Ceramic Flat Packages For High-speed And High-frequency

Abstract

The ceramic flat packages for high- speed and higln-frequency devices have been devel- oped. Signal lines of these packages need to be distributed clonstant circuit designs, and instal- lation of transmission lines will be required. When the packages are.designed, there are impor- tant that t he careful consideration of difference in quality amlong various transmission lines, and the estimate of resonance frequencies. We fabri- cated the prototypes of ceramic flat packages, using partial ground and pseudo rectangular coax- ial line, and reinforcing the ground by replacing the HSL uith the CCPW. The application frequency bandwidth of 48-leads package is obtained 20GHz, but did not r each as high as the cut-off frequency of pseudo rectangular c oaxial s ection. 1. Introducti~ As the advancement of devices in high-speed and high-frequency, high frequency characteristics of packages indispensable for these mounting are becoming all the more important ('I 01 . Packages are accordingly required to play the role of intermediator between the devices and printed circuit boards m aintaining high-speed, high-frequency performance. So signal lines of packages need to be distributed constant circuit and to incorporate the transmission line designs. For their pr21ctical application, the improvement is desirable to be d one only for t he internal structure without any effect on the external di- mensions of conventional packages. This paper describes structures of the trans- mission lines formed in packages, the quality of the transmission lines, and resonance in packages. Then we fabricated prototypes of ceramic flat packages with 50mils outer lead pitch, and report their transmi.ssion characteristics.