In this article, focusing structures for 220 GHz sheet beam TWTs are theoretically presented and simulated including uniform magnetic (UM), pole offset periodic cusped magnetic (PO-PCM) and periodic cusped magnetic tunable quadrupolar magnetic (PCM-TQM) focusing structures. Simulation demonstrated that a 30 kV, 0.1 sheet electron beam with a waist size of 0.59 × 0.11 mm2 with a PO-PCM focus structure had a 100% transmission rate at a distance of 85 mm. The PO-PCM focusing structure was fabricated and tested for stable long distance transmission and compared to the simulation with good agreement. Peak paraxial Bz measured 0.44T, paraxial By measured 80 Gauss, and these measurements also agreed well with the simulations.