Abstract: In accordance with an aspect of the present disclosure, a radio frequency front end system is provided. The radio frequency front end system comprises an RF path configured to propagate an RF signal between ports of the RF path, an RF coupler configured to extract a portion of a power of the RF signal propagating between the ports of the RF path, and a first RF coupler circuit. The first RF coupler circuit is coupled to the RF coupler and includes a first isolator configured to isolate at least one of a switching transient impedance and a charge spur from the RF path.

Abstract: One embodiment of the present invention provides a quadrature-mixing transmitter for wireless communication. The transmitter includes a quadrature modulator comprising an in-phase (I) channel and a quadrature (Q) channel, a calibration-signal generator configured to generate calibration signals that are sent to the I channel and the Q channel, and a calibration circuit configured to calibrate an imbalance between the I channel and the Q channel. The modulator, the calibration-signal generator, and the calibration circuit are located on a same integrated circuit (IC) chip, thereby facilitating on-chip calibration of the imbalance between the I channel and the Q channel.