A mechanically flexible and high-speed transmitter front-end system is as a hybrid System-in-Foil (HySiF) by combining Chip-Film Patch (CFP) technology, a bow-tie dipole antenna, and cost-effective 0.25 µm SiGe:C BiCMOS class-A mode power amplifier (PA) in a single compelling field. For the matter of a flexible system, the Si-chip is thinned down to 38 µm to be embedded into the polymer CFP carrier. For the sake of facilitating the thermal management of the die, an AlSiCu heat spreader is added underneath the thin silicon chip, thereby reducing the predicted temperature rise due to the self -heating loop inside the polymer.