The Birth of Commercial RF/Microwave CAD

The COMSAT representative told me that design engineers from large companies either used outside time-sharing or their own central mainframe computers. The first alternative was expensive and not fully secure. In the second case, engineers were using a computer that was purchased for business instead of scientific applications. He planned to form a group to develop a dedicated design system to automate the engineering departments, which would run on minicomputers. Digital Equipment (DEC) and Prime Computer Company had recently introduced powerful minicomputers that could handle the needs of 30 to 40 engineers simultaneously. Among other tools, such as a spreadsheet and word processor, he wanted COMPACT and a digital circuit simulator to be part of that system and sold to companies in the defense and telecommunications businesses.

The man sounded like a visionary. The more I heard, the more excited I became. I recalled a lengthy article in Business Week predicting that office automation would become a $5 billion business within the next five years. If that were true, IBM, General Electric, HP and other giants would enter that business and would squash my small company. Perhaps working with COMSAT would be the safe way to go. (As it turned out, most of today’s major software companies, like Microsoft, Adobe and Oracle were started by entrepreneurs.) Our discussion led to a merger agreement and the formation of COMSAT General Integration Systems (CGIS).

Figure 5 The opening of the CGIS building in Palo Alto hosted a meeting of COMSAT’s board of directors.

Instead of my crowded home office, our employees now worked in a fancy new building in Palo Alto (see Figure 5). My children, however, did not like the change. My daughter Nanci had just begun preschool and cried in class. “My daddy started to work and he’s not home anymore during the day,” she told the teacher. When the teacher asked her how long I had been out of work, she said, “He’s never worked.” A few days later, I met the teacher. “I’m so glad to hear that you’ve finally found a job,” she told me. “But apparently Nanci does not like the change.” I was confused. “I’ve been working full time since I turned 18. Where did you hear that I did not have a job?” “Nanci said that you’re no longer at home during the day,” she replied. When I finally understood, I explained that I began my home business the year Nanci was born. To her, a dad who was at home during the day could not possibly be “at work” at the same time.

With the help of new technical experts and professional programmers, COMPACT was vastly expanded, nearly 3x the size of the code. A new name, SUPER-COMPACT, and a new logo followed.^17–18 In early 1980, we released the program for VAX PDP-10 and Prime minicomputers (see Figure 6). Our plan was for the program to only run on those systems. However, within a week, one of our major customer’s vice presidents called. “We’re the most important U.S. defense contractor, and I am not going to bypass our multimillion-dollar large-scale computer system. Please make your new program run on that!” he demanded. I decided to make an exception. Soon after, other major companies followed; again, I caved by converting SUPER-COMPACT for their CDC and Cray computers. Our dream of simple, two computer system technical support vanished.

Figure 6 Early ad for COMPACT (a) vs. later ad promoting SUPER-COMPACT on Prime minicomputers (b).

At the peak, CGIS had over 200 employees. Unfortunately, within a year, I faced a major family problem that forced me to resign from CGIS. My non-compete agreement kept me away from CAD-related activity, so my next technical career several years later shifted to continuing education.

MAINFRAME TO PC

During the early 1980s, under the presidency of Ronald Reagan, defense-related activities were booming—requiring a wide range of high performance microwave components that were smaller and lighter. Interestingly, for several years, SUPER-COMPACT still had no significant competitors. A few smaller programs—such as Circuit Busters which became Eagleware—were offered for PCs, and HP released its in-house program, Microwave Design System (MDS), on UNIX-based workstations.

Finally, in 1984, a new company, EEsof, entered the market with Touchstone,¹⁹ running on the IBM PC and dropping the price of microwave CAD from the $60,000 to $100,000 range down to $10,000. One of the unique features of Touchstone was its “tune mode,” enabling designers to watch how the circuit’s performance changed with component tweaking. Managers of small companies were more willing to buy PCs with Touchstone, shared by several engineers, rather than installing and maintaining a minicomputer. The new program soon became a favorite among designers, opening the door to true competition for RF/microwave CAD.²⁰ Touchstone was enhanced with harmonic balance and became Libra. HP acquired EEsof and out of the combination of Libra and MDS, ADS emerged.

