Bed of Springs for Packaging of Microstrip Circuits in the Microwave Frequency Range

After the use of the bed of nails for removing cavity modes in microstrip circuit packages, we propose herein a new version of this periodic structure, based on helices (springs) instead of nails. This new structure, named bed of springs, is much more compact, and this allows its use at low frequencies where the bed of nails is not suitable as it is too bulky due to the required height of the nails (pins). The bandwidth of the proposed structure turns out to be similar to the case of bed of nails. Parametric studies are presented as a design tool and a demonstrator is manufactured and measured.