An agile matching network using phase detection for antenna tuning

This paper presents an integrated tunable matching network designed to minimize antenna mismatch in real time. A phase frequency detector (PFD) measures the phase shift between the voltage and the current at the input of the circuit. This PFD controls a charge pump that modifies the capacitance of a varactor and a capacitor array, which are the tuning elements of the circuit. All components are integrated on the same chip for low power and compact operation. The system can be used to tune matching networks connected to antennas having a time varying impedance for applications such as handsets. The overall capacitance ratio of the varactor and capacitor array is above 12 and the impact of the parasitics is relatively low with an average quality factor Q of 40. The IC is designed in IBM CMOS 0.13 μm technology.