What are the main industry developments you are seeing?
Evolving communication systems drive developments in our industry, so LTE and 5G represent many technologies that support enhanced mobile broadband, which is the natural development of LTE; massive machine-type communications — also known as the industrial IoT — which reflects low cost devices such as sensors and controls; and ultra-reliable, low latency communications, providing mission-critical infrastructure for services such as transportation, public safety and medical.
When we talk about future communication systems, we are actually talking about many diverse systems that will be implemented with a wide array of solutions. When we discuss the RF and microwave hardware components that will support all these different systems, three main trends have been true for some time and will continue to be true:
- First, performance — such as bandwidth, linearity and efficiency — is critical and will have a major impact on devices such as power amplifiers, filters, antennas.
- Second, integration, which we see in multi-technology modules and embedded devices, is critical for bringing high performing, cost-effective communications products to market quickly.
- Finally, the escalating cost of product development for complex systems requires more coordinated engineering efforts.
Are these trends a big driving factor in the development of your design tools?
Absolutely. We are very excited to be talking about the latest release (v13) of the NI AWR Design Environment, which introduces a number of innovative features and capabilities that support the development of complex high frequency electronics. These enable engineering teams to achieve the high performance and integration goals that our customers are focused on meeting.
Also included in v13 are capabilities that help our customers manage the escalating costs of product development, by helping individual engineers and engineering teams be more productive.
For people not as familiar with NI AWR software, please give us a little background.
Sure. NI AWR Design Environment integrates circuit, system and electromagnetic simulation within a single platform, enabling designers to accurately represent, analyze and optimize their products before costly fabrication and test. The platform includes our flagship product, Microwave Office, which is a leading RF and microwave circuit simulation tool. Visual System Simulator is our software for communication and radar system development and AXIEM and Analyst provide planar EM and arbitrary 3D EM analysis, used in passive component and interconnect modeling as well as antenna design.
NI AWR Design Environment plays a critical role by tying these simulators together, so information defining component details and the resulting electrical responses are seamlessly shared among simulators. The design trends driving today’s products can only be addressed when the designers can accurately represent their designs in simulation, by measuring performance factors such as bit error rate or error vector magnitude while applying the complex waveforms and modulation schemes being considered. They must also be able to easily define and optimize physical design through the use of fully embedded parametric EM simulation. Lastly, engineers need a reliable and efficient way to take design information and utilize it in the manufacturing process.
What are some of the latest features with the NI AWR Design Environment?
We have made many improvements and added new capabilities in a large number of areas within our product portfolio, largely driven by input from our customers. The main idea is that we provide engineers with a platform to define and simulate their products. So we have focused on the speed, accuracy and robustness of our simulator technologies — to give engineers confidence that their designs will work as predicted — as well as on the automation that helps them define their designs and manage data between EM, circuit and system simulators, measured data and third-party EM simulators and enterprise layout tools.
How does v13 help designers develop smaller, more integrated devices?
There are key new features that have been implemented to improve design flows for designers developing circuits on printed circuit boards and multi-chip modules, where different technologies are integrated in a single device.
In the case of a module that integrates multiple technologies, engineers may need to model several MMICs and perhaps an RFIC on a single laminate, as is the case for multi-chip modules. The RFIC may be designed by one team working with another team responsible for the module package interconnects and off-chip passive components. We have several customers doing precisely this type of design.
We are addressing multi-technology module design with enhanced support for multiple PDKs within a single project, making it easier to combine designs built from devices using different manufacturing processes and different layer stack-ups. We now support Spectre netlist simulation with the APLAC harmonic balance simulator in Microwave Office, as well as OpenAccess, which eliminates manual re-entry for schematic import and export of silicon designs created in Cadence Virtuoso.
Engineers are able to combine Cadence RFIC blocks with MMIC and PCB designs simulated in Microwave Office, as well as EM modeling from either AXIEM, Analyst or a third-party EM simulator.
NI AWR software has a long history of interfacing with other suppliers’ tools. Is the Cadence interface new, and what is new in the area of interoperability with other EM simulators?
Yes, we’ve always had a strategic commitment to focus on the technologies we do best and provide the best possible interoperability with other tools in the market that either offer capabilities we don’t provide or are the tool a customer may be using.
As our own EM tools have advanced, in terms of their speed and accuracy, a lot of our customers are discovering their benefits — a leading one being the tight integration with circuit and system simulation and how parametric physical design and optimization need sophisticated communication between these technologies to be most effective.
Our EM Socket technology provides the links to our EM technology as well as third-party tools from HFSS, CST and Sonnet. The EM Socket II architecture is new in v13 and provides a very capable and robust interface, including support for bi-directional data flows between Microwave Office and HFSS, for example. Designers can designate different simulators for a given EM structure and the environment will automatically manage the transfer of geometry, ports and simulation information to the specified simulator and insert the response into the larger simulation network.
We talked about integration earlier, and today’s circuits are often composed of complex building blocks that need to be stitched together in a circuit hierarchy. We have spent a lot of time developing one of the best open EDA platforms available to enable designers to manage this hierarchy across different simulators and third-party tools.
