Millimeter-wave frequencies were once thought as being on “the realm of possibility”—which is to say, at frequencies where no sane engineer would choose to work. But millimeter-wave frequencies, essentially those signals above 30 GHz, have become more and more a reality: With lower-frequency spectrum continuing to be apportioned off by government organizations like the FCC, the only broadband spectrum remaining is above 30 GHz.
Luckily, as more engineers find themselves working on active and passive components for the short-range, high-data-rate communications links possible at millimeter-wave frequencies, test-and-measurement equipment companies have responded with a healthy choice of test signal sources and analyzers. These are enabling the characterization of components for growing number of millimeter-wave applications, through the use of 77- and 79-GHz radar systems for vehicular collision warning and avoidance systems.
For those engineers who might at one time have considered millimeter waves as some form of “black magic,” the day is quickly coming when it may even be possible to find millimeter-wave test equipment on the test bench at an automobile deal or repair shop.
No, we are not surrounded by millimeter-wave devices and systems just yet. But success is supplying cost-effective component solutions for the many wireless communications infrastructure and portable product applications has taught many RF/microwave component suppliers—notably semiconductor suppliers for the portable devices—that what might have at one time seemed like an uncertain market can turn into a global phenomenon. The practical nature of millimeter-wave signals for radar, communications, and other secure, line-of-sight applications makes the technology attractive for a variety of uses. These include automotive, medical, industrial, and (of course) military applications.
At one time, anyone working from 2 to 18 GHz was easily identified as usually answering to a major contractor and most often working on some kind of radar or electronic-warfare (EW) system. Now, it is not so unusual to be working at 60 GHz or 77 or 79 GHz. Once millimeter-wave frequencies automatically meant the use of waveguide transmission lines. But now, coaxial connectors can support signals to 60 GHz and higher.
Of course, any progress in millimeter-wave markets will depend on the availability of equipment to test everything from antennas to YIG oscillators for these systems. Many engineers working at millimeter-wave frequencies have grown comfortable with the results provided by their commercial computer-aided-engineering (CAE) programs. These simulators are generally quite accurate, with models that have been reinforced by measurements. But until an engineer’s own design can be prototyped and characterized, few manufacturers would take a risk on starting production on an untested product.
Fortunately, test-and-measurement equipment manufacturers have not been blind to the rising interest in millimeter-wave frequencies. They have responded with an unprecedented number of signal and spectrum analyzers, vector network analyzers, signal generators, and oscilloscopes capable of reaching well beyond 30 GHz—and some as high as 77 and 79 GHz. These are truly enabling instruments for millimeter-wave markets poised and ready to grow quickly.
As one example, collision-avoidance and autonomous emergency braking (AEB) systems were once equipment included only within the most high-end vehicles. But as automotive manufacturers see the value of including automotive safety systems across the greater parts of their model lines, and as manufacturers of millimeter-wave components succeed in delivering more cost-effective components—and affordable test equipment is part of achieving component costs in line with automotive manufacturers cost goals—what was once thought of as science fiction will become a reality.