Microwave Journal

Rugged High-Performance VNA Cable Assemblies

October 15, 2012

Rugged High-Performance VNA Cable Assemblies

For VNA test applications with frequencies through 67 GHz, GORE® VNA Microwave/RF Test Assemblies offer extremely precise phase and amplitude stability when flexed and provide the highest accuracy and longest time interval between recalibrations. These test assemblies are designed to improve Vector Network Analyzer (VNA) performance in applications where precision, stability and repeatability are key requirements. These include testing antenna and radar systems going into aircraft, electronic warfare self-protection systems, amplifiers and other active devices – anything that operates at microwave frequencies.

Gore’s VNA assemblies are supplied with most original equipment VNAs because manufacturers recognize the improved performance that they provide to high-end, extremely precise and very expensive ($100,000 range) test instruments. The exceptional phase and amplitude stability of the test assemblies ensures accurate and repeatable measurements, exceeding specifications for phase and amplitude stability, with additional testing performed to guarantee their phase and amplitude performance with flexure (see Figure 1).

Figure 1

Figure 1 Typical phase (a) and amplitude (b) stability with flexure for Gore part number FE0BN0BM025.0.

Unlike conventionally designed RF test assemblies, GORE VNA Microwave/RF Test Assemblies provide the most reliable phase and amplitude stability with flexure. They remain electrically stable when flexed – easily withstanding the rigors of typical bench testing procedures – while maintaining excellent insertion loss and VSWR. These assemblies can withstand 40 lbs (18 kg) of accidental pull without permanent degradation of electrical characteristics and up to seven lbs. (3 kg) of pull during normal use without exceeding electrical stability specifications. With a minimum bend radius of 2.25 in (57.2 mm), their unique armor construction provides a high degree of flexibility for long flex life. They have an auto-limiting bend radius of 2.25 in (57.2 mm), and the spring-back is virtually zero.

Figure 2

Figure 2 Assembly features.

In addition to providing high-precision measurements, GORE VNA Microwave/RF Test Assemblies offer maximum reliability with a rugged, lightweight construction that enables longer service life, reduced downtime and lower operating costs over the life of the equipment. They feature exceptionally rugged cable construction and NMD-style connectors that withstand repetitive mating, flexure, crushing, twisting and kinking. Crush resistance is greater than 800 lbs/linear inch, and the cable is capable of up to 100,000 flexures at minimum bend radius, depending on the configuration. An abrasion-resistant polymer braid covers a flexible armor casing, while a strain-relief boot protects against forces affecting the internal cable-to-connector termination (see Figure 2).

Ruggedized, test-port style connectors are utilized for direct attachment to the VNA test ports, allowing use of adapters compatible with the test ports for optimum durability and stability. The test assemblies are available in the following standard lengths: 25 inch (0.64 meter), 38 inch (0.97 meter), and 48 inch (1.22 meter).

The NMD connectors are specifically engineered to optimize the performance of the assembly. These connectors mate with standard VNA systems, allowing mode-free broadband coaxial measurements from DC to maximum frequency. They have an auxiliary, large thread and bearing surface for mating with conventional connectors of the same type and for attaching either pin or socket adapters. They maintain a high center conductor, which yields better performance and reduces the frequency of recalibration.

The combination of this ruggedized construction and NMD-style connector ensures longer flex life with consistently durable and stable performance. GORE VNA Microwave/RF Test Assemblies offer the optimum level of electrical and mechanical performance for high-precision test applications.

W. L. Gore & Associates Inc.,
Landenberg, PA,
www.gore.com/microwave