• KIEE International Transactions on Electrophysics and Applications
• /
• v.2C no.5
• /
• pp.268-272
• /
• 2002

In this paper, we proposed a procedure to analyze a shielded-microstrip step discontinuity using the mode matching method (MMM) combined with the vector finite element method (VFEM), which is used to find the equivalent waveguide-model for a microstrip. In order to calculate the effective-widths and -dielectric permittivity of the equivalent waveguide-model corresponding shielded-microstrip, the propagation constant and characteristic impedance are calculated from the VFEM. MMM is then applied to find the scattering parameter in the planar waveguide. This technique makes it possible to take advantage of the high accuracy of the VFEM as well as the high efficiency of the MMM.

• Proceedings of the KIEE Conference
• /
• 2011.07a
• /
• pp.1664-1665
• /
• 2011

This paper presents a derivation of the capacitance of a shielded microstrip line using the Finite Element Method (FEM). The first approach adopts a 2-D version of Gauss's theorem and an approximation of integral to finite differencing. In this case, the choice of a contour and the size of a mesh affects the validity of the capacitance. Next, the method for deriving the capacitance by using of energy relation is shown. Finally, the simulation results are compared to those of the commercial tool (COMSOL) adopted FEM.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.45 no.4
• /
• pp.131-136
• /
• 2008

Two Ka-band 3-stage power amplifiers were designed and fabricated using $0.18-{\mu}m$ CMOS technology. For low loss matching networks for the amplifiers, two substrate-shielded transmission line structures, having good modeling accuracy up to 40 GHz were used. The measured insertion loss of substrate-shielded microstrip-line (MSL) was 0.5 dB/mm at 27 GHz. A 3-stage CMOS amplifier using substrate-shielded MSL achieved a 14.7-dB small-signal gain and a 14.5-dBm output power at 27 GHz in a compact chip area of 0.83$mm^2$. The measured insertion loss of substrate-shielded coplanar waveguide (CPW) was 1.0 dB/mm at 27 GHz. A 3-stage amplifier using substrate-shielded CPW achieved a 12-dB small-signal gai and a 12.5-dBm output power at 26.5 GHz. This results shows a potential of CMOS technology for low cost short-range wireless communication components and system.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.11 no.6
• /
• pp.388-395
• /
• 1986

Dispersion characteristics of shielded single, coupled and edge-offset microstrip structures are investigated by using hybrid mode analysis with Galerkin's method in the spectral domain. Two new basis functions for the longitudinal strip current are proposed and convergence rates of the solutions for the basis functions are compared. Current distribution of the coupled line is obtaind from that of the single line by using shift theorem of the Fourier transform. In addition, effects of off-centered inner strip conductor on dispersion are also discussed Numerical results include various structual parameters and are compared with other available data and good agreements are observed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.15 no.10 s.89
• /
• pp.944-951
• /
• 2004

In this paper, we proposed the method of the characteristic impedance and effective dielectric constant calculations of the shielded microstrip line with ground aperture using conformal mapping method. This method has advantages that can calculate the transmission parameters without using any other numerical method because present the closed form equations. First of all, we supposed the signal propagate with the microstrip mode(Quasi-TEM) and calculated the capacitance divide by three sections and calculated the characteristic impedance and effective dielectric constant using calculated capacitances. From the HFSS simulation result, calculated result was very similar to the simulation result within the five percent error range.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.7 no.8
• /
• pp.1621-1628
• /
• 2003

Packaging structures to block the propagation of higher­order modes in the shielded microstrip lines are designed. Packaging for microwave circuits is necessary, basically, to isolate and protect circuits from outside environments both physically and electrically. The drawback of packaging is the possibility of higher­order mode propagation, similar to waveguide modes, as the operating frequency increases. One of Possible choices for the higher­order mode suppression is to insert diaphragms to the housing structure. The shielding effects of diaphragms are analyzed using an FEM code. Several parameters such as dispersion, mode conversion, and higher­order mode transmission and reflection are analyzed. The effect of higher­order mode suppression is eminent as the depth or width of a diaphragm is increased in the air region of the microstrip line. It is shown that inductive diaphragm structure can lower ${S_21}$ for the second­order mode incidence by 30㏈, comparing with the conventional capacitive diaphragm structure. Packaging structure analyzed in this paper can be applied usefully to the design of the microwave system in a package such as transmit/receive modules.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.31 no.3A
• /
• pp.356-359
• /
• 2006

A monolithic SiGe HBT variable gain driver amplifier(VGDA) with high dB-linear gain control and high linearity has been developed as a driver amplifier with ground-shielded microstrip lines for 5-GHz transmitters. The VGDA consists of three blocks such as the cascode gain-control stage, fixed-gain output stage, and voltage control block. The circuit elements were optimized by using the Agilent Technologies' ADSs. The VGDA was implemented in STMicroelectronics' 0.35${\mu}m$ Si-BiCMOS process. The VGDA exhibits a dynamic gain control range of 34 dB with the control voltage range from 0 to 2.3 V in 5.15-5.35 GHz band. At 5.15 GHz, maximum gain and attenuation are 10.5 dB and -23.6 dB, respectively. The amplifier also produces a 1-dB gain-compression output power of -3 dBm and output third-order intercept point of 7.5 dBm. Input/output voltage standing wave ratios of the VGDA keep low and constant despite change in the gain-control voltage.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.39 no.10
• /
• pp.38-45
• /
• 2002

This paper presents the new Compact 2D ADI-FDTD(Alternating-Direction Implicit Finite-Difference Time-Domain) method, where the time step is no longer restricted by the numerical stability condition. This method is an accelerating algorithm for the conventional Compact 2D FDTD method. To validate this algorithm, we have analyzed the dispersion characteristics of the hollow rectangular waveguide and the shielded microstrip line. The results of the proposed method are very well agreed with those of both the conventional analytic method and the Compact 2D FDTD method. The CPU time for analysis of this method is very much reduced compared with the conventional Compact 2D FDTD method. The proposed method is valuable as a fast algorithm in the research of dispersion characteristics of the waveguide structures.