Between 4G and 5G, there are over 36 bands, which can make choosing the right ones for your product feel as overwhelming as going to a restaurant with a book-length menu in a foreign language. One tip is to start by identifying the country or region(s) where your device will be used. Next, choose a mobile operator – or multiple ones if the device will be used in several countries where no single operator has service.
These two choices instantly narrow down the options to the bands where the operator holds licenses. Now you know which bands to look for when choosing a radio module and antenna. If your device will be used in remote areas some or all the time — such as for tracking trucks that travel on rural interstates or agricultural sensors — choose a module and antenna that can support 3G fallback for reliable connectivity in places where 4G or 5G aren’t yet available.
The tables below are a helpful guide on the cellular band categories and typical frequency ranges used worldwide.
Band choices are critical because they directly affect your device’s size, battery life, performance, reliability, competitiveness, and business model. For example, suppose your device needs an internal antenna, such as for aesthetics. The band choices affect the antenna’s ground plane requirements and, in turn, the size and layout of the device’s printed circuit board (PCB).
The 4G and 5G bands currently in use in North America range from 600 MHz to 3.5 GHz. Antenna size and ground plane size vary significantly by band. Each carrier has its own minimum efficiency requirements for the bands where it holds licenses. If the antenna’s ground plane isn’t sized correctly to meet an operator’s efficiency requirements, then the device won’t be certified for use on its network. That’s just one example of why band choices should be one of the initial steps during product design rather than an afterthought. (For more information about how the carrier certification and pre-certification processes work, click here.)
Regardless of whether an antenna is embedded or external, the ground plane is one factor affecting total radiated power (TRP) and total isotropic sensitivity (TIS). Each mobile operator has its own TIS and TRP requirements, varying significantly by band. This highlights the importance of choosing an antenna capable of meeting the carrier certification requirements for each operator in each band that the device will use.
Carrier certification is also one reason it’s wise to make band decisions early in product development before designs for the PCB, device form factor, and other attributes are finalized. This avoids the need to make design changes later in the product development cycle to accommodate unexpected antenna requirements. Those changes can make achieving price point and profit goals difficult and delay the device’s market debut, giving competitors a first-mover advantage.
Launch delays are particularly bad for enterprise Internet of Things (IoT) products because law enforcement agencies, smart cities, utilities, automakers, and other users typically keep their devices in service for 10-15 years — or even longer. So, if a new IoT device isn’t available when potential customers are ready to purchase, the window of opportunity might not reopen for another decade.
Tips for Navigating the Options
Two RF engineering rules of thumb are helpful for choosing bands:
- At lower frequencies, signals travel farther and are better able to penetrate building materials. Start by considering where the devices will be used. For example, if the devices will be installed indoors or in underground utility vaults, consider using lower bands such as 900 MHz because higher frequencies struggle to penetrate concrete, brick, steel, and soil. This directly affects the performance and reliability of the device and the services that use it, such as smart utility applications.
- Higher frequencies support higher data rates. If the device will be used for bandwidth-intensive applications such as surveillance camera video, then focus on higher bands. The trade-off is that signals don’t travel as far at higher frequencies, so the application will require devices to be installed closer to base stations. If the devices will be installed in remote areas and support low-bandwidth applications, such as agriculture sensors that track soil humidity and temperature, then focus on lower bands.
Sometimes, the band choices are determined by what the target customers already use. Two examples are Band 14 (700 MHz) for FirstNet public safety agencies and the 3.5 GHz band for enterprises that want to use CBRS for private networks.
Another important consideration is whether the IoT device will be designed to give users the ability to switch mobile operators in the future. Instead of traditional SIM cards, many IoT devices now use an electronic SIM (eSIM), which can be updated over the air with a new operator’s profile. In those cases, the antenna needs to be able to support not only the bands used when the device is initially deployed but also the ones that potential future operators use. For example, the antenna should support both AT&T’s Band 12 and Verizon’s Band 13 to ensure network access when switching operators.
Similar considerations apply to the application’s business model. An example is a telemedicine service where patients have a device in their home for monitoring their vital signs, uploading that data to their physician, and conducting virtual office visits. That device will need to support multiple operators, each with its own set of bands, to ensure that it will always be able to establish a network connection at every customer’s home. This highlights the importance of choosing an antenna that’s flexible enough to cover a dozen or more bands and also meets the carrier certification requirements for each operator in each band.
Finally, many IoT devices rely on battery power. LTE Cat M1 and NB-IoT have ultra-low power consumption, making them ideal for battery-powered devices expected to last 10 years or longer, such as uploading usage data from water meters. In those cases, the band choices are determined by the frequencies that Cat M1 and NB-IoT devices can use, which varies by country and operator. An antenna offering the highest efficiency and gain in each band can further increase battery life. That’s because the transceiver doesn’t have to use as much power to transmit a usable signal or receive a weak one.
That’s a lot to consider, so device OEMs, systems integrators, IoT service providers, and other companies frequently turn to antenna experts. To get started, get in touch with Taoglas’ Engineering team by clicking the button below.
