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

Abstract

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.

Average power-handling capability of the signal line in coplanar waveguides on polyimide and GaAs substrates including the irregular line edge shape effects

“…When applying the above equations to evaluate the rise in temperature of the signal line, the rule of a 45°h eat-spread angle is assumed [10,11]. This means that the heat generated in the signal line flows down through the double-layer polyimide and GaAs.…”

“…To calculate the "average" ⌬T( f ), an appropriate model of heat flow is needed, which is similar to that given in [10,11] for a single microstrip line. The average thermal conductivity of GaAs is 2 (av) ϭ 32.2 W/(m K).…”

“…To the best of our knowledge, the average powerhandling capabilities (APHCs) of a microstrip line on double-layer polyimide and GaAs substrates were first studied by Bahl [1,10], and the APHCs of an edgecoupled microstrip lines were investigated in [11]. In these studies, appropriate thermal models were proposed to determine the rise in temperature of the microstrip lines.…”

Average Power Handling Capability of Corrugated Slow-Wave Transmission Lines

“…The parallel-plate model is also utilized in estimating the APHCs of multilayer microstrip lines [8] and various microwave passive components [9][10][11]. However, for the transmission lines with more complicated structures, such as coupled microstrip lines [12,13] and coplanar waveguides [14,15], the constantangle model is more often used when estimating the APHCs. Although the SWTLs are utilized in the design of various microwave circuits, to the best of the authors' knowledge, their APHCs have not yet been investigated.…”

Average Power Handling Capability of Microstrip Passive Circuits Considering Metal Housing and Environment Conditions

“…The APHC of microstrip lines was first studied in [1] and [3]. Later on, different works dealt with APHC for microstrip coupled lines [4], [5], coupled-line filters [6], [7], multilayer microstrip lines [8], and thin-film microstrip lines [9]- [11]. Basically, the procedure for its calculation is to determine the conductor and dielectric losses, then, the heat flow distribution in the microstrip cross section is derived to finally obtain the temperature rise that defines the maximum working input power.…”