We developed a new millimeter-wave plastic chip size package (CSP) to operate up to 100 GHz by using a thin-film substrate. It has a flip-chip distributed amplifier with inverted microstrip lines and the amplifier has a bandwidth of beyond 110 GHz. The transmission line on the substrate consists of grounded coplanar waveguides that yield low insertion loss and high isolation characteristics in coupled lines even in mold resin in comparison with conventional microstrip lines. The CSP amplifier achieved a gain of 7.8 dB, a 3-dB bandwidth of 97 GHz, and operated up to 100 GHz. To the best of our knowledge, this value is the highest operating frequency reported to date for a distributed amplifier sealed in a plastic CSP. We also investigated the transmission characteristics of lead-free solder bumps through experiments by assemblying CSPs on printed circuit boards and modeling them so that we could design the packages accurately.

This paper describes GaAs MMICs used in wireless LANs for spread spectrum communications on the ISM band. Both the transmitter and the receiver are incorporated inside the MMIC. In our experiment using prototypes at a center frequency of 2.45 GHz, the transmitter has a saturation output power of 21.4 dBm and the total current consumption is 131.2 mA. The receiver has a noise figure of3.2 dB and a gain of 12.2 dB.