Design of an isolated capacitor cell for three-dimensional RF circuit integration

A compact multilayer capacitor cell isolated with perforated ground was designed and fabricated using low-temperature ceramic co-firing (LTCC) technology for three-dimensional (3D) RF circuit application. The vertical transmission from any interferer placed 174 mum above the capacitor cell and the lateral transmission from any interferer 300 mum apart from the cell were controlled below -20 dB up to 15 GHz. The 2.8-pF capacitor shielded with perforated ground of 600-mum square edge and 800-mum pitch revealed a self-resonant frequency (SRF) of 7.6 GHz and Q factor of over 190 up to 3 GHz, which is an improvement of SRF by 0.8 GHz and Q factor by 224%, compared to the capacitor with a conventional blanket ground. (C) 2003 Wiley Periodicals, Inc.