How Do You Measure Phase Noise At D-Band Frequencies?

As next-generation communications, sensing, and radar systems expand into the D-Band spectrum, accurate phase noise characterization becomes essential to maintaining system performance. This article explores why D-Band (110–170 GHz) is gaining momentum and how designers can accurately measure phase noise at these challenging frequencies.

D-Band offers wide contiguous bandwidth, enabling emerging applications such as 6G wireless links, inter-satellite communications, and high-resolution radar and imaging. Shorter wavelengths allow compact, high-gain antennas with tightly focused beams, supporting higher data rates, lower latency, and finer spatial resolution. These same advantages, however, also make D-Band systems far more sensitive to phase noise.

Phase noise—short-term, random phase fluctuations in electronic signals—becomes increasingly problematic at higher frequencies. Frequency multiplication used to reach D-Band amplifies noise contributions, degrading modulation accuracy in communications, weakening coherence in inter-satellite links, and reducing range accuracy and image clarity in radar and imaging systems. Without precise measurement, these effects can undermine even well-designed hardware.

To address these challenges, the article outlines a proven D-Band phase noise measurement approach using dual-channel cross-correlation analysis. By statistically removing uncorrelated noise from mixers, frequency extenders, and local oscillators, this technique reveals the true phase noise of the device under test. A carefully configured setup—combining a high-quality RF source, frequency extenders, independent LO drives, and a real-time phase noise analyzer—enables accurate, repeatable measurements across the full D-Band range.

By understanding D-Band applications and deploying the right phase noise analysis tools, engineers can confidently validate high-frequency designs and accelerate the development of next-generation wireless, satellite, and sensing technologies.