Dr. Greg Henderson, Vice President of the RF and Microwave Business Unit of Analog Devices, has served in leadership roles in the microwave, semiconductor, and wireless communications industry for more than 20 years. Most recently, Henderson served as Vice President of the RF and Microwave Business Unit of Hittite Microwave Corp.—prior to its acquisition by Analog Devices. Henderson earned a bachelor’s degree in electrical engineering from Texas Tech University and was granted a Ph.D. in electrical engineering from the Georgia Institute of Technology. He holds seven patents in wireless communications and semiconductor technologies, and has published over 20 conference and journal papers.
First, can you tell us a little about your role at Analog Devices?
My role is Vice President of the RF and Microwave Business Unit of Analog Devices. In this role, I am responsible for the creation and execution of Analog Devices’ strategy for the full suite of RF and microwave products and solutions.
Greg Henderson, Vice President, RF and Microwave Business Unit,Analog Devices.
How are some of the various semiconductor technologies being utilized in terms of applications?
The complex mix of markets that we serve with RF and microwave solutions requires flexibility and careful consideration in terms of semiconductor and packaging technologies. Performance, development costs, margins, time-to-market, and integration levels all play a role in this critical selection.
CMOS is the primary candidate in the very-highest-volume markets, such as automotive and consumer, that require heavy digital and mixed-signal content to complement RF and analog signal processing. Here, high development costs due to design complexity and mask sets are justified by high volumes and revenues, though margins need to be carefully managed.
At the other extreme, for markets and applications that require the absolute best performance, such as military, aerospace, and instrumentation, broader technologies are essential. ADI leverages GaN/GaAs technologies for broadband microwave and millimeter-wave amplifiers and mixers, and SOI technology for low-loss, wideband, small-form-factor switches. These target best-in-class performance and often displace more exotic approaches, such as traveling-wave-tube amplifiers and PIN switches, due to better reliability, smaller size, and/or ease of use.
SiGe BiCMOS offers an important balance of integration and performance when compared to CMOS and GaN/GaAs for medium-volume applications such as cellular infrastructure, satellite communications, and military phased arrays. The improved performance level of SiGe BiCMOS can now address many microwave and millimeter-wave signal chains that were formally implemented with discrete components.
One topic that is not always discussed is packaging. What are some of the more recent developments in regard to packaging?
While ADI has expertise across a wide range of semiconductor technologies, co-packaging of these different technologies is becoming the real differentiator. This approach is not limited to semiconductor technologies, and includes passives, antennas, and waveguide interfaces. Co-packaging redefines system partitioning and enables a “best-of-all” approach in which system-on-chip (SoC) gives way to system-in-package (SiP).
In the microwave and millimeter-wave arena, package performance at the SiP and chip-scale levels is a significant contributor to solution performance. At ADI, we are extending these capabilities up through 100 GHz and can now provide surface-mount, chip-scale package solutions for products up through 70-80 GHz. Two such examples are our DigiMMIC, which is a 77-GHz CMOS integrated automotive radar solution, and our recently released dc-to-30-GHz wideband switch.
In addition, we offer SiP solutions for complete signal-chain integration in cellular infrastructure and point-to-point radio. We recently released a complete E-band SiP radio signal chain in a laminate-based, surface-mount package complete with a waveguide launch embedded in the package. These millimeter-wave markets now require small footprint SiP solutions just like in automotive radar and 5G.
How can today’s existing bandwidth be used more effectively?
All wireless communication modes (cellular, point-to-point backhaul, satellite) are going through rapid data-rate expansions to support modern demands such as streaming services and virtual reality. With the scarcity of wireless bandwidth, there is a growing need to maximize throughput in a given channel.
Fundamentally, there are two methods to increase data rates. The first is to move to higher-order modulation. The point-to-point market has taken this to what may be the maximum practical limit by supporting 4096 QAM modulation in the latest-generation systems. These high-order modulations require very low-phase-noise synthesizers and extremely linear Tx/Rx chains.
