Recent progress has substantially increased the operating frequency of large-area electronic (LAE) devices. Their integration into circuits has enabled unprecedented system-level capabilities, towards future wireless applications for the Internet of Things (IoT) and 5G/6G. These exploit large dimensions and flexible form-factors. In this work, we focus on giga-Hertz (GHz) zinc-oxide (ZnO) thin-film transistors (TFTs) as a foundational device for enabling GHz LAE circuits and systems. To further understand their operation and limits in the newly possible frequency regime, we incorporate the effects of temperature and of nonquasi-static (NQS) physics into the device models. We then analyze operation including these effects on a fundamental circuit block, the cross-coupled inductor-capacitor (LC) oscillator. It is used in representative LAE systems, namely a 13.56 𝑀𝑀𝑀𝑀𝑀𝑀 radiofrequency identification (RFID) reader array for near-field energy transfer, and a 1 𝐺𝐺𝑀𝑀𝑀𝑀 phased array for far-field radiation beam steering. Co-design of devices, circuits, and systems is essential for achieving flexible and meter-scale monolithic integrated LAE wireless systems. For these, understanding temperature limitations and the NQS effect is crucial.