Antenna-coupled thermal kinetic inductance detectors for ground-based millimeter-wave cosmology

We present our design for antenna-coupled thermal kinetic inductance detectors (TKIDs) designed for Cosmic Microwave Background (CMB) observations in the 150 GHz band. The next generation of telescopes studying the CMB will require large arrays of detectors on cryogenic focal planes to achieve high sensitivity at the cost of increased integration and readout complexity. TKIDs have demonstrated photon-limited noise performance comparable to traditional bolometers with a radiofrequency (RF) multiplexing architecture that enables the large detector counts needed. We characterize TKIDs fabricated for observing the CMB in a frequency band centered at 150 GHz and discuss the optical performance. These devices are a critical step towards fielding a Keck Array camera with 512 devices on the focal plane at the South Pole.