In this article, we demonstrate a new inductive-window 5.245-GHz-band-pass filter based on post-wall irises by standard PcB process on Epoxy FR4 substrate. A new and easy to build microstrip-to-waveguide transition that consists of three tapers is also designed to connect the filter to standard measurement system. Both simulated results and measurements have shown insertion-loss lower than 5 dB within 14% bandwidth around 5.245 GHz and input return loss better than 25 dB over the frequency range.