Brandon Kaplan, Corporate Communications


  • Existing options for sterilization of PPE such as dry heat and germicidal UV light take a minimum of 30 minutes to effectively disinfect static objects.
  • Microwave radiation has the potential to dramatically improve the speed at which this critical equipment can be sterilized and safely re-used, but a number of technical challenges remain for a practical real-world implementation of the technology.
  • Resonō, a New-York-City-based startup is using RF engineering to develop the world’s fastest, most effective and safest sterilization technology, and Mini-Circuits played a small part in supporting their development efforts.

At the early stages of the COVID-19 pandemic in March, dire shortages of personal protective equipment (PPE) for medical professionals on the frontline dominated headlines in national news. Efforts to bolster global supply chains for safety gear and improve production capacity were well publicized: President Trump activated the defense production act, and the federal government dispensed masks and other equipment from the Strategic National Stockpile. Mini-Circuits’ own team members in the company’s junior leadership development program organized a relief fund to support the AFYA foundation, a non-profit dedicated to sourcing and distributing PPE to hospitals and medical facilities in the New York City area. Meanwhile, doctors and nurses cared for patients every day in conditions that risked their health and further transmission of the virus.

In the frenzy to save lives and combat the spread, some of the world’s most brilliant scientists and engineers went to work on innovations that would accelerate treatment and prevention of the disease. While efforts to develop a vaccine and faster, more effective testing have taken center stage, new technologies for sterilization of medical equipment, surfaces and other objects – including PPE – have taken on new importance as well.

Hao Hu is the founder of Resonō, a New-York-City-based startup that develops RF disinfection technology to protect public spaces and communities against COVID-19 and other viruses. The company’s proprietary technology comes from a cross-pollination between RF engineering, virology and physics. After speaking with a friend who works as a virologist at a major New York City Hospital, Hu learned that the problem with PPE wasn’t only the difficulty sourcing a steady supply, but also the inefficiency of existing processes for cleaning and disinfecting existing stocks of PPE for safe and effective re-use.

Hao Hu is the head of operations at Jersey Microwave and founder of NYC-based start-up, Resonō.

“The healthcare system has a lot of options [for sterilization] already – UV germicidal lighting, steam, dry heat,” said Hu in an interview via Zoom. “But when you dig a little deeper, you realize all of those processes take a significant amount of time to be effective. The fastest available technologies that don’t degrade the performance of the PPE are UVC and dry heat, but both processes, to be effective, have been documented to take a minimum of half an hour, which makes them impractical.”

Hu partnered with his virologist friend and two senior engineers at Jersey Microwave, a developer of communications technology where he currently serves as head of operations, to explore whether RF and microwave technology could be used to realize a better, faster solution. There was no shortage of research documenting the effectiveness of microwave energy in killing pathogens. It’s practically common knowledge that you can sterilize a kitchen sponge by nuking it in your household microwave. But for a virus like SARS-CoV-2 in a real-world medical setting, the standards are higher, and the solution isn’t so simple.

“Your household microwave radiates at 2.4 GHz,” explained Hu. “But we all know what happens when you put something in the microwave, turn it on and forget about it. Things catch fire. So we did some research to see what other options in the RF spectrum may be useful for this application, and by experimenting a bit, we were able to identify the ideal frequency and power requirements.”

Hu and his partners were working on the initial proof of concept for Resonō’s technology in May at the height of the first wave in New York when he reached out to Mini-Circuits sales rep, David Stein at Spectrum Sales in Syosset, NY for help. They had most of their system built but still needed the right wideband amplifier to use as a driver for a much stronger power amplifier down the signal chain. Stein reviewed the requirements and recommended Mini-Circuits’ ZVE-3W-183+, a Class-A, four-stage amplifier capable of delivering up to 3W of output power across the 5.9 to 18 GHz frequency range.

Mini-Circuits ZVE-3W-183+ amplifier was provided as a sample for Resonō’s initial proof of concept.

Stein arranged for Hu and his team to sample the amplifier at no cost thanks to Mini-Circuits’ longstanding relationship with Jersey Microwave and the urgent importance of this particular project.

“We’ve done a number of sampling opportunities with Mini-Circuits and other companies before,” said Hu, “but I want to say that when I have to compare working with Mini-Circuits to other companies, you guys are by far the easiest to work with. David [Stein] has a tremendous hand in helping us manage that relationship, but we’re very happy with how responsive you guys are and how quick and open you are to discussing various partnership opportunities.”

Resonō is now working to further develop the initial proof of concept and miniaturize it into a portable system that can be used to disinfect static objects like PPE as well as surfaces and even air faster than any existing technology.

The use of RF and microwave energy for heating and sterilization is an example of an application in the emerging RF energy market. While Mini-Circuits’ role in supporting Resonō’s proof of concept involved signal processing at lower power levels, Mini-Circuits’ power amplifier design group in Lincoln, RI is now at work on a new solid state power amplifier line that will eventually extend into the kilowatt range. The new product line will support a wide range of medical, industrial and commercial applications in the RF energy space, so while Resonō’s remarkable technology is the first of its kind we’ve featured here, it won’t be the last.

Mini-Circuits is proud to play a small part in supporting Resonō in their mission to deliver the most effective, fastest and safest disinfection technology, and we wish them success with their ongoing development efforts.

Check out more RF amplifiers like the ZVE-3W-183+ >

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