Fast RF Mismatch Calibration Using Built-in Detectors

Due to increasing performance demands, RF circuits are increasingly integrated into fine-geometry processes which necessitates their post-production and in-field calibration. One of the most important parameters for RF performance is matching between various nodes in the circuit. Process, voltage, and temperature (PVT) variations and other environmental conditions such as objects in the near-field of an antenna can cause shifts in the RF matching between sources and the loads. To compensate for such shifts, generally a tunable element or a network is incorporated between the source and the load, which will enable post-production calibration. In this paper, we present a tuning algorithm that adjusts the tuning structures until a match is detected via built-in measurements. The proposed technique can be used both for post-production and for in-field calibration. It only requires three strategically placed power detectors along the transmission line connecting the source to the load and simple computations. Experimental results based on simulations and hardware measurements show that the technique can provide highly accurate matching between a source and a load component.