Misoon Mah

Vertical balun and Wilkinson divider

We report the development of a novel broadband 3D vertical balun exhibiting superior performance due to ground plane removal and unique 3D features. The balun offers /spl plusmn/5 degrees phase and /spl plusmn/0.5 dB amplitude imbalance, from 2.0-2.7 GHz. In addition, we present the performance of a 3D X-band 4-way Wilkinson divider.

Properties of the embedded transmission line (ETL)-an offset stripline with two dielectrics

In three-dimensional (3-D) circuits that employ multilevel metallization, a frequently encountered transmission line configuration is the embedded transmission line (ETL), which is essentially an offset stripline topology with two dielectrics. There is no closed-form expression available for either the characteristic impedance or effective dielectric constant, since the problem is analytically complex for an exact analysis. This work provides an approximate empirical formula for both the effective dielectric constant and the characteristic impedance, and compares them with full-wave simulations of the structure. A few percent error (typically, less than 3% for Z/sub 0/, and 5% for /spl epsi//sub eff/) is observed over a wide range of transmission line parameters.

An equivalent circuit approach for microstrip component analysis using the FDTD method

The conventional analysis of waveguide parameters for microstrip components using the finite-difference time-domain (FDTD) method is based on monitoring the traveling wave at multiple locations. The dispersion relations of the effective dielectric constant and the characteristic impedance usually exhibit oscillatory behavior. An equivalent circuit approach was utilized for these parameters. Together with the FDTD results, the inductance and the capacitance were evaluated. The phase velocity and the characteristics impedance were then calculated at a single monitor location. With this method, the oscillatory features in the dispersion relations were minimized.

Analysis of three-dimensional embedded transmission lines (ETL's)

Three-dimensional (3-D) circuits promise a significant reduction in circuit size and cost. In 3-D circuits, a few transmission line configurations are encountered including the offset stripline and the embedded transmission line (ETL), a stripline-like topology with two dielectrics. The ETL may have either two ground planes (similar to an offset stripline) or one ground plane (similar to an inverted microstrip). There is a need for an accurate solution to predict the effective dielectric constant and characteristic impedance of these transmission line structures. This paper provides an accurate (1% maximum error) closed-form empirical formula for the effective dielectric constant and compares it with full-wave simulations. In addition, this letter provides an empirical formula for the characteristic impedance and compares it with full-wave simulations of the structure. Close agreement between the two approaches is observed over a wide range of parameters.

Design methodology of microstrip lines using dimensional analysis

Dimensional analysis has been used to develop a new methodology in microwave integrated circuit design using microstrip lines. The analysis reveals a complete set of dimensionless products for the microstrip line. The dependencies between these products are established using the Pi theorem. Using commercial simulation tools and numerical fitting techniques, design formulas can be established. These design formulas calculate the desired microwave parameters, such as characteristic impedance, effective dielectric constants, and their frequency dependencies.

Input variable space reduction using dimensional analysis for artificial neural network modeling [of MMICs]

Dimensional analysis for artificial neural network modeling of passive components is demonstrated. Results show that using dimensional analysis to limit the number of input variables significantly reduces the amount of training vectors needed for model development, which in turn decreases model development time. Also, dimensional analysis allows for determination of appropriate input variable space and leads to increased model accuracy.

Inexpensive X-band 1/2 watt PA using 3D LTCC technology

We report the development of a very low cost (

3D multilayer monolithic microwave (M/sup 3/) passive transmitter module

5.00), self-packaged, broadband (5-11 GHz), power amplifier (PA) based on 3D LTCC technology. The PA has more than 1/2 watt output power across the band.

Effective dielectric constant of the embedded transmission line (ETL)-a multilayer stripline-like structure

An X-band multilayer monolithic microwave (M/sup 3/) filter and patch antenna were designed, processed and characterized to demonstrate a three dimensional X-band passive transmitter. Multiple layers of polyimide and metal were deposited on a metalized silicon wafer. A filter and a patch antenna which were processed at two different layers were coupled through a slot on a common ground plane. The X-band 3D-M/sup 3/ passive transmitter was characterized for the radiation patterns.

Three dimensional transmission lines and special elements design

Utilizing 3D circuits may reduce components cost significantly. An essential configuration to consider is the embedded transmission line (ETL), an offset stripline with two dielectrics. There is no closed-form solution for the effective dielectric constant. This paper provides an accurate (1% maximum error) approximate formula, and compares it with full wave simulations.