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Case Study:  Green Tape™ Decreases Size of Integrated Antenna Switch Diplexer Module

Challenge: Designing High Density Interconnects forAntenna Switch Diplexer Module Portable Wireless

Sorep-Erulec (Châteaubourg, France), the leading European-based manufacturer of circuits and modules using DuPont Green Tape™, has just introduced a new family of integrated antenna switches, diplexers, and filters for dual band portable wireless telephones. Sorep-Erulec has been designing and manufacturing high frequency and high density interconnect modules for performance-driven military and commercial applications for many years, and has developed processes and techniques to compete effectively in today's cost-driven portable wireless market.

The Sorep antenna switch/filter module shown combines GSM/DCS/PCS diplexing and RX TX antenna switching functions in a 9 X 10 mm footprint. A 26-pad peripheral ball grid array allows for efficient, high yield assembly. High-melting-point solder balls are used as spacers to allow for single-sided component placement, leaving a flat back side for ease of pick and place.

The module incorporates 13 embedded capacitors and inductors to form a diplexer and two low pass filters. Laser trimming is used to adjust the performance of the filters. Integrating capacitors and inductors into the substrate increases the overall module density by vertically stacking active and passive functions.

Solution: 3-D Passive Integration with Green Tapeā„¢ 951 Lowers Costs, Improves Yields

DuPont Green Tape™ is a key enabler for Sorep, and an integral part of the company's technology roadmap. Green Tape™ materials facilitate Sorep's innovative three-dimensional designs, which allow passive components to be incorporated into the substrate to reduce size, weight, and the number of solder joints, thus decreasing assembly costs and improving yields. The low-loss characteristic of DuPont Green Tape™ 951 tape dielectric is well-suited for applications in the 850 - 2400 MHz bands.

The Sorep antenna switch/filter is designed using co-fired Ag inner layer conductors and via fills on a large format panel which contains 132 individual units. Each circuit contains six conductor layers including power, ground, and signal. Precise thickness control and conductor printing allow for formation of reproducible controlled impedance structures.

Sorep is currently developing additional applications for the radio market. Front-end modules currently under study include filters, tunable filters, diplexers, switches, and amplifiers.

For more information, call DuPont at 1-800-284-3382, press 3.