Frequency‐dependent maximum average power‐handling capabilities of single and edge‐coupled microstrip lines on low‐temperature co‐fired ceramic (LTCC) substrates

The frequency‐dependent maximum average power‐handling capabilities (APHCs) of single and edge‐coupled microstrip lines (MLs) on low‐temperature co‐fired ceramic (LTCC) substrates are investigated in this article. Although LTCCs have excellent high‐frequency performance, the thermal conductivity is about 2.0–3.0 W/m°C, which is much smaller than that of sapphires, alumina, silicon, and GaAs. The method used to predict the APHC is based on the calculated conductive and dielectric attenuation constants for different modes, and the proposed multilayer thermal model for the temperature rise. Numerical investigations are carried out to examine the effects of geometric and physical parameters on the wideband pulse responses and maximum APHC for single finite‐ground thin‐film and coupled MLs, respectively. Methodologies to enhance the power‐handling capability which are useful in the design of high‐density microstrip interconnects on or embedded in multi‐layer LTCCs are proposed. © 2005 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2006.     

Wideband description of the finite‐ground coplanar waveguide‐type structures with discontinuities

Some mathematical models are proposed to accurately describe the frequency‐dependent series conductance and susceptance of the discontinuities in various finite‐ground capacitive series‐connected coplanar waveguides (FGCPWs). These models can predict the wideband self‐resonance characteristics in the air gap regions. Also, it is pointed out that the Heinrich's equation is applicable to compute the per‐unit‐length parameters of the uniform FGCPWs, though it was rarely used in the past 10 years. It is shown that Heinrich's equation can be used to capture the frequency‐dependent distributed resistance and inductance in a real chip environment. Using our proposed models with Heinrich's equation, numerical calculations are performed to show the effects of metallization surface conductivity and thickness of both capacitive and inductive series‐connected FGCPW geometries on their frequency‐dependent series resistances, series inductances and shunt capacitances. © 2007 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2007.