LAUSR

In this Letter, a compact and high-performance ultra-wideband (UWB) bandpass filter based on half-mode substrate integrated waveguide (HMSIW) is proposed. A novel slow-wave structure with lowpass characteristics is developed and loaded on the HMSIW to obtain the UWB frequency response and realise size-reduction. Moreover, two rectangular slots are etched on the transition structures of the microstrip-to-HMSIW to obtain a good UWB impedance matching. As a verification, a prototype is designed, simulated, fabricated and measured. Good agreements can be observed between simulated and measured performances.