Piezoelectric-based resonators are some of the most used devices in the world. Invisible to most people, they constitute key elements for your mobile phone communications. With the advent of 50, the current technologies for piezoelectric resonators need to leap forward in order to yield the very demanding requirements. Here, we briefly describe the challenges faced by these technologies, as well as what are the different options explored to improve the performance of the devices and thus yield filters that can respond to the phone carriers and phone manufacturer's requests.