passband is minimized significantly by the improved PSO.

Design of the miniaturized ultra-wide band (UWB) filter using the metamaterial characteristic

In this paper, a filter for the ultra-wide band (UWB) ranging 3GHz ~ 10.5GHz has been designed by taking the advantage of the metamaterial Composite Right & Left-Handed Transmission-line (CRLH-TL) with a Shorted Open Gap Ring Resonator (SOGRR) structure and an inter-digital line. In order to bring the remarkable improvement in an attempt to reduce the total metamaterial cell size, only one cell of the SOGRR with the inter-digital line is taken. This metamaterial filter will be shown to have the size of 15mm×15mm, the fractional bandwidth over 100%, the insertion loss much less than 1dB, and an acceptable return loss.

Optimum Sensor Nodes Deployment Using Fuzzy C-Means Algorithm

In this paper, a fuzzy c-means clustering algorithm is proposed to determine the optimum deployment of sensor nodes. It is for a given application space to improve energy efficiency and reduce cost. We performed simulation for ¡®L shaped area to find minimum number and optimum location of sensor nodes.

Robust optimum design of PIFA for RFID mobile dongle applications

A novel planar inverted F-antenna (PIFA) structure for a dongle-type RFID reader module with a resonant frequency of 920 MHz is proposed using a robust optimum design process. In order to take into account the robustness against noise factors, the Taguchi quality method is complemented to the evolutionary strategy optimization method. The validity of the proposed design process is verified through a noise test and comparisons of the computation and the experiment results.

Parameter Extraction and Optimal Design of Spiral Inductor Using Evolution Strategy and Sensitivity

For precise electromagnetic (EM) field simulation of the spiral inductor, electric conductivity of the inductor substrate is determined by evolution strategy to match the Taiwan Semiconductor Manufacturing Company (TSMC) process. Based on this parameter, patterned ground shield (PGS) of an on-chip spiral inductor is designed using deterministic optimization method. The design parameters are lengths and widths of ground strips and widths of slots. For sensitivity analysis, approximate adjoint variable method is used. Significant increase in Q-factor is observed in final design while reduction of inductance is minimal. Spiral inductor with optimized PGS is used in input matching circuit of 2.45-GHz low noise amplifier (LNA), which shows improved noise figure characteristics compared to non-PGS case.