Linearization technique of diplexer-free transmitter for carrier aggregation signals

We introduce a linearization technique of a transmitter for intra-band non-contiguous carrier aggregation signals at the 5GHz frequency band. The proposed technique is based on low power and narrow-band signal injection to compensate for out-band third-order intermodulation distortion (IMD3). Efficiency degradation due to mutual loading is addressed by designing the power amplifiers (PAs) to introduce high output impedance. We achieve a spur level of -52dBc and 1dB loss in saturated power (Psat) due to mutual PA loading. The high output impedance characteristic, together with IMD3 compensation, enable diplexer-free transmission of two carriers along the aggregated transmission band.