Package design for a microwave laser driver

A transmission line approach was employed in the design of the package for the laser driver. Two configurations were needed for routing the RF signal paths for the inputs and outputs. A modified microstrip, with ground shielding on both sides, was used to route the signal from the external lead to the central part of the package. A via, centered between two rows of ground vias, was used to route the signal path up to the chip level in the package. The results of electrical measurements performed on the four RF signal leads of the package are included. The measurements were made employing an HP-8510B network analyzer calibrated with a set of TRL fixtures. The results showed that the package would be good to 4.3 GHz for a return loss of -20 dB