Supporting RFICs with Spectre netlists and OpenAcess expands this philosophy on the circuit side, where other tools such as Virtuoso are commonly used to develop RFIC circuits. NI AWR Design Environment can incorporate this data as a netlist block or import the actual schematic-based design, in the case where elements within that design need to be manipulated by the designer in Microwave Office.
What about the integration with PCB design?
In v13, we have developed a more efficient flow between third-party layout tools and Microwave Office, with a new PCB import wizard now supporting IPC-2581 (A and B) and ODB++ (V7 and V8) files that are produced by most enterprise board tools, including Cadence Allegro, Mentor Graphics and Zuken. Importing these files produces a schematic layout representing the board geometry along with a STACKUP element defining the board cross-section. This new capability is intended for importing PCB designs and preparing them for EM simulation with AXIEM and Analyst.
5G is an active area of interest in the industry. What do you see happening there?
5G is driving so much of the requirements for products today and, fortunately for us, NI is very engaged in a number of the standards bodies that are defining the radio access and underlying technologies, which gives us a jump on developing the capabilities that will be required to design 5G products.
Achieving the aggressive goals of 5G is being addressed in several areas:
- One is spectral usage, which includes variations of orthogonal frequency division multiplexing (OFDM) based waveforms that were introduced with LTE release 8 and inter- and intra-band carrier aggregation.
- Another is enhancing over-the-air efficiency, with the expansion of MIMO and beam steering technologies.
- Finally, moving to higher frequencies, particularly above 6 GHz and into the millimeter wave range.
Several key areas have been central to the discussion on new waveforms, including spectral containment, scalability to higher carrier frequencies, PA efficiency and the effects of nonlinear PAs, MIMO extensibility and receiver complexity. OFDM shortcomings in LTE could get worse in the higher frequency bands due to filter and phase noise performance, wider bandwidths and amplifier technologies. Several candidate waveforms have been proposed, and we are supporting these in v13, including filterbank multicarrier (FBMC), generalized frequency division multiplexing (GFDM) and universal filtered multicarrier (UFMC). VSS includes reference receivers for the candidate waveforms, making it convenient to evaluate BER and EVM.
For PA design, new waveforms and carrier aggregation will make it more challenging to address linearity and efficiency requirements and to achieve the bandwidth to cover the intra-carrier bandwidths. We believe more sophisticated design support such as load-pull will be critical to success, so we are heavily invested in providing best-in-class functionality, including modulated signal load-pull and nested source/load-pull, which enables designers to study the impact of source match and harmonic terminations on PA performance.
We have also introduced new optimization capabilities that leverage the evolutionary algorithms that are part of the proprietary technology we introduced with Antsyn antenna design software, now applied to our optimization technology. These optimizers use recombination and selection to rapidly explore a large number of points randomly distributed over the design space. This results in a more efficient and faster approach to investigating design possibilities and identifying optimum solutions.
What new development relate to antenna design?
For antenna design and EM modeling in general, we have made simulation speed improvements of up to 50 percent in both AXIEM and Analyst, which means designers can solve twice the number of problems in the same amount of time. That becomes significant when you combine the more robust optimization technology in v13 with improvements in EM simulation speed and remote solving. It enables engineers to spend more time reviewing the impact of design choices on performance.
We’ve also made improvements to our meshing technologies, added new boundary conditions that can reduce certain problem sizes to improve speed and introduced new capabilities in port definitions that will help with EM problems embedded in circuits.
And we introduced Antsyn last year, which will help with design starts for antennas, which we anticipate will find their way into IoT and embedded antenna applications.
With some of the antenna technologies posed by 5G, such as MIMO, phased arrays and sophisticated beam management, over-the-air characterization will be very challenging. Such challenges will also push the envelope of simulation technology to accurately model MIMO systems above 6 GHz.
We introduced a very powerful phased array model last year in v12 that we have enhanced in v13, to enable the modeling of phased arrays with thousands of antenna elements and array configurations using various standards, as well as custom geometries. The phased array’s behavior can be easily defined through the parameter dialog box or through a data file containing configuration parameters such as gain and phase offset, theta/phi angles of incidence and signal frequency. The phased array model can be set to either transceiver (Tx) or receiver (Rx) modes. In Tx, the signal power exciting each element is calculated based on the signal setting defined by the user with various options. A number of commonly used gain tapers are implemented in the phased array block to control beam shape and reduce the sidelobe levels.
Along with various signal distribution schemes and support for frequency-dependent operation, the phased array model also allows the user to simulate array imperfections due to manufacturing flaws or element failure. Yield analysis can be applied to the block to evaluate sensitivity to the variance of any of the defining phased array parameters. Designers can define gain or full radiation pattern for each antenna element in the phased array. This allows them to use different radiation patterns for internal, edge and corner elements of the phased array. The radiation pattern of each antenna element will often be affected by its position in the phased array. These patterns may be measured in the lab or calculated with the AXIEM EM simulator.
VSS can also model the RF links of individual elements in the array. This is an important functionality, since RF links are not ideal and can cause array behavior to deviate significantly from its ideal one.