Microwave power detection using ferroelectric thin film varactors

Abstract

Ferroelectric, barium strontium titanate thin film varactors have been used to rectify and detect microwave signals with frequencies ranging from 2 GHz to 3 GHz. Anharmonic dipolar resonant frequencies from these thin fims were shown to have strong dependence on film thickness with some amount of voltage-controlled tunability. Experiments were performed using lock-in detection of a 100% amplitude modulated microwave signal with varying power levels. An on-resonant sensitivity of 0.6 mV/mW was observed. Power detection sensitivity was shown to have built-in bandpass filtering resulting from resonant line shape.

Keywords:

• Thin film varactors
• BST thin films
• anharmonic dipolar resonances
• power detection
• built-in bandpass filtering