Improved Shielding Effectiveness Model for Honeycomb Waveguide in Laser Controller Enclosures

Electromagnetic leakage through ventilation interfaces is a critical challenge in photonic instrumentation, where laser controllers and photoelectric readout circuits are highly sensitive to external interference. In photonic instruments, enclosure leakage may couple into laser controller and photoelectric readout circuits, degrading optical signal stability and electromagnetic cleanliness. To enable fast shielding assessment at the packaging stage, this paper proposes an improved semi-analytical shielding-effectiveness model for hexagonal honeycomb waveguides used in laser controller enclosures. Within a transmission matrix formulation, finite-conductivity loss is included through propagation constant correction, and inter-cell interaction is represented by an array-based coupling correction. The model captures high-frequency additional transmission effects that are not reflected in simplified independent-cell formulations. Validation against CST full-wave simulations from 1 to 40 GHz demonstrates improved agreement, particularly near cutoff and in the upper-frequency range, with substantially lower computational cost than full-wave optimization loops. Geometry-dependent trends are further quantified to support EMC co-design of ventilation and enclosure structures in photonic and optoelectronic platforms.