High Performance Components from DC to mmW for Space Applications

Satellites and space programs have traditionally been dominated by a few countries worldwide. However, recent advancements in launch vehicles have significantly reduced the costs of launching satellites into orbit, making it possible for large and small private companies to enter this new era of space exploration.

This new model, which utilizes reusable rockets with minimal maintenance between flights, has brought down launch costs substantially. It costs $1,500 USD per kilogram to launch a SpaceX Falcon Heavy, compared to $65,400 USD per kilogram for the Space Shuttle Program in 1981 for Heavy Rockets and $2,600 USD per kilogram for SpaceX Falcon 9 versus $38,800 USD per kilogram for the Delta II in 1990 for Medium Rockets (Figure 1).

Figure 1: Launch cost comparison in 2021 dollars

These reduced costs have lowered the barrier of entry for new companies designing and manufacturing satellites to perform various tasks, such as broadband internet, environmental sensing, and even direct-to-mobile phone calls.

With these market shifts and the emergence of new companies, there is an increased focus on “New Space” applications, which are low-cost satellites with a shorter mission life of a few years, compared to “Traditional Space” where satellites were designed to orbit for a decade or more.

GEO – MEO – LEO

Satellites are generally categorized into three types: Geosynchronous Orbit (GEO), Mid Earth Orbit (MEO), and Low Earth Orbit (LEO)

Figure 2: GEO – LEO – MEO Coverage

GEO and MEO satellites have traditionally dominated the space sector, primarily used by governments and militaries. These satellites are designed for long-term missions, often spanning over a decade, and require high reliability for continuous operation in harsh environments. GEO satellites orbit at an altitude of approximately 35,000 km, while MEO satellites operate between 2,000 km and 35,000 km, providing continental coverage with just one satellite. This traditional approach has enabled humans to reach the Moon, explore Jupiter, and provide GPS access in various devices, including cars, mobile phones, and even watches.

In contrast, LEO satellites offer emerging business opportunities due to the reduction in launch costs. This trend is leading to a shift away from the traditional, risk-averse, and high-capital investment approach towards more innovative solutions. Instead of designing components specifically for space, LEO satellites are now being up-screened commercial RF components and even automotive-grade components to meet reliability requirements. This approach results in reduced overall program costs, shortening the return on investment from 10 to 15 years for traditional space to a few years.

While GEO satellites may cover a larger area with a single satellite, LEO satellites achieve significant coverage with a constellation of satellites, often comprising hundreds. LEO satellite constellations fly as low as 160 km above the Earth, providing several advantages such as lower communication latency, higher data rates, lower launch costs, and increased reliability. Since LEO satellites are interconnected, if one satellite experiences an issue or goes offline, it can seamlessly transfer the task to other satellites, ensuring uninterrupted service.

High-Performance RF/Microwave Components

Satellites traditionally relied on RF/Microwave components specifically designed for space. However, with the rise of LEO applications, there is an increasing trend towards using commercial components, such as non-hermetic and plastic-packaged surface mount parts, which were unthinkable just a few years ago. Instead of investing in custom space-focused components, satellite companies are opting for commercial off-the-shelf (COTS) components and either screening or qualifying them for space applications. This shift has enabled satellite manufacturers to access vast portfolios of RF/Microwave components spanning from DC to sub-terahertz. Typical satellite frequencies range from 1 to 2 GHz (L band) to 27 to 40 GHz (Ka-band), which allows for higher data rates in broadband services. However, future demands for even higher data rates will necessitate frequency shifts to the V band, which operates up to 75 GHz. 

Various Frequency Bands

With the trend towards COTS components and expanding frequency coverage, satellite manufacturers now have access to a broader range of RF components to design and optimize their signal chains.

