Author: Alan Salari
1. Introduction
RF engineers play an important role in developing many revolutionary technologies in telecommunications, physics, and astronomy, to name a few. They are responsible for some of the most transformative technologies we use daily, such as cell phones, satellite communication (SATCOM), and radar systems.
There are approximately 22,000 Radio Frequency Engineers currently employed in the United States. This number grows with each passing year due to the rising importance of RF technologies and the high compensations these professionals receive. The average salary for an RF engineer in 2021 was approximately $100,000.
RF engineers perform the essential research and development functions required to advance key technologies in telecommunications, including SATCOM, defense and security, plasma engineering, radio astronomy, and quantum computing.
Modern RF engineers bring different sets of skills to the table than their predecessors from the semiconductor revolution. Their focus has shifted from component design to system design.
Earlier generations of RF engineers focused heavily on component-level design. However, modern chip manufacturing companies have handled most components and chip design processes. This includes companies such as Qorvo, Analog Devices, Skyworks, NXP Semiconductors, and Qualcomm.
Such manufacturers can now provide low-cost, high-performance and highly integrated chip solutions for use in various applications and sectors. This allows RF engineers to focus on advancing the technologies in other ways, especially by designing systems. Modern RF engineers are concerned with system-level designs and focus on achieving high-performance levels. An RF engineer must be capable of designing complex systems consisting of RF, digital, and analog subsystems that interact with one another.
In this article, we will examine the skills that modern RF engineers need to possess. Such engineers must have an in-depth understanding of the building blocks of their trade and familiarize themselves with the different ways to channel this knowledge and achieve their desired performance.
A modern RF engineer possesses an in-depth understanding of the following subjects:
1-RF components
2- System Design and Analysis
3- Simulation
4- PCB Design
5- RF Measurement and Characterization
6- EMC tests, FCC certification
7- Test Fixture Design for Mass Production
Quaxys provides interactive online courses that delve into the practical aspects of the subjects mentioned above. Explore our courses here.
2.1 RF components
An RF engineer must possess extensive knowledge of RF components before starting the system design process. This includes understanding lumped element LCR components, filters, amplifiers, oscillators, mixers, couplers, and other essential components.
RF engineers do not need to design such components for most applications, as chip solutions are already available. This frees them from the burden of designing these components themselves. However, they must still understand each component's functions and figures of merit. For example, an RF engineer designing an amplifier must be familiar with gain, 1 dB compression point, IP3, efficiency, noise figure, etc.
When a commercial off-the-shelf (COTS) solution does not exist, the RF engineer must analyze and design each component. This process can be complex and time-consuming.
2.2 System Design and Analysis
RF engineers must also be capable of analyzing and designing an RF system. They must possess a deep understanding of the system's key building blocks and the ways in which different components interact and affect its overall performance.
For example, when designing a system, the RF engineer should understand gain, noise figures, 1 dB compression points, and intermodulation products and how the system’s building blocks affect each of these parameters. They can then design systems that offer the desired results.
2.3 Simulation
Simulation tools have revolutionized product design. RF engineers can utilize simulation tools to analyze various designs and assess their performance without ever having to construct an actual printed circuit board (PCB). This saves valuable time and financial resources that can be devoted to other advances.
There are numerous RF simulation tools for RF engineers to choose from. This includes popular tools such as Advanced Design Systems (ADS), and Microwave Office. Each of these are useful for different types of RF simulations, but they may possess unique strengths. RF engineers should be familiar with at least one simulation tool before starting the design process.
2.4 PCB Design
PCB design is a core aspect of creating RF systems. In most cases, PCB technicians typically work with RF engineers to design the layout of a board. However, the RF engineer will still need to understand the layout principles to minimize issues such as couplings, noise, and unwanted resonances. The board layout is also essential for avoiding electromagnetic compatibility (EMC) issues that could jeopardize system performance.
2.5 RF Measurement and Characterization
Once the board manufacturing process has begun, the focus shifts to troubleshooting and optimizing different performance factors. An RF engineer must be capable of working with RF and microwave measurement instruments. For example, a network analyzer is used to perform component-level characterization such as gain, loss, and matching.
They must also use a spectrum analyzer for system-level characterization, such as EVM, ACPR, harmonics, and intermodulation measurements.
2.6 EMC tests, FCC certification
All commercial products must pass specific tests designated by the Federal Communication Commission (FCC) before they can be sold on the market. Such compliance tests ensure that the product does not cause unwanted interference with other equipment or frequency channels and meets other telecommunications requirements.
If system issues occur, the PCB design or components must be changed or redesigned. For example, this may occur if the system’s harmonics are higher than expected.
RF engineers must be familiar with EMC concepts to avoid such occurrences. They must also understand the relevant FCC limitations and requirements before updating their design to meet these requirements.
2.7 Test Fixture Design for Mass Production
Once the product has received FCC certification, it must be tested in the production line. Designing an RF product can be vastly different from the perspective of mass production in a production line. In-factory RF testing has unique challenges and requires well-designed test processes and fixtures that streamline production.
RF engineers need to collaborate with software developers to create automated test processes using software such as LabView, Python, or Matlab. They will also need to collaborate with a mechanical engineer to create a mechanical test fixture where the product is placed for testing purposes.
Such fixtures include a “lick” mechanism or push mechanism that connects the PCB or product with various test equipment and probes. Once the connection is established, an automatic test process runs and generates a measurement report indicating whether the test has failed or passed.
Conclusion
As you can see, RF engineers must possess various skills to design and test RF systems as required. Such skills can take a long time to understand and even longer to master. This creates bottlenecks in the industry and research, where RF engineers are required to be knowledgeable in these areas before working on advanced technologies that require knowledge of RF system design.
Key RF technology developments can be accelerated if the time RF engineers spend developing such skills is minimized. At Quaxys Academy, this is exactly what we aim to do.
Quaxys offers exceptional skills-based RF courses that bring RF engineers up to speed with key RF concepts and teach them the essential skills they need to solve real-world problems in industry and research. Most importantly, we offer a road map that accelerates the learning process and focuses on key areas where the RF engineers need training. Interactive online simulators, calculators, and valuable PDF resources and videos support this learning process. We also offer RF educational kits for some of our courses to deepen participants’ understanding of these concepts.