Agilent EEsof EDA Customer Success Stories: Fujitsu Quantum Devices Europe

The Company

Fujitsu manufactures a complete range of microwave Field Effect Transistors, hybrids, and GaAs MMICs for use in communications and radar systems. These applications include cellular and wireless phone and LAN systems, terrestrial radio, satellites and satellite system, phased array radar, DBS receivers, and so on.

The company's current offerings include discrete GaAs FETs and Integrated Devices using GaAs technology. Current products are low noise HEMTs, general purpose FETs, power FETs, frequency dividers, VSAT MMICs, amplifier MMICs and millimeter wave MMICs.

The Challenge

Many Fujitsu microwave design centers in Japan, the U.S., and Europe already use ADS for design GaAs technology FETs and integrated devices. Within the company, models and equivalent circuits are designed for use with ADS, to take advantage of the powerful simulation technology that ADS offers. The challenge, then, was to prove the value of ADS to designers at the European Design Centers by showing a high correlation between simulated and measured performance for a typical amplifier design. At the conclusion of this test project, Fujitsu designers were confident that ADS was the appropriate tool to standardize on for their design simulation and verification work.

The Solution

To prove the accuracy and value of ADS, Jamie Clark, a Fujitsu microwave design engineer, used it to simulate a 25dB MMIC amplifier, using small-signal S2P parameters for the FETS, and then individually matching them to 50 ohms. Next, he connected the individual matching circuits together with DC block capacitors and optimized the circuit. The result was a working amplifier design. Finally, the device was laid out using the ADS layout capability. As each change was made to the layout the circuit was re-simulated to ensure that performance was not compromised. And when the physical device was measured, the results showed a very good correlation with simulated data.

The Results

Because there are many ways to design a chip to meet a customer specification, designers typically create a range of amplifiers to see which one has the best performance. Things that vary from device to device usually include FET line-ups, number of amplifier stages, matching circuit topologies, and chip shapes and sizes.

"ADS allows us to change FET sizes and matching circuits easily and observe the physical changes to the overall chip. This decreases time spent in both the initial design stage, when the final specification is being decided upon, and during the final design stages, when overall chip size is critical to meeting project budget requirements," said Clark.

The Fujitsu Quantum Devices portfolio is constantly updated with new designs, which are introduced to the market in response to ever-evolving industry requirements. Improvements in the wafer process help make this rapid chip production possible. With ADS, the design phase is also shortened because designers obtain fast, accurate performance data early in the life of the design. This amplifier project helped Fujitsu designers to have confidence in the ADS solution and in the commitment that Agilent EEsof EDA has made to their business and their industry as a whole.

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