51 GHz frontend with flip chip and wire bond interconnections from GaAs MMICs to a planar patch antenna

In this paper the difference between flip chip and wire bond technology is demonstrated. Test assemblies with coplanar waveguides have been attached in flip chip and wire bond technology and measured up to 75 GHz. Further, the influence of a metallic lid on a coplanar waveguide structure is examined. To compare flip chip and wire bond interconnections, 51 GHz frontends with GaAs devices in coplanar waveguide technology have been realized. In one frontend the low noise amplifier (LNA) is connected to a planar patch antenna by wire bonding and in a second one by flip chip attachment. RF evaluations show the clear advantage of the flip chip version due to the lower insertion loss of the flip chip interconnections and the higher flexibility of mounting the MMICs directly on the back structure of the planar patch antenna, leading to reduced losses of the feedline.<>