Beyond the fundamental but highly technological challenges of ensuring the upcoming 5G network will work, there are several significant hurdles that will need to be overcome by operators. For example, spectrum availability is not limitless, with the radio frequencies of 3G and 4G increasingly crowded; 5G will have to operate at even higher frequencies to deliver the faster data speeds. This brings into play the mmWave band, which has its own unique challenges including the issues of reliability and ruggedness of cabling as a key hurdle. With median speeds of up to 1.4 Gbps at 28 GHz, 5G will be as much as 1000x faster than the previous incumbent (4G) in terms of download speeds. This step change in speed brings with it demands and complications never witnessed before in the wireless telecom segment.

Over the years, interconnects have gained a reputation as the weakest link in a system, especially when operating at the limit of performance. A new generation of cables has been developed that will stand up to the rigours of higher frequencies and in environments with high temperature and flexure. The challenge to companies like Junkosha who deliver these solutions - how to change engineers’ perceptions of cabling and interconnects into the future?

Phase Performance that Endures

At the higher mmWave frequency, “phase performance that endures” is a statement that cabling and interconnects must live up to, especially in the test and measurement environment. At these frequencies, interconnects are very small, meaning that connector design is a complicated activity. In addition, the amount of bending and stress the cabling is placed under is significant, resulting in an environment that requires phase stable cables to be installed. If the cabling is the first thing to let the engineer down, it remains the most system critical element in terms of reliability. This is why it is so important that engineers use cabling and interconnects that have been built for a 5G world.

High Performance Cabling Interconnects

Figure 1

Figure 1 MWX071 70 GHz mmWave cable.

As the move to 5G accelerates the requirement for more advanced “phase stable” interconnects, Junkosha has developed its latest mmWave cabling solution, the MWX071 (see Figure 1), in a bid to go beyond the 70 GHz barrier. Designed for applications including faster wireless communications and military radar, Junkosha’s latest interconnect provides Vector Network Analyzer (VNA) manufacturers with the capability to test very high frequency components that are at the heart of today’s highly sophisticated systems.

With this latest mmWave interconnect, Junkosha is continuing its move to design solutions that will meet the higher frequency demands of tomorrow’s 5G networks. Available with ruggedized NMD connector assemblies to deliver reliable and robust connections to the VNA, this new interconnect solution adds further breadth to the 5G oriented MWX0 series. The new MWX071 can be fitted with 1.85 mm M/F connectors making it the ideal system for precision measurements. It also features characteristics including a low dielectric constant and high flex life thanks to Junkosha’s precision engineered expanded-PTFE tape wrapping technology, meaning this new interconnect meets the need for a future proof, highest quality, cabling solution.

Figure 2

Figure 2 Insertion loss and phase change vs. frequency for 360° bending test over 60 mm round mandrel.

Figure 3

Figure 3 Phase stability over temperature for frequencies from 10 to 70 GHz.

Figure 2 shows the insertion loss and phase change of the MWX071 for bend testing. The cable was wrapped 360° around a 60 mm round mandrel. These cables are guaranteed within ±15 degrees at 70 GHz when delivered to the customer, though as can be seen typical deviation is around 5 degrees. Figure 3 shows the phase change versus temperature for various frequencies ranging from 10 to 70 GHz. The cable was measured in a chamber every 20°C from −30°C to 90°C after one hour of stabilization at each point. The graph shows excellent phase stability over the different temperatures.

Junkosha’s MWX071 adds breadth to its wide range of mmWave interconnects, which also includes the MWX051 and MWX061, both of which have also been designed for the 5G environment. Reaching up to 67 GHz, these mmWave cabling solutions have been created to withstand the most rigorous of testing environments for periods of approximately three and a half years (based on an internal Tick Tock test of 30,000 cycles, which equates to 30 tests per day, five days per week for 3.8 years).

Expanded PTFE Wrapping Expertise

Expanded PTFE is the key material needed to deliver a low dielectric constant, high flexure and phase stability in flexure and temperature deviation, all the desired attributes that are vital for mmWave data communications. At the core of Junkosha’s innovations are the company’s legacy fluoropolymer expertise and precision engineering which enables this unique expanded PTFE tape wrapping technique.

It is this technique, uniquely implemented by only two manufacturers in this sector, that allows Junkosha to deliver a flexible cabling assembly at these high frequencies that provides “phase performance that endures” over time.

A Connected Future

According to Masaru Omoto, product manager for Junkosha: “The demand for mmWave frequencies is no longer the preserve of military and research applications. 5G and high speed data applications are now driving innovation. For those familiar with the ‘Secret of Junkosha,’ it will be no surprise that we are continuing to push the boundaries of what is possible in the world of high frequency interconnects. A key enabler is our expertise and pedigree in expanded PTFE tape wrapping, which has allowed us to deliver flexible phase stable cables that endure.”

Lassi Kuosmanen, COB, partner at Signal Solution Nordic Oy, adds: “5G is our future, and we need to embrace it. It won’t stop there either. We are continually asked for cabling solutions that take us beyond current speeds and frequencies, moving us to a highly connected world in the future. However, with significant change comes significant challenges that will affect us all. The cabling and interconnects, often cited as the weakest link of many systems, is one such area that is in need of innovation. Thanks to organizations like Junkosha, interconnect innovations are at the heart of what they do, enabling future technologies for 5G that will bring about a wireless network that will change the mobile telecoms space forever.”

Irvine, Calif.