Low loss substrate integrated filters made by laser micro-machining of alumina substrates

This paper is focused on the use of low loss alumina substrates for the creation of compact Q band bandpass filters. The proposed process flow is based on the laser micro-machining of ceramic substrates in order to create small footprint and lightweight filters. The bandpass filter proposed in this study shows a 3.3% bandwidth around 39.31 GHz. The insertion loss of 1.51 dB experimentally confirms that an unloaded Q factor of 400 is obtained at 39 GHz. The filter dimensions are 5.98 mm × 2.76 mm × 0.6mm.