Coplanar-type Transmission Lines Research Articles

Si RFIC상에서 주기적 구조를 이용한 코프레너형 전송선로의 기본특성연구

In this study, a short-wavelength coplanar-type transmission line employing periodic ground structure (PGS) was developed for application to miniaturized on-chip passive component on Si Radio Frequency Integrated Circuit (RFIC). The transmission line employing PGS showed shorter wavelength and lower characteristic impedance than conventional coplanar-type transmission line. The wavelength of the transmission line employing PGS structure was 57 % of the conventional coplanar-type transmission line on Si substrate. Using the theoretical analysis, basic characteristics of the transmission line employing PGS (e.g., bandwidth, loss, impedance, and resonance characteristics) were also investigated in order to evaluate its suitability for application to a development of miniaturized passive on-chip components on silicon RFIC. According to the results, the bandwidth of the transmission line employing PGS was more than 895 ㎓ as long as T is less than 20 ㎛, and the resonance characteristic was observed in 1239 ㎓, which indicates that the PPGM structure is a promising candidate for application to a development of miniaturized on-chip passive components on Si RFIC.

Si RFIC상의 온칩 수동소자에의 응용을 위한 주기적 접지 금속막 선로를 이용한 단파장 전송선로 개발

In this study, highly miniaturized short-wavelength transmission line employing periodically perforated ground metal (PPGM) structures were developed for application to miniaturized on-chip passive component on Si RFIC. The transmission line employing PPGM structure showed shorter wavelength and lower characteristic impedance than conventional coplanar-type transmission line. The wavelength of the transmission line employing PPGM structure was 57% of the conventional coplanar-type transmission line on Si Radio Frequency Integrated Circuit (RFIC) substrate. Basic characteristics of the transmission line employing PPGM structure were also investigated in order to evaluate its suitability for application to a development of miniaturized passive on-chip components. According to the results, it was found that the PPGM structure is a promising candidate for application to a development of miniaturized on-chip passive components on Si RFIC.

Heterodyne mixing with a sandwich-type Josephson junction using a Bi-based high- oxide superconductor

A sandwich-type high- Josephson junction coupled with a coplanar-type transmission line was fabricated and heterodyne mixing characteristics were investigated. The junction was fabricated from a stacked film structure of (BSCCO/BSNCO/BSCCO) and the transmission line was made of sputter-deposited Pt film. The junction had a rectangular shape of . Current - voltage (I - V) curves of the junction showed weak-link-type characteristics. Two microwave sources of a frequency synthesizer and a sweep oscillator were used as a local oscillator (LO: 20 GHz) and a radio frequency signal source (RF: 19 GHz) for heterodyne mixing experiments. Intermediate signal (IF: 1 GHz) was transmitted through the transmission line and detected by a power meter. The conversion efficiency of -44 dB was estimated for an LO oscillator level of -23 dB m at 5.7 K when the junction was biased at the point below the first Shapiro step.

The influence of metallization thickness on the characteristics of cascaded junction discontinuities of shielded coplanar type transmission line

A full-wave analysis based on the mode-matching technique is applied to analyze cascaded junction discontinuities of coplanar-type transmission lines, coplanar waveguide (CPW) and finline. Results for a CPW-finline transition, a shielded CPW gap and a symmetric notch incorporating the finite metallization thickness effect are presented. The influence of metallization thickness on the coupling effect exhibited by cascaded junction discontinuities is also presented and discussed.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Characterization of shielded coplanar type transmission line junction discontinuities incorporating the finite metallization thickness effect

Frequency-dependent characteristics of shielded junction discontinuities between coplanar type transmission lines, specifically coplanar waveguide (CPW) and finline, are analyzed by the mode-matching technique. The effect of finite metallization thickness is also incorporated in the analysis for the first time. Scattering parameters of finline step discontinuity are compared with existing data to confirm the accuracy of the approach. Numerical results for finline step discontinuity, shielded CPW step discontinuity and CPW-finline transition are presented.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Propagation characteristics of coplanar-type transmission lines with lossy media

Lossy coplanar-type transmission lines are analyzed based on the hybrid-mode formulation by combining the spectral-domain approach with the perturbation method. Introducing a finite thickness of metallization and choosing the proper basis functions for the thick conductor model prevent the integrals used for calculating the conductor losses from becoming singular when evaluated at the conductor edge. An orthogonality relation is used to reduce the double infinite or semi-infinite integral to a single integral, thus reducing the computation effort drastically. Numerical computations by new basis functions for the thick conductor show convergence rates as fast as those for the zero-thickness cases. Numerical results include the effective dielectric constants, characteristic impedances, and total losses (conductor and dielectric losses) for slot lines and symmetrical and asymmetrical coplanar waveguides.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Effect of optical phonons on femtosecond pulse propagation in coplanar striplines

A full-wave analysis of the dispersion in coplanar-type transmission lines is made including the effect of material dispersion arising from a frequency-dependent complex dielectric constant such as due to optical phonon resonances in the substrate. The results are used to examine the distortion of femtosecond electrical pulses propagating in coplanar striplines made on ultrathin as well as thick GaAs substrates. A new closed-form dispersion formula for coplanar lines is also reported, valid for complex dielectric constants and all values of frequency and line dimensions.

Dispersion of Picosecond Pulses in Coplanar Transmission Lines

The dispersion of coplanar-type transmission lines has been extended to the terahertz regime to examine the distortion of picosecond electrical pulses. Dispersion of coplanar waveguides is compared to equivalent microstrip lines. Agreement with available experimental data is demonstrated for coplanar strips, An approximate dispersion formula for coplanar waveguides is also reported for CAD applications.

Asymmetrical coupled coplanar-type transmission lines with anisotropic substrates

In the paper, the asymmetrical coupled coplanar-type transmission lines (C-CTLs) are investigated. The analytical method for the general structure of asymmetrical C-CTLs with anisotropic media is presented, based on the quasistatic and the hybrid-mode formulations, for the first time. The line characteristics of interest, e.g., the propagation constants and the characteristic impedances, of the various types of C-CTLs with anisotropic substrates are also presented.

Quasi-Static Characteristics of Asymmetrical and Coupled Coplanar-Type Transmission Lines

In this paper, variational expressions for the capacitances of' asymmetrical and coupled coplanar-type transmission lines are derived. The methods employed are quite general, and are useful for analyzing various types of coplanar-type transmission lines, with either an isotropic or anisotropic substrate. An accurate and efficient method of calculation is provided for the variational expressions, and some numerical results are presented.