  Focal plane arrays consisting of low-noise, polarisation-sensitive detectors
have made possible the pioneering advances in the study of the cosmic microwave
background (CMB). To make further progress, the next generation of CMB
experiments (e.g. CMB-S4) will require a substantial increase in the number of
detectors compared to the current stage 3 instruments. Arrays of kinetic
inductance detectors (KIDs) provide a possible path to realising such large
format arrays owing to their intrinsic multiplexing advantage and relative
cryogenic simplicity. In this proceedings, we report on the design of a novel
variant of the traditional KID design; the antenna-coupled lumped-element KID.
A polarisation sensitive twin-slot antenna placed behind an optimised
hemispherical lens couples power onto a thin-film superconducting microstrip
line. The power is then guided into the inductive section of an aluminium KID
where it is absorbed and modifies both the resonant frequency and quality
factor of the KID. We present the various aspects of the design and preliminary
results from the first set of seven-element prototype arrays and compare to the
expected modelled performance.