Marki Microwave High-Performance Components and Space Heritage

To address the needs of new satellite requirements, Marki has a broad portfolio of active and passive components that cover frequencies from DC to above 100 GHz. Our current product portfolio provides solutions from the RF front end all the way to the ADC/DAC interface (Figure 3). These include passive devices such as power dividers, equalizers, attenuators, filters and baluns and active devices such as amplifiers, mixers, multipliers, and detectors in multiple packages – bare die, surface mount, connectorized, and waveguides.

Figure 3: Marki Microwave Product Offering

As satellites incorporate phase array antennas or other high channel count systems, component size, translates to overall size and weight, become more relevant. Marki addresses the need for optimized Size, Weight and Power (SWaP), with our patented chip scale packaging (CSP), which offers plastic surface mount package technology that has electrical performance comparable to bare die. Marki’s currently offers various components along the signal chain (Figure 4) such as equalizer, attenuators, mixers, filters, etc…

Figure 4: CSP product offering and physical scale.

CSP technology utilizes hot via technology and removes bond wires, reducing parasitic effects which allows bare die electrical performance up to 85GHz. CSP packages also offer up to 75% reduction in size compared to traditional surface mount QFN packages (Figure 5).

Figure 5: Component size reduction moving from the QFN package to an equivalent chip scale package for the same MMIC die.

The majority of Marki’s components from bare die, surface mount, connectorized, and waveguides can be up-screened and qualified for space applications. Marki has up-screened and qualified components for space applications for over 20 years. We follow MIL-PRF-38534, MIL-PRF-35835, MIL-PRF-27, or NASA EEE-INST-002 standards. These standards serve as guidelines to screen and qualify commercial components to standard military levels or to the highest level of reliability for space.

Space qualification standards are typically based on the type of package. A bare die amplifier would adhere to MIL-PRF-38534, a plastic surface mount package amplifier would follow NASA EEE-INST-002, and a hermetic package amplifier would adhere to MIL-PRF-38535. Each package type necessitates specific package-related qualification steps to ensure that the components meet reliability standards. During the 100% screening process, hermetic packages require Gross and Fine Leak testing to guarantee hermiticity, while plastic packages require X-Ray to inspect the internal adhesion of the die after temperature cycling.

Regardless of the standard followed, all space qualifications include 100% screening of all the parts, which typically include: visual inspection, electrical tests, temperature cycling, burn-in, radiography, etc. After 100% screening of components, a sample (size dependent on qualification level) quantity is removed to perform additional rigorous qualification steps such as: 1000 hours life test burn-in, biased or unbiased burn-in, mechanical shock/vibration, constant acceleration, and over-temperature testing per component datasheet. Finally, a qualification report is generated to provide lot traceability, electrical data, certification from laboratories, equipment used to perform the qualification, X-ray results, and any additional relevant information.

Screening and qualification standards usually have recommended guidelines based on the mission’s objectives and risk tolerance. For example, NASA EEE-INST-002, the standard for non-hermetic plastic surface mount packages, encompasses three levels of screening, each with slight variations. During 100% screening, Level 1 (the highest level) demands a 240-hour burn-in at 125°C, while Levels 2 and 3 only require 160 hours. Similarly, for qualification, Level 1 necessitates High Temperature Operating Life Testing for 1000 hours, whereas Level 3 only requires 500 hours.

Ultimately, which standard or screening level to follow is typically based on the type of mission, risk tolerance, schedule, and cost. The published standards serve as guidelines and can be customized to align with specific mission requirements. Marki collaborates closely with each customer to customize and ensure that the screening and qualification processes meet mission objectives while effectively managing costs and adhering to schedules.

Conclusion

The space industry is currently at an inflection point where private companies are introducing quick decision-making, risk-taking, and rapid iteration, which ultimately fuels innovation and growth. As satellite trends shift towards up-screening commercial off-the-shelf (COTS) parts to high reliability standards suitable for space, Marki Microwave is well-positioned to support our customers with high-performance radio frequency (RF) components. Furthermore, we collaborate closely with each customer to develop customized plans for up-screening and qualifying components to meet mission requirements while reducing costs and shortening development timelines.