Terahertz Integral Field Unit with Universal Nanotechnology (TIFUUN) is a wideband spectral mapper operating at (sub)-millimeter wavelengths. The instrument is under development for ground-based astronomy and will be deployed to the ASTE telescope in Chile. In this work, the building blocks for TIFUUN’s wideband (2:1) mappers are discussed. These components are based on multi-lens focal plane arrays of leaky lens antennas coupled to filter banks based on Microwave Kinetic Inductance Detectors.