Paper

{
  "raw_xml": "<entry>\n    <id>http://arxiv.org/abs/2603.05150v1</id>\n    <title>Equivalent Circuit Modeling of Mutually Resistively Coupled Microwave Cavities with Enhanced Phase Sensitivity Using Thin Metallic Foils</title>\n    <updated>2026-03-05T13:17:56Z</updated>\n    <link href='https://arxiv.org/abs/2603.05150v1' rel='alternate' type='text/html'/>\n    <link href='https://arxiv.org/pdf/2603.05150v1' rel='related' title='pdf' type='application/pdf'/>\n    <summary>We formulate and validate an equivalent circuit model describing mutual resistive coupling between three microwave cavity resonators interconnected via thin metallic foils. Each cavity is represented as a lumped LCR circuit, while the foils act as a dissipative interface that mediates energy exchange via mutual resistance. This coupling mechanism produces interference effects and a controllable anti-resonance when the input resonators are amplitude- and phase-balanced, a behavior not achievable with standard microwave antenna probes. All three resonators operated in the TM$_{010}$ mode, where two input resonators each excited the third via a thin copper foil. Analytical expressions are derived for the mutual resistance and coupling coefficient of these foils in this geometry. Under balanced conditions, a sharp anti-resonance emerges with a near order-of-magnitude enhanced phase sensitivity at the resonant frequency of the output cavity, consistent with model predictions. The experimentally extracted mutual coupling coefficients, $Δ_{13}=(5.00\\pm0.01)\\times10^{-6}$ and $Δ_{23}=(4.10\\pm0.01)\\times10^{-6}$, fall within the calculated range $Δ_{n3}\\approx(1\\text{--}48)\\times10^{-6}$ derived from the foil's electromagnetic properties, where the spread is dominated by the estimated foil thickness uncertainty of $(9\\pm1)\\,μ\\mathrm{m}$. These results confirm that resistive coupling can occur across a number of skin depths of a metallic interface, providing a new means of engineering controlled interference in multi-resonator systems. The approach offers potential applications in precision microwave experiments, phase-sensitive detection, and tests of fundamental electromagnetic interactions.</summary>\n    <category scheme='http://arxiv.org/schemas/atom' term='physics.app-ph'/>\n    <published>2026-03-05T13:17:56Z</published>\n    <arxiv:primary_category term='physics.app-ph'/>\n    <author>\n      <name>Michael T. Hatzon</name>\n    </author>\n    <author>\n      <name>Graeme R. Flower</name>\n    </author>\n    <author>\n      <name>Robert C. Crew</name>\n    </author>\n    <author>\n      <name>Jeremy F. Bourhill</name>\n    </author>\n    <author>\n      <name>Michael E. Tobar</name>\n    </author>\n  </entry>"
}