Coaxial cables and connectors support and multitude of functions in modules, subsystems, systems, and test etups. In the simplest terms, they provide a transmission path for high-frequency analog and high-speed digital signals. How well they do this depends on a number of factors, including materials, design, and workmanship. As this short survey will show, choices for microwave cables, cable assemblies, and connectors are many and selecting a supplier is often a matter of finding a company that can deliver on time.

Astrolab, Inc, (www.astrolab.com) is a long-time leader in cables and connectors as well adapters and phase shifters. The company’s patented minibend® cable assemblies are flexible replacements for 0.086-in.-diameter semirigid cables and simplify the interconnection of components within microwave modules. Usable at frequencies to 24 GHz, the original minibend cables are 99.9 percent lead free and are triple shielded for high isolation. The loss for a 3-in. section is 0.19 dB at 2 GHz and 0.55 dB at 18 GHz. For flexure testing in which a minibend assembly was flexed 90 deg. just behind the connector in a 0.25-in. radius, the amount of phase shift was a mere 1.4 deg. at 24 GHz and 1.2 deg. at 18 GHz. For a test in which the same assembly was flexed 180 deg. with a 0.4-in. radius in the middle of the cable assembly, the phase change was 3.9 deg. at 24 GHz and 2.9 deg. at 18 GHz.

Micro-Coax (www.micro-coax.com) offers a wide range of RF and microwave cables and assemblies, including the UTiFlex flexible microwave cable assemblies. The firm’s UFA125 cable assemblies, for example, have an outer diameter of 0.125 in. (3.175 mm) and minimum bend radius of 0.2 in. (5.08 mm). They offer phase stability versus flexure of 3 deg. at 10 GHz and 5 deg. at 18 GHz. Rated for 10,000 flexures, they are usable to 50 GHz and feature shielding effectiveness (SE) of better than 100 dB at 1 GHz. The insertion loss is 0.14 dB/ft at 1 GHz, 0.82 dB/ft at 26.5 GHz, and 1.17 dB/ft at 50 GHz. The cables are designed for operating temperatures from –65 to +165°C.

Huber + Suhner (www.hubersuhner.com) is well known for its high-performance cables and cable assemblies, including the SUCOFORM-141-000 hand-formable microwave cables. Designed to provide the performance of semi-rigid cables but without the need for machine forming, these cables can be used with crimped, clamped, and soldered connectors at frequencies through 4 GHz. They can be hand formed to a bend radius as small as 8 mm.

IW, the former Insulated Wire (www.iw-microwave.com), is a veteran supplier of high-quality coaxial cables. The company’s 1501 cable operates to 45 GHz with an outside diameter of 0.15 in. and a bend radius of 0.75 in. The velocity of propagation is 84 percent and the time delay is 1.2 ns/ft. The company also offers cable assemblies based on this and other cable types, with combinations of straight and right-angle connectors.

EZ Form Cable Corp. (www.ezform.com) offers semi-rigid cable that it is easily bent to finished shape and still maintains its set after bending. This property makes it ideal for use with automated bending equipment as well as hand forming. The cable is qualified to MIL-C-17 and is listed on the United States Defense Logistics Agency’s Qualified Products List (QPL). Recent cable product-line expansions include EZ Form AL, an aluminum-jacketed semi-rigid cable that was granted MIL-C-17 qualification, and EZ Flex 250, 141, 86, 47 and EZ Flex 401, 402, and 405 flexible cables with the performance of MIL-C-17 semi-rigid cables. For harsh environments, the company launched a new EZArmored Ruggedized Cable series that combines EZ Flex high-performance cables with a nearly indestructible armor jacket.

RF DEPOT (www.rfdepot.com) is also a supplier of MIL-C-17 qualified coaxial cables from stock. Semi-rigid and flexible cable assemblies are assembled to exacting tolerances, with a typical flexible cable assembly tolerance of ±0.0375 in. or 1.5 percent, whichever is greater. The firm also offers pass/fall testing to 40 GHz.

SV Microwave (www.svmicro.com) supplies connectors and cable assemblies from DC to 50 GHz, with phase matching and space qualification available. The cable assemblies can be supplied with a wide range of connectors, including miniature SMA, ZMA, SVK 2.92-mm, 2.4-mm, SMB, SMC, and blindmate BMA, blind-mate BMZ, blind-mate BZ, subminiature MCX, SSMA, blind-mate BMMA, 1.85-mm, micro-miniature MMCX, Type N, TNC, 7-mm, BNC, C, 7-16, HN, SC, and LC connectors.

Meggitt Safety Systems (www.stablecable.com) manufactures silicon-dioxide (SiO2) cable for harsh environments such as aboard the Space Shuttle. The company’s cable assemblies have been installed on the majority of military aircraft since 1960 and used in space, cryogenic, and research applications where reliable, repeatable results are critical. The silicon-dioxide cable systems can be used at temperature extremes from –271 to over +1000°C and can withstand vibration levels to 45 g’s. The cables, which are usable to 26 GHz, feature 80-percent velocity of propagation and shielding as high as 120 dB.

Haverhill Cable and Manufacturing Corp. (www.haverhillcable.com) is a supplier of semi-rigid, hand-formable, and flexible coaxial cables for microwave, military, and telecommunications applications. The cables, which are available for 50- and 75-ohm systems and with diameters from 0.020 to 0.250 in., are fully qualified for MIL-C-17 and space applications.

The HPI 120 Interconnect Assembly from Semflex (www.semflex.com) is a cable assembly that provides low-loss performance through 50 GHz and is designed for use with a variety of connectors, including 2.4-mm, 2.92-mm, 3.5-mm, and SMA connectors. With a nominal outer diameter of 0.125 in., the cable employs triple shielding mechanisms to achieve better than –90 dB leakage at 18 GHz.

Gore (www.gore.com) is known for its material expertise in a wide range of industries, but is also a leading supplier of cables, connectors, and cable assemblies for aerospace, military, commercial, aircraft, and measurement applications. The firm’s PHASEFLEX® 110 GHz Test Assemblies help measurement systems such as vector network analyzers extract the most accurate broadband results at frequencies through 110 GHz. The cables offer torque and crush resistance and stability with flexure and temperature, all while remaining very flexible. For example, an assembly bent 90 deg. around a mandrel with 1-inch radius exhibited only 4.3 deg. phase change and only 0.05 dB amplitude change at 110 GHz. When the assembly was returned to its original configuration, phase and amplitude returned to their original values. The assemblies also offer very low loss; typical insertion loss of a 16 cm assembly at 110 GHz is 2.1 dB. A wide range of suppliers offer cable assemblies for test applications, including companies often associated with other product lines, such as Mini-Circuits (www.minicircuits.com) and Synergy Microwave Corp. (www.synergymwave.com).