An Integrated Power Detector for a 5GHz RF PA

A fully integrated power detector is presented that detects both instantaneous RF voltage and current. Both signals are multiplied using an on-chip low-noise, high linearity mixer to measure the real power delivered to the load of an integrated PA operating at $5\mathrm {G}\mathrm {H}\mathrm {z}$ in predictive $45\mathrm {n}\mathrm {m}$ CMOS technology. The dynamic range of the detector is $23.~72\mathrm {d}\mathrm {B}$ with an accuracy of $< \pm 0.5\mathrm {d}\mathrm {B}$. Even under antenna load mismatch the detector is able measure the real power delivered to the load up to a voltage standing wave ration of 2.7:1 with an error $< \pm 0.6\mathrm {d}\mathrm {B}.$ The power detector has no effect on the PA performance and can be integrated under the large output matching transformer, resulting in a cost efficient design.