Fifty years brings with it many changes—in the case of Merrimac Industries (West Caldwell, NJ), most for the better. Founded in 1954, the 50-year-old microwave pioneer has been highly regarded for its ability to solve technical challenges with small volume production. From its humble beginnings as a "sideline business" for its three founders, the firm has grown into a business with facilities in three

countries and 130,000 ft.2 manufacturing space, a high-volume manufacturer of highly-integrated multilayer microwave circuits that also provides a wide array of RF and microwave technology solutions.

Merrimac's first name—Merrimac Research and Development, Inc.—correctly identified its activities. The firm was founded by three men who had begun their own "weekend businesses" and decided to combine their efforts into a single organization. Paul Terranova was director of an engineering group at ITT; Dr. Harold Sydel was director of research at Bell Laboratories; and Dr. Arthur Oliner was professor of electrophysics at Polytechnic Institute of Brooklyn. Oliner, a distinguished scientist, is still active in the industry and at Merrimac at age 83 (see sidebar).

Like many successful engineering companies, Merrimac began life in a garage. The rented space was located at 914 Lyons Ave., Irvington, NJ, and many early employees came from ITT. At Merrimac, they tamed many challenging electromagnetic (EM) problems into the form of practical hardware designs. While the company did manufacture standard products such as ferrite microwave attenuators, waveguide couplers, magic tees, and stripline power dividers, it was primarily regarded as a research and development organization.

By 1966, the company had 35 employees and about $1 million in revenue, prompting its officers to move to a 52,000-ft.2 facility at its current location in West Caldwell, NJ. One of Merrimac's most impressive successes was its work in producing components rugged enough to perform in space at a time when the "race for space" was capturing the world's attention. Merrimac components had been part of the electronics packages for satellites since 1961, including Voyager I (still transmitting data after 26 years and nearly 9 billion miles from Earth).

In 1972, the company changed its name to Merrimac Industries, Inc., doubled the size of its facilities in West Caldwell, and created a "hi-rel" group to handle increasing space-qualified and hi-reliability work. By the 1980s, Merrimac supplied hardware to almost every satellite builder and systems integrator from E-Systems and Northrop Grumman, to Lockheed-Martin, Space Systems/Loral, General Dynamics, Rockwell, Goodyear, Marconi, TRW, and Boeing.

Merrimac's current strong business position has required creative changes in virtually every area of the company over the years, including a 75-percent reduction in customer base. This change apportions greater resources to fewer (but more profitable) customers. Educational and training programs have been dramatically increased with the inception of Merrimac University (a broad-based internal educational program that utilizes professors from various universities). More modern design and manufacturing equipment has been purchased in recent years, and an innovative customer relationship program was crafted for space customers to reduce time, cost, and complexity in the procurement process. This program, called Merrimac Space Qualified Products (MSQP), has since been expanded to include military programs as well. The company also began extensively using videoconferencing and an extranet to more efficiently conduct design reviews and other technical meetings.

The company's 52,000 ft.2 of manufacturing and engineering space in West Caldwell, NJ has been expanded over the years to now total 72,000 ft.2 The company created a 36,000-ft.2 manufacturing facility in San Jose, Costa Rica and also acquired Filtran Microcircuits Inc., of Ottawa, Ontario, Canada, a highly regarded producer of microstrip, bonded stripline, and thick metal-backed Teflon (PTFE) and mixed-dielectric multilayer circuits. Filtran provides the company with some of the most precision fine-line etching capabilities in the industry, which makes it extremely well suited for millimeter-wave circuit fabrication.

The company's greatest technological advancement has been the development of and investment in Multi-Mix Microtechnology, an advanced multilayer manufacturing technology. The story of this technology begins in the 1990s, during a time when the cellular communications industry was expanding rapidly. At that time, and after 12 years of negative growth, Merrimac's board of directors approached one of its own members, Mason N. Carter (Fig. 1), to run the company as CEO and determine what was needed to reverse the firm's losing streak.

Carter reviewed the company's core products and discovered three specific areas that needed to be addressed. First, it was essential that the core product line be expanded to include more types of devices. This could be achieved by drawing on the company's broad expertise in passive component development. Second, it would be important to establish relationships either through acquisitions or partnerships with companies that had competencies complementary to those of Merrimac. The third and greatest challenge was to find and develop a technology that could satisfy the needs of both military and commercial customers for smaller, lighter, highly integrated, less-expensive solutions, without sacrificing performance or reliability.

