by Kevin Walker, Sr Director of Technical Business Development, Benchmark
Smaller is often better, especially for military electronic systems. Miniaturization is critical for electronic circuits and systems to provide the many functions needed in shrinking applications, such as portable communications, radar, and electronic warfare (EW) systems in manned and unmanned vehicles. Fortunately, Benchmark’s experienced engineers and extensive design and manufacturing tools have long supported the trends in size, weight, power, and cost (SWaP-C) for defense electronics applications. Vertical integration of design, manufacturing, and test capabilities enables seamless integration of different electronic technologies, including analog, digital, RF/microwave, millimeter wave (mmWave), and photonics circuitry into solutions that meet complex defense electronic requirements with increased functionality in smaller sizes.
Make It Smaller, yet Faster
Miniaturization is crucial for many electronic systems, even as they become more complex and run at higher data rates. At Benchmark, we have taken on the different roadblocks to miniaturization, especially as applications reach into the millimeter wave frequency range or integrate fiber optic transmission lines in the never-ending quest for additional bandwidth. We have conquered challenges such as signal coupling as circuits become smaller and more densely packed with components and efficient thermal management as smaller circuits operate at higher power levels. For any high-performance RF design, precision microelectronic assembly is essential to avoid shorts and interference. Without trust in your assembly process, it can be impossible to diagnose whether performance problems result from design shortcomings or shoddy workmanship. Accurate die placement and precision wire bonding are essential for high-frequency performance.
Even as more applications rely on higher frequencies, the old adage that RF engineering is black magic still resonates. Cross-talk, cavity resonance, and signal interference multiply as frequencies rise, and assembly form factors shrink. So what’s the “spell” to achieve performance? Integrating design engineering, manufacturing process engineering, and test into one team that can develop, produce, and test designs in an iterative, tightly coupled closed-loop feedback approach.
For example, using bare die to remove superfluous packaging is a common SWaP reduction strategy, one which also offers performance benefits as wire bond lengths are often reduced. But underfill, the most common micro-e assembly process to ensure the die is securely attached, can interfere with RF performance. A combined design and manufacturing process development team may need to consider altering the number of bumps, corner or edge bonding, or, if underfill is unavoidable, experimenting with various material options. Once the most likely designs are assembled, robust test procedures can determine which design and process best balances reliability and performance.
In some lucky situations, size reductions and improved performance go hand in hand. Advanced microelectronic wire bonding processes can reduce the length of wire bonds, improving circuit performance. This can complicate circuit board design; trace locations must be precise, and separation distance between traces respected to avoid unwanted interference. To reap the combined SWaP and performance benefits, a team needs expertise in RF design, including at the substrate level, materials, manufacturing processes, and test to ensure the interconnect is compatible with the components.
As military applications are developed with increased functionality in smaller sizes, users seek more bandwidth to support those functions. Bandwidth can be expensive but available at higher electromagnetic (EM) and electro-optical (EO) wavelengths; Benchmark’s designers and manufacturing engineers are familiar with both technologies as transmission-line routes for increased functionality. Many defense-related applications, such as unmanned aerial vehicles (UAVs), are applying SWaP-C guidelines to these applications to increase functionality even as electronic systems are miniaturized. For example, designers may combine radar, lidar sensors, and communications functionality into a single UAV electronic housing.
For electronic designers and manufacturers of such highly integrated solutions, the challenges of combining once separate functions into a single circuit assembly or module are far-reaching: from the choice of antenna to the design of a graphical user interface (GUI), with many technologies in-between. Design and manufacturing challenges include integrating analog, digital, RF, and optical components and circuits on smaller, more thermally efficient circuit boards.
In mixed-technology systems, interposers can be an excellent solution to balance performance and cost. When the frequency in use for the RF portion requires a ceramic substrate, using a ceramic board measuring many centimeters on each side would add a significant cost. Instead, the RF components can be placed on a smaller ceramic interposer in a System-in-Package (SiP) configuration. Developing an assembly that leverages a SiP, both the design and manufacturing processes, requires RF design expertise since communication between the interposer and the rest of the board is critical to overall system performance. These boards can be very high density, so precision manufacturing is critical to avoid disrupting RF signals.
The advanced manufacturing needs of defense applications are very real and growing, both in capabilities and production volumes, requiring a solution provider with expertise in engineering design and manufacturing. Miniaturized multifunction system solutions require a practical combination of hardware and software, such as software-defined radio (SDR) that can be applied to communications, EW, and radar.
Making Smaller Solutions a Reality
Benchmark’s design and manufacturing engineers use the latest tools and technologies to attain far-reaching goals. They leverage SMT and microelectronics hybrid assembly and packaging, microwave, mmWave, and photonics circuits, and system-to-substrate design into electronic solutions for military communications, EW, and radar. These tools support smaller, lighter electronic systems that use less power with higher performance than the previous generation.
I have seen this engineering integration work; the knowledge sharing between our design and manufacturing teams helps Benchmark meet challenging SWaP-C requirements for military communications, EW, and radar systems operating well into the millimeter wave frequency range. By sharing knowledge and skills among our teams and partners, we help create military systems that are smaller, lighter, and less power-hungry than in the past, even while operating at higher data rates and processing speeds by combining optical and millimeter wave circuit technologies.
Although design and manufacturing engineers often seem to be speaking in different languages, this is not the case at Benchmark. Our engineering teams may initially approach a problem differently, but we listen to each other to find the best solution for a customer. We carefully consider our skills and tools to create designs that make optimum use of our design prowess, manufacturing resources, and test equipment to find best case solutions.
Kevin Walker grows Benchmark’s RF, microelectronics, and photonics business, working closely with customers and our engineering teams. Kevin has a Bachelor of Science in Engineering and over 30 years of diverse industry experience. He introduced Liquid Crystal Polymer (LCP) substrate materials to our industry while in a leadership role at Rogers, and developed LCP based circuit applications as General Manager of Micro Systems Technologies. His experience ranges from thin film microwave circuit fabrication, and high speed/microwave circuit materials, to commercial microwave circuit fabrication and assembly, implantable medical device assembly, and military microwave interconnect products.
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