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Antenna-coupled microwave kinetic inductance detectors are emerging as a compelling solution for the next generation of cosmic microwave background (CMB) experiments, which require focal plane arrays with a substantial increase in the number of detectors and multi-band observation capabilities. We present the design and fabrication of multichroic pixels using this architecture, optimized for B-mode polarization observation. The pixel incorporates an improved dual bowtie slot antenna placed at the second focus of an elliptical lens, covering an octave frequency range from 100 GHz to 300 GHz. We aim to achieve bandwidths exceeding 20% for two CMB-atmospheric transparent subbands at 150 GHz and 220 GHz while maintaining adequate linear polarization sensitivity with a cross-polarization level below −17 dB across the entire range. The captured signal is then passed through a superconducting microstrip low-pass filter to remove excessive colors before being fed into the diplexer, where the two bands are separated. These bands are then coupled to the inductive section of MKIDs, effectively modifying the resonant frequency and quality factor of the corresponding resonators. The demonstration sample is fabricated using five photomask layers, employing niobium and aluminum as the superconducting materials, and is currently undergoing testing.
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