Leif Bergstedt

A new concept for microwave MCMs

The drive in the industry towards smaller, lighter, more efficient products encompasses all types of products, including microwave communication. At Ericsson Microwave Systems, customer demand for a product which integrates the microwave control unit with the antenna in the mast has been noted. This means that the indoor control units become redundant and there is less hardware. This packaging concept is based on the fact that the electronics are placed behind the flat antenna unit for efficient use of the available area. The technical concept is a multilayer PTFE thermoplastic motherboard design and split-function MCMs with possibilities for buried capacitors etc. The chip environment is split between the MCM and the motherboard. The motherboard has shielded conductors and a common ground plane with the MCM. The chips are placed level with the substrate to which they are connected with bond wires, and therefore the wires can be made shorter than if the chips were placed on the board as in ordinary chip and wire cases. The reduced wire length is most significant in order to achieve good electrical performance. To meet market demand, we have designed an electronics packaging system for multi-frequency purposes, for products ranging from 5-40 GHz. Current antenna integrated electronics are mostly military applications designed in exclusive materials for advanced production methods. On entering a market for commercial applications, new methods must be implemented to reach cost-effective targets. This paper presents some possible methods for reaching this goal.