Understanding filter performance for quantum computing

The need

Filtronic, an expert in complex radio frequency challenges, design high-performance mmWave sub-systems which are essential components used in industries including defence and space. They approached NPL for support with the testing and assessment of filter modules used in quantum computing systems. These filters operate at extremely low temperatures, and Filtronic lacked the capability to test their performance under cyrogenic conditions. Their customers couldn’t provide this data either, leaving Filtronic without the evidence needed to validate improvements and negotiate specifications confidently.

The solution

Filtronic partnered with NPL through the Measurement for Quantum (M4Q) programme. NPL colleagues used advanced cryogenic equipment to measure how Filtronic’s filters performed at temperatures as low as 500 millikelvin. The team carried out calibrated tests to compare performance at room temperature and cryogenic conditions, focusing on key metrics like signal loss and frequency response. NPL provided a detailed test report with S-parameter data, giving Filtronic the quantitative insights they needed.

The impact

Thanks to NPL’s support, Filtronic now has reliable data showing how their filters improve at cryogenic temperatures. 

This has: 

• Accelerated product development: Filtronic significantly reduced design times by using design rules validated by cryogenic S-parameter testing.

• Enabled smarter design choices: The data informs future miniaturised systems.

• Opened new commercial opportunities: Filtronic secured a new contract and is exploring new markets.