The second approach is to maximize the use of the channel through multi-antenna systems, often referred to as massive MIMO or phased-array solutions. Massive-MIMO systems rely on the spatial diversity of the physical channel to increase overall system capacity by sending coded data over a large array of antennas (up to 128 channels for current cellular implementations). In phased-array applications, beamsteering technology concentrates and targets RF energy in “beams” for individual users or groups of users. This improves the link budget and allows multiple beams to be sent with data to multiple users simultaneously.
Massive-MIMO and phased-array systems have a big impact on semiconductor content, because they represent a 10X-100X increase in the number of RF channels/radios compared to more traditional alternatives. To address this need, Analog Devices is developing solutions with much higher levels of integration, mostly in SiGe and CMOS technologies. This allows us to support single-chip, multichannel Tx and Rx solutions for next-generation massive-MIMO and phased-array solutions—with channel counts of up to 16 antennas in a single chip.
You have gone on record saying that wireless sensing is a rapidly emerging market. Can you tell us more about this market and where you see it going?
Real-world sensing technology has been advancing steadily, and it’s no surprise that, coupled with the Internet of Things (IoT), the development of smarter sensing technology is required to further automate the smarter world in which we live.
ADI’s new 24-GHz integrated solution is enabling a new generation of non-contact sensors, which increasingly are being used in mass-market applications such as automotive ADAS, industrial sensing, and consumer products. These wireless radar sensors provide real-time object detection information such as object presence, movement, position, or angle, as well as velocity and range from a few centimeters up through several hundred meters from the sensor.
Until recently, radar sensors at gigahertz frequencies were realized using complex and costly discrete solutions, which limited their broad market adoption. ADI’s 24-GHz silicon radar chipset provides a high-performance, small-size, low-cost, easy-to-use solution for object detection and collision avoidance. These sensors have a broad application base and are being adopted in automotive safety systems, traffic-monitoring controls, UAV collision avoidance, security monitoring—even healthcare devices used for vital-signs monitoring.
Radar sensors, compared to optical/vision or ultrasonic-based sensors, provide accurate measurements over a much longer range and wider field of view in very difficult environments that might include dust, smoke, snow, fog, or poor lighting conditions. While radar technology is not a panacea for all sensing requirements, it is being coupled with other sensor technologies to create “sensor fusion” solutions that are reliable, accurate, and robust.
It seems like no interview is complete without mentioning 5G. Can you tell us a little bit about some of the 5G-related activity taking place at Analog Devices?
The possibility of new network topologies, use cases, connectivity scenarios, and the associated technology challenges that we need to overcome—as an industry—is a very exciting place for ADI. We have been making significant investments in both sub-6-GHz and millimeter-wave 5G components, and remain committed to the communications infrastructure market.
In terms of our technology and products, we are in a very strong position to offer customers a complete 5G signal chain. ADI has over a decade of leadership, experience, and success from the digital interface to the antenna. That means we extend from bits all the way to microwave, and now with 28-GHz and 39-GHz waveforms, even to millimeter-wave.
The technology expertise and manufacturing infrastructure that comes from our long history in the communications market are proving vital in the development of our 5G products. We are also finding that we are able to leverage our work in developing integrated solutions for military phased-array radar applications into solutions for 5G. In emerging markets such as 5G, it is important to provide technology leverage from other markets—and ADI is making significant investments in multi-antenna phased-array solutions in the military, 5G, and satellite communications markets.
Currently, we have available a compelling selection of data converters, up- and down-frequency converters, PLL/VCOs, switches, and beamformer/phase-shifter ICs that fit the full range of 5G prototype designs. These products enable our customers to build high-performance, fully functional 5G terminal and base-station systems.
We are actively participating in our customer’s trial systems and helping to create the ecosystem for these next-generation solutions. We continue to make investments in each of these product areas, and will offer even higher-performance, more integrated baseband, RF, microwave, and millimeter-wave products in the coming years. We plan to be a big part of the 5G revolution to come.