Realisation of a DECT VCO circuit with MCM-D technology

Wireless radio applications such as DECT require highly integrated transceiver solutions. In particular, the integration of the RF front-end poses a great challenge in these applications, as traditional front-end implementations require a large number of components. As most of these components are passive devices and as the active devices are integrated on only a few chips, cost effective integration of those devices into the interconnection substrate is a very attractive approach. This paper presents the use of thin film MCM-D technology for the integration of a VCO circuit. The circuit itself contains a resonator, a negative resistance and an isolation amplifier stage, which are all integrated on the MCM glass substrate. In this approach, only 4 active devices (2 diodes and 2 bipolar transistors) have to be placed on the module; the 28 other passives (including inductors, capacitors and resistors) are fabricated within the glass substrate, using multilayer thin film techniques. The use of integrated passives also allows size reduction by a factor of five as compared to discrete realization of the same function.