American Standard Leads the Industry in RF/Microwave PCBs
January 25, 2015 | Dan Beaulieu, D.B. Management GroupEstimated reading time: 10 minutes
RF/microwave is one of the fastest growing segments of the PCB market today, and American Standard Circuits is one of the industry leaders in fabricating of RF/microwave PCBs. The company is also one of the true innovators, developing new processes and technologies for its customers.
Leading that charge for the company is Application Engineering Manager John Bushie. With over 25 years of industry experience, John has been able to apply his experience to ASC’s R&D to the point that the company is now the “go-to” company for the RF/microwave industry sector.
I sat down with John recently to catch up with him about his company and the industry. Not knowing much about this industry segment, I found this interview most interesting and enlightening.
Dan: Hi John. I have to say that I have been looking forward to talking with you and getting to know more about RF boards. Thanks for taking the time to speak with me.
John: Thank you, Dan. I always like talking about this technology, so I appreciate being able to do this interview.
Dan: Great. So, first of all, tell me about the company. Let’s talk about American Standard and its role in the microwave marketplace.
John: Sure. ASC has been an innovator in the fabrication of complex RF/microwave PCBs for well over 25 years. From the days when the RF world consisted of signal-to-noise ratios on the order of a million to 1 on simple large, double-sided PCBs. Today the same type of board may consist of layer counts up to 30 layers utilizing RF/microwave, flexible, IMS, conductive bonding and the full range of traditional rigid materials. The PCBs we manufacture regularly have blind and buried vias, cavities, heat sinks, and they can even contain embedded resistors and capacitors. All of this technology is delivered in the current quick-turn environment.
Dan: For over 20 years? That must make the company one of the first ones to be involved in this technology.
John: Well, the industry had been around for many years, but yes, ASC was one of the leaders. Think about it for a minute: Everything we do today is wireless, from cell phones to Bluetooth to just about everything electronic. And you can’t have wireless technology without RF/microwave technology so the market is bigger than ever and growing all the time.
Dan: Sorry to interrupt, but you were saying that back then circuitry was analog-based…and now?
John: No problem. As I said, it was all analog-based back then, which meant RF circuitry with a dedicated single function formed discrete components of an RF assembly. Contrast that with today’s smaller, digital, highly integrated assemblies where we are manufacturing hybrid multilayers which are either conductively bonded to a variety of heat sink materials or pre-bonding materials to form circuitry with blind vias plated directly to aluminum and copper. It’s been extremely interesting seeing the advancements in RF circuitry and packaging over that time.
Dan: Can you talk about some of the challenges you face working in this technology?
John: The challenge for us has always been keeping up with the changes in customer requirements whether it is from a technological standpoint by adding a process like blind via sputtering or in quality assurance, meeting aerospace requirements by adding a full CAD/CAM system directly interfaced with an automated CMM. The commitment has always been there to add the technology to stay at the leading edge of whereever it is our customers are going, which is in line with what we always strive to do, provide solutions.
Dan: John, tell us a little bit about yourself. What is your background in this industry?
John: I started in the PCB business back in the late '80s working for a "trying hard, but failing" standard technology circuit board shop. At that time the owners saw the emerging market for the cellular infrastructure build-out. Committing to new processing methods and ways of thinking about PCBs allowed us to expand into this RF/microwave field, manufacturing a wide variety of circuitry on ultra-low loss materials. This was quite an education, I tell you. Understanding and meeting the unique requirements for circuit performance at these higher frequencies really required a change in thinking from the standard DC circuitry of the day.
Dan: I assume you’ve worked at a number of shops over the course of your career?
John: Yes, I have. I guess like many people in this area (Chicagoland) I worked at several fabricators. Starting at WestTronics which became Poly Circuits, which was my introduction into the world of PCBs. Helping this company become a world class supplier of RF/microwave circuitry was a fantastic experience. I then worked at another local PCB fabricator, developing this technology. I later had the opportunity to work with hundreds of PCB shops around the world, as the technical services manager with Taconic, while supplying microwave laminates to the PCB industry.
Dan: If you’re like the rest of us, you must have gathered some unique knowledge from every company you’ve worked with, right?
John: Absolutely. Working at several fabricating facilities allowed me to see how different shops and people approached the variety of challenges, an invaluable lesson. Getting an opportunity to work for a premier RF/microwave material supplier was also an incredible learning experience because I was also able to see how many RF/microwave designers and PCB fabricators throughout the world met the challenges they faced using those materials in the RF/microwave space.
Dan: Are you guys at ASC able to handle just about all RF/microwave requirements?
John: Honestly, there are seldom any materials or requirements we have reluctance to process or meet. That’s not to say there haven’t been jobs we have even had to admit were not feasible. That’s a critical aspect, being able to tell an engineer that you do not believe that a current design is reliably manufacturable given the current state of technology. However, it’s the ability to offer usable suggestions and alternatives which adds great value to our customer/supplier relationship.
