This is the second installment in our RF Components for Radar series. In the first installment, we provided an overview of the key functional units in radar, including duplexing, filtering, power amplification, waveform generation, low-noise amplification (LNA), receiving and analog-to-digital conversion (ADC). Here, we’ll focus on duplexing.  

Radio frequency (RF) power dividers are designed to split an incoming signal into multiple outputs such that there’s a portion of the original signal’s power in each output. Given their critical function, power dividers play a particularly important role in antenna systems, telecommunications, and signal processing.

Defense applications tend to operate at high voltages and wide temperature ranges. They require components with increased efficiency, reduced size, and high power density. Because a wideband gap (WBG) semiconductor embodies these characteristics, defense and aerospace systems are increasingly using Gallium Nitride (GaN) for power conversion. 

To protect people and critical equipment, military-grade electronic devices must be designed to function reliably while operating in incredibly harsh environments. Therefore, instead of continuing to use traditional silicon semiconductors, in recent years, electronic device designers have started to use wide band-gap (WBG) materials such as silicon carbide (SiC) to develop the semiconductors required for military device power supplies. In general, WBG materials can operate at much higher voltages, have better thermal characteristics, and can perform switching at much higher frequencies. Therefore, SiC-based semiconductors provide superior performance compared to silicon, including higher power efficiency, higher switching frequency, and higher temperature resistance as shown in Figure 1.

From military aircraft to electronic warfare defense systems, aerospace and defense applications are placing new demands on their power electronics. Defense electronics systems must function reliably for their lifetime while operating at higher voltages and wider temperature ranges, and all while becoming smaller, lighter, and consuming less power.

As countries around the world continue to work on more sophisticated ways to conduct military missions – including weaponry that can reach intended targets quicker with even greater accuracy while remaining virtually undetectable – aerospace and defense companies are pushing the missile speed boundaries. Military aircraft and weaponry today are capable of traveling at supersonic speeds and are even entering hypersonic speed territory. 

After decades of viewing MIL-SPECs as the gold standard for qualifying and screening parts for viability in space, NASA has recently changed course, and is adopting commercial-off-the-shelf (COTS) parts as an option for a variety of space applications. Burgeoning changes in industry trends, a drive to remain competitive, and the desire to guide budget-constrained missions pushed the organization to commission a NASA Engineering and Safety Center (NESC) study to evaluate the reliability of COTS parts. Upon completion of the study, NASA aims to create a consistent set of requirements at the agency level to minimize risk and impact of part selection/usage on the performance of NASA spaceflight technology.

Innovating essential high technology systems with demanding specifications is always challenging; making any sort of difference requires extensive resources and deep subject matter knowledge.

But that’s what keeps it interesting.

When launching expensive mission-critical equipment and people into space, there is absolutely no room for failure of any component. Therefore, if you are an RF system designer working on an aerospace application, you must be sure you are selecting high-quality, high-reliability electronic components for all your designs. But do you have a process in place for this type of component selection? At Knowles Precision Devices, we know it can be a challenging to navigate component selection for aerospace applications as there are many combinations of standards and tests that can be performed to space-qualify parts.

Space missions present a unique set of environmental challenges that demand high reliability down to the smallest electronic components. Mission failures could cost human lives. From in-flight systems to power supplies, every single system contributes to the success of a space project, so they must maintain high quality and safety standards for long durations.