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Joung, Myoung-Sub,Park, Jun-Seok,Kim, Hyeong-Seok IEEE 2005 IEEE transactions on magnetics Vol.41 No.5
This paper demonstrates new systematic approaches to equivalent circuit model extraction for defected ground structure (DGS) directly from full-wave frequency domain simulation. The DGS circuits being modeled may be either lossy or lossless. Adaptive frequency sampling (AFS) is used to minimize the computational effort of electromagnetic (EM) simulation while critically assisting in determining the cutoff frequency and attenuation pole location of the DGS circuits. A simple circuit model for lossy DGS circuits without any optimization of lumped element component values is presented. Furthermore, lossless circuit model relative complex along with a determined starting point of optimization of lumped element values is also presented in detail. The overall results are an efficient and accurate means to produce the complete equivalent models of DGS circuit for the design of various RF and microwave circuits such as oscillators that may require the high accurate nonlinear design procedures.
Coupling Performance Analysis of a Buried Meshed-Ground in a Multi-layered Structure
Joung, Myoung-Sub,Park, Jun-Seok,Kim, Hyeong-Seok,Lim, Jae-Bong,Cho, Hong-Goo The Korean Institute of Electrical Engineers 2004 KIEE International Transactions on Electrophysics Vol.4C No.6
Since the manufacturing process in the LTCC process does not allow solid ground planes between ceramic layers to isolate the signal lines, the buried ground should be realized as a meshed ground plane. Both characteristic impedances of the signal lines and couplings between different signal layers are influenced by the properties of these meshed planes. In this paper, we propose a new analysis method for coupling behavior between internal transmission lines, which are isolated by the buried meshed-ground planes. The coupling behavior between layers isolated by meshed-ground planes is investigated by the coupled-transmission line model for the isolated layers. The coupling factors between isolated lines with the meshed-ground are extracted by 2-D FEM calculations.
A Design of 5.8 GHz Oscillator using the Novel Defected Ground Structure
Myoung-Sub Joung,Jun-Seok Park,Jae-Bong Lim,Hong-Goo Cho 한국전자파학회JEES 2003 Journal of Electromagnetic Engineering and Science Vol.3 No.2
This paper presents a 5.8-GHz oscillator that uses a novel defected ground structure(DGS), which is etched on the metallic ground plane. As the suggested defected ground structure is the structure for mounting an active device, it is the roles of a feedback loop inducing a negative resistance as well as a frequency-selective circuit. Applying the feedback loop between the drain and the gate of a FET device produces precise phase conversion in the feedback loop. The equivalent circuit parameters of the DGS are extracted by using a three-dimensional EM simulation and simple circuit analysis method. In order to demonstrate a new DGS oscillator, we designed the oscillator at 5.8-GHz. The experimental results show 4.17 dBm output power with over 22 % dc-to-RF power efficiency and -85.8 dBclHz phase noise at 100 kHz offset from the fundamental carrier at 5.81 GHz.
Design and Implementation of Broadband Antenna and Diplexer for Dual- Band Handsets
Joung, Myoung-Sub,Park, Jun-Seok,Kim, Hyeong-Seok,Lim, Jae-Bong,Cho, Hong-Goo The Korean Institute of Electrical Engineers 2004 KIEE International Transactions on Electrophysics Vol.4C No.6
In this paper, a ceramic antenna and diplexer are designed for dual-band handset ap plications. Basically, the antenna is designed by using the meander line configuration. The diplexer presented in this paper is composed of both low- and high-pass filters. We have designed the low- and high-pass filters with attenuation poles to improve the attenuation performances of the diplexer. The attenuation poles are located at each rejection frequency region so as to improve the shrinkage characteristic of the diplexer. In order to accomplish the volume effectiveness, the antenna and the diplexer have been designed and fabricated in a multi-layer structure. The diplexer designed with a multi-layer structure has inductors and capacitors, which are implemented by LTCC (Low Temperature Co-fired Ceramics) process technique. Design of the multi-layer antenna and diplexer has been achieved by employing the full 3-D EM simulation. The designed antenna and diplexer offer excellent return loss and broadband performances with highly isolated rejection performance.
Joung, Myoung-Sub,Park, Jun-Seok,Kim, Hyeong-Seok,Lim, Jae-Bong,Cho, Hong-Goo The Korean Institute of Electrical Engineers 2004 KIEE International Transactions on Electrophysics Vol.4C No.6
In this paper, the optimal design of a novel microstrip directional coupler with a grooved housing for high directivity characteristic is presented. It will be shown that the high directivity of the microstrip coupler can be achieved simply by attaching an optimized housing structure. over the microstrip, which is much easier to fabricate than other conventional types. The dimensions of the proposed structure are maximized by using (1+1) evolution strategy (ES) combined with the deterministic algorithm. To improve the effectiveness of the results, efficient optimization procedures suitable for the model are proposed. From these results, it is determined that the proposed structure indicates an improved directivity. The optimized results are verified by full wave analysis at the center frequency of 850MHz.