The Low Down on High Frequency - mmWave Myths
2020-03-26 | 7 min read
What is mmwave?
Welcome to the world of 5G. In that world, networks will heavily utilize millimeter-Wave frequency spectrum bands. These bands, above 24 GHz, have the ability to support large bandwidths and high throughput. As the number of users with cell phones, connected cars, and other wireless devices increases, the capacity of the network must follow.
You may have heard of some people protesting mmWave and 5G development. Do these protests or even hesitations have substance, or should we catapult into the newest wireless communication technology? Below, I’ll explain 4 of the most common myths regarding mmWave, if you should believe them, and if the concerns are valid, what we can do to mitigate issues.
Let's get started.
Myth Number 1: mmWave frequencies will harm your health
Yes, cell phone towers and cell phones emit radiation. However, there are a few different types of radiation: non-ionizing, which comes from our electronics, and ionizing, which comes from the sun or medical imaging machines like X-rays. It is true that the higher the frequency, the more potential harm can be done, but mmWave frequencies (24 GHz to 300 GHz) don’t fall in to the non-ionizing radiation category. More research needs to be done to fully understand the effect of this frequency range on humans, but for now, there’s no need to panic. While there may be some radiation exposure, you actually get a decent amount of your daily radiation dose from eating a banana, but no one fears their daily smoothie...
Myth Number 2: mmWave won’t be able to travel through walls
Having a high frequency means having a short wavelength. This means that the waves see a little more trouble when passing through objects, such as walls, your body, trees, etc. So, honestly, this one is pretty much true. However, don’t lose hope for the mmWave and 5G revolution just yet. By now, you have probably heard of small cell deployment. Smaller base stations will provide more dense areas of cellular coverage, compensating for the short wavelengths' inability to travel long distances.
Another possible solution to this is that 5G mmWave networks can cover outdoor usage and indoor usage separately, but we may need to brainstorm new ways to cover indoor to outdoor (and vice versa) coverage. And while this may seem like an issue, it actually could increase efficient spectrum use. We could potentially reuse bands when out of range, decreasing the number of bands needed.
Myth Number 3: The terms mWave and 5G can be used interchangably
We’ll start with 5G, since that’s why so many people are interested in mmWave. While the two are closely related, 5G will use many more technologies than just mmWave. mmWave helps to increase the bandwidth available for cellular networks by breaking in to the above 24 GHz range, allowing for more high data rate spectrum usage. However, 5G also utilizes the sub-6 GHz spectrum. mmWave high frequencies can propagate information much faster but are easily blocked. Lower frequencies can travel long distances but transmit data more slowly. mmWave is a crucial component of the explosion of 5G development and is necessary for meeting the promises of ultra-fast networks, but there’s still more to 5G. The phrases aren’t interchangeable, but most often can be used together.
Myth Number 4: mmWave will be used only for cellular communication
Not true! These high frequency waves have use cases across the board. From image processing to medical research, mmWave provides a new frequency band for innovation across the board. For example, mmWaves are used in explosive detection due to the ability of the short wavelength to travel through the human body. The reflected waves can be used by an imaging system to estimate sizes and shapes of concealed objects. While the exact type of object wouldn’t be obvious, the images created can at least detect unexpected concealed objects.
Other applications, such as video transmission, will improve greatly. Wireless video transmission, such as from a laptop to a TV or wireless HD projectors, will be supported by mmWave technologies. The wireless capabilities don’t stop there – a PCI express wireless version is already available, and some companies have expressed interest in developing a wireless USB 3.0. Chip-to-chip wireless links would also be made possible, allowing device design breakthroughs.
Many other applications utilize the high frequency bands of millimeter wave frequencies. Astronomists use this band for telescope imaging. This satellite-based remote sensing helps identify oxygen particle radiation in the upper atmosphere, which helps scientists predict and measure temperature. Radar also heavily utilizes mmWave bands, especially for short-range applications. This radar helps in shooting down missiles, tracking beams of bullets, and more.
With these things in mind, testing and avoiding issues becomes an integral part of development. Knowing how your 5G device will respond to specific environments or stimulus can help make your design more robust once it’s deployed. Using software like PathWave Vector Signal Analysis (89600 VSA) (now with even more powerful capabilities!) or Pathwave X-Series Measurement Applications on a signal analyzer gives you a window into the mmWave spectrum. These software applications are best used with a Keysight Signal analyzer paired with a high-frequency signal generator, such as pairing analyzers like the MXA or UXA with the VXG signal generator.