Tootfinder

„This year, over 11.7 million people applied for Schengen short-stay visas. Globally, demand rose by more than 13%.
But for African applicants, that just meant more money lost.
Analysts estimate Africans lost €60 million (around US$67.5 million) in visa fees in 2024 alone — just for rejections.“
Via Sham Jaff's excellent newsletter https:…

Wideband Glide-Symmetric Slow-Wave Structure for Millimeter-Wave Sheet Beam TWTs
Robert Marosi, Muhammed Zuboraj, Filippo Capolino
https://arxiv.org/abs/2505.22927

Wideband Glide-Symmetric Slow-Wave Structure for Millimeter-Wave Sheet Beam TWTs
We introduce a slow-wave structure (SWS) for a millimeter-wave sheet-beam traveling-wave tube (TWT) with wide bandwidth. The wideband and stable operation is enabled through the topological properties associated with glide-symmetry that close the bandgap at the $3π$-point and also make the on-axis interaction impedance negligible for the backward wave. This space harmonic structure is designed to operate in the $V$-band over 55-68 GHz with synchronism to a 5.2 kV, 11 mA sheet electron beam tha…