Fully Canonical Pseudo-Elliptic Bandpass Filters on Multilayer Liquid Crystal Polymer Technology

Microstrip pseudo-elliptic bandpass filters, operating in the X-band, have been designed and implemented on multilayer liquid crystal polymer (LCP) technology for the first time. Folded open loop resonators printed on different dielectric surfaces and sharing the same ground plane are coupled through slots etched in the ground plane. Fully canonical filtering and modularity have been achieved through introduction of internal nonresonant nodes. Multilayer configuration is realized through thermocompression bonding of thin sheets of LCP. The designed fourth-order filter exhibits a low insertion loss of 3.2 dB at 9.9 GHz