MmWave technology is a cornerstone of upcoming 5G networks.
The term mmWave refers to a specific part of the radio frequency spectrum between 24GHz and 100GHz, which has a very short wavelength. This section of the spectrum is pretty much unused, so mmWave technology aims to greatly increase the amount of bandwidth available.
Lower frequencies are more heavily congested with TV and radio signals, as well as current 4G LTE networks, which typically sit between 800 and 3,000MHz. Another upside of this short wavelength is that it can transfer data even faster, though its transfer distance is shorter.
While lower frequency bands cover much greater distances, they offer slower data speeds. High-frequency mmWave bands cover much smaller areas but can carry much more data – selling points to 5G broadband.
The objective with mmWave is to increase the data bandwidth available over smaller, densely populated areas. It will be a key part of 5G in many cities, powering data in sports stadiums, malls and convention centers, as well as basically anywhere data congestion might be a problem.
The 5G mmWave Antenna Challenge
A key challenge for 5G device makers has been mmWave antenna design. The problem that engineers face is that while mmWaves enable super-fast data speeds over 5G networks, these high frequency radio signals are easy to physically block. The fear was that 5G devices might need unsightly external antennas to sufficiently capture the mmWaves.
Unlike the lower 800MHz to 5GHz radio frequencies used in most wireless devices today, mmWave spectrum (including the 24-39GHz range) generally requires a “line of sight” between the transmitting and receiving devices — specifically, a straight line or arc without another physical object in the way.
One way around this issue has been the use of antenna array supporting either face or edge placement in a cellphone, for example. Tests show that both orientations have similar performance, so the choice depends on other design trade-offs, such as phone thickness. Whichever configuration is used, several of the antenna modules are placed at different locations in the phone, ensuring coverage regardless of phone orientation and compensating for signal blockage when a hand is holding the phone.
The arrays use patch and dipole antennas, either single or dual polarization. The arrays provide spherical coverage in each polarization and beam steering of ±45 degrees around boresight.
Other technical challenges for developing a viable mmWave radio for a 5G phone:
- Maintaining sufficient link margins during transmit and receive.
- Maximizing phone battery life by minimizing power consumption.
- Minimizing the temperature rise of the module and phone with the thermal design.
- Minimizing the size of the mmWave radio, with a form factor compatible with a smartphone.
Want to learn more? Tonex offers 5G and mmWave Antenna Engineering Training, a 3-day course that covers the theory and practice of antenna engineering, communications, radar, commercial and military applications.
For more information, questions, comments, contact us.