Carter set out to find a solution to the third requirement. One of the most promising yet difficult to achieve involved fusion bonding of fluoropolymer composite substrates to form a multilayer structure for microwave circuits. In a tiny fraction of the space required by conventional technologies, this technique allowed nearly any kind of microwave element, from passive elements to discrete semiconductors and MMICs, as well as plated-through viaholes, to be integrated. The technology yielded self-contained products without need for further packaging, without need of tuning (in the case of filters), with the potential for multiple functions, with repeatable performance, and which could be could be produced in large volume at low cost. It appeared also that this process had the potential to deliver parts that, while measuring and weighing orders of magnitude less than their conventional counterparts, could often exceed their performance in many areas, even in power-handling capability.

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Carter recognized that if Merrimac could harness the power of this process, the company could address major challenges posed by customers for more performance and higher functional integration in less space at less cost. With support from the board, the company developed the process into what is now known as Multi-Mix technology, for which Merrimac has multiple patents for methods of manufacture and design.

Multi-Mix, a vertically integrated process, is based on fluoropolymer composite substrates that are formed into a multilayer structure using fusion bonding. The fusion process provides a homogeneous dielectric medium with superior electrical performance at microwave and millimeter-wave frequencies. The bonded layers can contain embedded semiconductor devices, MMICs, etched resistors, circuit patterns, and plated-through viaholes, to form a surface-mount module that requires no further packaging (Fig. 2). In fact, the assembly itself becomes the package. The result is a small-outline, low-profile structure that is lightweight, compatible with microstrip or coplanar waveguide, and suitable for both high-volume and low-volume production. A complete description of Multi-Mix can be found on Merrimac's website (www.merrimacind.com).

At present, Merrimac is creating Multi-Mix single-function and-multifunction modules that meet the challenges of the wireless world for size, weight, and cost reduction, while also applying it to aerospace and defense projects. The results are dramatic. The company's PHC-2D-1.0G delay-line discriminator, for example, operates from 750 to 1.25 GHz and is half the size and 5 percent of the weight of conventional designs, while also delivering better performance. It integrates a wide variety of components including five power dividers, six quadrature hybrids, and eight video detector circuits, all contained in eight layers of bonded material that measure 2.0 × 2.0 × 0.25 in. and weigh 1.5 oz.

The latest Multi-Mix advance is Multi-Mix PICO, which cuts size an additional 84 percent (or more) with a corresponding reduction in weight. The small size of PICO devices belies the fact that they can handle RF input power to 100 W CW with heat sinking, while matching their larger Multi-Mix counterparts in other performance areas (Fig. 3).

Most recently, Merrimac introduced a family of Xapper delay lines for use in power-amplifier (PA) linearization schemes, such as feedforward and predistortion circuits. The DLL family of delay lines (see advertisement on p . 92) are rugged, fusion-bonded, multilayer stripline components that serve as low-loss alternatives to coaxial and filter-based delay structures for PA linearization applications.

Multi-Mix has wide application in military systems as well as in wireless infrastructure at RF through millimeter-wave frequencies. In wireless base stations, filters, isolators, couplers, combiners, delay lines, and other components are used in third-generation (3G) tower-mounted amplifiers, receiver multicouplers, and multicarrier amplifiers. Many of these functions can be integrated into Multi-Mix multilayer modules.

Merrimac never abandoned the aerospace and defense markets in favor of the "wireless revolution." As a result, the company is well positioned in key military systems, including the F-22, Joint Strike Fighter (JSF), Joint Tactical Radar System, and Future Combat System (FCS) programs. In addition, it has developed Multi-Mix into a technology capable of reducing the size, cost, and weight of microwave functions by orders of magnitude. Multi-Mix is well suited for commercial and military single- and multifunction modules.

The present-day Merrimac has greatly expanded its manufacturing facilities and, with Filtran Microcircuits, its ability to handle the most precision high-speed and millimeter-wave circuits. This diversification should serve the company well in the future, for aerospace/defense, commercial, and homeland-security customers.