Printed Circuit Design & Fab - August 2008 - (Page 33)

MICROWAvE laMinatE tablE 1. Benchmarked substrates and their parameters. including the above-mentioned minute ripple, is less than +/- 0.05 dB across the entire frequency range. For example, this repeatability is about +/- 0.02 dB in the 76 GHz range, which is the frequency of an automotive mm-wave radar system. To execute the above-mentioned smoothening, it was possible to reduce the error. Since measuring the transmission loss at that frequency is about 0.5 dB, it would appear that the measurement system has enough precision for comparing the differences between the substrates. tablE 2. Benchmarking. Measurement Results and Benchmarking The benchmarked substrates and parameters are indicated in tablE 1. The substrates, samples 1 through 4, are part of the development of the fluoropolymer copper-clad laminate. Sample 5 is the Rogers RT/Duroid 5880, and sample 6 is the major fluoropolymer copper-clad laminate material from Japan. The rms surface roughness (Rq) is the effective roughness as mentioned before. The top-side surface roughness was directly measured by stylus profilometer, and the bottom-side roughness was measured on the dielectric surface after the copper foil was etched off. Each substrate has eight kinds of characteristic impedance (Z1, Z2, Z3, Z4, Z5, Z6, Z7, Z8) of the transmission line in descending order. We benchmarked the transmission loss average of these eight lines. The average transmission losses in the 40 GHz and 76 GHz ranges are indicated in tablE 2. It was found that the transmission loss of the fluoropolymer copper clad laminate material is the same level as or less than sample 5, the Rogers RT/Duroid 5880. Separating Transmission Loss into Dielectric and Conductive Loss From measured transmission losses, we executed the loss separating procedure and compared the loss factors. First, we chose three kinds of impedance Z1, Z4 and Z8 from six kinds of substrate. For GerberStasis Film To Software Archiving Services GerberStasis services were designed to provide flexible cost options to companies seeking to develop a comprehensive back up plan for their legacy film libraries. While scanning films to TIF or JPEG files creates a software image, it also increases the cost to convert that image to a usable Gerber file for future production. Precision Images, LLC offers a strategic approach to legacy archiving that allows the customer to select the backup version based on the probability of the PCB being manufactured in the future. For as little as $5.00 per layer you can achieve the following benefits: • • • • • • Dimensional and feature size accuracy. PCB industry’s standard data format. Photoplot images for continued reverse engineering on any scanning system. Import to Gerber CAD/CAM systems as reference layers. Import to many PCB design programs as reference layers. Convert to DXF for import into AutoCAD as reference. Precision Images, LLC • 727 544-0201 • www.precision-images.biz AUGUST 2008 printEd circuit dEsign & faB 33 http://www.precision-images.biz http://www.precision-images.biz

Table of Contents Feed for the Digital Edition of Printed Circuit Design & Fab - August 2008

Printed Circuit Design & Fab - July 2008 Contents Our Line Market Watch Around the World Happenings ROI Tip Jar Software Performance Interconnect Strategies Final Finish Forum Product Development Challenges in a Global Market Innovative Modeling Supports Co-Design of the Power Supply Chain, Part 2 Low-Loss Fluoropolymer Copper Clad Laminate Qualifying PCBs Outsourced in Asia Copper Plating and Microvia Fill for Advanced PCBs Off the Shelf Marketplace Ad Index BGA Bulletin

Printed Circuit Design & Fab - August 2008

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