COMSAT sold SUPER-COMPACT to Ulrich Rohde in 1985, and the software’s computational approach shifted to EM-based models, validated by Raytheon and Texas Instruments as part of DARPA’s MIMIC program. Compact Software merged with Ansoft in 1997, and later with Ansys.

In 1994, Applied Wave Research (AWR) formed to provide computer-aided design tools for RF and microwave designers. In 1998, at the International Microwave Symposium in Baltimore, AWR demonstrated Microwave Office, which combined circuit simulation, EM analysis and schematic capture in a single package. AWR’s portfolio expanded to offer additional capabilities, including Visual System Simulator and AXIEM. The company was acquired by National Instruments in 2011, then sold to Cadence in 2020.

With the wide adoption of the PC and new companies forming to tap the processing power available to every design engineer, computerized RF/microwave design became an industry.^21,22 Communication circuit and system designers now have the luxury of conveniently accessing linear and nonlinear, analog and digital circuit and system simulation and optimization, as well as 3D EM simulation with interactive graphics.

Sometimes, I wish I had started my career decades later, so I’d be able to use all these new design tools.

RF Industry Icons Podcast: Les Besser

Acknowledgment

The author wishes to express his appreciation to Prof. John Bandler and Dr. Edward Niehenke for their helpful reviews.

References

1. “BASIC Programming,” Wikipedia, https://en.wikipedia.org/wiki/BASIC_Programming.
2. L. W. Nagel and D. O. Pederson, “Simulation Program with Integrated Circuit Emphasis (SPICE),” 16th Midwest Symposium on Circuit Theory, April 1973.
3. “Time-sharing,” Wikipedia, https://en.wikipedia.org/wiki/Time-sharing.
4. “Teletype Model 33,” Wikipedia, https://en.wikipedia.org/wiki/Teletype_Model_33.
5. L. Besser, “Combine S-parameters with Timesharing,” Electronic Design, August 1968.
6. L. Besser, “A Fast Computer Routine to Design High Frequency Circuits,” IEEE ICC Conference, June 1970.
7. L. Besser and R. Newcomb, “A Scattering Matrix Program for High-frequency Circuit Analysis,” IEEE Conf. on Systems, Networks and Computer Systems, January 1971.
8. J.W. Bandler, “Optimization Methods for Computer-aided Design,” (invited), IEEE Trans. Microwave Theory Tech., Vol. MTT-17, 1969. Appearing in Microwave Integrated Circuits, J. Frey, Ed. Artech House, 1975.
9. J.W. Bandler, “A Review of Computer-oriented Circuit Optimization,” (invited), IEEE Int. Conf. on Communications Record, June 1971, pp. 3.18-3.22.
10. “Fortran,” Wikipedia, https://en.wikipedia.org/wiki/Fortran.
11. “Punched Card,” Wikipedia, https://en.wikipedia.org/wiki/Punched_card.
12. L. Besser, COMPACT User Manual, Tymshare Publications, 1973.
13. R. Davis, “Microwave Circuit Design Is Now as Close as Your Telephone,” Microwaves, August 1973.
14. L. Besser, “Computerized Optimization of Transistor Amplifiers and Oscillators Using COMPACT,” European Microwave Conference, September 1973.
15. L. Besser, F. Ghoul and C. Hsieh, “Design A High-Power S-Band Doubler,” Microwaves, June 1974.
16. L. Besser, “Use Computer as a Tool for RF Circuit Design,” Microwave Systems News, February 1974.
17. L. Besser, W. Brown and R. Wales, “System Merges Total Computer Control,” Microwave Systems News, April 1980.
18. L. Besser and S. March, “Advanced CAD Techniques for the 1980’s,” IEEE MTT Symposium, June 1981.
19. “Touchstone file,” Wikipedia, https://en.wikipedia.org/wiki/Touchstone_File.
20. L. Besser and C. Abronson, “Computers as Microwave Tools,” Microwaves & RF, March 1987.
21. D. Vye, “How Design Software Changed the World - Part 1,” Microwave Journal, July 2009.
22. D. Vye, “How Design Software Changed the World - Part 2,” Microwave Journal, August 2009.