Flexible 110 GHz Test Cable Assemblies
Precision test cable assemblies that provide low loss and high performance at 110 GHz are hard to come by. Now add the requirement for true flexibility and they become even more difficult to obtain. Gore, a producer of precision microwave cable and cable assemblies, has now introduced the GORE™ PHASEFLEX“ 110 GHz Test Assemblies, the newest addition to its PHASEFLEX Microwave Test Assemblies product family. These new test cable assemblies feature torque and crush resistance, as well as stability with flexure and temperature, while operating at relatively low loss up to 110 GHz.
The GORE PHASEFLEX 110 GHz Test Assemblies provide excellent phase and amplitude stability with flexure over a wide range of temperature. At 110 GHz, a 16-cm long PHASEFLEX assembly bent 90° around a 1" diameter mandrel has a change in phase of 4.3° and a change in amplitude of 0.05 dB (typical). When the assembly is returned to its original configuration, its phase and amplitude return to their original values. This type of performance assures accurate and repeatable measurements are achieved without the need to repeat time-consuming calibrations between measurements.
Figure 1 shows a cross-sectional diagram of the cable’s construction. In addition to being flexible, the cables exhibit virtually no springback, thus allowing for easy test setup and minimizing stresses on the device under test, probe tips and adapters caused by cable tension. The cable assemblies can be flexed, reformed or repositioned repeatedly without fear of damage or performance degradation.
The cable’s internal construction provides for a very rugged assembly that makes it crush resistant, while still maintaining a small outer diameter of 0.167" nominal. Even with this small size, the assemblies are still low loss. Typical insertion loss for a 16 cm assembly at 110 GHz is 2.1 dB. Figure 2 shows typical VSWR and insertion loss performance.
The cable assemblies’ specifications include a characteristic impedance of 50 Ω, a frequency range of DC to 110 GHz, a nominal cable outer diameter of 0.167" (4.2 mm) and an operating temperature of –55° to +125°C. Coupling torque is 4 ±0.5 in-lb and the assembly can experience 500 minimum mating cycles without degradation. The connectors are passivated stainless steel 303, with gold-plated BeCu center conductors and Ultem™ dielectric beads. If a connector is damaged it can typically be repaired for less than the price of a new cable assembly.
GORE PHASEFLEX 110 GHz Test Assemblies are available at varying lengths to suit specific applications and can be configured with 1 mm pin and/or socket connectors. Ordering information and additional details can be obtained by phone or on the company’s Web site.
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W.L. Gore & Associates Inc.,