A Review of the 1997 Wireless Workshop

Frank Bashore
Microwave Journal Staff

The 1997 Wireless Workshop was held October 26–29 to serve as a technical forum for approximately 85 engineering and technical representatives of leading companies involved in the design and manufacturing of materials and circuits for today's wireless communications systems. As in the past, the workshop was hosted by Rogers Corp., Merix Corp., Taconic Advanced Dielectric Division (ADD) and M-Wave. The IEEE MTT-S was a technical co-sponsor. This year's event was held just north of Phoenix in Carefree, AZ, a quiet and beautiful setting, located away from the hustle and bustle of the booming wireless equipment market that is driving the industry today. The program's goal is to provide an interchange of ideas among the designers and manufacturers of wireless circuit board materials, assemblies and components.

Barry Spielman of Washington University again led the conference as program chairman and Sharon Aspden of Rogers Corp. served as general chairman. The technical steering committee comprised Joe Barrera of Whisper Communications, Ed Niehenke, formerly of Northrop-Grumman, Dave Rowe of Sierra Monolithics and David Light of Tessera.

The program began on Sunday with a welcoming reception at the Carefree Inn under the evening sky of the Arizona desert. Many of the attendees are regular participants and took the opportunity to renew old friendships, and catch up on events and changes in other organizations. The new faces were eagerly welcomed and rapidly became part of the group.

The technical program was properly kicked off with a stimulating keynote address by Daniel Artusi, general manager of the Wireless Infrastructure Systems Division of Motorola Semiconductor Products Sector. Artusi spoke of "Wireless Communications — The Global Revolution Continues," an up-to-date look at today's wireless market and new technologies that are emerging to cope with the demands the industry will face in the next millennium, and the performance requirements of these new systems. The address set the tone for a stimulating program to follow.

Tutorials were presented by Art Aguayo and Nick Santhanam of Rogers Corp. and Taconic ADD, respectively, on "Dielectric Constant Test Methods for Low Loss Substrates"; and John Bushie of Taconic ADD on "PTFE and Hybrid Multilayer Bonding and Fabrication." This year's design competition actively involved the participants as they attempted to produce the most outrageous solutions to the hypothetical problem. There was no lack of enthusiasm or creativity, and the competition was fierce.

The technical paper presentations included "The Measurement of RF Dielectric Properties with Series Resonant Microstrip Elements," by Donald A. Rudy of Lucent Technologies Bell Laboratories, which described the use of microstrip circuitry to determine the properties of high performance, high frequency PCB materials. Robert Traut of Rogers Corp. presented "A Proposed IPC Test Method for Complex Permittivity of RF Circuit Board Substrates by Resonances up to 14 GHz," describing a long stripline specimen probed for microwave resonance through adjustable air gaps at the ends, permitting resonant measurements over a wide frequency range for determining complex permittivity of a dielectric. David Light of Tessera presented "mBGA" CSP: A Compliant Chip Size Package Technology for Semiconductors," detailing his company's ball grid array IC chip package, and its properties and advantages. Another paper described the nature of surface treatments used for preparing the bonding interfaces in multilayer PCBs using epoxy, polyimide and polytetrafluoroethylene laminates entitled "Analysis of Surface Treatment for Multilayer Bonding Interfaces," by Joe Turek of M-Wave.

Jeanne Pavio of Motorola SPS presented a paper entitled "Comparison of Thermal Performance with LDMOS Die in Micro 250 Package: Using High Conductivity Epoxy, Eutectic Attach, Solder and Standard Conductive Epoxy." Frank Sullivan of Raytheon's Electronic Systems Division presented "Low Temperature Cofired Ceramic Applications for Microwave Multichip Modules." The paper explained how this technique is a viable option for use as a multilayered transmission medium for microwave and mm-wave circuit applications. Patrick Roblin of Ohio University presented a description of modeling, fabrication and analysis of microstrip antennas, and described the properties and suitability of a new PCB substrate material for this application. The paper was entitled "New PCB Substrate Used for Patch Antenna Fabrication."

A panel discussion was lead by Joe Barrera and comprised Dan Swanson of M/A-COM, Frank Sullivan, Bob Daigle of Rogers Corp. and Craig Sutton of Filtran. The discussion focused on "The Real Cost of Making a 2.4 GHz PCB."

The final day led off with a paper entitled "New Microwave PCB Substrates Offer New Opportunities and Cost Reductions Compared to Traditional Technology," by Olivier Prévotat of Thomson-CSF. This paper explained how using new microwave PCB substrates can reduce microwave circuit costs dramatically compared to using traditional technology on alumina. David Hairfield of Raytheon E-Systems presented "Design of a Wideband, High Dynamic Range Downconverter for Use in AMPS Cellular Base Stations," in which he described the design from concept through production and explained the innovative packaging techniques employed. Another innovative concept discussed was "Integrated Resistor Networks for High Frequency Multilayer Printed Circuit Boards," by Chad Wilson of Northrop Grumman's Electronic Sensors and Systems Division. The concept of using planar resistor technology to integrate resistors into a laminated PCB was described.

The final presentation, prepared by Suzanne Seymour of Taconic ADD, was entitled "Design for Low Cost Manufacturing," in which details were outlined that should be considered to bring a design to production quickly and within budget. Many of these details involved material considerations and fabrication techniques.

The four-day workshop was a productive event that provided information on new techniques and solutions that can increase productivity and performance in the design and manufacturing of wireless products of the future. The concept of suppliers and users meeting in a noncompetitive environment to discuss state-of-the-art techniques and solutions benefits all attendees significantly.

Although the workshop's technical proceedings are not generally available, copies of individual papers can be obtained by contacting Sharon Aspden, Rogers Corp., Microwave Materials Division, 100 S. Roosevelt Ave., Chandler, AZ 85226 (602) 961-1382. The 1998 Wireless Workshop is scheduled for the fall of next year.