IEEE Africon (2015 : Addis Ababa, Ethiopia)2015-09-302015-09-302015-09Stander, T 2015, 'Inline Ka-band transitional combline / evanescent-mode filter in conventional RF substrate using grounded vias', IEEE AFRICAN 2015 conference proceedings, pp. 361-364.http://hdl.handle.net/2263/50111Paper presented at the IEEE Africon 2015 : IEEE Africon Green Innovation for African Renaissance, 14-17 September 2015, Addis Ababa, Ethiopia.The Ka-band is considered a viable band for future 5G backhaul links. Planar filters in this frequency range have low aspect ratios for substrates thicker than 10 mil, since the required 50 Ω line width becomes comparable to a guided wavelength. This paper proposes the use of grounded through-hole plated vias as transitional combline / evanescent-mode resonators. The principle is demonstrated with a 4th order, 27.5 – 29.5 GHz filter in a conventional 32 mil thickness RF substrate. The simulated filter features below 2 dB insertion loss across the band and occupies 3.8 x 1 mm board space.en© 2015 IEEE - All rights reserved.Microwave filtersMicrostrip filtersSubstratesPresentation