A 4-pole interdigital filter has been demonstrated at 60 GHz with a bandwidth of 10 it is made using micromachining and a multi-layer bonding. The filter is an airfilled three-dimensional structure. It is formed of five layers which are bonded together. Each layer is micromachined SU-8 based, 200-mum thick, and finished with 1.5 mum gold coating. The resonators are thick stripline-like and enclosed in a cavity. The input and output are transitions from a coplanar structure to a rectangular coaxial line, which are then coupled into the cavity. The filter is only 3.7 mm by 2.0 mm in size and 1.0 mm in height. The measured insertion loss is 1.1 dB and the return loss is below -9 dB. The bandwidth of the tested filter is broadened due to fabrication imperfections, which have been identified by modelling and discussed in the paper.
| Original language | English |
|---|
| Title of host publication | International Workshop on Microwave Filters |
|---|
| Place of Publication | Toulouse, France |
|---|
| Publication status | Published - 1 Nov 2009 |
|---|
| Name | Proceedings of the 2009 International Workshop on Microwave Filters |
|---|