Wireless IoT (internet of things) devices use very little power, with watchsized batteries capable of lasting a device's entire lifetime. Current wireless communication technology relies on duty cycling, which is both difficult to synchronise and power inefficient. Passive wake-up radio utilises a separate 'wake-up' packet sent alongside the data packets. The radio can then remain in deep-sleep until an incident wake-up packet has its RF energy harvested, and this energy can then switch the radio on and signal whether to transmit or receive data. Since the device spends most of its time in deep-sleep with this design, rather than duty cycling, it will result in significant power consumption improvements. However, it comes at the cost of lower receiver sensitivity and a current max wake-up range of ~10m, which is far too low to be viable for most IoT applications. To attempt to overcome this, we propose to use SAW (surface acoustic wave) devices within the wake-up radio architecture as a voltage multiplier. These devices have a very high gain & Q-factor, which will shift the radio design from broadband to narrowband. The project will investigate opportunities to improve the sensitivity/range of the wake-up passive radio through the process of designing, fabricating, and implementing SAW devices within the radio design. Alongside this, the project will require modification of current architecture to accommodate the new narrowband requirements presented.