Dispersion Engineering of Planar Sub-millimeter Wave Waveguides and Resonators with Low Radiation Loss

TL;DR

This paper introduces dispersion-engineered planar transmission lines and resonators that significantly reduce radiation loss at mm-wave and THz frequencies, enabling low-loss, scalable circuits for advanced applications.

Contribution

It presents the first design of planar dispersion-engineered structures that suppress radiation leakage, achieving ultra-high Q-factors above 10^6 at 553 GHz.

Findings

Radiation Q-factors above 10^6 at 553 GHz achieved

Effective suppression of radiation leakage in planar resonators

Potential for low-loss THz circuitry in various applications

Abstract

Mm-wave and THz superconducting circuits find numerous applications in areas ranging from quantum information and sensing to high-energy physics. Planar THz transmission lines and resonators are fabrication-friendly, compact, and scalable, and they can be efficiently interfaced with external signals and controls. However, planar circuits radiate strongly at high frequencies, which precludes their use in loss-sensitive applications. Here, we present the design and characterization of planar dispersion-engineered transmission lines that effectively suppress radiation leakage in desired mm-wave bands. We extend this concept to design planar resonators with extremely low radiation leakage, resulting in radiation Q-factors above 106 at 553 GHz. Low-loss planar THz circuitry will impact many application domains, including broadband communications, quantum information, radio astronomy, and cosmology.