Why Antenna Decisions Make or Break Your Entire System — and Your Bottom Line
Discontinuous Reception (DRX) and Power Saving Mode (PSM) are among the features in LTE and 5G that were created to meet demand for sensors and other IoT devices whose batteries can last for the better part of a decade. They’re also examples of why antennas should always be a top consideration at the beginning of the device design process rather than weeks or months later.
Experience shows that when antennas are an afterthought, there’s a high risk that the device will need to be re-engineered to accommodate them. For instance, components may need to be shuffled to free up PCB space for the antenna. Another common problem is that the antenna isn’t efficient enough or in the wrong board position to meet carrier certification requirements for signal strength, data throughput, and other performance criteria.
That rework is time consuming. So is resubmitting the device for carrier certification. The longer all that takes, the more time competitors have to sell their devices. And with DRX and other technologies maxing out battery life, those smart cities, utilities, and other customers won’t be in the market for replacements for another five years or longer.
OEMs that get their antennas right, right from the start, get that business — potentially tens of thousands of devices per customer in the case of smart grids, for instance. Those that treat antennas like an afterthought miss those windows of opportunity and have to wait several years for their next chance with those large-scale customers.
Bottom line: Antennas aren’t just another component. Instead, they play a critical, fundamental role in the success of both the device and the OEM selling it. Read on to learn more.
Maximize Reliability and Performance
Many IoT devices have compact form factors, which means they require small antennas and have limited PCB space. These two factors directly affect the device’s ability to maintain a reliable, high-performance connection.
Small antennas such as chips have limited impedance bandwidth and efficiency and thus are highly sensitive to their PCB placement. The PCB boosts the chip’s radiation because currents are excited on the PCB ground plane. (For a deeper dive, see “Why Antenna Placement on PCBs is Critical for Chip Antenna Radiation Performance.”)
If processors, memory, and other components get first dibs on the board, then the chip will end up in a spot where these currents are not properly induced. The antenna’s performance will suffer, and so will all of the applications that use it. That’s avoidable by choosing the antenna at the beginning of the design process and then following its integration guide recommendations for PCB location and minimum ground plane size.
Pass Carrier Certification the First Time
Each mobile operator uses certification testing to ensure that a device meets its specific performance and network requirements. For example, to be certified for use on AT&T’s network, LTE NB-IoT devices must have antennas that support bands 24 and 12.
NB-IoT and Cat M1 devices also must meet each operator’s total radiated power (TRP) and total isotropic sensitivity (TIS) requirements. If a device will use multiple networks, such as for roaming or as single-SKU products, then there’s the added challenge of passing multiple operators’ certification requirements.
To ensure their devices pass certification on the first submission, savvy device OEMs use Taoglas’ engineering services such as CSA.30, which tests TRP performance, and CSA.31, which covers TIS. Each test takes just 2-3 days and enables OEMs to leverage Taoglas’ decades of experience with hundreds of different types of devices and networks.
CSA.30 and CSA.31 are examples of how pre-certification catches and corrects poor integration and other problems so they devices can pass carrier certification and get to market faster — and land customers before competitors do. (For more information, see “Why Cellular Pre-Certification is Critical and How to Successfully Navigate the Process.”)
Minimize TCO
Although DRX and PSM maximize battery life, OEMs can’t rely on them alone to meet customer requirements for device longevity. For example, Taoglas services such as ISA.10, CSA.10, and CSA.20 help OEMs assess the feasibility of their design and each antenna option, and use testing to ensure that they’re perfectly integrated and tuned so the whole system performs as expected.
These services also help ensure that an antenna choice or integration design complements DRX, PSM, and other power-saving technologies rather than undermining them. One example is impedance matching, which ensures that the antenna can broadcast all of the signal that the transmitter provides. If there’s mismatch, then some of the signal is reflected at the transmitter. This wastes battery life because the transmitter is using power that literally goes nowhere.
Another example is choosing an antenna with high efficiency. This complements eDRX and PSM by enabling the transceiver to use less power to transmit a usable signal every time it wakes up.
Finally, proper impedance matching and high-efficiency antennas directly affect total cost of ownership (TCO) for customers. It’s expensive to replace hundreds or thousands of devices whose batteries failed prematurely, especially if they’re in remote or other difficult-to-reach locations. By considering antennas at the start of the design process, OEMs can maximize service life and minimize TCO — and create the kind of brand reputation that has customers coming back when it finally is time to replace those devices.
Get in touch for orders or any queries: sales@rfdesign.co.za / +27 21 555 8400
Courtesy of Taoglas
