A mobile wireless communications device includes a housing an antenna, and radio frequency (RF) circuitry. A transceiver is connected to the antenna and a processor is operative with the RF circuitry. The transceiver includes an In-phase and Quadrature (I/Q) Modulation and Power Amplification circuit having an In-phase (I) circuit with a modulator mixer and power amplifier circuit. A Quadrature (Q) circuit includes a modulator mixer and power amplifier circuit. A power combiner receives the separately amplified In-phase and Quadrature signals and sums and outputs the signals as a combined I and Q signal. The I and Q circuits are isolated from the combined I and Q signal to enhance antenna matching and transmitted radiated power (TRP) and reduce harmonic emission from the power amplification circuits.