  ALMA has been operating since 2011, but has not yet been populated with the
full suite of intended frequency bands. In particular, ALMA Band 2 (67-90 GHz)
is the final band in the original ALMA band definition to be approved for
production. We aim to produce a wideband, tuneable, sideband-separating
receiver with 28 GHz of instantaneous bandwidth per polarisation operating in
the sky frequency range 67-116 GHz. Our design anticipates new ALMA
requirements following the recommendations in the 2030 ALMA Development
Roadmap. The cryogenic cartridge is designed to be compatible with the ALMA
Band 2 cartridge slot, where the coldest components -- the feedhorns, orthomode
transducers, and cryogenic low noise amplifiers -- operate at a temperature of
15 K. We use multiple simulation methods and tools to optimise our designs for
both the passive optics and the active components. The cryogenic cartridge
interfaces with a room temperature cartridge hosting the local oscillator (LO)
and the downconverter module. This warm cartridge is largely based on GaAs
semiconductor technology and is optimised to match the cryogenic receiver
bandwidth with the required instantaneous LO tuning range. Our collaboration
has designed, fabricated, and tested multiple technical solutions for each of
the components, producing a state-of-the-art receiver covering the full ALMA
Band 2 & 3 atmospheric window. The receiver is suitable for deployment on ALMA
in the coming years, and is capable of dual-polarisation, sideband-separating
observations in intermediate frequency bands spanning 4-18 GHz, for a total of
28 GHz on-sky bandwidth per polarisation channel. We conclude that the 67-116
GHz wideband implementation for ALMA Band 2 is now feasible, and this receiver
is a compelling instrumental upgrade that will enhance observational
capabilities and scientific reach.
