Editor’s Note: Welcome to our weekly Reality Check column. We’ve gathered a group of visionaries and veterans in the mobile industry to give their insights into the marketplace.
Out of sight, out of mind. That sums up the state of cell phone antennas, which most mobile users rarely think about since they became embedded. The irony is that at the same time, antennas have become more important than ever when it comes to delivering the reliability and performance mobile users have been promised.
Today’s mobile consumers expect high data rates, exceptional voice quality and longer battery life. Delivering on these expectations is highly reliant on the capabilities of the antenna within the device. Just as important, the more efficient an antenna is, the less network capacity it uses for each call or data session. That means carriers are under less pressure to buy spectrum, split cells or both.
These benefits apply to all air interfaces and all devices, including smartphones and tablets. These benefits also show why it’s highly important for the antenna to be taken into consideration at the beginning of the design development process as opposed to the end. By helping to ensure optimal data rates and reliable calls, antennas are a proven, highly effective way for wireless carriers and device vendors to differentiate their products in the eyes of customers.
More bands in less volume
In today’s mobile devices, screens and batteries typically get the most real estate, followed by circuit boards and chips, with antennas generally squeezed into any bits of remaining space. That integration order creates two challenges: antennas often can’t be placed in the most ideal location in terms of performance, and antennas have to be as physically small as possible.
The problem of limited space is getting worse because although vendors and carriers know that customers want bigger screens and longer battery life, they also know that these same consumers want devices that are thin and lightweight. LTE illustrates how difficult it is for device vendors to satisfy these competing preferences due to the increasing number of bands that will need to be covered:
–LTE’s current implementation uses two antennas. LTE has more than 40 possible bands, and the ones in commercial use today span 700 MHz through 2.7 GHz.
–The same LTE antenna(s) need to support 3G fallback because it will take carriers years to build out their LTE network to match the 3G footprint. If the device is designed for global roaming, then it will typically need to support five bands.
–At least one for Wi-Fi because many carriers use 802.11 to reduce the burden on their 3G and LTE networks.
–A GPS antenna.
This mix of possible LTE bands is why some carriers are requiring vendors to provide LTE smartphones and tablets that support 13 or more bands. Current passive antenna technology will not be able to cover all of the bands necessary for LTE phones in the future and deliver on the promises of faster connection speeds and greater network capacity.
The future is active
LTE highlights the value of active antenna systems, which are key for meeting carrier, vendor and consumer requirements for both multi-band support and attractive device designs. An active antenna system may have one or multiple antennas with advanced circuitry to tune across multiple bands. For example, a single active antenna can enable global roaming by tuning across all commercial frequencies including LTE, and all 2G, 3G and 4G bands. One way of thinking of an active design is that the antenna system interacts with the rest of the RF system as a peer component rather than a passive strip of metal.
Just as important, device front ends also must be designed with the antenna system in mind. The current strategy of designing a front end and then trying to match an antenna to it can continue, but will lead to less efficient designs. Instead, architecting ways for the RF system and antenna to actively communicate with each other makes it possible to wring out a few more dB of performance. For example, when an antenna’s gain is increased 1 dB, the power amplifier in the handset or tablet can be throttled back 1 dB. Increase the gain 2 dB, and the power can be reduced 2 dB. The increased gain enables better voice quality, real-world throughput that matches the carrier’s marketing claims, more reliable calls, lower emissions, and less pressure to buy additional spectrum and infrastructure. The reduced power consumption additionally means longer battery life.
The rise of LTE coincides with a profound shift in how carriers, device vendors and other ecosystem members view antennas. The challenge of integrating multiple antennas in small form factor devices at the tail-end of development is becoming very difficult. Instead, the future is active antenna and RF systems, which are fundamentally different. Active architectures give device vendors more design flexibility, enabling them to meet the requirements of both the LTE spec and their carrier customers more easily and cost-effectively.
Design flexibility is key to realizing a rapid time-to-market, which is critical in today’s competitive smartphone and tablet market. Active antenna and RF systems provide greater flexibility by allowing more degrees of freedom in the antenna design through techniques such as active impedance matching. As the design process evolves, the antenna system can dynamically tune to changes in device configuration, leading to faster TTM. With passive technology, the antenna needs to be re-tuned each time the device configuration changes.
An additional benefit is a 50% reduction in physical volume while still maintaining specification compliance. Not only can the volume be significantly reduced, the antenna system can also be dynamically tuned for known challenge areas in specification compliance.
The many benefits of active antenna and RF systems mean smaller mobile devices while providing a consistently reliable, high-performance user experience.
Over the next few months, this column will look at how RF system design is changing to a variety of industry trends and opportunities. One example is the enterprise market, where reliable, high-performance devices are must-haves for carriers and vendors that want to target high-value verticals such as health care. The enterprise opportunity includes cloud-based services, which are only as useful – and worth paying for – as the wireless connection to them.
Barry Matsumori brings more than 25 years of experience in technology and telecom to his position as Chief Marketing and Strategy Officer of Ethertronics. He is responsible for overseeing the development of long term strategies as well as the development of new product lines. He will also support customers for existing Ethertronics products.
Prior to Ethertronics, Matsumori was VP of wireless connectivity for Qualcomm CDMA Technologies and was responsible for product management, business development and marketing for all module products including Gobi and InGeo. He was also responsible for the development of the M2M strategy and products for Qualcomm.
Matsumori has worked with terrestrial and satellite communications at Qualcomm, Loral Space Systems, & General Dynamics. He has also had prior experience growing early stage companies in executive management roles in engineering, business development and operations. Matsumori holds a BS in business from Arizona State University and an MS in Electrical Engineering degree from the University of Arizona.
