Recycling Microwave Hairpin Filters Using Laser Micromachining

The work demonstrates an approach to recycle previously manufactured filter designs by laser micromachining its resonant structure as a method of reducing manufacturing costs and time. A hairpin filter centred at 6 GHz is tuned to 8.3 GHz whilst maintaining low insertion loss (IL) and sufficient return loss (RL) in the pass-band. The relationship between the shift in centre frequency against the tapping length is investigated to ensure acceptable filter performance at the highest tuned frequency.