Test and measurement (T&M) is a crucial application where cabling innovations are constantly required. As we move into a 5G-enabled world, the cables and interconnects used in T&M processes must be of the highest standards and reliability, pushing to ever higher frequencies. 5G represents the next evolution of mobile communications and promises to enable many new applications, such as autonomous vehicles and virtual reality.
With 5G, significant design and measurement hurdles must be overcome. As the frequency spectrum is limited, 5G must operate at higher frequencies to deliver faster data speeds. As 5G taps into these mmWave frequencies, cabling and interconnects must be robust to meet the rigorous performance requirements. Whether used in system development or device characterization, precision and repeatability are required, and this capability must be sustained within the production test environment after a system is commissioned.
Cable assemblies in a test environment are often used with vector network analyzers (VNAs), probably the core instrument for testing and characterizing components, then ensuring they function properly when integrated together. Accuracy is crucial in any test setting, particularly for metrology grade cabling, which offers the ultimate precision and demands the highest reliability for testing and calibration. With the smaller wavelengths at mmWave frequencies, flexure and movement can have a significant impact on the accuracy of measurements, and this is accentuated as the frequencies increase.
PHASE STABILITY
Figure 1 Typical phase stability vs. frequency before, during and after flexing a strait 25 in. cable assembly 180 degrees around a 2.25 in. mandrel.
Figure 2 MWX004 cable assembly.
In response to these challenging requirements, global cabling and interconnect pioneer Junkosha launched the 8 Series VNA Test Assembly, designed to be a high-quality metrology-grade VNA test cable for users requiring high precision. Using Junkosha’s precision expanded PTFE tape wrapping technology, the 8 Series metrology grade cable exhibits excellent phase and amplitude stability with flexure, within ± 1.5 degrees and ± 0.08 dB at 50 GHz, respectively, for a 25 in. long cable (see Figure 1). The figure shows the phase performance of the cable assembly before, during and after being flexed around a 2.25 in. radius mandrel. The 8 Series is flexible and can maintain this level of performance when bent 180 degrees around a 2.25 in. radius mandrel, with no spring back. The assembly has impressive performance durability—50,000 tick-tock cycles typical—and has high phase stability over temperature. With a 2.4 mm connector, the cable assembly is specified to 50 GHz, and a ruggedized port-side NMD connector is available to ensure direct and reliable connection to the VNA. Other versions will follow during the coming months. The 8 Series can be shipped with a VNA or as part of an after-sale package to replace existing cables.
The key application area for the new metrology grade microwave/mmWave VNA test cable assembly is in measuring the device under test (DUT) when designing a high frequency component from scratch. In addition to devices and coaxial components, the metrology grade cable can be used to develop other coaxial cables. With a calibration level standard bench test, the cable assembly is well suited for national institutes, calibration laboratories, service providers or any application where repeatability is key.
PUSHING TO 145 GHz
Within the last 18 months, Junkosha has launched a range of high performance mmWave cabling solutions in addition to the 8 Series, such as the MWX004 (see Figure 2). The MWX004 can uniquely operate up to 145 GHz and has the high phase stability associated with Junkosha, as well as the highest performing dielectric material and high flex life. The MWX004 was designed for applications operating above 100 GHz and systems such as LiDAR for connected and autonomous vehicles.
A world requiring constant wireless connectivity demands more efficient use of the available frequency spectrum, which requires innovative technologies. The use of mmWave frequencies has become a requirement for many new applications, whether commercial, space or defense. To enable systems to deliver the required performance at mmWave frequencies, phase performance that endures is a requirement that cable assemblies and interconnects must achieve, especially in the T&M environment. Junkosha’s latest interconnect solutions provide VNA manufacturers with the capability to test these high frequency networks that will soon be at the heart of the next generation of highly sophisticated systems.
Both the 8 Series VNA Test Assembly and MWX004 will be featured at this year’s European Microwave Week.
Junkosha,
Irvine, Calif.
www.junkosha.com/en/products/cable
Masaru Omoto: momoto@junkosha.com