Dan: So you have been involved in this technology for a while now, how has it evolved over the years? What is different today as opposed to when you started out?
John: With the maturing of any technology you see a drive for higher and higher levels of integration. Multiple circuitry groups combined into a single hybrid package often with two and three sub- assemblies bonded into double and triple blind multilayers. Further increasing functionality is the combination of often two, three or more materials into one assembly. All in an attempt to maximize functionality and increase the economy of the overall product.
Dan: Can you tell us about your customers? What kind of companies are you working with and what sort of end products are they building?
John: With the increase in high-frequency applications, whether it is wired data transmission or wireless communication, the increase in requirements for low-loss, controlled thickness materials has been incredible. For example, some of our customers are using these types of hybrid circuit designs to manufacture subcomponents such as couplers and filters which are later assembled into larger systems for another customer utilizing ultra low-loss materials in the radio front end and RF power amplifier. Working with companies building everything from point to point communications in a commercial setting to avionics packages for military air craft. Aerospace is another fascinating business segment, predominantly because of the unique performance requirements of such a challenging environment.
Since the massive buildout of cellular/wireless and HDTV slowed in the late '90s and early 2000s there has been a shift in the types of products utilizing low loss materials. The applications have been generally smaller in scale. Customers are using these products in more specialized applications such as high-frequency signal generation and testing equipment. Smaller customized data transmission and wireless communications. These products have always been used in radar and avionics systems but the level of sophistication has increased dramatically. The aerospace and military is constantly developing new applications for sensing, telemetry and communication. The use in medical diagnostic and imaging equipment is still expanding. There are seemingly endless applications in data transmission and non-contact sensing.
Dan: What are the advantages of RF/microwave boards over traditional printed circuit boards?
John: When I was working back in the late '80s and early '90s building RF/microwave circuitry the term “controlled impedance” was unheard of. The main reason being controlled impedance was a function of the tightly controlled materials and etching tolerances required for these types of circuits. There was no need to try to measure the outcome as it was specified on the front end. The extremely low-loss materials used and the tight dielectric constant and thickness control, coupled with line width tolerances as tight as 0.0005” on one ounce copper allows for circuitry which functions up to frequencies as high as 100 GHz at the correct impedance for proper matching.
It’s all about control and consistency. Related to the conductive circuitry, this means trace width, height, shape and surface roughness. Relative to the dielectric it is thickness, dielectric constant and composition (isotropic vs. anisotropic). All of these characteristics affect impedance which ultimately impacts the circuit performance not only within a PCB but from board to board. When the frequencies get as high as 100 GHz the sensitivity to any changes in the aforementioned properties have a greater and greater effect.
One of our customers uses these types of PCBs for radar in vehicular collision avoidance with a small approximately 2x3” radar system with transmit and receive integrated into this small package. Others manufacture couplers as components in these RF systems. In fact some of our coupler products are so tightly controlled that we are one of the few manufacturers in the world capable of manufacturing this product, which is subsequently sold into China. All of this means we get to work with some of the industry leaders in satellite, radar, automotive safety, RF/microwave components, test equipment, avionics and medical. The applications are seemingly endless.
Dan: Where do you see the industry going when it comes to RF/microwave technology?
John: There is continuing need to increase performance whether it is for higher and higher frequencies, such as the shift in vehicular collision avoidance radar from 24 GHz to 77 Ghz or the need for lower and lower loss materials in ever increasing package densities. The selections of materials for these applications is growing rapidly. Fortunately for us this allows us to create greater functionality in a smaller package.
In short, the industry has ever decreasing packaging requirements with more highly integrated systems. Gone are the days of separate PCBs for each function in a microwave circuit. Now, multiple functions are integrated into a single, often 6-20 layer RF circuit board. Sometimes these PCBs are comprised of 2, 3, 4 and 5 different materials. The combination of materials, thicknesses and manufacturing techniques is what drives the complexity of the overall manufacturing on these parts. These are the challenges that PCB fabricators have faced and will face in the future.
Dan: Here is your chance to talk about your company. Why should customers come to you at American Standard for their RF/microwave boards?
John: In short, because of ASC's commitment to being a solution provider. This means forming a partnership with our customers to achieve their design/product goals. We do this by working with our customers to create design and manufacturing solutions. This not only helps to make a product that is achievable but commercially viable as well. It’s this desire to work with our customers, often in an iterative fashion, with the determination to resolve the issues as they are presented. Often this may require us to change our processes or the manner in which we manufacture. There is a commitment to problem solving which ultimately leads to success.
Dan: John, once again thanks for talking with me today. Do you have any last comments before we wrap this up?
John: Dan, thank you for giving me the opportunity to talk about a couple of the things I find truly fascinating: the futures of the RF and microwave industry and our customers.
As the world goes wireless the RF/microwave market will continue to grow. I love the idea that companies like American Standard are not only keeping up but leading the way with this technology.
For more information, visit www.asc-i.com.